docs/doxygen/overviews/internationalization.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        internationalization.h
   3 // Purpose:     topic overview
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows licence
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10
  11 @page overview_i18n Internationalization
  12
  13 @tableofcontents
  14
  15 Although internationalization of an application (i18n for short) involves far
  16 more than just translating its text messages to another message - date, time
  17 and currency formats need changing too, some languages are written left to
  18 right and others right to left, character encoding may differ and many other
  19 things may need changing too - it is a necessary first step. wxWidgets provides
  20 facilities for message translation with its wxLocale class and is itself fully
  21 translated into several languages. Please consult wxWidgets home page for the
  22 most up-to-date translations - and if you translate it into one of the
  23 languages not done yet, your translations would be gratefully accepted for
  24 inclusion into future versions of the library!
  25
  26 The wxWidgets approach to i18n closely follows the GNU gettext package.
  27 wxWidgets uses the message catalogs which are binary compatible with gettext
  28 catalogs and this allows to use all of the programs in this package to work
  29 with them. But note that no additional libraries are needed during run-time,
  30 however, so you have only the message catalogs to distribute and nothing else.
  31
  32 During program development you will need the gettext package for working with
  33 message catalogs. @b Warning: gettext versions @< 0.10 are known to be buggy,
  34 so you should find a later version of it!
  35
  36 There are two kinds of message catalogs: source catalogs which are text files
  37 with extension .po and binary catalogs which are created from the source ones
  38 with @e msgfmt program (part of gettext package) and have the extension .mo.
  39 Only the binary files are needed during program execution.
  40
  41 Translating your application involves several steps:
  42
  43 @li Translating the strings in the program text using wxGetTranslation or
  44     equivalently the @c _() macro.
  45 @li Extracting the strings to be translated from the program: this uses the
  46     work done in the previous step because @c xgettext program used for string
  47     extraction recognises the standard @c _() as well as (using its @c -k
  48     option) our wxGetTranslation and extracts all strings inside the calls to
  49     these functions. Alternatively, you may use @c -a option to extract all the
  50     strings, but it will usually result in many strings being found which don't
  51     have to be translated at all. This will create a text message catalog - a
  52     .po file.
  53 @li Translating the strings extracted in the previous step to other
  54     language(s). It involves editing the .po file.
  55 @li Compiling the .po file into .mo file to be used by the program.
  56 @li Installing the .mo files with your application in the appropriate location
  57     for the target system (@see overview_i18n_mofiles).
  58 @li Setting the appropriate locale in your program to use the strings for the
  59     given language: see wxLocale.
  60
  61
  62 @section overview_i18n_mofiles Installing translation catalogs
  63
  64 The .mo files with compiled catalogs must be included with the application.
  65 By default, wxFileTranslationsLoader is used to load them from files installed
  66 alongside the application (although you could use wxResourceTranslationsLoader
  67 or some custom loader too).
  68
  69 The files are expected to be in the resources directory (as returned by
  70 wxStandardPaths::GetLocalizedResourcesDir(wxStandardPaths::ResourceCat_Messages).
  71 If the message catalogs are not installed in this default location you may
  72 explicitly use wxFileTranslationsLoader::AddCatalogLookupPathPrefix() to still
  73 allow wxWidgets to find them, but it is recommended to use the default
  74 locations when possible.
  75
  76 Depending on the platform, the default location differs. On Windows, it is
  77 alongside the executable. On Unix, translations are expected to be in
  78 "$prefix/share/locale". On OS X, application bundle's @em Resources subdirectory
  79 is used.
  80
  81 In all cases, translations are searched for in subdirectories named using the
  82 languages codes from ISO 639. The .mo file(s) should be located either directly
  83 in that directory or in LC_MESSAGES subdirectory. On OS X, ".lproj" extension
  84 is used for the per-languages Resources subdirectories.
  85
  86 Here's how an app would typically install the files on Unix:
  87 @code
  88 /usr/bin/myapp
  89 /usr/share/locale/de/LC_MESSAGES/myapp.mo
  90 /usr/share/locale/fr/LC_MESSAGES/myapp.mo
  91 @endcode
  92 And on OS X:
  93 @code
  94 MyApp.app/Contents/MacOS/MyApp
  95 MyApp.app/Contents/Resources/de.lproj/myapp.mo
  96 MyApp.app/Contents/Resources/fr.lproj/myapp.mo
  97 @endcode
  98 And on Windows:
  99 @code
 100 C:\Program Files\MyApp\myapp.exe
 101 C:\Program Files\MyApp\de\myapp.mo
 102 C:\Program Files\MyApp\fr\myapp.mo
 103 @endcode
 104 It is of course possible to use the Unix layout everywhere instead.
 105
 106
 107 @section overview_i18n_menuaccel Translating Menu Accelerators
 108
 109 If you translate the accelerator modifier names (Ctrl, Alt and Shift) in your
 110 menu labels, you may find the accelerators no longer work. In your message
 111 catalogs, you need to provide individual translations of these modifiers from
 112 their lower case names (ctrl, alt, shift) so that the wxWidgets accelerator
 113 code can recognise them even when translated. wxWidgets does not provide
 114 translations for all of these currently. wxWidgets does not yet handle
 115 translated special key names such as Backspace, End, Insert, etc.
 116
 117
 118 @see
 119 @li The gettext Manual: http://www.gnu.org/software/gettext/manual/gettext.html
 120 @li @ref overview_nonenglish - It focuses on handling charsets related problems.
 121 @li @ref page_samples_internat - Shows you how all this looks in practice.
 122
 123 */