     START-INFO-DIR-ENTRY
     * gcompris: (gcompris.info).   Educational games for small children.
     END-INFO-DIR-ENTRY

This is the documentation of GCompris. It contains both a user manual and implementation detail suitable for developpers.

Copyright 2001 Free Software Foundation, Inc.

Permission is  granted to copy,  distribute and/or modify  this document under the  terms of the GNU  Free Documentation License,  Version 1.1 or any later  version published  by the Free  Software Foundation;  with no Invariant  Sections, no Front-Cover  Texts and  no Back-Cover  Texts.  A copy  of the  license  is included  in  the section  entitled "GNU  Free Documentation License".

Gcompris
********

Introduction
************

Why GCompris
============

GCompris intent is to provide a central location where a user can find different kind of small educational content called 'boards'.

Today there is already a lot of free software that provides a small education content. Unfortunatly, it is difficult to track, intall and use them because they do not evolve at the same speed and offer their own user interface.

GCompris aims to provide a unique user interface that gives access to different boards.

GCompris is part of the GNU project.

User Manual
***********

Control
=======

All controls are designed to be user friendly for the youngest. For this reason, GCompris does not stick to the Gnome standard for user interfaces. GCompris is controlled with a mouse. It cannot be used without a mouse or a pointer device.

Gameplay
========

Main window
-----------

Once started, GCompris presents a graphical view that includes from top to bottom:

 1. Boards icon list

     Each icon represent a board. When you move the mouse over them, they are highlighted and the name and description of the board is displayed in the board description area.

 2. Boards description area

     Display a small description of what the highlited board icon is about. Note that the descriptions are internationalized which means translated in a target language (See Internationalization Issues for more information on Internationalization).

 3. Control bar: The control bar is always present in GCompris. This icons are contextual which means that when an icon is not meaningfull in a specific context, it is simply not displayed.

     The control bar contains the icons from left to right:

      1. Help: In some case, a board can be too complex to be described in the Board description area. In this case this will provide access to the additionnal instructions.

      2. Level: Some boards provide different level. The number of levels is board dependant.

      3. OK: Some boards do not automatically detect that the child has finish the given task. Clicking here is similar to entering RET on the keyboard and thus the RET key is a shortcut.

      4. End: End the current board if any, otherwise Exit GCompris. When entered at the board menu level, it will create a dialog window to confirm the Exit of GCompris.

      5. About: Display the about box for gcompris with the version number, the author, the licence and links to online resources.

      6. Configure: Display the configuration box for gcompris. Configuration can be done at gcompris level when no boards is selected. If a board is selected, it can provides configuration options. Configuration is persistent and saved in the gnome file in the user home directory under '.gcompris'.

Starting a game
---------------

At the menu level, just click on the board icon.

Ending a game
-------------

In the control bar, select the right most icon.

Internationalization Issues
***************************

Is my language supported?
=========================

GCompris is internationalized and today it already supports different languages.

To be sure you're one is done, you can check the 'po' directory found within GCompris source package. If your language is translated, it will contain a file of the form fr.po where fr means French.

If your language is not supported, you can provide help by doing it for GCompris. For instructions, contact the official project maintainer.

How to translate GCompris for my language
=========================================

First, add your locale name in ALL_LINGUAS in configure.in recreate the configure file with autoconf

Second, generate a fresh or new file gcompris.pot by using the command cd gcompris/po make update-po

Now, get the file gcompris.pot, copy it to a file named XX.po where XX stands for your locale like 'it' for Italian.

Read the file, it contains all the english text found in GCompris. You just need to write your translation in the empty area after each Engish sentence.

To check your translation, you must install gcompris with make install at the top level.

Then, send the translation to the GCompris maintainer. He/She will add it into the next official release.

Developers Guide
****************

Why adding boards to GCompris
=============================

If you have a game idea that you feel suitable for children, you can create a new project, let's call it gIdea. If you start from scratch, you will have to implement a menu, a status bar, user feedback mecanism and so on.

If gIdea is not a complex and huge program, it can be easier and faster for you to implement your gIdea as a GCompris board. This way, you benefit from all the current infrastucture and can focus only on your very Idea.

For the end user, it is also easier to have a unique interface to a bunch of different boards instead of having to install gIdea1 gIdea2 and so on.

It is not the intent of GCompris to becomes a new programming language. It is implemented in C and boards are implemented in C also. Boards and GCompris dynamically linked at runtime (plugins) which makes it possible to distribute new boards independently of the gcompris core.

Current implementation is based on the Gnome Canvas widget (see http://www.gnome.org documentations). The Gnome Canvas provides a high level widget that free programmers of bitmap manipulation when doing graphical application. In current implementation, it is not possible to write boards using another widget. If it appears that the Canvas is not powerfull enough, GCompris will have to be modified to support other widgets.

Another approach is to have smarter boards that can read data files and behaves accordingly. In this case we can envision a GCompris board editor that will let non programmer add content to GCompris. Since the target of GCompris is definitly teachers and educators, this option seems very promising. Note that following this track, the shape board already receives its data through an XML file.

How to add boards to GCompris
=============================

The whole picture
-----------------

GCompris API
------------

GCompris provides several sercices to boards developpers. These services are described in the file gcompris/gcompris.h

  * GnomeCanvasItem *gcompris_set_background(GnomeCanvasGroup *parent, gchar *file);

     Set the background image for your game. You can get help from gameutil.h to load the image.

  * void gcompris_bar_set_level (GcomprisGame *gcomprisGame);

     The user did fine and has to go to the next level. Before calling it, gcomprisGame->level must be updated by the board.

  * void gcompris_bar_set_timer (guint time);

     The timer is a progress bar that is usually used to inform the user of were he/she is in the board. This value must be in the range 0 to 'maxtimer' given with bar_set_maxtimer()

  * void bar_set_maxtimer (guint time);

     Set the max value of the progress bar.

     So when you create a board, you must include gcompris/plugin.h to have access to those methods (this is already included in gcompris/gcompris.h).

     plugin.h also define the BoardPlugin structure. It is the heart of GCompris. Each board creates its own BoardPlugin and give it back to Gcompris when called in the get_bplugin_info() entry point:

     BoardPlugin* *get_bplugin_info ();

     The BoardPlugin returned structure must contains callbacks to your implementation methods.

     The BoardPlugin structure must provide callbaks to at least:

  * void *GcomprisStartBoard     (GcomprisBoard *gcomprisBoard);

     This is called by GCompris when this board has been requested by the user

  * void *GcomprisEndBoard      (void);

     This is called by GCompris when the user clicked 'end' in the control bar.

Optionnaly, a GComprisGame structure can contains callbacks to:

  * gint *GcomprisKeyPress     (guint keyval);

     If the board wants to receive user keypress, it must provide this callback method. The keyval is not filtered and is returned as Gnome return it. Check the Gnome documentation to understand how to manipulate it.

  * void *GcomprisOK           (void);

     This method is called when the user click the 'OK' button in the control bar. It is a good practice to make the enter and return key behaves as the 'ok' button, but it may not be always appropriate. For this reason, it is the responsibility of the board implementation to do it.

  * void *GcomprisSetLevel     (guint level);

     This is called with the level requested by the user. You provide the maximum number of level you support in gcomprisGame->maxlevel. Gcompris will take care to call it only with a valid level value.

Example of duplicating an existing board to create your own
-----------------------------------------------------------

This describes all the steps required to add a new board to GCompris.

As an example, I describe here how I created the clock game.

 1. Copy an existing game (closest to your new board). cp algebra.c clockgame.c

 2. Edit src/boards/Makefile.am and add the file to the list of lib_LTLIBRARIES Then add at the end the entries for libclockgame_la_LDFLAGS, libclockgame_la_LIBADD and libclockgame_la_SOURCES. Look at examples in src/boards/Makefile.am to see how to do that.

 3. In clockgame.c replace all 'algebra' by 'clockgame'

 4. In clockgame.c set the proper information for the new game:

     if(g_strcasecmp(gcomprisBoard->type, "clockgame")==0)

     You must then create or copy the board description to the proper location

     cp boards/algebra.xml boards/clockgame.xml

     Then edit clockgame.xml with a proper description and icon. Set the icon file at the location given in clockgame.xml.

 5. In boards/Makefile.am add your file in the list. Respect the alphanumeric order. Same step in po/POTFILES.in

 6. make should compile everything fine.

 7. make install is mandatory or the icon won't be find at runtime.

 8. Now running gcompris should show up the new icon and you should be able to play the game you did copy. Now it's time to code the board in clockgame.c

 9. Update the po files:

     cd gcompris/po

     edit POTFILES.in and add src/clockgame.c)

     make

     make update-po

 10. Now you can add the translation in the po files.

 11. 'make' and then 'make install' will compile and install your translation.

GNU Free Documentation License
******************************

Version 1.1, March 2000

     Copyright © 2000 Free Software Foundation, Inc.
     59 Temple Place, Suite 330, Boston, MA  02111-1307, USA

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