Frogans Technology                                                 OP3FT
FSDL 3.0                                              September 12, 2018
Preliminary Draft #7
ISBN n/a



           Frogans Slide Description Language - 3.0 - Extracts

  <resimage>, <respixels>, <resdraw>, <respath>, and <layer> elements



Abstract

   This document sets forth the third generation of the markup language
   used to create Frogans slides.  Frogans slides are interconnected,
   free-form pages which make up Frogans sites.  This language, based on
   XML, covers both the format used for FSDL documents, each one
   describing a Frogans slide, and the format used for FSDL-Request
   documents, each one being sent conditionally by Frogans Player to the
   server when the end user browses to a new Frogans slide.

Status

   This document is a preliminary draft, for examination, review, and
   evaluation by the developer community.

   Aspects of this document may be discussed publicly on the Frogans
   technology mailing lists, accessible at the following permanent URL:
   https://lists.frogans.org/.


Location

   This document is accessible at the following permanent URL: 
   https://www.frogans.org/en/resources/fsdl/access.html


Copyright Statement

   This document must be used in compliance with the Frogans Technology
   User Policy, accessible at the following permanent URL:
   https://www.frogans.org/en/resources/ftup/access.html.

   Copyright (C) 2018 OP3FT.  All rights reserved.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Background  . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Purpose . . . . . . . . . . . . . . . . . . . . . . . . .   6
     1.3.  Intended Audience . . . . . . . . . . . . . . . . . . . .  13
     1.4.  Frogans sites and Web sites . . . . . . . . . . . . . . .  14
     1.5.  Changes in this Version . . . . . . . . . . . . . . . . .  33
     1.6.  Compliance  . . . . . . . . . . . . . . . . . . . . . . .  33
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .  34
   3.  Communications with Servers Hosting Frogans Sites . . . . . .  35
   4.  Frogans Slide Design Concepts . . . . . . . . . . . . . . . .  36
   5.  Protecting the Interests of End Users . . . . . . . . . . . .  37
     5.1.  Network Usage Rules . . . . . . . . . . . . . . . . . . .  37
     5.2.  Memory Usage Rules  . . . . . . . . . . . . . . . . . . .  37
     5.3.  Usability Rules . . . . . . . . . . . . . . . . . . . . .  37
     5.4.  End-User Privacy  . . . . . . . . . . . . . . . . . . . .  37
   6.  Overall Format of FSDL Documents  . . . . . . . . . . . . . .  38
     6.1.  Defining the Root - <frogans-fsdl> Element  . . . . . . .  38
   7.  Laying Out a Frogans Slide in an FSDL Document  . . . . . . .  39
     7.1.  Defining Files - <file> Element . . . . . . . . . . . . .  39
     7.2.  Preparing Image Resources - <resimage> Element  . . . . .  40
     7.3.  Preparing Pixels Resources - <respixels> Element  . . . .  51
     7.4.  Preparing Drawing Resources - <resdraw> Element . . . . .  61
     7.5.  Preparing Path Resources - <respath> Element  . . . . . .  68
     7.6.  Setting Script-Adaptive Fonts - <setfont> and <font>
           Elements  . . . . . . . . . . . . . . . . . . . . . . . .  82
     7.7.  Preparing Text Resources - <restext> and <text>
           Elements  . . . . . . . . . . . . . . . . . . . . . . . .  83
     7.8.  Setting Filters - <setfilter> and <filter> Elements . . .  84
     7.9.  Setting Reliefs - <setrelief> and <relief> Elements . . .  85
     7.10. Setting Shadows - <setshadow> and <shadow> Elements . . .  86
     7.11. Preparing Merge Resources - <resmerge> and <merge>
           Elements  . . . . . . . . . . . . . . . . . . . . . . . .  87
     7.12. Adding Layers - <layer> Element . . . . . . . . . . . . .  88
     7.13. Assembling Multi-Layer Buttons - <button> Element . . . . 104
   8.  Adding Advanced Browsing Features to an FSDL Document . . . . 105
     8.1.  Auto-Refresh and Slide Show - <next> Element  . . . . . . 105
     8.2.  Obtaining User Input - <entry> Element  . . . . . . . . . 106
     8.3.  Setting Return-to-Server Data - <setdata> and <data>
           Elements  . . . . . . . . . . . . . . . . . . . . . . . . 107
     8.4.  Managing Frogans Slide Sessions - <session> Element . . . 108
     8.5.  Redirecting to Another Frogans Slide - <redirect>
           Element . . . . . . . . . . . . . . . . . . . . . . . . . 109
   9.  Verification of FSDL Documents  . . . . . . . . . . . . . . . 110



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   10. Format of FSDL-Request Documents  . . . . . . . . . . . . . . 111
   11. Future Enhancements . . . . . . . . . . . . . . . . . . . . . 112
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . . 113
     12.1. Normative References  . . . . . . . . . . . . . . . . . . 113
     12.2. Informative References  . . . . . . . . . . . . . . . . . 113
   Appendix A.  Scripts and Fonts  . . . . . . . . . . . . . . . . . 115
     A.1.  Generic and language-localized Scripts  . . . . . . . . . 115
     A.2.  Physical Fonts  . . . . . . . . . . . . . . . . . . . . . 115
   Appendix B.  Rendering Algorithms . . . . . . . . . . . . . . . . 116
     B.1.  Decoding Image Files  . . . . . . . . . . . . . . . . . . 116
     B.2.  Resizing Image Selections . . . . . . . . . . . . . . . . 116
     B.3.  Resizing Miniature Bitmaps  . . . . . . . . . . . . . . . 116
     B.4.  Drawing Geometric Forms . . . . . . . . . . . . . . . . . 116
     B.5.  Drawing Bezier Curves . . . . . . . . . . . . . . . . . . 116
     B.6.  Drawing Blocks of Text  . . . . . . . . . . . . . . . . . 116
     B.7.  Filtering Resources . . . . . . . . . . . . . . . . . . . 116
     B.8.  Applying Reliefs to Resources . . . . . . . . . . . . . . 116
     B.9.  Blurring Resources  . . . . . . . . . . . . . . . . . . . 116
     B.10. Rotating Resources  . . . . . . . . . . . . . . . . . . . 116
     B.11. Sharpening Resources  . . . . . . . . . . . . . . . . . . 116
     B.12. Combining Merge Resources or Layers . . . . . . . . . . . 116
     B.13. Adding Shadows Underneath Parts of Merge Resources and
           Layers  . . . . . . . . . . . . . . . . . . . . . . . . . 116




























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1.  Introduction

1.1.  Background

   Started in 1999, the Frogans project aims to introduce a new medium
   for publishing content and services on the Internet, called Frogans.

   From a technical standpoint, this new medium is designed as a new
   generic software layer running on top of the original Internet
   infrastructure, i.e. the TCP and IP protocols and the Domain Name
   System (DNS), alongside other existing generic software layers such
   as E-mail or the World Wide Web.

   The goal of Frogans as a medium is to enable the publishing of
   Frogans sites.  A Frogans site is made up of free-form pages called
   Frogans slides which are interconnected.

   The technology making up the new medium, i.e. the Frogans technology,
   includes a markup language called the Frogans Slide Description
   Language, or FSDL, used to create Frogans slides.

   Frogans slides are interactive and highly visual.  Each Frogans slide
   is rendered identically on all end-user devices regardless of the
   screen size and regardless of the means of interaction: pointing
   device, touch screen, etc.  End-user devices today include
   smartphones, tablets, desktop and laptop computers, watches, and
   virtual reality headsets.

   A Frogans site can contain an unlimited number of Frogans slides.  It
   can be hosted on a server located anywhere in the world.  The server
   is chosen by the publisher of the Frogans site, who can be any
   individual or organization in any country.  End users use Frogans
   Player to access a Frogans site via its Frogans address, and then
   browse the Frogans site from Frogans slide to Frogans slide.

   Frogans slides can be either static or dynamic, i.e. generated on the
   fly by the server in conjunction with any back-end server such as a
   database server, in order to automatically update or personalize the
   Frogans site for the end user.

   At the time the FSDL language was originally designed, the goals were
   to define a language with the following fundamental characteristics:

   *  It had to be a description language and not a programming
      language; notably, it had to make it possible to define all end-
      user interactivity of each Frogans slide using simple descriptors,
      without having to write scripts.




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   *  It had to enable the creation of Frogans slides in any shape, that
      appear on screen via non-rectangular windows.

   *  It had to support all the graphical features of Frogans slides,
      including image manipulations, color gradients, fonts, right-to-
      left and vertical text, resource filtering, masks, shadows,
      buttons, and the leapout effect.

   *  It had to be secure by design in order to ensure the protection of
      end users; for example, Frogans slides could not incorporate
      programs to be executed on the end-user device.

   *  It had to be quick and simple to learn and use, even when creating
      advanced Frogans slides; to that end, it had to integrate into a
      single language, with a limited number of elements, all aspects of
      Frogans slides, such as content, layout, style, user interaction,
      and state information management.

   *  It had to be based on markups and provide a clear and
      comprehensible structure closely related to the layout of the
      Frogans slide, in order to be easily hand-coded, using a basic
      text editor.

   Furthermore, the language had to include strict parsing rules, for
   three reasons.  First, when combined with a helpful error reporting
   system, this would make it easy for authors and authoring tools to
   create, maintain, share, and reuse Frogans slides.  Second, this
   would help ensure precise and uniform rendering of Frogans slides, by
   eliminating the need for implementations such as Frogans Player to
   guess the author's intentions or recover from errors when parsing
   non-compliant documents.  Third, given that strict parsing rules are
   more straightforward to implement than loose ones, this would reduce
   the risk of possible implementation bugs which could lead to security
   breaches.

   The HTML language [HTML] used for structuring and presenting content
   on the World Wide Web was not chosen as a basis for the FSDL language
   as it could not directly achieve all of these goals without modifying
   and drastically simplifying its syntax, while integrating into the
   HTML language features provided by CSS [CSS] and JavaScript
   [JavaScript].

   The Extensible Markup Language (XML) defined by the W3C [XML] was
   chosen as the basis for the FSDL language because it presents several
   advantages: XML offers a foundation for designing languages with
   strict parsing rules; XML supports internationalization as it is
   based on the Unicode Standard [Unicode]; and XML-based documents are
   easily authored, stored, processed, and transmitted.  The main



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   disadvantage of XML is its verbosity which makes XML-based documents
   longer to parse than more concise or binary formats.  However, when
   compared to the processing required to render Frogans slides, and
   given the relatively small size of FSDL documents, this disadvantage
   is negligible.  XML has since become a mature and widely-adopted
   standard.

   The first generation of the FSDL language achieving the preceding
   goals was described in informal specifications.  The second
   generation was formally described in versions 2.0 and 2.1 of the
   Frogans Slide Description Language specification released in 2002 and
   in 2004 [FSDL-HIST].  All these versions of the FSDL language are no
   longer in use.

1.2.  Purpose

   The purpose of this document is to set forth the third generation of
   the FSDL language.

   This new generation must retain all the fundamental characteristics
   of the FSDL language but must not attempt to ensure backward
   compatibility with the previous generation.  Ensuring such
   compatibility would make the language more complex, and is
   unnecessary given that all versions of the FSDL language
   corresponding to the previous generation are no longer in use.

   This new generation must redesign certain parts of the FSDL language,
   improve capabilities, and add new features in order to meet the needs
   of stakeholders involved in the publication of Frogans sites.

   The following domains must be addressed: the communications between
   Frogans Player and servers hosting Frogans sites, the design of
   Frogans slides, and the protection of end-user interests.

   As concerns the communications between Frogans Player and servers
   hosting Frogans sites:

   *  The network protocols that could be used for publishing Frogans
      sites were intrinsically tied to the FSDL specification, meaning
      that a new version of the specification was required whenever
      there was a need to change the usage profile of an existing
      network protocol, or to support a new network protocol.

      The FSDL language must be redesigned to work on top of Uniform
      Content Server Request (UCSR) [UCSR], a new framework designed and
      developed by the OP3FT to make the Frogans technology independent
      from data-transport protocols.  The UCSR framework provides a
      client application with an abstraction layer for uniformly



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      requesting and receiving data from a content server, while
      ensuring a predetermined security level.

   *  The method that authors of FSDL documents had to use in order to
      refer to other FSDL documents and auxiliary files in the Frogans
      site root directory was complex and offered insufficient
      functionality.  For example, the static or dynamic nature of the
      referred file was not defined explicitly but depended on the
      context, and there were no means for sharing an auxiliary file
      among several resources or for embedding an auxiliary file in an
      FSDL document.

      The FSDL language must introduce, within an FSDL document, an
      improved method for referring to other files.

   *  The method that authors of FSDL documents had to use in order to
      define return-to-server data associated with referred files
      (either FSDL documents or auxiliary files) or with Frogans slide
      sessions did not directly support Unicode characters [Unicode] and
      offered insufficient functionality.  For example, authors of FSDL
      documents could not share return-to-server data among several
      referred files and they had to concatenate return-to-server data
      items into a single value.

      The FSDL language must introduce, within an FSDL document, an
      improved method for defining return-to-server data.

   *  When a request containing return-to-server data was sent by
      Frogans Player to the server hosting the Frogans site, the data
      groups making up the return-to-server data in the request were not
      insulated from one another, which made it difficult to add new
      kinds of groups in the future.  In addition, the request did not
      contain by design any information on whether it was for an FSDL
      document or for an auxiliary file.  Likewise, a request for an
      FSDL document did not contain any contextual information, such as
      that the end user triggered a button leading to another Frogans
      slide of the Frogans site, or that the end user took no action
      before the next Frogans slide began to load.

      The FSDL language must introduce a new structured document, called
      the FSDL-Request document, to be sent conditionally by Frogans
      Player to the server hosting the Frogans site.

   *  The methods available to Frogans site publishers for enabling end
      users to enter information to be sent to the server hosting the
      Frogans site were insufficient and must be replaced.  Either the
      publisher had to set the Frogans address of the Frogans site so as
      to require the end user to enter a personal identifier or a login



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      and password when opening the Frogans site (this information was
      sent to the server in the request for the home slide).  Or the
      publisher had to require the end user to enter the information in
      small increments through a series of Frogans slides (for example,
      each Frogans slide would enable the end user to trigger one of
      several buttons, each button representing a single number, letter,
      or word).

      The FSDL language must introduce, within an FSDL document, a
      simple method for enabling end users to enter information, where
      the entry takes place after the end user has triggered a button in
      order to browse to another Frogans slide.  In order to be
      compatible with all devices, including those with small screens
      which are easily controlled by voice, this method must induce
      publishers to create Frogans sites which invite end users to
      engage in a dialog, by entering information one field at a time,
      rather than via forms with multiple fields.

   *  The method available to Frogans site publishers for enabling end
      users to download a file of any type from the server hosting the
      Frogans site to the end-user device, which was introduced in the
      second generation of the FSDL language, was potentially dangerous
      and must be removed.  For example, this method could be used by
      malicious publishers to deliver files containing viruses which
      could infect end-user devices lacking adequate anti-virus
      protection.

   *  The method available to Frogans site publishers for enabling end
      users to download an image file to be displayed in a larger size
      on the screen, which was introduced in the second generation of
      the FSDL language, must be removed.  This method was inappropriate
      for end-user devices with small screens and therefore could drive
      Frogans site publishers to develop two different versions of the
      same Frogans site: one for end-user devices with a large screen,
      and another for those with a small screen.

      Driving Frogans site publishers to develop various versions of the
      same Frogans site in order to take into account specific
      characteristics (such as screen size, memory, or processing power)
      of certain end-user devices obviously runs against the founding
      principles of the Frogans technology defined in the OP3FT Bylaws
      [BYLAWS].

   As concerns the design of Frogans slides:

   *  The method for rendering Frogans slides in Frogans Player used an
      area whose dimensions in pixels depended on screen characteristics
      of the end-user device (i.e. the size of the screen, its



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      resolution, the resulting pixel density) and the intended distance
      between the end user and the screen.  This could cause the text in
      a given Frogans slide to be rendered differently on different end-
      user devices.  Indeed, because of the rules required by many
      writing systems for positioning and substituting glyphs when
      rendering text, proportionally changing both the dimensions in
      pixels of a text area and the font size does not necessarily
      result in an identical appearance for the text, even when using
      scalable fonts.  For example, the number of lines in the text area
      can change.

      As a result, this method did not fully comply with the founding
      principle of the Frogans technology whereby a Frogans slide is
      rendered identically on all end-user devices and must be replaced.

      The FSDL language must introduce a method for rendering Frogans
      slides using an area whose dimensions in pixels are fixed.  In
      order to take into account screen characteristics of the end-user
      device and the intended distance between the end user and the
      screen, the FSDL language must also introduce a new concept,
      called the scaling factor, as well as a complementary method based
      on that concept to be used in Frogans Player for displaying
      rendered Frogans slides.

   *  Given the new method for rendering Frogans slides, the virtual
      grid made up of points representing abstract positions which was
      used by authors to lay out Frogans slides is no longer relevant.

      The FSDL language must be redesigned so that the layout of Frogans
      slides is based on a virtual grid made up of pixels, called the
      Frogans slide rendering canvas.

   *  Authors of FSDL documents had to define the overall shape of the
      Frogans slide separately from the content that would fill in the
      shape of the Frogans slide.  Given that the shape was rendered as
      a binary mask, each pixel of the rendered Frogans slide was either
      fully opaque or fully transparent.  This look has become outdated
      and must be replaced.  End users today are accustomed to seeing
      windows with several levels of transparency on their screens.

      The FSDL language must be redesigned so that authors of FSDL
      documents can create Frogans slides directly using superimposed
      layers, each one with an alpha channel.  As a result, Frogans
      slides no longer necessarily have sharp edges and the FSDL
      language must therefore also introduce a new method enabling end
      users to resize Frogans slides on devices with a pointing device,
      in order to replace the resize method which used the edges of the
      Frogans slide.



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   *  Authors of FSDL documents already had the possibility of
      including, in an FSDL document, text to be displayed based on
      writing systems from around the world (including right-to-left and
      vertical writing systems).  But there were two issues: first, the
      method for rendering text did not support the rendering of text
      based on complex scripts (such as Arabic, Devanagari, and Thai);
      and second, the rendering of text could lead to different results
      on different end-user devices because the method used by authors
      of FSDL documents to refer to fonts was based on fonts installed
      locally on the end-user device, and when a referred font was not
      in fact installed, then it was substituted by another installed
      font.

      As a result, the method used by authors of FSDL documents to refer
      to fonts did not fully comply with the founding principle of the
      Frogans technology whereby a Frogans slide is rendered identically
      on all end-user devices and must be replaced.

      The FSDL language must introduce an improved method for rendering
      text based on complex scripts.  The FSDL language must also
      introduce, within an FSDL document, a new method for referring to
      fonts which is exclusively based on a set of selected fonts to be
      embedded in implementations such as Frogans Player.

   As concerns the protection of end-user interests:

   *  In order to protect the interests of end users, the FSDL language
      had a limitation on the total size, in bytes, of a Frogans slide
      including the FSDL document and its auxiliary files.  This
      limitation is important for end users permanently or temporarily
      connected to a low-bandwidth network, for instance, as well as for
      end users who subscribe to mobile Internet access services with a
      monthly data allotment and who, if they exceed their allotment,
      suffer bandwidth limitations or must pay additional fees.

      However, given the new method for rendering Frogans slides, this
      limitation on the total size, in bytes, of the Frogans slide could
      be exceeded in many cases and must be adapted.  Indeed, with this
      new method, the dimensions in pixels of pre-authored images
      contained in auxiliary files need to be large enough to remain
      independent from the screen characteristics of the end-user
      device.

      The FSDL language must continue to limit the size, in bytes, of a
      Frogans slide, but must include two separate limits: one
      concerning the maximum size of an FSDL document, and another one,
      which must be increased, concerning the total size of a Frogans
      slide including the FSDL document and its auxiliary files.



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   *  When rendering Frogans slides, there was no limitation on the
      amount of memory required.  In particular, the surface, in pixels,
      of Frogans slide components was not taken into account.  The only
      factor that could limit memory usage was the limitation on the
      number of elements in the FSDL document corresponding to Frogans
      slide components, which was applied when the FSDL document was
      validated.  This lack of an effective limitation must be corrected
      because it could prevent end users having devices with limited
      memory from browsing certain Frogans sites (whether these devices
      are older, inexpensive, or designed for a specific use), which
      obviously runs against the founding principles of the Frogans
      technology defined in the OP3FT Bylaws.

      The FSDL language must introduce new rules to limit the amount of
      memory required to render a Frogans slide.  These rules must be
      applied after the FSDL document is validated and before rendering
      the Frogans slide, and must take into account relevant Frogans
      slide components defined in the FSDL document.

   *  When rendering Frogans slides, there was no limitation on the
      total surface, in number of pixels, of the pre-authored images
      used.  This lack of a limitation also raises memory usage issues
      and must be corrected.

      The FSDL language must introduce a new rule to limit the total
      surface, in number of pixels, of all the pre-authored images used
      to render a Frogans slide.  This rule must be applied when
      rendering the Frogans slide.

   *  Given the new possibility for authors of FSDL documents to create
      Frogans slides directly using superimposed layers, each one with
      an alpha channel, the rules ensuring that end users can see and
      easily move the Frogans slide on the screen are no longer
      sufficient.  Due to the fact that parts of a Frogans slide can be
      very transparent, end users could have problems seeing the Frogans
      slide on the screen, seeing whether any one of the buttons of the
      Frogans slide has been selected, moving the Frogans slide on the
      screen, or selecting each button of the Frogans slide.

      The FSDL language must introduce a new set of rules, called
      usability rules, ensuring that end users can see and easily use
      the Frogans slide on all devices, regardless of the means of
      interaction: pointing device, touch screen, etc.  These rules must
      be applied when rendering the Frogans slide.

   *  The method available to Frogans site publishers for enabling a
      third party to collect statistics about end-user browsing on their
      Frogans site must be removed because it raised privacy issues.



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      Although this method provided a useful means for independently
      measuring the traffic on a Frogans site, the third party
      collecting the statistics could use this method to track end users
      and compile long-term records of their browsing histories, without
      informing them, asking their permission, or giving them control
      over how their personal data was used.

      Given that no solution could be found that enables a third party
      to collect statistics while fully protecting end-user privacy,
      this method must be simply removed from the FSDL language and not
      replaced.  The respect of privacy is a founding principle of the
      Frogans technology.

   Furthermore, the third generation of the FSDL language must
   introduce, in response to requests from authors of FSDL documents,
   new practical features for designing Frogans slides, such as:

   *  enhancement of image resources, in order to add support for an
      image file containing a collection of images, and for embedding an
      image file as text characters in the FSDL document

   *  path resources, intended to provide a means for including Bezier
      curves in a Frogans slide

   *  script-adaptive fonts, intended to provide a means for defining
      fonts to be selected automatically when rendering sequences of
      characters of a text resource that correspond to different writing
      systems

   *  merge resources, intended to provide a means for preparing a new
      resource that gathers or mixes several other resources

   After all the preceding changes have been made to the FSDL language,
   any future modifications to the FSDL language will be set forth in a
   new document bearing a new version number.  Indeed, as stated in the
   OP3FT Bylaws, the technical specifications of the Frogans technology
   are not modified once published.

   New versions of the FSDL specification will be prepared as needed,
   notably in order to take into account feedback and suggestions from
   the various stakeholders involved in the publication of Frogans
   sites.  For the list of future enhancements under discussion at the
   time this version of the FSDL specification is being completed, see
   Section 11).

   In order to make it possible for all implementations such as Frogans
   Player to render Frogans slides identically on all end-user devices,
   right down to the pixel level, this specification must define the



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   rendering algorithms to be used for resources, for transformations
   applied to resources, for combining parts of merge resources, for
   combining layers, and for adding shadows.

1.3.  Intended Audience

   This document is intended for those involved in the publication of
   Frogans sites, such as Frogans site publishers, Frogans site
   designers, Frogans site developers, Frogans site hosts, and Frogans
   site indexers.

   This document is also intended for:

   *  creators of resources based on the FSDL language, such as online
      tutorials, videos, blogs, or books

   *  developers wishing to implement software based on the FSDL
      language, such as an authoring tool or a CMS (Content Management
      System)

   *  trainers and consultants offering services related to the FSDL
      language

   This document is also intended for anyone wishing to understand the
   principles and concepts related to the communications between Frogans
   Player and servers hosting Frogans sites, the design of Frogans
   slides, and the protection of end-user interests.
























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1.4.  Frogans sites and Web sites

   When the World Wide Web was introduced in the early 1990s, the goal
   was to provide people with a medium for publishing content and
   services on the Internet, in the form of Web sites.  From a technical
   standpoint, the medium was designed as a new generic software layer
   running on top of the original Internet infrastructure, i.e. the TCP
   and IP protocols and the Domain Name System (DNS).  From the outset,
   the medium was made up of a set of core mechanisms for formatting
   content (HTML), fetching content over the Internet (HTTP), and
   linking documents (URL).  Over the years, these core mechanisms have
   been enhanced.  They have also been completed by various innovative
   mechanisms (such as CSS, JavaScript, and SSL), which in turn have
   also been enhanced.

   When the Frogans project was started in 1999, the goal was also to
   provide people with a medium for publishing content and services on
   the Internet.  From a technical standpoint, this medium was also
   designed as a new generic software layer running on top of the
   original Internet infrastructure.  However, this medium was not meant
   for publishing Web sites but Frogans sites, a new kind of site
   founded upon a different format.  This format was conceived to enable
   end users to explore and interact with online content and services in
   a simpler and more secure way.

   This new medium was intended to be complementary to the World Wide
   Web for publishing content and services on the Internet, and not to
   replace it, just like instant messaging was not intended to replace
   and did not replace E-mail as a medium for exchanging messages on the
   Internet.

   From the beginning, the philosophy behind the design and development
   of the new medium was fundamentally different from that of the World
   Wide Web. This philosophy was built around the fact that typical end
   users have very limited technical knowledge and have neither the time
   nor the desire to increase their technical skills.  In this
   philosophy, end users should not be dominated by the technology they
   are using.  They should not be required to expand their technical
   knowledge in order to have full control over aspects of the
   technology that can directly impact their lives.  End users'
   interests should always take center stage, and not the technology.
   Finally, the extra design and development efforts this entails when
   creating the technology should not be a valid reason for failing to
   comply with this philosophy.

   Given the complexity and variety of technical subjects involved in a
   medium for publishing content and services on the Internet, the
   technology making up the new medium, i.e. the Frogans technology, was



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   bound to include multiple components, such as those for managing the
   format, addressing system, and browsing of Frogans sites.  In order
   to comply with the philosophy behind the new medium, a prerequisite
   was that these components fit together as a coherent whole.  To meet
   this prerequisite, a new paradigm was used, different from that of
   the World Wide Web. In this new paradigm, all these components had to
   be complementary and inseparable, and they had to be designed,
   developed, and released under the coordination of a single authority.

   Furthermore, in order to ensure that the design and development of
   the new medium would be conducted in a neutral, open, and transparent
   manner, the coordinating authority had to be independent from special
   interest groups and major players as regards its policy decisions.
   Thus it was decided that its financial resources would not come from
   membership fees or sponsorship, as is the case for the consortium
   leading the World Wide Web, but from part of the fees for the
   addressing services associated with Frogans sites.  This would also
   ensure that the financial resources of the coordinating authority
   would increase automatically in line with the adoption of the new
   medium and with the growing costs required to promote, protect, and
   ensure the progress of the technology making up the new medium.

   Later, in 2012, the Frogans technology would be irrevocably
   transferred by the company which had led the Frogans project from the
   start to a dedicated, non-profit organization acting as the
   coordinating authority, the OP3FT, so as to perpetuate the right of
   the community to use the Frogans technology in the form of an open
   standard, available to all, free of charge.

   Also from the beginning, the new medium was designed so as to enable
   a new kind of communication between end users and publishers of
   content and services.

   Compared to the World Wide Web, the new medium was intended to
   suggest publishing content and services which involve:

   *  visual rather than text-based communication
   *  focused content rather than long pages
   *  natural interaction rather than complex user interfaces

   For instance, a Frogans site could be used to communicate with an end
   user in the form of an engaging dialogue involving short, frequent
   exchanges.

   Finally, for the new medium to be widely adopted by both end users
   and publishers of content and services, it had to be perceived as a
   medium providing a fundamentally different end-user experience from
   the World Wide Web.



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   Today, after 18 years of research, development, and testing, Frogans
   as a medium is perceived by end users in a very different way from
   the World Wide Web. It is perceived as invisible, universal, safe,
   and as protecting privacy.

   1.  Frogans as a medium is perceived by end users as invisible

       When end users browse Frogans sites for the first time, the first
       thing that strikes them compared to browsing Web sites is that
       Frogans sites have a limited size on the screen and that the
       browser they were familiar with has completely disappeared.
       Frogans sites give the impression of floating directly on the
       screen.  They are not surrounded by any technical controls such
       as menu bars, location and search bars, toolbars, sidebars,
       status bars, and scroll bars.  Only the content of the Frogans
       sites appears on the screen.

       Unlike Web sites which are confined within large system windows
       that may in turn be subdivided into multiple tabs, Frogans sites
       live in freedom on the screen, independently from one another.

       The way that Frogans sites inhabit the screen makes end users
       forget about the medium.  As a result, Frogans as a medium is
       perceived by end users as invisible.

       This perception by end users is reinforced by the format of
       Frogans sites, which also makes end users forget about the
       medium.  This format, which is predominantly visual, enables
       Frogans sites to take on any shape, making them look like small
       objects on the screen.  Frogans sites can thus feel simple,
       familiar, and attractive.

       Interacting with Frogans sites is natural, which makes end users
       forget about the medium too.  For example, Frogans sites are
       moved by grabbing them anywhere.  They are smoothly resized from
       their center.  They are explored via graphical buttons for
       browsing that are blended directly into their content.

       By being perceived as invisible by end users, Frogans, as a
       medium, can be seen as taking its first step on the path to
       Arthur C. Clarke's third law: "Any sufficiently advanced
       technology is indistinguishable from magic" [Clarke].

   2.  Frogans as a medium is perceived by end users as universal

       Browsing Frogans sites and browsing Web sites both require a
       device as well as a network connection in order to access the
       Internet.



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       With Web sites, when end users switch from one type of device to
       another using a given Web site, they need to adapt to the content
       of the Web site and how its pages are browsed, which can vary
       unpredictably.  For example:

       -  On devices with small screens, some functionalities of the Web
          site may not be available due to a lack of space.

       -  On devices with touch screens, the content of the Web site may
          be reorganized into fewer pages, which are larger and require
          additional scrolling.

       Furthermore, with Web sites, end users spend too much time
       waiting for Web pages and all their content to load when the
       available bandwidth of their network connection is limited for
       whatever reason.  This includes, for example:

       -  urban locations that are not covered efficiently by a wireless
          mobile network, such as a subway tunnel or certain areas of a
          building

       -  urban locations where the network infrastructure is congested
          during peak hours, for example in the evening when end users
          start consuming lots of bandwidth once they get home

       -  rural regions, as well as parts of the world, where high-
          bandwidth network connections have not been deployed

       With Frogans sites, the situation is very different regarding
       both devices and network connections:

       *  Any given Frogans site always appears exactly the same on all
          devices.  Frogans sites, unlike Web sites, do not change when
          end users switch from one device to another, regardless of the
          type of device or the screen size.

       *  Any given Frogans site can be browsed anytime, anywhere, over
          any network connection.  Frogans sites, unlike Web sites,
          always load quickly, even when the available bandwidth is
          limited.  This is due to the fact that the amount of data to
          be loaded is small by design.

       As a result, Frogans as a medium is perceived by end users as
       universal.

       End users can browse Frogans sites over the course of the day
       without worrying about the device or the network.  For example,
       while at home end users may browse Frogans sites on a tablet over



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       a wireless local area network; while on the go they may browse
       the same Frogans sites on a smartphone over a wireless mobile
       network; and while at the office they may continue to browse
       these Frogans sites on a desktop computer over a wired network.

       Going forward, end users can easily imagine browsing these
       Frogans sites floating on top of TV programs on a TV set, or
       using them on a watch, on glasses, on a virtual reality headset,
       on a refrigerator, as well as on any connected device with a
       screen.

   3.  Frogans as a medium is perceived by end users as safe

       Security has always been a key concern for end users accessing
       content and using services on the Internet.

       When browsing Web sites, as regards security, typical end users
       are in an environment that creates permanent, indirect pressure
       on them.  For example:

       -  Typical end users are aware that, regardless of any
          precautions they take, browsing Web sites can be dangerous.
          They regularly read in the news about exploited security
          vulnerabilities in Web browsers or in the software libraries
          the Web browser depends on, which can result in end users
          losing control of their device, losing their data forever, or
          having to pay a ransom to recover it.

       -  Typical end users also know that these critical problems
          affecting them can arise as they browse any Web site, even the
          most reputable.  They get in serious trouble from the moment
          when an attacker succeeds in corrupting the Web site content
          in order to exploit unpatched security vulnerabilities related
          to Web browsers.  This corruption can take place either on the
          Web site publisher's server or on a third party server which
          is beyond the publisher's technical control, in cases where
          part of the Web site content is provided by a third party,
          such as an online advertising network.

       -  If typical end users try to take the bull by the horns in
          order to mitigate such security risks, or at least understand
          their options, they have almost no chance to succeed.  When
          looking into the security settings of their Web browser, they
          are suddenly overwhelmed by the number of possible settings
          and by the complexity and variety of the concepts involved.
          Adjusting Web browser security settings appropriately requires
          technical knowledge, without which there is always a risk of
          making things worse.



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       -  When typical end users browse Web sites and are interrupted
          unexpectedly by a security notification from their Web
          browser, they do not always understand the technical issue at
          stake, the exact degree of risk they are facing, or the
          question asked.  In such situations they are never sure if
          they are making the right decision, and they may end up
          choosing at random, which can be harmful to their security.
          Likewise, the exact meaning or scope of the security-related
          icons displayed by the Web browser can be unclear.  For
          example, on a given Web site, the presence and colors of the
          padlock can vary from one device to another depending on the
          Web browser used.

       When browsing Frogans sites, by contrast, end users do not have
       to take care of complicated security matters.  End users have no
       security settings to adjust and they are never required to make
       decisions following security notifications.  The environment is
       simple and reassuring.  As a result, Frogans as a medium is
       perceived by end users as safe.

       Security considerations have always been given the highest
       priority during the design and development of the Frogans
       technology.  Combined with the efforts to achieve simplicity,
       these considerations have led to an end-to-end security model for
       Frogans as a medium for publishing content and services on the
       Internet.

       This end-to-end security model directly eliminates a whole series
       of potential threats.  It has the following key technical
       properties:

       *  The identifiers of Frogans sites, called Frogans addresses,
          are secure by design.  For example:

          -  Frogans addresses are short and simple, and do not contain
             any technical information that could confuse typical end
             users.

          -  Frogans addresses are checked for security at registration
             time.  All Frogans addresses have to comply with technical
             rules which take into account and combine the outcome of
             various work by the Unicode Consortium, the IETF, ICANN,
             and various domain name registry operators concerning
             international identifiers.

          -  Frogans addresses are technically resolved on the Internet
             through a global system which is bootstrapped from a
             dedicated Top Level Domain (TLD) and which makes use of



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             digital signatures in order to ensure data origin
             authentication, data integrity, and authenticated denial of
             existence.

          -  Frogans addresses never redirect.  When end users open a
             given Frogans site using its Frogans address, this Frogans
             address cannot be substituted automatically by another.

       *  Connections to Frogans site servers are operated in a purely
          deterministic manner.  For example:

          -  The technical parameters of the connection to a given
             Frogans site server are known prior to establishing the
             connection.  These technical parameters are defined in
             advance by the Frogans site publisher and are retrieved
             when resolving the Frogans address.  These technical
             parameters predetermine the security level of the
             connection.  They include, for instance, the UCSR path
             which defines the combination of protocols to be used for
             the connection.  When security protocols are used, this
             eliminates potential man-in-the-middle attacks exploiting
             changes in protocols while the connection is being
             established.

          -  The predetermined security level of the connection to a
             given Frogans site server applies for the entire content of
             the Frogans site.  This is due to the fact that all the
             content of a given Frogans site is hosted on a single
             server.  If the predetermined security level with the
             Frogans site server is not reached, i.e. if any of the
             technical parameters cannot be applied, then the connection
             fails automatically.  End users have no means for lowering
             the security level, changing the technical parameters, or
             altering their application.

          -  If the connection relies on a public key certificate
             received from the Frogans site server, then a hash of this
             certificate is known prior to establishing the connection.
             This hash is part of the technical parameters retrieved
             when resolving the Frogans address.  It is matched against
             the certificate received from the Frogans site server in
             order to ensure that the connection is established with the
             real server.

          -  When it has been verified, the identity of the publisher of
             a given Frogans site is known prior to establishing the
             connection.  The verified identity is part of the technical
             parameters retrieved when resolving the Frogans address.



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             It is displayed near the Frogans address.  Identity
             verification, performed in advance by trusted third
             parties, is available for Frogans site publishers who need
             to provide end users with a trustworthy confirmation of
             their identity.

          -  The method for considering whether an established
             connection is secure, as regards privacy and reliability,
             is predictable.  The connection to a given Frogans site
             server is considered to be secure if it is established
             using a UCSR path that complies with the rules set forth in
             a publicly available security policy.  These rules are
             common to all Frogans sites.

          -  End users are made aware that the established connection to
             a Frogans site server is considered to be secure, as
             regards privacy and reliability, via a single specific icon
             displayed near the Frogans address.  End users need no
             technical knowledge to determine if the connection is
             secure.  The specific icon has only one shape and color.
             End users only need to check whether or not this icon is
             displayed.

       *  The nature of the files conveying the content of Frogans sites
          is innocuous.  For example:

          -  The files serving as the foundation of Frogans slides,
             called FSDL documents, are text files in XML format
             containing simple descriptors.  There is no programming
             code in FSDL documents.  The descriptors are sufficient for
             managing button selection, the leapout effect, and the
             entry of information.  No scripts need to be run on end-
             user devices.

          -  The files used to enrich the content of Frogans slides,
             called auxiliary files, are based on simple and well-tested
             formats, such as PNG, JPEG, and GIF for image files.
             Auxiliary file formats are mature, formally-specified, and
             are not vulnerable to subversion due to their complexity.
             For instance, auxiliary files do not include font files.
             Fonts used to render the content of Frogans sites are
             directly embedded in Frogans Player to ensure identical
             rendering on all devices.

          -  FSDL documents and auxiliary files are the only kinds of
             files that are accepted from servers.  Dangerous files such
             as executable files or files containing macros are
             rejected.  Furthermore, except for providing a button



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             leading to a resource on the World Wide Web, Frogans sites
             have no means for enabling end users to download files and
             store them on their devices.

          -  FSDL documents and auxiliary files are not modifiable
             dynamically on end-user devices.  Once loaded from the
             server and accepted, their innocuous nature cannot change.
             The only way to update the content of Frogans slides is on
             the server side, by generating new Frogans slides as end
             users browse the Frogans site.

       *  Protective measures are applied systematically when treating
          files received from Frogans site servers.  For example:

          -  FSDL documents are decoded, parsed and validated following
             strict processing rules.  If an error is detected at any
             point, then no attempt is made to recover from the error
             and an error message is displayed instead of the Frogans
             site.  This eliminates potential attacks exploiting
             implementation bugs in code intended to recover from
             errors.

          -  Auxiliary files are decoded using software embedded in
             Frogans Player and not using external software libraries
             available on the device.  This eliminates potential attacks
             exploiting security vulnerabilities on devices with an
             operating system that either has not been updated or whose
             version life cycle has ended.

          -  FSDL documents and auxiliary files are kept in random
             access memory and are never written to the local storage of
             the end-user device.  The auxiliary file cache, which is
             specific to each Frogans site, is also kept in memory.
             This eliminates potential attacks exploiting dangerous
             files stored on end-user devices.

          -  There are no means for end users to bypass the protective
             measures.  End users cannot unintentionally introduce
             weaknesses through inappropriate security settings or
             hazardous risk assessments.

          -  If files received from the server of a given Frogans site
             do not strictly comply with specified or expected formats,
             then the treatment is canceled immediately.  The problem
             can only be solved by the Frogans site publisher.






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       *  The software used to browse Frogans sites is protected against
          malware.  For example:

          -  Frogans Player does not include any add-on module system.
             There are no means to modify the behavior of Frogans Player
             via third-party software.  This eliminates potential
             attacks exploiting extensions to introduce hostile or
             intrusive software.

          -  Frogans Player is always downloaded from a single official
             location (https://get.frogans/).  End users are thereby
             sheltered from downloading and installing Frogans Player
             versions that have been potentially altered to include
             malicious software.  In order to prevent confusion by end
             users concerning the right place to get Frogans Player,
             distributing Frogans Player from anywhere other than the
             official location is not allowed.  In cases where a third-
             party software downloading platform, also referred to as a
             store, is the only means for end users with a given device
             to obtain Frogans Player in a secure environment, then end
             users are redirected from the official location to that
             store.

          -  In the case where a version of Frogans Player is created by
             an independent developer, e.g. in order to offer early
             access to Frogans sites for end users with a specific
             device that is not yet supported, the source code of this
             version is reviewed and recompiled.  End users are thereby
             sheltered from using Frogans Player versions that
             potentially contain malicious software such as computer
             viruses, spyware, or ransomware.  This version is made
             available for download from the single official location,
             along with all the other versions.  It is subsequently
             updated as necessary, even if the independent developer is
             unavailable for any reason, such as being monopolized by
             another project or switching to a new occupation.

       In this end-to-end security model, from network protocols to file
       formats, implementations are required to be conservative in what
       they do and also in what they accept from others.  This
       precautionary principle is more conservative than the robustness
       principle defined by Jon Postel back in 1980 for the Transmission
       Control Protocol [RFC761], which requires implementations to be
       liberal in what they accept.  But the robustness principle, also
       known as Postel's Law, is intended to ensure the high reliability
       for TCP, not the security of an online publishing system running
       at a higher level than TCP.




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       Furthermore, this end-to-end security model includes the means
       for efficiently resolving a vulnerability that might appear in
       the design or implementation of a technical specification
       involved in the Frogans technology.  If the vulnerability
       concerns the design of a security protocol, then the security
       policy rules, which are reloaded by Frogans Player on a regular
       basis, are updated immediately.  Subsequently, if the connection
       to the server of a given Frogans site uses that protocol, then
       end users browsing that Frogans site are made aware that the
       connection is not considered to be secure.  Once the problem has
       been resolved at the design or implementation level, the affected
       versions of Frogans Player are made obsolete and replaced with
       updated versions for all users worldwide.

       But for end users to enjoy this safe environment when browsing
       Frogans sites, a minimum amount of vigilance is required.  This
       vigilance involves both end users and Frogans site publishers.
       For instance:

       -  End users need to remain vigilant as regards the security of
          the device they are using.  If a device is compromised in any
          way, such as malware taking over the device, then all bets are
          off.  In this case, there is no way to ensure that Frogans
          Player will run as expected, just like any other software
          installed on the device.  For example, the executable files of
          Frogans Player may have been altered or replaced.  Frogans as
          a medium cannot play the role of the operating system or anti-
          virus software in order to prevent a device from being
          compromised.

       -  End users also need to remain vigilant whenever they obtain or
          give sensitive information via a Frogans site.  In such cases,
          they always need to check the Frogans address, the verified
          identity of the publisher when it is provided, and the
          presence of the specific icon indicating that the connection
          is secure.  Frogans as a medium does not impose a central
          entity for controlling the content of Frogans sites prior to
          their publication or following updates, and therefore cannot
          prevent fake Frogans sites from being published, at least
          temporarily.  In addition, Frogans as a medium cannot prevent
          the theft or alteration of sensitive information via a man-in-
          the-middle attack if the security level of the connection
          defined by the Frogans site publisher is insufficient.

       -  Frogans site publishers need to remain vigilant as regards the
          security of their servers.  Frogans as a medium is intended to
          provide end users with a safe environment when browsing
          Frogans sites, not to protect servers against attacks.  It is



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          up to publishers to apply best practices for operating their
          servers in a secure manner and upgrading them as necessary.

       With Frogans as a medium, end users can explore online content
       and services with confidence and without worrying about security
       threats.  End users do not hesitate to browse new Frogans sites,
       whoever the publisher is, or to share Frogans sites with other
       people.


   4.  Frogans as a medium is perceived by end users as protecting
       privacy

       Privacy has long been a concern for end users accessing content
       and using services on the Internet.  Many countries around the
       world have taken up the cause, enacting laws and regulations
       intended to protect the privacy of their citizens.  As the
       Internet plays an ever-expanding role in people's lives, the
       importance of protecting privacy continues to grow.

       When browsing Web sites, typical end users put their privacy at
       risk due to various invasive tracking mechanisms that enable Web
       site publishers and third parties to automatically collect
       information about them.  For example:

       -  When typical end users browse a given Web site, the Web site
          publisher can use cookies in order to keep track of previous
          visits.  These cookies, referred to as persistent first-party
          cookies, work automatically: Web browsers manage them in the
          background, silently, including their reception from the Web
          site publisher's server, their storage on the end-user's
          device, and their re-transmission whenever a resource is
          loaded from the server.

       -  When typical end users browse across different Web sites whose
          content is managed in part by a third party, such as an
          analytics company or an online advertising network, the third
          party can use cookies in order to precisely track end users as
          they browse across these Web sites.  These cookies, referred
          to as third-party cookies, work automatically and in the same
          way as persistent first-party cookies.

       -  Besides persistent first-party cookies and third-party
          cookies, other invasive tracking mechanisms can be used by Web
          site publishers and third parties in order to track end-user
          browsing activities automatically.  These mechanisms include,
          for example, Flash cookies and HTML5 cookies.  These
          mechanisms also include Web browser fingerprinting, which



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          enables to uniquely identify and track end users by combining
          various properties available via their Web browser, such as
          the screen resolution and the system fonts installed, and the
          way their Web browser renders a given image differently from
          other Web browsers.

       On Web sites where invasive tracking mechanisms are used, end
       users are usually put in a very unfavorable position.  The
       notifications concerning these mechanisms, such as those found in
       the content of Web sites, do not usually give end users viable
       options to refuse these mechanisms.  Such notifications merely
       inform end users that if they want to continue browsing these Web
       sites, or if they want to maintain an acceptable browsing
       experience, then they have to accept the use of these mechanisms
       by Web site publishers and third parties.

       Web site publishers tell end users that their Web sites use these
       mechanisms in order to improve the end-user experience.  However,
       if typical end users want to dig deeper and find out what
       information about them is collected automatically by these
       mechanisms, for what exact purpose, how long it will be kept, and
       whom it is shared with, they realize that getting answers to
       their questions is far too complex and time-consuming.  For
       example:

       -  If typical end users try to get answers from Web site
          publishers, they discover that the dedicated Web pages
          disclosing details on the use of invasive tracking mechanisms
          are often long to read, are different from one Web site to
          another, and rely on technical concepts that are beyond the
          reach of typical end users.  Furthermore, these Web pages do
          not contain answers concerning invasive tracking mechanisms
          that are outside the operational control of the Web site
          publisher, such as third-party cookies.

       -  If typical end users try to get answers directly from their
          Web browser, e.g. to verify the claims of a given Web site
          publisher or to see all the information about them collected
          automatically by third parties, they discover that this
          information is hard to access.  In some cases, notably on
          mobile devices with small screens, this information is not
          accessible at all, as a result of the efforts of Web browser
          makers to simplify the user interface.  In addition, when Web
          browsers enable end users to access cookies, the list of
          cookies, as well as their names, contents, and in some cases
          their origins, are mostly opaque and vary from one Web site to
          another.




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       As a result of this situation, typical end users of Web sites
       might want to get rid of invasive tracking mechanisms in order to
       regain control of their privacy.  But when they try to do so,
       assuming they manage to access the privacy settings in their Web
       browser, they face a series of obstacles at diverse levels that
       makes them give up.  For example:

       -  Typical end users can delete some or all of the cookies from
          their Web browser.  But this does not disable this type of
          invasive tracking mechanism, it only deletes tracking data.
          As soon as these end users resume browsing, Web site
          publishers and third parties can send new cookies.

       -  Typical end users can block all cookies in their Web browser
          for some or all Web sites.  But their browsing experience may
          be overly limited.  For instance, they may no longer be able
          to browse Web sites which require them to log on.  In order to
          restore their browsing experience, they must stop blocking all
          cookies or must block them more selectively.

       -  When typical end users try to block cookies selectively, e.g.
          by cookie type or on a site-by-site basis, they discover that
          on devices with small screens privacy settings are usually
          oversimplified.  In other cases, typical end users discover
          that privacy settings are far too complicated, i.e. they are
          obscure or interrelated, or they require technical knowledge
          to understand their purpose and impact.

       -  For some Web browsers, there are extensions intended to
          increase control over invasive tracking mechanisms.  But the
          way these anti-tracking extensions work causes certain Web
          sites to not perform correctly.  In such cases, the extension
          settings must be adjusted, which is too complicated for
          typical end users.

       -  Some privacy settings such as "Do Not Track" are effective
          only if they are accepted and applied voluntarily by Web site
          publishers and third parties, which is obviously not the case
          for tracking companies.

       -  If typical end users finally manage to get rid of certain
          invasive tracking mechanisms, then ironically they become even
          easier to track, given that very few end users block such
          mechanisms.

       Invasive tracking mechanisms that automatically collect
       information about end users are not likely to disappear from Web
       sites anytime soon.



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       First, eliminating these mechanisms would require amputating the
       technical features they rely on, or blocking Web sites from using
       them.  This would be an unacceptable step backwards for both Web
       site publishers and end users given that these features provide
       advanced functionalities for Web sites.  For instance,
       eliminating Web browser fingerprinting would require amputating
       or blocking the canvas element in HTML5 used for rendering
       advanced graphics.

       Second, even if some countries were to enact further laws and
       regulations intended to give typical end users full control over
       the information collected automatically about them, and if a new
       non-invasive tracking mechanism were to be designed and developed
       to make that possible, this would raise further issues.  It is
       very likely that some other countries would reject this new
       mechanism or would adopt a different, incompatible one, and that
       the vast majority of publishers, who run small and medium-sized
       Web sites, could not afford the additional costs required to
       upgrade them.

       This inextricable situation with invasive tracking mechanisms for
       Web sites is not accidental.  On the World Wide Web, when
       technical features are being designed and developed, it seems
       that the voices of those who defend the end user's right to
       privacy are insufficiently taken into account, and that
       functionality always wins out over privacy.  For example, during
       the early years of the World Wide Web, when its fundamental
       design was shaped, these voices were not given enough
       consideration due to fierce competition between Web browser
       makers.

       At that time, many innovative technical features, such as the
       ability to manage state information via cookies, were designed
       and released in Web browsers directly, without first going
       through the usual standardization processes that take place in
       standards developing organizations, where such voices resonate.
       And when the standardization process occurs later, after the
       technical feature has been widely deployed, it is often too late
       for those voices to be taken into account.

       With Frogans sites, the situation is very different regarding
       privacy.  For all the design decisions related to the Frogans
       technology, privacy has been taken into account and given
       precedence over functionality when necessary.

       This puts end users on an equal footing with Frogans site
       publishers.  As a result, Frogans as a medium is perceived by end
       users as protecting privacy.



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       Frogans as a medium for publishing content and services on the
       Internet protects the privacy of end users at multiple levels.
       For example:

       *  The medium isolates end users from third parties.

          When browsing a given Frogans site, end users communicate
          exclusively with the publisher of the Frogans site.  End users
          do not communicate with any third parties.  This is because
          all the content of any Frogans site is hosted on the server of
          the Frogans site publisher.

          If the publisher of a given Frogans site wants to include
          content provided by third parties, such as advertisements,
          then the publisher needs to aggregate this third-party content
          on its server along with its own content.  This aggregation
          offers Frogans site publishers a side benefit by giving them
          the opportunity to fully control and validate the third-party
          content in their Frogans sites.

       *  The medium makes publishers accountable to end users.

          Upon request by the publisher of a given Frogans site, end
          users may choose to give information about themselves.  In
          this case, the Frogans site publisher is the exclusive
          recipient of this information.

          From a legal standpoint, according to the Frogans Technology
          User Policy, if the publisher of a given Frogans site obtains
          information about end users, then it becomes responsible for
          protecting this information.  The publisher remains
          responsible for this protection if it shares this information
          with third parties.  Prior to obtaining and possibly sharing
          such information, the publisher is required to draw up and
          publish a privacy policy for its Frogans site in order to
          disclose its exact intentions.

       *  The medium prevents the leaking of information.

          When end users browse Frogans sites, information sent to
          Frogans site publishers is limited to what end users give
          voluntarily.  No information is sent behind the back of end
          users.

          For instance, Frogans site publishers do not know what type of
          device end users are using.  They also do not know the
          language, operating system, screen resolution, or any other
          device characteristics.  Such information is not made



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          available to Frogans site publishers, and no technical means
          exist for obtaining it.

          If the HTTP protocol is chosen by the publisher for the
          connection to the Frogans site server, then the HTTP request
          header fields sent to the server do not leak any such
          information.  For example, the "User-Agent" header field
          merely contains "Frogans Player", irrespective of the type of
          end-user device and the Frogans Player version number.

          The fact that such information is not made available to
          Frogans site publishers is not troublesome because publishers
          do not have to design different versions of their Frogans
          sites for different devices.  This is due to the founding
          principle of the Frogans technology whereby Frogans slides are
          rendered identically on all end-user devices regardless of
          their characteristics.

       *  The medium precludes invasive tracking.

          When browsing Frogans sites, by default, end users who
          previously visited a given Frogans site cannot be recognized
          by the Frogans site publisher when they return to the Frogans
          site.  End users can be recognized only if they have granted
          permission to the publisher during a previous visit.

          End users have a practical means, based on Favorites, for
          granting these permissions to publishers on a site-by-site
          basis.  If end users want to grant permission, they just need
          to add the Frogans site to their Favorites.  In order to
          remove permission, they just need to remove the Frogans site
          from their Favorites.  However, publishers can always choose
          not to support the recognition of returning end users, e.g.
          for security reasons.

          This convergence between Favorites and consent to be
          recognized when returning to a Frogans site is explained to
          end users when they add or remove a Frogans site from their
          Favorites.

          While protecting end users against invasive tracking, Frogans
          as a medium does not deprive them of useful features that may
          be provided by Frogans site publishers, such as logging on to
          their Frogans sites, adding items to a shopping cart, or
          getting personalized content.  But, unless the Frogans site is
          in the end user's Favorites, these features only work over the
          course of one visit.  By default, Frogans slide sessions,
          which are defined by the Frogans site publisher to manage



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          state information, are forgotten automatically by Frogans
          Player when the end user puts an end to the visit by closing
          the Frogans site.

          Finally, Frogans site publishers cannot use fingerprinting
          techniques to circumvent protection against invasive tracking.
          This is because using such techniques would require at least
          four methods, none of which exists by design in the Frogans
          technology: incorporating a script or a program in a Frogans
          slide, executing the script or program on the end user device,
          making use of specific APIs provided by Frogans Player, and
          sending the results of the script or program back to the
          server.

       *  The medium sandboxes information between publishers.

          When an end user browses several Frogans sites simultaneously,
          the publishers of these Frogans sites are isolated from one
          another.

          Publishers have no means to obtain the list of other Frogans
          sites that are being browsed by the end user.  They cannot
          even know whether other Frogans sites are being browsed.
          Likewise, publishers cannot obtain the list of Frogans sites
          recently visited by the end user, nor the list of Favorites.

          Furthermore, each Frogans site has its own separate cache on
          the end-user device.  This cache is used to manage auxiliary
          files loaded from the Frogans site server, and is kept in
          random access memory only.  It is isolated from the other
          caches, even in the case where other Frogans sites are hosted
          on the same server.

       Thanks to these multiple levels of protection, end users are in
       control of their privacy when they browse Frogans sites.  They
       determine exactly what information they are willing to give to a
       Frogans site publisher and whether they can be recognized.  They
       do not have to make efforts to understand and master complicated
       notions and their corresponding settings.  There are no cookies
       with Frogans sites.

       But obviously there are certain levels for which Frogans as a
       medium cannot protect the privacy of end users.  For instance:

       -  In the case where a Frogans site publisher receives
          information given voluntarily by end users under the terms of
          a privacy policy, Frogans as a medium does not provide
          protection of end users' privacy if this information is



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          stolen, e.g due to lax security of the Frogans site server.

       -  When using the Internet as the data-transport network for
          browsing Frogans sites, the very nature of the Internet
          Protocol requires that the IP address of the end-user device
          be transmitted to the server.  This address can be used by
          Frogans site publishers in an attempt to determine the
          geographical location of end users, or to recognize end users
          returning to their Frogans sites.  However, the exploitation
          of IP addresses by publishers is not always reliable given
          that some Internet Service Providers (ISPs) regularly reassign
          IP addresses to different end users.  In addition, end users
          may hide their IP address from publishers by connecting to the
          Internet through an anonymous proxy, a virtual private network
          (VPN), or an anonymization network such as Tor.

       -  As regards network surveillance, which can be understood as a
          violation of privacy, questions remain open because Frogans as
          a medium uses the same telecommunications infrastructure and
          the same core traffic and routing protocols as other generic
          software layers on the Internet.

       With Frogans as a medium, protecting the privacy of end users is
       not an obstacle to progress and innovation.  This protection
       results from the design of the Frogans technology, which has
       always focused on simplicity and security, and from the constant
       attention paid to privacy when modifying existing features or
       developing new ones.























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7.2.  Preparing Image Resources - <resimage> Element

   The <resimage> element prepares an image resource that is based on an
   image file.  The image file contains a pre-authored image, which is
   created previously using image editing software.

   The <resimage> element is a child of the <frogans-fsdl> element (see
   Section 6.1).  The <resimage> element does not contain any children.
   It does not contain text characters.

   As stated in the Frogans slide design concepts (Section 4):

   -  The image resource is intended to be used in the Frogans slide as
      the foundation of a layer (see the <layer> element in
      Section 7.12) or as part of a merge resource (see the <resmerge>
      and <merge> elements in Section 7.11).

   -  The image resource can be used once or several times in the
      Frogans slide.

   The image resource is identified using a component identifier
   (Section 6) which is determined by the value of the "resid" attribute
   of the <resimage> element.

   The size, in pixels, of the image resource depends on the value of
   the "size" attribute of the <resimage> element.

   The image file on which the image resource is based is defined using
   a <file> element (see Section 7.1).  As a result, the image file is
   either a static or a dynamic auxiliary file in the Frogans site root
   directory (Section 3), or is embedded as text characters in the
   <file> element, depending on the value of the "nature" attribute of
   the <file> element.

   The image file is referred to using a component identifier which is
   determined by the value of the "fileref" attribute of the <resimage>
   element.

   The image file is encoded using one of the following image formats:
   PNG [PNG], JPEG [JPEG], or GIF [GIF].

   If the image file contains information on the degree of opacity of
   its pixels, such as an alpha channel that can be defined using the
   PNG image format, then this information is used when preparing the
   image resource.  Otherwise, the pixels in the image file are
   considered fully opaque when preparing the image resource.

   As stated in the Frogans slide design concepts, in order to avoid on-



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   screen distractions (Section 4), if the image file is encoded using
   the GIF image format and contains an animation, then only the first
   frame is used when preparing the image resource.  Likewise, if the
   image file is encoded using the APNG image format and therefore
   contains an animation [APNG], then only the first frame is used when
   preparing the image resource.

   For more information on the process to decode image files, see
   Appendix B.1.

   If the image file is an auxiliary file, then according to
   Appendix B.1 on decoding image files, the image file extension is not
   required in the "name" attribute of the <file> element.

   As stated in the memory usage rules for protecting end-user interests
   (Section 5.2), the width and height of the pre-authored image are
   both limited to 1,024 pixels.

   A selection of the pre-authored image is used, representing either
   the entire pre-authored image, or an extract of the pre-authored
   image.  Using an extract of the pre-authored image can be helpful if,
   in order to reduce latency for loading the Frogans slide, the pre-
   authored image is an image sprite, i.e. it contains a collection of
   images.

   The image selection depends on the values of the "selection" and
   "bounds" attributes of the <resimage> element.  By default, the image
   selection is the entire pre-authored image.

   The way in which the image selection is incorporated in the image
   resource depends on the values of the "aspect", "adjust", and
   "origin" attributes of the <resimage> element.  The size, in pixels,
   of the image selection is not necessarily the same as the size, in
   pixels, of the image resource.

   If the image file is an auxiliary file, then its size, in bytes, is
   subject to the overall file size limitations applicable to the
   Frogans slide stated in the network usage rules for protecting end-
   user interests (Section 5.1).

   If the image file is embedded as text characters in the <file>
   element, then the text characters represent the contents of the image
   file encoded using Base64 (see Section 7.1).

   Embedding an image file as text characters in the <file> element
   reduces latency for loading the Frogans slide, because both the FSDL
   document and the image file are loaded at the same time.  Embedding
   an image file can also simplify the task for generating both the FSDL



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   document and the image file on the fly (i.e. dynamically) on the
   server hosting the Frogans site.

   However, embedding an image file as text characters in the <file>
   element leads to an overhead to be taken into account in the overall
   file size limitations applicable to the Frogans slide (Section 5.1),
   because the number of text characters required to encode the image
   file is approximately 1.33 times the size in bytes of the image file.
   Furthermore, depending on the character encoding of the FSDL document
   (Section 6), more than one byte may be necessary to encode each text
   character.  Finally, an embedded image file cannot benefit from
   potential inclusion in the auxiliary file cache (Section 3).

   The <resimage> element has the following attributes:

   resid - Mandatory

      The identifier of the image resource.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      As a result, the value cannot have been utilized previously in the
      FSDL document as a component identifier.

         Examples of accepted values:
         resid='foo1'
         resid='Foo1'
         resid='foo2'
         resid='foo_1'

         Examples of refused values:
         resid=''
         resid='foo-1'
         resid='foo/1'
         resid='foo.1'
         resid='foo 1'
         resid='foo1,foo2'

   size - Mandatory

      The size of the image resource.

      The value of the attribute represents the width and height, in
      pixels, of the image resource.

      As stated in the Frogans slide design concepts (Section 4), the
      width of the image resource is an integer between 1 and 640



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      (inclusive) and its height is an integer between 1 and 480
      (inclusive).

      The value of the attribute is a string in the 'width,height'
      pattern where: ',' is the U+002C COMMA character; and 'width' and
      'height' are substrings representing respectively the width and
      height of the image resource.  Each substring contains between one
      and three decimal characters (inclusive).  Each decimal character
      of the substring is in the range from '0' to '9' (U+0033 DIGIT
      ZERO to U+0039 DIGIT NINE, inclusive).  The substring does not
      contain any leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         size='40,200'
         size='400,200'

         Examples of refused values:
         size=''
         size='400,0'
         size='400,550'
         size='400'
         size='400 200'
         size='040,200'
         size='400, 200'
         size='+400,200'
         size='400,-200'
         size='400.5,200'

   fileref - Mandatory

      The identifier referencing the image file on which the image
      resource is based.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      The value of the attribute has been utilized previously in the
      FSDL document as a component identifier for a <file> element (see
      Section 7.1).

         Examples of accepted values:





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         fileref='foo1'
         fileref='Foo1'
         fileref='foo2'
         fileref='foo_1'

         Examples of refused values:
         fileref=''
         fileref='foo-1'
         fileref='foo/1'
         fileref='foo.1'
         fileref='foo 1'
         fileref='foo1,foo2'

   selection - Optional

      The image selection used in the image resource.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'entire' indicates that the image selection is the entire pre-
         authored image.

      *  'extract' indicates that the image selection is an extract of
         the pre-authored image.  The extract depends on the value of
         the "bounds" attribute of the <resimage> element.

      The default value is 'entire'.

   bounds - Applicable only if the value of the "selection" attribute
            equals 'extract'.  Mandatory if applicable.

      The bounds of the image selection used in the image resource.

      The value of the attribute represents the left, top, right, and
      bottom coordinates, in pixels, of the image selection in the pre-
      authored image.

      The left and top coordinates are integers between 0 and 1,023
      (inclusive).  The right and bottom coordinates are integers
      between 1 and 1,024 (inclusive).

      The image selection uses an x,y coordinate system where: the x and
      the y coordinates of the pixel at the top-left corner of the pre-



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      authored image are both zero; values on the x axis increase
      towards the right; values on the y axis increase towards the
      bottom.

      The image selection is made as follows:

      *  The left coordinate is equal to the x coordinate of the pixel
         at the top-left corner of the image selection.

      *  The top coordinate is equal to the y coordinate of the pixel at
         the top-left corner of the image selection.

      *  The right coordinate is equal to one plus the x coordinate of
         the pixel at the bottom-right corner of the image selection.
         The right coordinate is greater than the left coordinate.

      *  The bottom coordinate is equal to one plus the y coordinate of
         the pixel at the bottom-right corner of the image selection.
         The bottom coordinate is greater than the top coordinate.

      As a result, the width of the image selection is equal to the
      right coordinate minus the left coordinate, and the height of the
      image selection is equal to the bottom coordinate minus the top
      coordinate.

      The value of the attribute is a string in the
      'left,top,right,bottom' pattern where: ',' is the U+002C COMMA
      character; and 'left', 'top', 'right', and 'bottom' are substrings
      representing respectively the left, top, right, and bottom
      coordinates.  Each substring contains between one and four decimal
      characters (inclusive).  Each decimal character of each substring
      is in the range from '0' to '9' (U+0030 DIGIT ZERO to U+0039 DIGIT
      NINE, inclusive).  The substrings do not contain any leading '0'
      (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         bounds='50,30,150,130'
         bounds='250,30,450,130'

         Examples of refused values:
         bounds=''





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         bounds='50,30,1500,130'
         bounds='150,30,50,130'
         bounds='50,30'
         bounds='50 30 150 130'
         bounds='050,30,150,130'
         bounds='50, 30,150,130'
         bounds='+50,30,150,130'
         bounds='50,-30,150,130'
         bounds='50.5,30,150,130'

      During the rendering of the Frogans slide, when preparing the
      image resource:

      *  If the left coordinate is greater than the width of the pre-
         authored image minus one, then the image selection is empty.
         In this case, the prepared image resource is fully transparent.

      *  If the top coordinate is greater than the height of the pre-
         authored image minus one, then the image selection is empty.
         In this case, the prepared image resource is fully transparent.

      *  If the right coordinate is greater than the width of the pre-
         authored image, then the right coordinate is considered to be
         equal to the width of the pre-authored image.

      *  If the bottom coordinate is greater than the height of the pre-
         authored image, then the bottom coordinate is considered to be
         equal to the height of the pre-authored image.

   aspect - Optional

      The aspect of the image selection in the image resource.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'base' indicates that the image selection is resized,
         maintaining its original proportions, such that the whole image
         selection occupies either the entire width or the entire height
         of the image resource.  Any remaining parts of the image
         resource that are not occupied by the image selection are fully
         transparent.  The placement of the image selection in the image
         resource depends on the value of the "adjust" attribute of the
         <resimage> element.



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      *  'spread' indicates that the image selection is resized, without
         maintaining its original proportions, such that the image
         selection occupies the entire width and height of the image
         resource.

      *  'zoom' indicates that the image selection is resized,
         maintaining its original proportions, such that the image
         selection occupies the entire width and height of the image
         resource.  The image selection is cropped in order to fit in
         the image resource if its proportions are different from the
         proportions of the image resource.  The placement of the image
         selection in the image resource depends on the value of the
         "adjust" attribute of the <resimage> element.

      *  'echo' indicates that the image selection is resized,
         maintaining its original proportions, such that the whole image
         selection occupies either the entire width or the entire height
         of the image resource.  Any remaining parts of the image
         resource that are not occupied by the image selection are
         covered by copies of the image selection that are placed next
         to one another, either vertically or horizontally.  Copies of
         the image selection are cropped in order to fit in the image
         resource if their placement makes them extend beyond the edge
         of the image resource.  The placement of the image selection in
         the image resource depends on the value of the "adjust"
         attribute of the <resimage> element.

      *  'tile' indicates that the image selection is not resized.  Any
         remaining parts of the image resource that are not occupied by
         the image selection are covered by copies of the image
         selection that are placed next to one another, both vertically
         and horizontally.  The image selection and copies of the image
         selection are cropped in order to fit in the image resource if
         their placement makes them extend beyond the edge of the image
         resource.  The placement of the image selection in the image
         resource depends on the value of the "origin" attribute of the
         <resimage> element.

      The default value is 'base'.

      For more information on the process to resize image selections,
      see Appendix B.2.

   adjust - Applicable only if the value of the "aspect" attribute
            equals 'base', 'zoom', or 'echo'.  Optional if applicable.






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      The adjustment of the image selection in the image resource.

      The value of the attribute represents an integer between -100 and
      100 (inclusive).

      The adjustment is applied, either horizontally or vertically, as
      follows:

      *  An adjustment of -100 corresponds to the LT placement, where
         the image selection is placed so that its left or top edge
         matches the left or top edge of the image resource.

      *  An adjustment of 0 corresponds to the central placement, where
         the image selection is centered vertically or horizontally in
         the image resource.

      *  An adjustment of 100 corresponds to the RB placement, where the
         image selection is placed so that its right or bottom edge
         matches the right or bottom edge of the image resource.

      *  An adjustment between -100 and 0 (exclusive) corresponds to a
         proportional placement, where the image selection is placed
         according to the absolute value of the adjustment, starting
         from the central placement and moving towards the LT placement.
         For instance, an adjustment of -25 corresponds to a placement
         where the image selection is placed one-quarter of the way from
         the central placement towards the LT placement.

      *  An adjustment between 0 and 100 (exclusive) corresponds to a
         proportional placement, where the image selection is placed
         according to the value of the adjustment, starting from the
         central placement and moving towards the RB placement.  For
         instance, an adjustment of 75 corresponds to a placement where
         the image selection is placed three-quarters of the way from
         the central placement towards the RB placement.

      The default value is 0.

      The value of the attribute is a string in the 'pd' pattern where:
      'p' is a substring representing the sign of the adjustment; and
      'd' is a substring representing the absolute value of the
      adjustment.  The 'p' substring is either an empty string,
      indicating that the value of the adjustment is greater than or
      equal to zero, or is the '-' (U+002D HYPHEN-MINUS) character.  The
      'd' substring contains between one and three decimal characters
      (inclusive).  Each decimal character of the 'd' substring is in
      the range from '0' to '9' (U+0033 DIGIT ZERO to U+0039 DIGIT NINE,
      inclusive).  The 'd' substring does not contain any leading '0'



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      (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), and '.'  (U+002E FULL STOP).

         Examples of accepted values:
         adjust='0'
         adjust='-100'
         adjust='100'
         adjust='-25'
         adjust='75'

         Examples of refused values:
         adjust=''
         adjust='-0'
         adjust='-120'
         adjust='150'
         adjust='-025'
         adjust='075'
         adjust='- 25'
         adjust='+100'
         adjust='-25.5'

   origin - Applicable only if the value of the "aspect" attribute
            equals 'tile'.  Optional if applicable.

      The origin in the image selection used in the image resource.

      The value of the attribute represents the x and y coordinates, in
      pixels, of the origin in the image selection.  The x and y
      coordinates correspond to the horizontal and vertical coordinates,
      respectively, of the pixel in the image selection that is placed
      in the top-left corner of the image resource.

      The x and y coordinates are integers between 0 and 1,023
      (inclusive).

      The x and y coordinates of the top-left corner of the image
      selection are both zero.

      The default value is '0,0'.

      The value of the attribute is a string in the 'x,y' pattern where:
      ',' is the U+002C COMMA character; and 'x' and 'y' are substrings
      representing respectively the x and y coordinates.  Each substring
      contains between one and four decimal characters (inclusive).
      Each decimal character of each substring is in the range from '0'



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      to '9' (U+0033 DIGIT ZERO to U+0039 DIGIT NINE, inclusive).  The
      substrings do not contain any leading '0' (U+0033 DIGIT ZERO)
      characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         origin='0,0'
         origin='50,30'
         origin='250,30'

         Examples of refused values:
         origin=''
         origin='50,3000'
         origin='50'
         origin='50 30'
         origin='050,30'
         origin='50, 30'
         origin='+50,30'
         origin='50,-30'
         origin='50.5,30'

      During the rendering of the Frogans slide, when preparing the
      image resource:

      *  If the x coordinate is greater than the width of the pre-
         authored image minus one, then the x coordinate is considered
         to be equal to the width of the pre-authored image minus one.

      *  If the y coordinate is greater than the height of the pre-
         authored image minus one, then the y coordinate is considered
         to be equal to the height of the pre-authored image minus one.
















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7.3.  Preparing Pixels Resources - <respixels> Element

   The <respixels> element prepares a pixels resource that is based on a
   miniature bitmap.

   The <respixels> element is a child of the <frogans-fsdl> element (see
   Section 6.1).  The <respixels> element does not contain any children.
   It contains text characters.

   As stated in the Frogans slide design concepts (Section 4):

   -  The pixels resource is intended to be used in the Frogans slide as
      the foundation of a layer (see the <layer> element in
      Section 7.12) or as part of a merge resource (see the <resmerge>
      and <merge> elements in Section 7.11).

   -  The pixels resource can be used once or several times in the
      Frogans slide.

   The pixels resource is identified using a component identifier
   (Section 6) which is determined by the value of the "resid" attribute
   of the <respixels> element.

   The size, in pixels, of the pixels resource depends on the value of
   the "size" attribute of the <respixels> element.

   The miniature bitmap is made up of individual pixels, organized in
   columns and rows.

   The miniature bitmap is resized, without maintaining its original
   proportions, such that the miniature bitmap occupies the entire width
   and height of the pixels resource.

   The pixels resource can be used, for instance, as a background with
   color gradients, or as a mask with transparency gradients.

   For more information on the process to resize miniature bitmaps, see
   Appendix B.3.

   The number of columns of the miniature bitmap depends on the value of
   the "columns" attribute of the <respixels> element.  The number of
   rows of the miniature bitmap depends on the value of the "rows"
   attribute of the <respixels> element.

   Each individual pixel of the miniature bitmap is defined using four
   components: the R, G and B components (color) and the A component
   (transparency).




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   The R, G, B, and A components of the individual pixels of the
   miniature bitmap are all defined in the same way, depending on the
   value of the "pix" attribute of the <respixels> element.

   The definition of all the individual pixels of the miniature bitmap
   can be either:

   *  an rgba definition, where, for an individual pixel, the values of
      the R, G, B, and A components are defined in the text characters
      of the <respixels> element.

   *  an rgb definition, where, for an individual pixel, the values of
      the R, G, and B components are defined in the text characters of
      the <respixels> element, and the value of the A component depends
      on the value of the "alpha" attribute of the <respixels> element.

   *  an a definition, where, for an individual pixel, the values of the
      R, G, and B components depend on the value of the "color"
      attribute of the <respixels> element, and the value of the A
      component is defined in the text characters of the <respixels>
      element.

   *  a y definition, where, for an individual pixel, the values of the
      R, G, and B components are defined in the text characters of the
      <respixels> element, and the value of the A component depends on
      the value of the "alpha" attribute of the <respixels> element.
      Using this definition, the R, G, and B components share the same
      value, corresponding to the luminance of the individual pixel,
      hence the color of the individual pixel is on a gray scale.

   *  a ya definition, where, for an individual pixel, the R, G, B and A
      components are defined in the text characters of the <respixels>
      element.  Using this definition, the R, G, and B components share
      the same value, corresponding to the luminance of the individual
      pixel, hence the color of the individual pixel is on a gray scale.

   The text characters of the <respixels> element contain a list of
   items.  Each item corresponds to an individual pixel.

   The individual pixels are ordered row by row, from the top-left to
   the bottom-right pixel of the miniature bitmap.  The number of items
   in the list is the product of the number of rows and the number of
   columns.

   All items in the list are strings using one of the following
   patterns:





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   *  '#rrggbbaa': this pattern corresponds to the rgba definition.

   *  '#rrggbb': this pattern corresponds to the rgb definition.

   *  '#aa': this pattern corresponds to the a definition.

   *  '#yy': this pattern corresponds to the y definition.

   *  '#yyaa': this pattern corresponds to the ya definition.

   In the patterns above: '#' is the U+0013 NUMBER SIGN character; 'rr',
   'gg', and 'bb' are substrings representing respectively the R, G, and
   B components; 'aa' is a substring representing the A component; and
   'yy' is a substring representing the value shared by the R, G, and B
   components (luminance).  Each substring contains two hexadecimal
   characters.  Each hexadecimal character of each substring is in one
   of the following ranges: from '0' to '9' (U+0030 DIGIT ZERO to U+0039
   DIGIT NINE, inclusive), from 'A' to 'F' (U+0041 LATIN CAPITAL LETTER
   A to U+0046 LATIN CAPITAL LETTER F, inclusive), from 'a' to 'f'
   (U+0061 LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F,
   inclusive).

   As a result, the pattern does not contain any white space characters
   defined in Section 6.

      Examples of accepted items:
      #004698bf
      #004698
      #bf
      #3a
      #3abf
      #3Abf
      #3ABF

      Examples of refused items:
      004698bf
      #
      #004698b
      #00469
      #b
      #3ab
      # 004698bf
      #004698 bf
      #0004698bf

   The separator character used to separate items in the list is the ';'
   (U+003B SEMICOLON) character.




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   White space characters, as defined in Section 6, can optionally be
   included before and after the ';' (U+003B SEMICOLON) separator
   characters in the list.  These white space characters are ignored.

   The list cannot contain empty items.  As a result, there is no
   separator character either before the first item or after the last
   item in the list.  Furthermore, there cannot be two consecutive
   separator characters in the list.

      Examples of accepted item lists:
      #004698bf;#ffbf00ff;#00469840
      #004698;#ffbf00;#001c46
      #bf;#ff
      #3abf;#00ff;#3abf;#ff00

      Examples of refused item lists:
      #004698bf;#ffbf00;#00469840
      #004698;#bf;#3abf
      #004698bf#ffbf00ff
      #004698bf #ffbf00ff
      ;#004698bf;#ffbf00ff
      #004698bf;#ffbf00ff;
      #004698bf;;#ffbf00ff

   During the rendering of the Frogans slide, when preparing the pixels
   resource, individual pixels of the miniature bitmap can be invisible
   pixels, i.e. the level of the A component (transparency) is equal to
   zero.  In this case, as stated in the Frogans slide design concepts,
   the levels of the R, G and B components (color) of the individual
   pixel are considered to be equal to zero.

   The <respixels> element has the following attributes:

   resid - Mandatory

      The identifier of the pixels resource.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      As a result, the value cannot have been utilized previously in the
      FSDL document as a component identifier.

         Examples of accepted values:
         resid='foo1'
         resid='Foo1'





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         resid='foo2'
         resid='foo_1'

         Examples of refused values:
         resid=''
         resid='foo-1'
         resid='foo/1'
         resid='foo.1'
         resid='foo 1'
         resid='foo1,foo2'

   size - Mandatory

      The size of the pixels resource.

      The value of the attribute represents the width and height, in
      pixels, of the pixels resource.

      As stated in the Frogans slide design concepts (Section 4), the
      width of the pixels resource is an integer between 1 and 640
      (inclusive) and its height is an integer between 1 and 480
      (inclusive).

      The value of the attribute is a string in the 'width,height'
      pattern where: ',' is the U+002C COMMA character; and 'width' and
      'height' are substrings representing respectively the width and
      height of the pixels resource.  Each substring contains between
      one and three decimal characters (inclusive).  Each decimal
      character of the substring is in the range from '0' to '9' (U+0033
      DIGIT ZERO to U+0039 DIGIT NINE, inclusive).  The substring does
      not contain any leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         size='40,200'
         size='400,200'

         Examples of refused values:
         size=''
         size='400,0'
         size='400,550'
         size='400'





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         size='400 200'
         size='040,200'
         size='400, 200'
         size='+400,200'
         size='400,-200'
         size='400.5,200'

   columns - Mandatory

      The number of columns of the miniature bitmap on which the pixels
      resource is based.

      The value of the attribute represents an integer between 1 and 16
      (inclusive).

      The value of the attribute is a string containing between one and
      two decimal characters (inclusive).  Each decimal character of the
      string is in the range from '0' to '9' (U+0030 DIGIT ZERO to
      U+0039 DIGIT NINE, inclusive).  The string does not contain any
      leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         columns='1'
         columns='16'
         columns='9'

         Examples of refused values:
         columns=''
         columns='-9'
         columns='20'
         columns='09'
         columns='+9'
         columns='9.5'

   rows - Mandatory

      The number of rows of the miniature bitmap on which the pixels
      resource is based.

      The value of the attribute represents an integer between 1 and 16
      (inclusive).





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      The value of the attribute is a string containing between one and
      two decimal characters (inclusive).  Each decimal character of the
      string is in the range from '0' to '9' (U+0030 DIGIT ZERO to
      U+0039 DIGIT NINE, inclusive).  The string does not contain any
      leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         rows='1'
         rows='16'
         rows='9'

         Examples of refused values:
         rows=''
         rows='-9'
         rows='20'
         rows='09'
         rows='+9'
         rows='9.5'

   pix - Mandatory

      The way of defining all the individual pixels of the miniature
      bitmap on which the pixels resource is based.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'rgba' indicates that all the individual pixels of the
         miniature bitmap use an rgba definition.

      *  'rgb' indicates that all the individual pixels of the miniature
         bitmap use an rgb definition.

      *  'a' indicates that all the individual pixels of the miniature
         bitmap use an a definition.

      *  'y' indicates that all the individual pixels of the miniature
         bitmap use a y definition.




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      *  'ya' indicates that all the individual pixels of the miniature
         bitmap use a ya definition.

   color - Applicable only if the value of the "pix" attribute equals
           'a'.  Optional if applicable.

      The color of the individual pixels of the miniature bitmap on
      which the pixels resource is based.

      The value of the attribute represents the levels of the R, G, and
      B components of the color.  The level of each component is
      represented using two hexadecimal digits.

      As stated in the Frogans slide design concepts (Section 4), the
      level of each one of the R, G, and B components is in the range
      from 00 (0) to ff (255).

      The default value is '#0000ff'.

      The value of the attribute is a string in the '#rrggbb' pattern
      where: '#' is the U+0013 NUMBER SIGN character; and 'rr', 'gg',
      and 'bb' are substrings representing respectively the R, G, and B
      components.  Each substring contains two hexadecimal characters.
      Each hexadecimal character of each substring is in one of the
      following ranges: from '0' to '9' (U+0030 DIGIT ZERO to U+0039
      DIGIT NINE, inclusive), from 'A' to 'F' (U+0041 LATIN CAPITAL
      LETTER A to U+0046 LATIN CAPITAL LETTER F, inclusive), from 'a' to
      'f' (U+0061 LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F,
      inclusive).

      As a result, the value of the attribute does not contain any white
      space characters defined in Section 6.

         Examples of accepted values:
         color='#0000ff'
         color='#004698'
         color='#001c46'
         color='#ffbf00'
         color='#Ffbf00'
         color='#FFBF00'

         Examples of refused values:
         color=''
         color='ffbf00'
         color='#'
         color='#ffbf'





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         color='# ffbf00'
         color='#ffbf 00'
         color='#0ffbf00'
         color='#00f'

   alpha - Applicable only if the value of the "pix" attribute equals
           either 'rgb' or 'y'.  Optional if applicable.

      The transparency of the individual pixels of the miniature bitmap
      on which the pixels resource is based.

      The value of the attribute represents the level of the A component
      of the individual pixels.  The level of the A component is
      represented using two hexadecimal digits.

      As stated in the Frogans slide design concepts, the level of the A
      component is in the range from 00 (0) to ff (255), where the level
      00 corresponds to a fully transparent pixel and ff corresponds to
      a fully opaque pixel.

      The default value is '#ff'.

      The value of the attribute is a string in the '#aa' pattern where:
      '#' is the U+0013 NUMBER SIGN character; and 'aa' is a substring
      representing the A component.  Each substring contains two
      hexadecimal characters.  Each hexadecimal character of each
      substring is in one of the following ranges: from '0' to '9'
      (U+0030 DIGIT ZERO to U+0039 DIGIT NINE, inclusive), from 'A' to
      'F' (U+0041 LATIN CAPITAL LETTER A to U+0046 LATIN CAPITAL LETTER
      F, inclusive), from 'a' to 'f' (U+0061 LATIN SMALL LETTER A to
      U+0066 LATIN SMALL LETTER F, inclusive).

      As a result, the value of the attribute does not contain any white
      space characters defined in Section 6.

         Examples of accepted values:
         alpha='#ff'
         alpha='#00'
         alpha='#bf'
         alpha='#Bf'
         alpha='#BF'

         Examples of refused values:
         alpha=''
         alpha='bf'
         alpha='#'





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         alpha='#b'
         alpha='# bf'
         alpha='#b f'
         alpha='#0bf'















































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7.4.  Preparing Drawing Resources - <resdraw> Element

   The <resdraw> element prepares a drawing resource that is based on a
   geometric form.

   The <resdraw> element is a child of the <frogans-fsdl> element (see
   Section 6.1).  The <resdraw> element does not contain any children.
   It does not contain text characters.

   As stated in the Frogans slide design concepts (Section 4):

   -  The drawing resource is intended to be used in the Frogans slide
      as the foundation of a layer (see the <layer> element in
      Section 7.12) or as part of a merge resource (see the <resmerge>
      and <merge> elements in Section 7.11).

   -  The drawing resource can be used once or several times in the
      Frogans slide.

   The drawing resource is identified using a component identifier
   (Section 6) which is determined by the value of the "resid" attribute
   of the <resdraw> element.

   The size, in pixels, of the drawing resource depends on the value of
   the "size" attribute of the <resdraw> element.

   The geometric form is either a rectangle, a rounded rectangle, or an
   ellipse, depending on the value of the "figure" attribute of the
   <resdraw> element.

   The geometric form is drawn either as a line or as a filled area,
   depending on the value of the "stroke" attribute of the <resdraw>
   element.  If the geometric form is drawn as a line, then the
   thickness of the line depends on the value of the "thick" attribute
   of the <resdraw> element.

   The geometric form covers the entire width and height of the drawing
   resource.

   If the geometric form is drawn as a line, then the thickness of the
   line is fully included in the drawing resource, i.e. it does not
   extend beyond the edge of the drawing resource.

   A rounded rectangle is a rectangle with four rounded corners, where
   each corner is one quarter of an ellipse.  For a rounded rectangle:

   *  The width and height of the ellipse used to draw the corners
      depend on the value of the "round" attribute of the <resdraw>



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      element.

   *  The top-left, top-right, bottom-left, and bottom-right corners
      correspond respectively to the top-left, top-right, bottom-left,
      and bottom-right quarters of the ellipse.

   *  If the width of the ellipse is equal to the width of the drawing
      resource, then the top and bottom of the rounded rectangle are
      both a semi-ellipse.

   *  If the height of the ellipse is equal to the height of the drawing
      resource, then the left and right sides of the rounded rectangle
      are both a semi-ellipse.

   *  If the width and height of the ellipse are equal respectively to
      the width and height of the drawing resource, then the rounded
      rectangle becomes an ellipse.

   The color of the drawing resource depends on the value of the "color"
   attribute of the <resdraw> element.

   For more information on the process to draw geometric forms, see
   Appendix B.4.

   The <resdraw> element has the following attributes:

   resid - Mandatory

      The identifier of the drawing resource.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      As a result, the value cannot have been utilized previously in the
      FSDL document as a component identifier.

         Examples of accepted values:
         resid='foo1'
         resid='Foo1'
         resid='foo2'
         resid='foo_1'

         Examples of refused values:
         resid=''
         resid='foo-1'
         resid='foo/1'





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         resid='foo.1'
         resid='foo 1'
         resid='foo1,foo2'

   size - Mandatory

      The size of the drawing resource.

      The value of the attribute represents the width and height, in
      pixels, of the drawing resource.

      As stated in the Frogans slide design concepts (Section 4), the
      width of the drawing resource is an integer between 1 and 640
      (inclusive) and its height is an integer between 1 and 480
      (inclusive).

      The value of the attribute is a string in the 'width,height'
      pattern where: ',' is the U+002C COMMA character; and 'width' and
      'height' are substrings representing respectively the width and
      height of the drawing resource.  Each substring contains between
      one and three decimal characters (inclusive).  Each decimal
      character of the substring is in the range from '0' to '9' (U+0033
      DIGIT ZERO to U+0039 DIGIT NINE, inclusive).  The substring does
      not contain any leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         size='40,200'
         size='400,200'

         Examples of refused values:
         size=''
         size='400,0'
         size='400,550'
         size='400'
         size='400 200'
         size='040,200'
         size='400, 200'
         size='+400,200'
         size='400,-200'
         size='400.5,200'

   figure - Mandatory




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      The geometric form on which the drawing resource is based.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'rect' indicates that the geometric form is a rectangle.

      *  'roundrect' indicates that the geometric form is a rounded
         rectangle.

      *  'ellipse' indicates that the geometric form is an ellipse.  If
         the width and height of the drawing resource are equal, then
         the geometric form is a circle.

   stroke - Mandatory

      The way of drawing the geometric form on which the drawing
      resource is based.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'on' indicates that the geometric form is drawn as a line.  The
         thickness of the line depends on the value of the "thick"
         attribute of the <resdraw> element.

      *  'off' indicates that the geometric form is drawn as a filled
         area.

   thick - Applicable only if the value of the "stroke" attribute equals
           'on'.  Optional if applicable.

      The thickness of the line in the drawing resource.

      The value of the attribute represents an integer between 1 and 64
      (inclusive).

      The thickness is in pixels.





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      The default value is '8'.

      The value of the attribute is a string containing between one and
      two decimal characters (inclusive).  Each decimal character of the
      string is in the range from '0' to '9' (U+0030 DIGIT ZERO to
      U+0039 DIGIT NINE, inclusive).  The string does not contain any
      leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         thick='1'
         thick='64'
         thick='9'

         Examples of refused values:
         thick=''
         thick='-9'
         thick='80'
         thick='+9'
         thick='9.5'

   round - Applicable only if the value of the "figure" attribute equals
           'roundrect'.  Optional if applicable.

      The dimensions of the ellipse used to draw the corners of the
      rounded rectangle on which the drawing resource is based.

      The value of the attribute represents the width and height, in
      pixels, of the ellipse.

      The width of the ellipse is an integer between 1 and 640
      (inclusive) and its height is an integer between 1 and 480
      (inclusive).

      The default value is '16,16'.

      The value of the attribute is a string in the 'width,height'
      pattern where: ',' is the U+002C COMMA character; and 'width' and
      'height' are substrings representing respectively the width and
      height of the ellipse.  Each substring contains between one and
      three decimal characters (inclusive).  Each decimal character of
      each substring is in the range from '0' to '9' (U+0033 DIGIT ZERO
      to U+0039 DIGIT NINE, inclusive).  The substrings do not contain
      any leading '0' (U+0033 DIGIT ZERO) characters.



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      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         origin='16,16'
         origin='40,200'
         origin='400,200'

         Examples of refused values:
         origin=''
         origin='400,0'
         origin='400,550'
         origin='400'
         origin='400 200'
         origin='040,200'
         origin='400, 200'
         origin='+400,200'
         origin='400,-200'
         origin='400.5,200'

      During the rendering of the Frogans slide, when preparing the
      drawing resource:

      *  If the width of the ellipse is greater than the width of the
         drawing resource, then the width of the ellipse is considered
         to be equal to the width of the drawing resource.

      *  If the height of the ellipse is greater than the height of the
         drawing resource, then the height of the ellipse is considered
         to be equal to the height of the drawing resource.

   color - Optional

      The color of the drawing resource.

      The value of the attribute represents the levels of the R, G, and
      B components of the color.  The level of each component is
      represented using two hexadecimal digits.

      As stated in the Frogans slide design concepts (Section 4), the
      level of each one of the R, G, and B components is in the range
      from 00 (0) to ff (255).

      The default value is '#0000ff'.





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      The value of the attribute is a string in the '#rrggbb' pattern
      where: '#' is the U+0013 NUMBER SIGN character; and 'rr', 'gg',
      and 'bb' are substrings representing respectively the R, G, and B
      components.  Each substring contains two hexadecimal characters.
      Each hexadecimal character of each substring is in one of the
      following ranges: from '0' to '9' (U+0030 DIGIT ZERO to U+0039
      DIGIT NINE, inclusive), from 'A' to 'F' (U+0041 LATIN CAPITAL
      LETTER A to U+0046 LATIN CAPITAL LETTER F, inclusive), from 'a' to
      'f' (U+0061 LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F,
      inclusive).

      As a result, the value of the attribute does not contain any white
      space characters defined in Section 6.

         Examples of accepted values:
         color='#0000ff'
         color='#004698'
         color='#001c46'
         color='#ffbf00'
         color='#Ffbf00'
         color='#FFBF00'

         Examples of refused values:
         color=''
         color='ffbf00'
         color='#'
         color='#ffbf'
         color='# ffbf00'
         color='#ffbf 00'
         color='#0ffbf00'
         color='#00f'




















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7.5.  Preparing Path Resources - <respath> Element

   The <respath> element prepares a path resource that is based on a
   plane containing Bezier curves.

   The <respath> element is a child of the <frogans-fsdl> element (see
   Section 6.1).  The <respath> element does not contain any children.
   It contains text characters.

   As stated in the Frogans slide design concepts (Section 4):

   -  The path resource is intended to be used in the Frogans slide as
      the foundation of a layer (see the <layer> element in
      Section 7.12) or as part of a merge resource (see the <resmerge>
      and <merge> elements in Section 7.11).

   -  The path resource can be used once or several times in the Frogans
      slide.

   The path resource is identified using a component identifier
   (Section 6) which is determined by the value of the "resid" attribute
   of the <respath> element.

   The size, in pixels, of the path resource depends on the value of the
   "size" attribute of the <respath> element.

   Each Bezier curve contained in the plane is either:

   *  a linear Bezier curve, which has a starting point and an ending
      point.

   *  a conic Bezier curve, which has a starting point, an ending point,
      and one control point.  A conic Bezier curve is also referred to
      as a quadratic Bezier curve.

   *  a cubic Bezier curve, which has a starting point, an ending point,
      and two control points.

   Each Bezier curve can be used in the plane either as:

   *  a simple Bezier curve, meaning that it is independent from all the
      other Bezier curves contained in the plane, or

   *  a part of a composite Bezier curve.  A composite Bezier curve is
      made up of two of more linear, conic, or cubic Bezier curves,
      joined end to end in any combination, such that the ending point
      of one curve coincides with the starting point of the next curve.




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   The plane can contain any combination of simple and composite Bezier
   curves.

   In order to position the starting, ending, and control points of the
   simple and composite Bezier curves in the plane, the plane uses an
   x,y coordinate system where: the x and the y coordinates of a point
   in the plane represent the distances of the point from the x and y
   coordinate axes; the x coordinate is an integer which increases
   towards the right from 0 to 2,048; and the y coordinate is an integer
   which increases towards the bottom from 0 to 2,048.

   The plane can be cropped in order to select which part of the plane
   is apparent in the path resource, depending on the values of the
   "crop" and "corners" attributes of the <respath> element.

   For instance, the plane can be cropped automatically in cases where
   the x,y coordinates of the starting, ending, and control points of
   the Bezier curves contained in the plane do not use the full range
   from 0 to 2,048.  Furthermore, the plane can be cropped using custom
   coordinates in order to exclude certain parts or control points of
   Bezier curves, or in order to draw, on a fixed scale, graphs
   representing data that is generated on the fly (i.e. dynamically) on
   the server hosting the Frogans site.

   All the simple and composite Bezier curves are drawn either as lines
   or as filled areas, depending on the value of the "stroke" attribute
   of the <respath> element.  If the simple and composite Bezier curves
   are drawn as lines, then the thickness of the lines depends on the
   value of the "thick" attribute of the <respath> element.

   If the simple and composite Bezier curves are drawn as lines, then
   they can all be closed depending on the value of the "close"
   attribute of the <respath> element.

   If a simple Bezier curve is closed, then a straight line is drawn
   from its ending point to its starting point.

   If a composite Bezier curve is closed, then a straight line is drawn
   from the ending point of its last Bezier curve to the starting point
   of its first Bezier curve.  A composite Bezier curve cannot be closed
   correctly by appending a linear Bezier curve whose ending point is
   the starting point of the first Bezier curve of the composite Bezier
   curve.

   If the simple and composite Bezier curves are drawn as filled areas,
   then the rule used to determine these filled areas depends on the
   value of the "fill" attribute of the <respath> element.




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   The way in which the apparent part of the plane is mapped to the path
   resource depends on the values of the "spread" and "adjust"
   attributes of the <respath> element.  The size, in x,y coordinates,
   of the apparent part of the plane is not necessarily the same as the
   size, in pixels, of the path resource.

   If the simple and composite Bezier curves are drawn as lines, and if
   their starting, ending, and control points are all included in the
   apparent part of the plane, then the thickness of the lines is fully
   included in the path resource, i.e. it does not extend beyond the
   edge of the path resource.

   The color of the path resource depends on the value of the "color"
   attribute of the <respath> element.

   The text characters of the <respath> element contain a list of items.
   Each item can be either:

   *  a jump item, which corresponds to the starting point of a simple
      or composite Bezier curve

   *  a linear item, which corresponds to the ending point of a linear
      Bezier curve

   *  a conic item, which corresponds to the ending point and the
      control point of a conic Bezier curve, or

   *  a cubic item, which corresponds to the ending point and both
      control points of a cubic Bezier curve

   Each simple and composite Bezier curve contained in the plane is
   represented as a sequence of items in the list:

   *  A simple Bezier curve is represented as a jump item followed by
      one linear, conic, or cubic item.

   *  A composite Bezier curve is represented as a jump item followed by
      any combination of two or more linear, conic, or cubic items.

   The simple and composite Bezier curves contained in the plane are
   included one after another in the list.

   As a result, the list starts with a jump item, cannot end with a jump
   item, and cannot contain two consecutive jump items.

   Each item in the list is a string using one of the following
   patterns:




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   *  'Ju:xstart,ystart': this pattern corresponds to a jump item.

   *  'Li:xend,yend': this pattern corresponds to a linear item.

   *  'Co:xend,yend,xcp1,ycp1': this pattern corresponds to a conic
      item.

   *  'Cu:xend,yend,xcp1,ycp1,xcp2,ycp2': this pattern corresponds to a
      cubic item.

   In the patterns above: 'Ju', 'Li', 'Co', and 'Cu' are case-sensitive
   string constants representing the kind of item; ':' is the U+003A
   COLON character; ',' is the U+002C COMMA character; 'xstart' and
   'ystart' are substrings representing respectively the x and y
   coordinates of a starting point; 'xend' and 'yend' are substrings
   representing respectively the x and y coordinates of an ending point;
   'xcp1' and 'ycp1' are substrings representing respectively the x and
   y coordinates of either the control point of a conic Bezier curve, or
   the first control point of a cubic Bezier curve; and 'xcp2' and
   'ycp2' are substrings representing respectively the x and y
   coordinates of the second control point of a cubic Bezier curve.
   Each substring contains between one and four decimal characters
   (inclusive).  Each decimal character of each substring is in the
   range from '0' to '9' (U+0030 DIGIT ZERO to U+0039 DIGIT NINE,
   inclusive).  The substrings do not contain any leading '0' (U+0033
   DIGIT ZERO) characters.

   As a result, the item does not contain any of the following
   characters: white space characters defined in Section 6, '+' (U+002B
   PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and '.'  (U+002E FULL STOP).

      Examples of accepted items:
      Ju:200,1000
      Li:200,1000
      Co:200,1000,450,1300
      Cu:200,1000,450,1300,1850,300

      Examples of refused items:
      200,1000
      J200,1000
      Ju200,1000
      Ju 200,1000
      Ju=200,1000
      ju:200,1000
      JU:200,1000
      Ju:200,2400





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      Ju:200
      Ju:200 1000
      Ju:0200,1000
      Ju:200, 1000
      Ju:+200,1000
      Ju:200,-1000
      Ju:200.5,1000
      Li:200
      Co:200,1000
      Co:200,1000,450
      Cu:200,1000,450,1300
      Cu:200,1000,450,1300,1850

   The separator character used to separate items in the list is the ';'
   (U+003B SEMICOLON) character.

   White space characters, as defined in Section 5.5, can optionally be
   included before and after the ';' (U+003B SEMICOLON) separator
   characters in the list.  These white space characters are ignored.

   The list cannot contain empty items.  As a result, there is no
   separator character either before the first item or after the last
   item in the list.  Furthermore, there cannot be two consecutive
   separator characters in the list.

   The number of items in the list is between 2 and 512 (inclusive).

      Examples of accepted item lists:
      Ju:10,50;Li:200,1000
      Ju:10,50;Co:200,1000,450,1300
      Ju:10,50;Cu:200,1000,450,1300,1850,300
      Ju:10,50;Li:500,100;Li:200,1000
      Ju:10,50;Li:500,100;Co:200,1000,450,1300
      Ju:10,50;Li:500,100;Cu:200,1000,450,1300,1850,300
      Ju:10,50;Li:75,1400;Ju:1400,1600;Li:500,100
      Ju:10,50;Li:75,1400;Ju:1400,1600;Li:500,100;Co:200,1000,450,1300

      Examples of refused item lists:
      Li:75,1400;Ju:1400,1600;Li:500,100
      Ju:10,50;Li:75,1400;Ju:1400,1600
      Ju:10,50;Li:75,1400;Ju:200,1000;Ju:1400,1600;Li:500,100
      Ju:10,50Li:200,1000
      Ju:10,50 Li:200,1000
      ;Ju:10,50;Li:200,1000
      Ju:10,50;Li:200,1000;
      Ju:10,50;;Li:200,1000

   For more information on the process to draw Bezier curves, see



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   Appendix B.5.

   The <respath> element has the following attributes:

   resid - Mandatory

      The identifier of the path resource.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      As a result, the value cannot have been utilized previously in the
      FSDL document as a component identifier.

         Examples of accepted values:
         resid='foo1'
         resid='Foo1'
         resid='foo2'
         resid='foo_1'

         Examples of refused values:
         resid=''
         resid='foo-1'
         resid='foo/1'
         resid='foo.1'
         resid='foo 1'
         resid='foo1,foo2'

   size - Mandatory

      The size of the path resource.

      The value of the attribute represents the width and height, in
      pixels, of the path resource.

      As stated in the Frogans slide design concepts (Section 4), the
      width of the path resource is an integer between 1 and 640
      (inclusive) and its height is an integer between 1 and 480
      (inclusive).

      The value of the attribute is a string in the 'width,height'
      pattern where: ',' is the U+002C COMMA character; and 'width' and
      'height' are substrings representing respectively the width and
      height of the path resource.  Each substring contains between one
      and three decimal characters (inclusive).  Each decimal character
      of the substring is in the range from '0' to '9' (U+0033 DIGIT
      ZERO to U+0039 DIGIT NINE, inclusive).  The substring does not
      contain any leading '0' (U+0033 DIGIT ZERO) characters.



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      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         size='40,200'
         size='400,200'

         Examples of refused values:
         size=''
         size='400,0'
         size='400,550'
         size='400'
         size='400 200'
         size='040,200'
         size='400, 200'
         size='+400,200'
         size='400,-200'
         size='400.5,200'

   crop - Mandatory

      The cropping applied to the plane on which the path resource is
      based.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'none' indicates that no cropping is applied to the plane.  The
         x and y coordinates of the point at the top-left corner of the
         apparent part of the plane are both zero.  The x and y
         coordinates of the point at the bottom-right corner of the
         apparent part of the plane are both 2,048.

      *  'auto' indicates that the plane is cropped automatically.  The
         x and y coordinates of the point at the top-left corner of the
         apparent part of the plane are xmin and ymin, where xmin is the
         smallest x coordinate and ymin is the smallest y coordinate of
         all the starting, ending, and control points of all the Bezier
         curves contained in the plane.  The x and y coordinates of the
         point at the bottom-right corner of the apparent part of the
         plane are xmax and ymax, where xmax is the largest x coordinate
         and ymax is the largest y coordinate of all the starting,



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         ending, and control points of all the Bezier curves contained
         in the plane.

      *  'custom' indicates that the plane is cropped using custom
         coordinates.  The x,y coordinates of the points at the top-left
         and bottom-right corners of the apparent part of the plane
         depend on the value of the "corners" attribute of the <respath>
         element.

   corners - Applicable only if the value of the "crop" attribute equals
             'custom'.  Mandatory if applicable.

      The top-left and bottom-right corners of the apparent part of the
      plane on which the path resource is based.

      The value of the attribute represents the x and y coordinates of
      the points at the top-left and bottom-right corners of the
      apparent part of the plane.

      The x and y coordinates of the point at the top-left corner are
      integers between 0 and 2,047 (inclusive).  The x and y coordinates
      of the point at the bottom-right corner are integers between 1 and
      2,048 (inclusive).

      The x and y coordinates of the point at the bottom-right corner
      are greater respectively than the x and y coordinates of the point
      at the top-left corner.

      The value of the attribute is a string in the 'xtl,ytl,xbr,ybr'
      pattern where: ',' is the U+002C COMMA character; and 'xtl' and
      'ytl' are substrings representing respectively the x and y
      coordinates of the point at the top-left corner and 'xbr' and
      'ybr' are substrings representing respectively the x and y
      coordinates of the point at the bottom-right corner.  Each
      substring contains between one and four decimal characters
      (inclusive).  Each decimal character of each substring is in the
      range from '0' to '9' (U+0030 DIGIT ZERO to U+0039 DIGIT NINE,
      inclusive).  The substrings do not contain any leading '0' (U+0033
      DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:





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         corners='10,50,200,1000'
         corners='200,50,450,1000'

         Examples of refused values:
         corners=''
         corners='10,50,2400,1000'
         corners='450,50,200,1000'
         corners='10,50'
         corners='10 50 200 1000'
         corners='010,50,200,1000'
         corners='10, 50,200,1000'
         corners='+10,50,200,1000'
         corners='10,-50,200,1000'
         corners='10.5,50,200,1000'

   stroke - Mandatory

      The way of drawing all the simple and composite Bezier curves
      contained in the plane on which the path resource is based.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'on' indicates that all the simple and composite Bezier curves
         are drawn as lines.  The thickness of the lines depends on the
         value of the "thick" attribute of the <respath> element.

      *  'off' indicates that all the simple and composite Bezier curves
         are drawn as filled areas.

   thick - Applicable only if the value of the "stroke" attribute equals
           'on'.  Optional if applicable.

      The thickness of the lines in the path resource.

      The value of the attribute represents an integer between 1 and 64
      (inclusive).

      The thickness is in pixels.

      The default value is '8'.






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      The value of the attribute is a string containing between one and
      two decimal characters (inclusive).  Each decimal character of the
      string is in the range from '0' to '9' (U+0030 DIGIT ZERO to
      U+0039 DIGIT NINE, inclusive).  The string does not contain any
      leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         thick='1'
         thick='64'
         thick='9'

         Examples of refused values:
         thick=''
         thick='-9'
         thick='80'
         thick='+9'
         thick='9.5'

   close - Applicable only if the value of the "stroke" attribute equals
           'on'.  Optional if applicable.

      Whether to close all the simple and composite Bezier curves
      contained in the plane on which the path resource is based.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'on' indicates that all the simple and composite Bezier curves
         are closed.

      *  'off' indicates that none of the simple and composite Bezier
         curves are closed.

      The default value is 'off'.








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   fill - Applicable only if the value of the "stroke" attribute equals
          'off'.  Optional if applicable.

      The rule used to determine the filled areas in the path resource.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'non-zero' indicates that the non-zero winding rule is used.

      *  'even-odd' indicates that the even-odd fill rule is used.

      The default value is 'non-zero'.

   spread - Mandatory

      Whether the apparent part of the plane is spread when mapped to
      the path resource.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'on' indicates that the apparent part of the plane is mapped to
         the path resource, without maintaining its original
         proportions, such that the apparent part of the plane covers
         the entire width and height of the path resource.

      *  'off' indicates that the apparent part of the plane is mapped
         to the path resource, maintaining its original proportions,
         such that the apparent part of the plane covers either the
         entire width or the entire height of the path resource.  Any
         remaining parts of the path resource that are not covered by
         the apparent part of the plane are fully transparent.  The
         placement of the apparent part of the plane in the path
         resource depends on the value of the "adjust" attribute of the
         <respath> element.







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   adjust - Applicable only if the value of the "spread" attribute
            equals 'off'.  Optional if applicable.

      The adjustment of the apparent part of the plane in the path
      resource.

      The value of the attribute represents an integer between -100 and
      100 (inclusive).

      The adjustment is applied, either horizontally or vertically, as
      follows:

      *  An adjustment of -100 corresponds to the LT placement, where
         the apparent part of the plane is placed so that its left or
         top edge matches the left or top edge of the path resource.

      *  An adjustment of 0 corresponds to the central placement, where
         the apparent part of the plane is centered vertically or
         horizontally in the path resource.

      *  An adjustment of 100 corresponds to the RB placement, where the
         apparent part of the plane is placed so that its right or
         bottom edge matches the right or bottom edge of the path
         resource.

      *  An adjustment between -100 and 0 (exclusive) corresponds to a
         proportional placement, where the apparent part of the plane is
         placed according to the absolute value of the adjustment,
         starting from the central placement and moving towards the LT
         placement.  For instance, an adjustment of -25 corresponds to a
         placement where the apparent part of the plane is placed one-
         quarter of the way from the central placement towards the LT
         placement.

      *  An adjustment between 0 and 100 (exclusive) corresponds to a
         proportional placement, where the apparent part of the plane is
         placed according to the value of the adjustment, starting from
         the central placement and moving towards the RB placement.  For
         instance, an adjustment of 75 corresponds to a placement where
         the apparent part of the plane is placed three-quarters of the
         way from the central placement towards the RB placement.

      The default value is 0.

      The value of the attribute is a string in the 'pd' pattern where:
      'p' is a substring representing the sign of the adjustment; and
      'd' is a substring representing the absolute value of the
      adjustment.  The 'p' substring is either an empty string,



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      indicating that the value of the adjustment is greater than or
      equal to zero, or is the '-' (U+002D HYPHEN-MINUS) character.  The
      'd' substring contains between one and three decimal characters
      (inclusive).  Each decimal character of the 'd' substring is in
      the range from '0' to '9' (U+0033 DIGIT ZERO to U+0039 DIGIT NINE,
      inclusive).  The 'd' substring does not contain any leading '0'
      (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), and '.'  (U+002E FULL STOP).

         Examples of accepted values:
         adjust='0'
         adjust='-100'
         adjust='100'
         adjust='-25'
         adjust='75'

         Examples of refused values:
         adjust=''
         adjust='-0'
         adjust='-120'
         adjust='150'
         adjust='-025'
         adjust='075'
         adjust='- 25'
         adjust='+100'
         adjust='-25.5'

   color - Optional

      The color of the path resource.

      The value of the attribute represents the levels of the R, G, and
      B components of the color.  The level of each component is
      represented using two hexadecimal digits.

      As stated in the Frogans slide design concepts (Section 4), the
      level of each one of the R, G, and B components is in the range
      from 00 (0) to ff (255).

      The default value is '#0000ff'.

      The value of the attribute is a string in the '#rrggbb' pattern
      where: '#' is the U+0013 NUMBER SIGN character; and 'rr', 'gg',
      and 'bb' are substrings representing respectively the R, G, and B
      components.  Each substring contains two hexadecimal characters.



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      Each hexadecimal character of each substring is in one of the
      following ranges: from '0' to '9' (U+0030 DIGIT ZERO to U+0039
      DIGIT NINE, inclusive), from 'A' to 'F' (U+0041 LATIN CAPITAL
      LETTER A to U+0046 LATIN CAPITAL LETTER F, inclusive), from 'a' to
      'f' (U+0061 LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F,
      inclusive).

      As a result, the value of the attribute does not contain any white
      space characters defined in Section 6.

         Examples of accepted values:
         color='#0000ff'
         color='#004698'
         color='#001c46'
         color='#ffbf00'
         color='#Ffbf00'
         color='#FFBF00'

         Examples of refused values:
         color=''
         color='ffbf00'
         color='#'
         color='#ffbf'
         color='# ffbf00'
         color='#ffbf 00'
         color='#0ffbf00'
         color='#00f'
























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7.12.  Adding Layers - <layer> Element

   The <layer> element defines a layer to be added to the Frogans slide.

   The <layer> element is a child either of the <frogans-fsdl> element
   (see Section 6.1) or of a <button> element (see Section 7.13).  The
   <layer> element does not contain any children.  It does not contain
   text characters.

   As stated in the Frogans slide design concepts (Section 4):

   -  If the <layer> element is a child of the <frogans-fsdl> element,
      then the layer is intended to be included directly in the Frogans
      slide.

   -  If the <layer> element is a child of the <button> element, then
      the layer is intended to be used for assembling a button.

   -  The layer is added on top of any other layers defined previously
      in the FSDL document.

   -  The foundation of the layer is a prepared resource, which can be
      either an image, pixels, draw, path, text, or merge resource (see
      respectively the <resimage> element in Section 7.2, the
      <respixels> element in Section 7.3, the <resdraw> element in
      Section 7.4, the <respath> element in Section 7.5, the <restext>
      element in Section 7.7, and the <resmerge> element in
      Section 7.11).

   The layer is identified using a component identifier (Section 6)
   which is determined by the value of the "layerid" attribute of the
   <layer> element.

   The layer can be included in the lead representation, the vignette
   representation, or both representations of the Frogans slide,
   depending on the value of the "leapout" attribute of the <layer>
   element.  The values of the other attributes of the <layer> element
   are applicable to the representations of the Frogans slide in which
   the layer is included.

   The prepared resource used as the foundation of the layer is referred
   to using a component identifier which is determined by the value of
   the "resref" attribute of the <layer> element.

   The size, in pixels, of the layer on the Frogans slide rendering
   canvas depends on the size, in pixels, of the prepared resource.

   The alignment and position of the layer on the Frogans slide



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   rendering canvas depend on the values of the "align" and "pos"
   attributes of the <layer> element.

   The following optional transformations are applied successively to
   the resource:

   *  flip, depending on the value of the "flip" attribute in the
      <layer> element

   *  filter, depending on the value of the "filterref" attribute in the
      <layer> element

   *  relief, depending on the value of the "reliefref" attribute in the
      <layer> element

   *  blur, depending on the value of the "blur" attribute in the
      <layer> element

   *  rotation, depending on the value of the "angle" attribute in the
      <layer> element

   *  sharpness, depending on the value of the "sharpness" attribute in
      the <layer> element

   *  opacity, depending on the value of the "opacity" attribute in the
      <layer> element

   The transformations are applied to a copy of the prepared resource,
   which is used for the layer only.  As a result, if the prepared
   resource is to be used as the foundation of other layers defined
   subsequently in the FSDL document, then the transformations for the
   layer do not apply to the other layers.

   The layer is combined into the Frogans slide rendering canvas in a
   way that depends on the value of the "combine" attribute of the
   <layer> element.

   A shadow can be added underneath the layer, depending on the value of
   the "shadowref" attribute of the <layer> element.

   If the layer is to be used for assembling a button, then the
   visibility of the layer in the button depends on the value of the
   "visible" attribute of the <layer> element.

   If the value of the "visible" attribute of a <layer> element is not
   equal to 'always', then the only possible value of the "combine"
   attribute is 'clip'.




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   The reactivity of the layer depends on the value of the "reactivity"
   attribute of the <layer> element.

   The <layer> element has the following attributes:

   layerid - Mandatory

      The identifier of the layer.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      As a result, the value cannot have been utilized previously in the
      FSDL document as a component identifier.

         Examples of accepted values:
         layerid='foo1'
         layerid='Foo1'
         layerid='foo2'
         layerid='foo_1'

         Examples of refused values:
         layerid=''
         layerid='foo-1'
         layerid='foo/1'
         layerid='foo.1'
         layerid='foo 1'
         layerid='foo1,foo2'

   leapout - Mandatory

      The way the layer leaps out in the Frogans slide.

      The value of the attribute belongs to a set of named values.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'all' indicates that the layer is included in all
         representations of the Frogans slide, i.e. in both the lead and
         the vignette representations.

      *  'lead' indicates that the layer is included in the lead
         representation only.

      *  'vignette' indicates that the layer is included in the vignette
         representation only.



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      If the <layer> element is a child of a <button> element, then the
      value of the attribute is 'lead'.

   resref - Mandatory

      The identifier referencing the resource used as the foundation of
      the layer.

      The value of the attribute is a component identifier.  The value
      is compliant with the rules presented in Section 6.

      The value of the attribute has been utilized previously in the
      FSDL document as a component identifier for one of the following
      resource elements: <resimage> (see Section 7.2), <respixels> (see
      Section 7.3), <resdraw> (see Section 7.4), <respath> (see
      Section 7.5), <restext> (see Section 7.7), or <resmerge> (see
      Section 7.11).

         Examples of accepted values:
         resref='foo1'
         resref='Foo1'
         resref='foo2'
         resref='foo_1'

         Examples of refused values:
         resref=''
         resref='foo-1'
         resref='foo/1'
         resref='foo.1'
         resref='foo 1'
         resref='foo1,foo2'

   align - Optional

      The way the resource used as the foundation of the layer is
      aligned relative to the position of the layer on the Frogans slide
      rendering canvas.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'left-top' indicates that the resource is aligned in a way such
         that the top-left corner of the resource, as determined before
         any rotation or blur effect is applied, coincides with the



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         position of the layer.

      *  'left-middle' indicates that the resource is aligned in a way
         such that the point half-way between the top-left and bottom-
         left corners of the resource, as determined before any rotation
         or blur effect is applied, coincides with the position of the
         layer.

      *  'left-bottom' indicates that the resource is aligned in a way
         such that the bottom-left corner of the resource, as determined
         before any rotation or blur effect is applied, coincides with
         the position of the layer.

      *  'center-top' indicates that the resource is aligned in a way
         such that the point half-way between the top-left and top-right
         corners of the resource, as determined before any rotation or
         blur effect is applied, coincides with the position of the
         layer.

      *  'center-middle' indicates that the resource is aligned in a way
         such that the vertical and horizontal center of the resource,
         as determined before any rotation or blur effect is applied,
         coincides with the position of the layer.

      *  'center-bottom' indicates that the resource is aligned in a way
         such that the point half-way between the bottom-left and
         bottom-right corners of the resource, as determined before any
         rotation or blur effect is applied, coincides with the position
         of the layer.

      *  'right-top' indicates that the resource is aligned in a way
         such that the top-right corner of the resource, as determined
         before any rotation or blur effect is applied, coincides with
         the position of the layer.

      *  'right-middle' indicates that the resource is aligned in a way
         such that the point half-way between the top-right and bottom-
         right corners of the resource, as determined before any
         rotation or blur effect is applied, coincides with the position
         of the layer.

      *  'right-bottom' indicates that the resource is aligned in a way
         such that the bottom-right corner of the resource, as
         determined before any rotation or blur effect is applied,
         coincides with the position of the layer.






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      The default value is 'center-middle'.

      During the rendering of the Frogans slide on the Frogans slide
      rendering canvas, when determining, in pixels, the points half-way
      between two corners of the resource, as well as the vertical and
      horizontal center of the resource, non-integer values are rounded
      down, i.e. towards the top-left corner of the resource.

   pos - Mandatory

      The position of the layer on the Frogans slide rendering canvas.

      The value of the attribute represents the x and y coordinates, in
      pixels, of the position of the layer on the Frogans slide
      rendering canvas.

      The x coordinate is an integer between -640 and 1,280 (inclusive).
      The y coordinate is an integer between -480 and 960 (inclusive).

      The value of the attribute is a string in the 'px,qy' pattern
      where: ',' is the U+002C COMMA character; 'p' and 'q' are
      substrings representing respectively the sign of the x and the y
      coordinates; and 'x' and 'y' are substrings representing
      respectively the absolute value of the x and the y coordinates.
      The 'p' substring is either an empty string, indicating that the
      value of the x coordinate is greater than or equal to zero, or is
      the '-' (U+002D HYPHEN-MINUS) character.  The 'x' substring
      contains between one and four decimal characters (inclusive).  The
      'q' substring is either an empty string, indicating that the value
      of the y coordinate is greater than or equal to zero, or is the
      '-' (U+002D HYPHEN-MINUS) character.  The 'y' substring contains
      between one and three decimal characters (inclusive).  Each
      decimal character of the 'x' and 'y' substrings is in the range
      from '0' to '9' (U+0033 DIGIT ZERO to U+0039 DIGIT NINE,
      inclusive).  The 'x' and 'y' substrings do not contain any leading
      '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), and '.'  (U+002E FULL STOP).

         Examples of accepted values:
         pos='500,300'
         pos='1050,300'
         pos='-90,300'
         pos='500,630'





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         pos='500,-110'

         Examples of refused values:
         pos=''
         pos='-0,300'
         pos='2000,300'
         pos='-900,300'
         pos='500'
         pos='500 300'
         pos='0500,300'
         pos='500, 300'
         pos='+500,300'
         pos='500.5,300'

   flip - Optional

      The flip effect applied to the resource used as the foundation of
      the layer.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'none' indicates that the resource is not flipped, i.e. the
         resource is not modified.

      *  'xdir' indicates that the resource is flipped in the x
         direction (i.e. horizontally), along the vertical axis.

      *  'ydir' indicates that the resource is flipped in the y
         direction (i.e. vertically), along the horizontal axis.

      *  'xydir' indicates that the resource is flipped in both the x
         direction (i.e. horizontally) and the y direction (i.e.
         vertically), respectively along the vertical and horizontal
         axes.

      The default value is 'none'.

   filterref - Optional

      The identifier referencing the filter applied to the resource used
      as the foundation of the layer.





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      The value of the attribute is either an empty string, or it is a
      component identifier.  In the latter case, the value is compliant
      with the rules presented in Section 6.

      If the value is an empty string, then no filter is applied to the
      resource.

      If the value is a component identifier, then it has been utilized
      previously in the FSDL document as a component identifier for a
      <setfilter> element (see Section 7.8).

      The default value is '' (the empty string).

         Examples of accepted values:
         filterref=''
         filterref='foo1'
         filterref='Foo1'
         filterref='foo2'
         filterref='foo_1'

         Examples of refused values:
         filterref='foo-1'
         filterref='foo/1'
         filterref='foo.1'
         filterref='foo 1'
         filterref='foo1,foo2'

      For more information on the process to filter a resource, see
      Appendix B.7.

   reliefref - Optional

      The identifier referencing the relief effect applied to the
      resource used as the foundation of the layer.

      The value of the attribute is either an empty string, or it is a
      component identifier.  In the latter case, the value is compliant
      with the rules presented in Section 6.

      If the value is an empty string, then no relief effect is applied
      to the resource.

      If the value is a component identifier, then it has been utilized
      previously in the FSDL document as a component identifier for a
      <setrelief> element (see Section 7.9).

      The default value is '' (the empty string).




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         Examples of accepted values:
         reliefref=''
         reliefref='foo1'
         reliefref='Foo1'
         reliefref='foo2'
         reliefref='foo_1'

         Examples of refused values:
         reliefref='foo-1'
         reliefref='foo/1'
         reliefref='foo.1'
         reliefref='foo 1'
         reliefref='foo1,foo2'

      For more information on the process to apply reliefs to a
      resource, see Appendix B.8.

   blur - Optional

      The blur effect applied to the resource used as the foundation of
      the layer.

      The value of the attribute represents the x and y radiuses of the
      blur effect.

      The x and y radiuses are integers between 0 and 32 (inclusive).

      An x radius of 0 in conjunction with a y radius of 0 corresponds
      to no blur effect.

      The layer includes all pixels, resulting from the blur effect,
      that extend beyond the edges of the resource.

      The default value is '0,0'.

      The value of the attribute is a string in the 'xradius,yradius'
      pattern where: ',' is the U+002C COMMA character; and 'xradius'
      and 'yradius' are substrings representing respectively the x
      radius and the y radius of the layer.  Each substring contains
      between one and two decimal characters (inclusive).  Each decimal
      character of the substring is in the range from '0' to '9' (U+0033
      DIGIT ZERO to U+0039 DIGIT NINE, inclusive).  The substring does
      not contain any leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).



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         Examples of accepted values:
         blur='0,0'
         blur='32,32'
         blur='5,0'
         blur='0,5'
         blur='5,32'

         Examples of refused values:
         blur=''
         blur='5,44'
         blur='5'
         blur='5 32'
         blur='05,32'
         blur='5, 32'
         blur='+5,32'
         blur='5,-32'
         blur='5.5,32'

      For more information on the process to blur a resource, see
      Appendix B.9.

   angle - Optional

      The angle of rotation, in degrees, applied to the resource used as
      the foundation of the layer.

      The value of the attribute represents an integer between -180 and
      180 (inclusive).

      The rotation is applied as follows:

      *  An angle between -180 and -1 (inclusive) corresponds to
         counterclockwise rotation.

      *  An angle of 0 corresponds to no rotation, i.e. the resource is
         not modified.

      *  An angle between 1 and 180 (inclusive) corresponds to clockwise
         rotation.

      The default value is 0.

      The value of the attribute is a string in the 'pn' pattern where:
      'p' is a substring representing the sign of the angle; and 'n' is
      a substring representing the absolute value of the angle.  The 'p'
      substring is either an empty string, indicating that the value of
      the angle is greater than or equal to zero, or is the '-' (U+002D
      HYPHEN-MINUS) character.  The 'n' substring contains between one



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      and three decimal characters (inclusive).  Each decimal character
      of the 'n' substring is in the range from '0' to '9' (U+0033 DIGIT
      ZERO to U+0039 DIGIT NINE, inclusive).  The 'n' substring does not
      contain any leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), and '.'  (U+002E FULL STOP).

         Examples of accepted values:
         angle='0'
         angle='-180'
         angle='180'
         angle='-45'
         angle='90'

         Examples of refused values:
         angle=''
         angle='-0'
         angle='-240'
         angle='360'
         angle='-045'
         angle='090'
         angle='- 45'
         angle='+90'
         angle='-45.5'

      For more information on the process to rotate a resource, see
      Appendix B.10.

   sharpness - Optional

      The sharpness effect applied to the resource used as the
      foundation of the layer.

      The value of the attribute represents an integer between 0 and 8
      (inclusive).

      A sharpness of 0 corresponds to no sharpness effect.

      The default value is 0.

      The value of the attribute is a string containing one decimal
      character.  The decimal character of the string is in the range
      from '0' to '8' (U+0030 DIGIT ZERO to U+0038 DIGIT EIGHT,
      inclusive).





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      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         sharpness='0'
         sharpness='8'
         sharpness='5'

         Examples of refused values:
         sharpness=''
         sharpness='9'
         sharpness='+5'
         sharpness='-5'
         sharpness='5.5'

      For more information on the process to sharpen a resource, see
      Appendix B.11.

   opacity - Optional

      The opacity effect applied to the resource used as the foundation
      of the layer.

      The value of the attribute represents an integer between 0 and 100
      (inclusive).

      The opacity effect is applied as follows:

      *  An opacity of 0 corresponds to an opacity effect where the
         resource becomes fully transparent.

      *  An opacity of 100 corresponds to no opacity effect, i.e. the
         resource is not modified.

      *  An opacity between 0 and 100 (exclusive) corresponds to an
         opacity effect where the A component (transparency) of each
         visible pixel in the resource is reduced in proportion to the
         opacity.  For instance, an opacity of 75 corresponds to
         reducing the A component (transparency) of each visible pixel
         in the resource to three-quarters of the its value.

      As a result, the opacity effect does not increase the A component
      (transparency) of any pixel in the resource.

      The default value is '100'.




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      The value of the attribute is a string containing between one and
      three decimal characters (inclusive).  Each decimal character of
      the string is in the range from '0' to '9' (U+0030 DIGIT ZERO to
      U+0039 DIGIT NINE, inclusive).  The string does not contain any
      leading '0' (U+0033 DIGIT ZERO) characters.

      As a result, the value of the attribute does not contain any of
      the following characters: white space characters defined in
      Section 6, '+' (U+002B PLUS SIGN), '-' (U+002D HYPHEN-MINUS), and
      '.'  (U+002E FULL STOP).

         Examples of accepted values:
         opacity='100'
         opacity='0'
         opacity='75'

         Examples of refused values:
         opacity=''
         opacity='-25'
         opacity='150'
         opacity='075'
         opacity='+75'
         opacity='75.5'

   combine - Mandatory

      The way the layer is combined into the Frogans slide rendering
      canvas.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'add' indicates that the layer is added into the Frogans slide
         rendering canvas.  This way of combining can modify both the A
         component (transparency) and the R, G, and B components (color)
         of pixels of the Frogans slide rendering canvas.

      *  'clip' indicates that the layer is clipped into the Frogans
         slide rendering canvas.  This way of combining can modify the
         R, G, and B components (color) of pixels in the Frogans slide
         rendering canvas.  It cannot modify the transparency (A
         component) of any pixels of the Frogans slide rendering canvas.





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      *  'cutout' indicates that the layer is cut out from the Frogans
         slide rendering canvas.  This way of combining can modify the A
         component (transparency) of pixels of the Frogans slide
         rendering canvas.  It cannot modify the R, G, and B components
         (color) of any pixels of the Frogans slide rendering canvas.

      *  'inter' indicates that the layer is intersected with the
         Frogans slide rendering canvas.  This way of combining can
         modify the A component (transparency) of pixels of the Frogans
         slide rendering canvas.  It cannot modify the R, G, and B
         components (color) of any pixels of the Frogans slide rendering
         canvas.

      As a result, if the layer is the first layer defined in the FSDL
      document and the value is not equal to 'add', then the layer is
      not visible in the Frogans slide.

      For more information on the process to combine layers, see
      Appendix B.12.

   shadowref - Optional

      The identifier referencing the shadow added underneath the layer.

      The value of the attribute is either an empty string, or it is a
      component identifier.  In the latter case, the value is compliant
      with the rules presented in Section 6.

      If the value is an empty string, then no shadow is added
      underneath the layer.

      If the value is a component identifier, then it has been utilized
      previously in the FSDL document as a component identifier for a
      <setshadow> element (see Section 7.10).

      The default value is '' (the empty string).

         Examples of accepted values:
         shadowref=''
         shadowref='foo1'
         shadowref='Foo1'
         shadowref='foo2'
         shadowref='foo_1'

         Examples of refused values:
         shadowref='foo-1'





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         shadowref='foo/1'
         shadowref='foo.1'
         shadowref='foo 1'
         shadowref='foo1,foo2'

      For more information on the process to apply shadows underneath a
      layer, see Appendix B.13.

   visible -  Applicable only if the <layer> element is a child element
              of a <button> element.  Mandatory if applicable.

      The visibility of the layer of the button.

      The attribute is based on a string set which represents the
      possible values of the attribute.

      The value of the attribute is case-sensitive.

      The value can be:

      *  'always' indicates that the layer of the button is always
         visible, i.e. whether or not the button is selected.

      *  'not-selected' indicates that the layer of the button is
         visible only if the button is not selected.

      *  'selected' indicates that the layer of the button is visible
         only if the button is selected.

   reactivity - Optional

      The reactivity of the layer of the button.

      The default value is '#7f'.

      The value of the attribute is a string in the '#aa' pattern where:
      '#' is the U+0013 NUMBER SIGN character; and 'aa' is a substring
      representing the A component.  The substring contains two
      hexadecimal characters.  Each hexadecimal character of the
      substring is in one of the following ranges: from '0' to '9'
      (U+0030 DIGIT ZERO to U+0039 DIGIT NINE, inclusive), from 'A' to
      'F' (U+0041 LATIN CAPITAL LETTER A to U+0046 LATIN CAPITAL LETTER
      F, inclusive), from 'a' to 'f' (U+0061 LATIN SMALL LETTER A to
      U+0066 LATIN SMALL LETTER F, inclusive).

      As a result, the value of the attribute does not contain any white
      space characters defined in Section 6.




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         Examples of accepted values:
         reactivity='#ff'
         reactivity='#00'
         reactivity='#bf'
         reactivity='#Bf'
         reactivity='#BF'

         Examples of refused values:
         reactivity=''
         reactivity='bf'
         reactivity='#'
         reactivity='#b'
         reactivity='# bf'
         reactivity='#b f'
         reactivity='#0bf'




































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