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288 lines
10 KiB
288 lines
10 KiB
This file's purpose is to guide contributors and developers to help on the
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digiKam project.
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========================================================================
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10 golden rules for starting with open source
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========================================================================
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Before to contribute to digiKam project, please take a look to this link:
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http://schlitt.info/applications/blog/index.php?/archives/541-10-golden-rules-for-starting-with-open-source.html
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========================================================================
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Source code formatting:
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========================================================================
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Adhere to this style guide strictly while adding new code to digiKam or
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working on existing code.
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-------------------------------------------------------------------------
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* Indentation length
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-------------------------------------------------------------------------
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Indent with 4 spaces exactly.
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for eg:
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void function()
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{
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....int a; // 4 spaces from beginning
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....for (int i=0; i<10; i++) // 4 spaces from beginning
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....{ // 4 spaces from beginning
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........a = i; // 4 spaces from previous indent block
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Emacs by default will indent to 4 spaces
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vim users add this to you .vimrc
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set tabstop=4
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-------------------------------------------------------------------------
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* Tabs vs Spaces
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-------------------------------------------------------------------------
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Absolutely no tabs. Use a sensible editor which will convert tabs to spaces.
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This will reduce unnecessary changes in your cvs commits.
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Emacs by default will convert tab to spaces.
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For vim users, add this to your .vimrc
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set expandtab
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-------------------------------------------------------------------------
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* Line length
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-------------------------------------------------------------------------
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Line length should never exceed 80 chars (unless really necessary - these
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cases are rare). Having long lines greatly reduces readability of code
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-------------------------------------------------------------------------
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* Bracketing
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-------------------------------------------------------------------------
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In almost all cases, {} brackets should start on a newline and should be
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aligned with previous line (follow the indentation spaces). for eg.
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class A
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{ //new line
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...
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for (int i=0; i<10; i++)
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{ //new line
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if (a == foobar)
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{ //new line
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...
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}
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else
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{ // new line
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..
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}
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-------------------------------------------------------------------------
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* Positioning of Access modifiers
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-------------------------------------------------------------------------
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public, private, protected, public slots, ... should be aligned to the
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beginning of the line with no margin
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class A
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{
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public: // aligned to left
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...
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private slots: // aligned to left
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Follow a consistent order in defining these attributes. The recommended
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order is public, protected (functions), private (functions),
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signals, public slots, protected slots, private slots, private (variables)
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========================================================================
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Class, file and Variable names:
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========================================================================
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-------------------------------------------------------------------------
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* Class and filenames
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-------------------------------------------------------------------------
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- filenames should always be in lower-case
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- class names should match the filenames. Capitalize the first letter and
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other letters logically to improve readability
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-------------------------------------------------------------------------
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* Protected Member variables
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-------------------------------------------------------------------------
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- protected member variable names should always be of the form m_varName.
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- Captilize logically so that it becomes easy to read it. Do not capitalize
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the first letter after _ (Use m_varName not m_VarName)
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- variable names should be indicative of their functionality and also of
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the type they belong too if they are instances of qt widgets.
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for eg, QCheckBox* m_autoRotateCheckBox;
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-------------------------------------------------------------------------
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* Non-Member variables
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-------------------------------------------------------------------------
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- non-member variables should follow the same naming convention as the member
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variables, except for the leading m_
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-------------------------------------------------------------------------
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* Private Member variables
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-------------------------------------------------------------------------
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- private member variables must be stored in a d private container to reduce
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compilation time and improve binary compatibilty between digiKam components.
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See more informations how to use a 'd' private class at this url:
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http://developer.kde.org/policies/librarypolicy.html
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========================================================================
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Comments and Whitespace
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========================================================================
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Use whitespaces liberally to improve readability. Add blank lines between logical
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sections of the code.
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Comment as much as possible. Position comments at the beginning of the
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section/line you want to comment, NEVER at the end of the line
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// put your comments here
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a = (b == foobar) ? 1 : -1;
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a = (b == foobar) ? 1 : -1; // you are asking for trouble by putting comments here
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========================================================================
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Header files
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========================================================================
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- Add copyright to top of every file. Use the same header than others digiKam
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source code.
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- Double inclusion protection defines are all upper case letters and are
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composed of the classname and a H suffix separated by underscore
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#ifndef ANOTHERNICECLASS_H
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#define ANOTHERNICECLASS_H
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class AnotherNiceClass
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{
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...
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}
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#endif
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- Use forward declarations as much as possible.
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class QFileInfo;
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class A
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{
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....QFileInfo* m_fileInfo;
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========================================================================
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General recommendations
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========================================================================
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Please take a look into KDE contrib page tips before to write code/patches for
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digiKam project : http://techbase.kde.org/Contribute
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Use the same .cpp/.h header than the rest of digiKam project.
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Use a decent editor which does auto-indentation/syntax-highlighting for you.
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I personally use Emacs (Renchi) or Kdevelop (Gilles).
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There are excellent initializer scripts in the kdesdk
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package for xemacs and vim which can substantially increase your productivity.
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Just to give a taste of what i can do with emacs (and kdesdk):
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* automatically insert copyright (and ifdefs) in new files.
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* insertion of class function definitions for declared class
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functions in header with one keystroke
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* switch between header and declaration files with one keystroke
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* go to corresponding definition/declaration with one keystroke
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* tab completion of variable/function names already declared.
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========================================================================
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GDB Backtrace
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========================================================================
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If you found a context to crash digiKam, you can provide a backtrace using GDB debugger.
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digiKam need to be compiled with all debug info else the backtrace will not suitable.
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There is a configure option for that:
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# make -f Makefile.cvs
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# ./configure --enable-debug=full
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# make
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# su
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# make install.
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To make a backtrace with GDB use following command:
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# gdb digikam
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> run
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> ...
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> _crash here_
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> ...
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> bt
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> _the backtrace is here_
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> quit
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Post this backtrace at the right place (B.K.O or devel ML) for investigations by developers.
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========================================================================
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Memory leak
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========================================================================
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To check any memory leak problem in digiKam, valgrind is your friend (http://valgrind.org)
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Try this command line to use with valgrind :
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valgrind --tool=memcheck --leak-check=full --error-limit=no digikam
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========================================================================
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Profiling with cachegrind
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========================================================================
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Valgrind also includes a tool to find out in which parts of your code time is spent.
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valgrind --tool=callgrind digikam
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Profiling can be disabled at startup to limit the output to the code you are interested in.
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Start with
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valgrind --tool=callgrind --instr-atstart=no digikam
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and prepare the situation you want to profile. Then, in another console, start profiling with
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"callgrind_control -i on" and, after the situation has passed, request a profile dump with
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"callgrind_control -d".
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The resulting callgrind.out files need to be viewed with the kcachegrind program, e.g.:
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kcachegrind callgrind.out.16693.1
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=================================================================================
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API Documentation Validation, User Documentation Validation, Source Code Checking
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=================================================================================
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The following site check on a dayly basis for the a.m. errors:
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www.englishbreakfastnetwork.org/krazy/
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It can be very useful, in particular before major releases.
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Don't trust it blindly! Sometimes they propose too advanced modifications that are no compatible with the prevailant include files.
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========================================================================
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Usability issues
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========================================================================
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OpenUsability project has define default menu structure and keyboard shortcuts:
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http://wiki.openusability.org/guidelines/index.php/Appendices:Keyboard_Shortcuts
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========================================================================
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Generate API documentation
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========================================================================
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To generate API documentation, you need to install:
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- Doxygen program (http://www.doxygen.org).
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- Dot program (http://www.graphviz.org)
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Go to 'project' sub-folder and just run doxygen binary program. A new subfolder
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named 'api' will be create. Warning, this can take a while.
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