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6<title>Internationalization with Qt</title>
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19 <a href="index.html">
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21 | <a href="classes.html">
22<font color="#004faf">All&nbsp;Classes</font></a>
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32<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Internationalization with Qt</h1>
33
34
35<p> <!-- index internationalization --><a name="internationalization"></a><!-- index i18n --><a name="i18n"></a>
36<p> The internationalization of an application is the process of making
37the application usable by people in countries other than one's own.
38<p> <!-- toc -->
39<ul>
40<li><a href="#1"> Step by Step
41</a>
42<ul>
43<li><a href="#1-1"> Use QString for all User-visible Text
44</a>
45<li><a href="#1-2"> Use tr() for all Literal Text
46</a>
47<li><a href="#1-3"> Use QKeySequence() for Accelerator Values
48</a>
49<li><a href="#1-4"> Use QString::arg() for Dynamic Text
50</a>
51<li><a href="#1-5"> Produce Translations
52</a>
53<li><a href="#1-6"> Support for Encodings
54</a>
55<li><a href="#1-7"> Localize
56</a>
57</ul>
58<li><a href="#2"> Dynamic Translation
59</a>
60<li><a href="#3"> System Support
61</a>
62<ul>
63<li><a href="#3-1"> Unix/X11
64</a>
65<li><a href="#3-2"> Windows
66</a>
67</ul>
68<li><a href="#4"> Note about Locales on X11
69</a>
70<li><a href="#5"> Relevant Qt Classes
71</a>
72</ul>
73<!-- endtoc -->
74
75<p> In some cases internationalization is simple, for example, making a US
76application accessible to Australian or British users may require
77little more than a few spelling corrections. But to make a US
78application usable by Japanese users, or a Korean application usable
79by German users, will require that the software operate not only in
80different languages, but use different input techniques, character
81encodings and presentation conventions.
82<p> Qt tries to make internationalization as painless as possible for
83developers. All input widgets and text drawing methods in Qt offer
84built-in support for all supported languages. The built-in font engine
85is capable of correctly and attractively rendering text that contains
86characters from a variety of different writing systems at the same
87time.
88<p> Qt supports most languages in use today, in particular:
89<ul>
90<li> All East Asian languages (Chinese, Japanese and Korean)
91<li> All Western languages (using Latin script)
92<li> Arabic
93<li> Cyrillic languages (Russian)
94<li> Greek
95<li> Hebrew
96<li> Thai and Lao
97<li> All scripts in Unicode 3.2 that do not require special processing
98</ul>
99<p> On Windows NT/2000/XP and Unix/X11 with Xft (client side font support)
100the following languages are also supported:
101<ul>
102<li> Bengali
103<li> Devanagari
104<li> Dhivehi (Thaana)
105<li> Gujarati
106<li> Gurmukhi
107<li> Kannada
108<li> Khmer
109<li> Malayalam (X11 only)
110<li> Myanmar (X11 only)
111<li> Syriac
112<li> Tamil
113<li> Telugu
114<li> Tibetan (X11 only)
115</ul>
116<p> Many of these writing systems exhibit special features:
117<p> <ul>
118<p> <li> <b>Special line breaking behavior.</b> Some of the Asian languages are
119written without spaces between words. Line breaking can occur either
120after every character (with exceptions) as in Chinese, Japanese and
121Korean, or after logical word boundaries as in Thai.
122<p> <li> <b>Bidirectional writing.</b> Arabic and Hebrew are written from right to
123left, except for numbers and embedded English text which is written
124left to right. The exact behavior is defined in the <a href="http://www.unicode.org/unicode/reports/tr9/">Unicode Technical Report
125#9</a>.
126<p> <li> <b>Non spacing or diacritical marks</b> (accents or umlauts in European
127languages). Some languages such as Vietnamese make extensive use of
128these marks and some characters can have more than one mark at the
129same time to clarify pronunciation.
130<p> <li> <b>Ligatures.</b> In special contexts, some pairs of characters get
131replaced by a combined glyph forming a ligature. Common examples are
132the fl and fi ligatures used in typesetting US and European books.
133<p> </ul>
134<p> Qt tries to take care of all the special features listed above. You
135usually don't have to worry about these features so long as you use
136Qt's input widgets (e.g. <a href="qlineedit.html">QLineEdit</a>, <a href="qtextedit.html">QTextEdit</a>, and derived classes)
137and Qt's display widgets (e.g. <a href="qlabel.html">QLabel</a>).
138<p> Support for these writing systems is transparent to the programmer
139and completely encapsulated in Qt's text engine. This means that you
140don't need to have any knowledge about the writing system used in a
141particular language, except for the following small points:
142<ul>
143<p> <li> <a href="qpainter.html#drawText">QPainter::drawText</a>( int x, int y, const <a href="qstring.html">QString</a> &str ) will always
144draw the string with it's left edge at the position specified with
145the x, y parameters. This will usually give you left aligned strings.
146Arabic and Hebrew application strings are usually right
147aligned, so for these languages use the version of drawText() that
148takes a <a href="qrect.html">QRect</a> since this will align in accordance with the language.
149<p> <li> When you write your own text input controls, use <a href="qfontmetrics.html#charWidth">QFontMetrics::charWidth</a>() to determine the width of a character in a
150string. In some languages (e.g. Arabic or languages from the Indian
151subcontinent), the width and shape of a glyph changes depending on the
152surrounding characters. Writing input controls usually requires a
153certain knowledge of the scripts it is going to be used in. Usually
154the easiest way is to subclass <a href="qlineedit.html">QLineEdit</a> or <a href="qtextedit.html">QTextEdit</a>.
155<p> </ul>
156<p> The following sections give some information on the status
157of the internationalization (i18n) support in Qt.
158<p> See also the <a href="linguist-manual.html">Qt Linguist</a> manual.
159<p> <h2> Step by Step
160</h2>
161<a name="1"></a><p> Writing multi-platform international software with Qt is a gentle,
162incremental process. Your software can become internationalized in
163the following stages:
164<p> <h3> Use <a href="qstring.html">QString</a> for all User-visible Text
165</h3>
166<a name="1-1"></a><p> Since QString uses the Unicode encoding internally, every
167language in the world can be processed transparently using
168familiar text processing operations. Also, since all Qt
169functions that present text to the user take a QString as a
170parameter, there is no char* to QString conversion overhead.
171<p> Strings that are in "programmer space" (such as <a href="qobject.html">QObject</a> names
172and file format texts) need not use QString; the traditional
173char* or the <a href="qcstring.html">QCString</a> class will suffice.
174<p> You're unlikely to notice that you are using Unicode;
175QString, and <a href="qchar.html">QChar</a> are just like easier versions of the crude
176const char* and char from traditional C.
177<p> <h3> Use tr() for all Literal Text
178</h3>
179<a name="1-2"></a><p> Wherever your program uses <tt>"quoted text"</tt> for text that will
180be presented to the user, ensure that it is processed by the <a href="qapplication.html#translate">QApplication::translate</a>() function. Essentially all that is necessary
181to achieve this is to use <a href="qobject.html#tr">QObject::tr</a>(). For example, assuming the
182<tt>LoginWidget</tt> is a subclass of QWidget:
183<p> <pre>
184 LoginWidget::LoginWidget()
185 {
186 <a href="qlabel.html">QLabel</a> *label = new <a href="qlabel.html">QLabel</a>( tr("Password:"), this );
187 ...
188 }
189</pre>
190
191<p> This accounts for 99% of the user-visible strings you're likely to
192write.
193<p> If the quoted text is not in a member function of a
194<a href="qobject.html">QObject</a> subclass, use either the tr() function of an
195appropriate class, or the <a href="qapplication.html#translate">QApplication::translate</a>() function
196directly:
197<p> <pre>
198 void some_global_function( LoginWidget *logwid )
199 {
200 <a href="qlabel.html">QLabel</a> *label = new <a href="qlabel.html">QLabel</a>(
201 LoginWidget::tr("Password:"), logwid );
202 }
203
204 void same_global_function( LoginWidget *logwid )
205 {
206 <a href="qlabel.html">QLabel</a> *label = new <a href="qlabel.html">QLabel</a>(
207 qApp-&gt;<a href="qapplication.html#translate">translate</a>("LoginWidget", "Password:"),
208 logwid );
209 }
210</pre>
211
212<p> If you need to have translatable text completely
213outside a function, there are two macros to help: QT_TR_NOOP()
214and QT_TRANSLATE_NOOP(). They merely mark the text for
215extraction by the <em>lupdate</em> utility described below.
216The macros expand to just the text (without the context).
217<p> Example of QT_TR_NOOP():
218<pre>
219 QString FriendlyConversation::greeting( int greet_type )
220 {
221 static const char* greeting_strings[] = {
222 QT_TR_NOOP( "Hello" ),
223 QT_TR_NOOP( "Goodbye" )
224 };
225 return tr( greeting_strings[greet_type] );
226 }
227</pre>
228
229<p> Example of QT_TRANSLATE_NOOP():
230<pre>
231 static const char* greeting_strings[] = {
232 QT_TRANSLATE_NOOP( "FriendlyConversation", "Hello" ),
233 QT_TRANSLATE_NOOP( "FriendlyConversation", "Goodbye" )
234 };
235
236 QString FriendlyConversation::greeting( int greet_type )
237 {
238 return tr( greeting_strings[greet_type] );
239 }
240
241 <a href="qstring.html">QString</a> global_greeting( int greet_type )
242 {
243 return qApp-&gt;<a href="qapplication.html#translate">translate</a>( "FriendlyConversation",
244 greeting_strings[greet_type] );
245 }
246</pre>
247
248<p> If you disable the const char* to <a href="qstring.html">QString</a> automatic conversion
249by compiling your software with the macro QT_NO_CAST_ASCII
250defined, you'll be very likely to catch any strings you are
251missing. See <a href="qstring.html#fromLatin1">QString::fromLatin1</a>() for more information.
252Disabling the conversion can make programming a bit cumbersome.
253<p> If your source language uses characters outside Latin-1, you
254might find <a href="qobject.html#trUtf8">QObject::trUtf8</a>() more convenient than
255<a href="qobject.html#tr">QObject::tr</a>(), as tr() depends on the
256<a href="qapplication.html#defaultCodec">QApplication::defaultCodec</a>(), which makes it more fragile than
257QObject::trUtf8().
258<p> <h3> Use <a href="qkeysequence.html">QKeySequence</a>() for Accelerator Values
259</h3>
260<a name="1-3"></a><p> Accelerator values such as Ctrl+Q or Alt+F need to be
261translated too. If you hardcode <tt>CTRL+Key_Q</tt> for "Quit" in
262your application, translators won't be able to override
263it. The correct idiom is
264<p> <pre>
265 <a href="qpopupmenu.html">QPopupMenu</a> *file = new <a href="qpopupmenu.html">QPopupMenu</a>( this );
266 file-&gt;<a href="qmenudata.html#insertItem">insertItem</a>( tr("&amp;Quit"), this, SLOT(quit()),
267 QKeySequence(tr("Ctrl+Q", "File|Quit")) );
268</pre>
269
270<p> <h3> Use <a href="qstring.html#arg">QString::arg</a>() for Dynamic Text
271</h3>
272<a name="1-4"></a><p> The QString::arg() functions offer a simple means for substituting
273arguments:
274<pre>
275 void FileCopier::showProgress( int done, int total,
276 const <a href="qstring.html">QString</a>&amp; current_file )
277 {
278 label.setText( tr("%1 of %2 files copied.\nCopying: %3")
279 .arg(done)
280 .arg(total)
281 .arg(current_file) );
282 }
283</pre>
284
285<p> In some languages the order of arguments may need to change, and this
286can easily be achieved by changing the order of the % arguments. For
287example:
288<pre>
289 <a href="qstring.html">QString</a> s1 = "%1 of %2 files copied. Copying: %3";
290 <a href="qstring.html">QString</a> s2 = "Kopierer nu %3. Av totalt %2 filer er %1 kopiert.";
291
292 <a href="qapplication.html#qDebug">qDebug</a>( s1.<a href="qstring.html#arg">arg</a>(5).arg(10).arg("somefile.txt").ascii() );
293 <a href="qapplication.html#qDebug">qDebug</a>( s2.<a href="qstring.html#arg">arg</a>(5).arg(10).arg("somefile.txt").ascii() );
294</pre>
295
296<p> produces the correct output in English and Norwegian:
297<pre>
2985 of 10 files copied. Copying: somefile.txt
299Kopierer nu somefile.txt. Av totalt 10 filer er 5 kopiert.
300</pre>
301
302<p> <h3> Produce Translations
303</h3>
304<a name="1-5"></a><p> Once you are using tr() throughout an application, you can start
305producing translations of the user-visible text in your program.
306<p> <a href="linguist-manual.html">Qt Linguist</a>'s manual provides
307further information about Qt's translation tools, <em>Qt Linguist</em>, <em>lupdate</em> and <em>lrelease</em>.
308<p> Translation of a Qt application is a three-step process:
309<p> <ol type=1>
310<p> <li> Run <em>lupdate</em> to extract translatable text from the C++ source
311code of the Qt application, resulting in a message file for
312translators (a <tt>.ts</tt> file). The utility recognizes the tr() construct
313and the QT_*_NOOP macros described above and produces <tt>.ts</tt> files
314(usually one per language).
315<p> <li> Provide translations for the source texts in the <tt>.ts</tt> file, using
316<em>Qt Linguist</em>. Since <tt>.ts</tt> files are in XML format, you can also
317edit them by hand.
318<p> <li> Run <em>lrelease</em> to obtain a light-weight message file (a <tt>.qm</tt>
319file) from the <tt>.ts</tt> file, suitable only for end use. Think of the <tt>.ts</tt> files as "source files", and <tt>.qm</tt> files as "object files". The
320translator edits the <tt>.ts</tt> files, but the users of your application
321only need the <tt>.qm</tt> files. Both kinds of files are platform and
322locale independent.
323<p> </ol>
324<p> Typically, you will repeat these steps for every release of your
325application. The <em>lupdate</em> utility does its best to reuse the
326translations from previous releases.
327<p> Before you run <em>lupdate</em>, you should prepare a project file. Here's
328an example project file (<tt>.pro</tt> file):
329<p> <pre>
330 HEADERS = funnydialog.h \
331 wackywidget.h
332 SOURCES = funnydialog.cpp \
333 main.cpp \
334 wackywidget.cpp
335 FORMS = fancybox.ui
336 TRANSLATIONS = superapp_dk.ts \
337 superapp_fi.ts \
338 superapp_no.ts \
339 superapp_se.ts
340</pre>
341
342<p> When you run <em>lupdate</em> or <em>lrelease</em>, you must give the name of the
343project file as a command-line argument.
344<p> In this example, four exotic languages are supported: Danish, Finnish,
345Norwegian and Swedish. If you use <a href="qmake-manual.html">qmake</a>, you usually don't need an extra project
346file for <em>lupdate</em>; your <tt>qmake</tt> project file will work fine once
347you add the <tt>TRANSLATIONS</tt> entry.
348<p> In your application, you must <a href="qtranslator.html#load">QTranslator::load</a>() the translation
349files appropriate for the user's language, and install them using <a href="qapplication.html#installTranslator">QApplication::installTranslator</a>().
350<p> If you have been using the old Qt tools (<tt>findtr</tt>, <tt>msg2qm</tt> and <tt>mergetr</tt>), you can use <em>qm2ts</em> to convert your old <tt>.qm</tt> files.
351<p> <em>linguist</em>, <em>lupdate</em> and <em>lrelease</em> are installed in the <tt>bin</tt>
352subdirectory of the base directory Qt is installed into. Click Help|Manual
353in <em>Qt Linguist</em> to access the user's manual; it contains a tutorial
354to get you started.
355<p> While these utilities offer a convenient way to create <tt>.qm</tt> files,
356any system that writes <tt>.qm</tt> files is sufficient. You could make an
357application that adds translations to a <a href="qtranslator.html">QTranslator</a> with
358<a href="qtranslator.html#insert">QTranslator::insert</a>() and then writes a <tt>.qm</tt> file with
359<a href="qtranslator.html#save">QTranslator::save</a>(). This way the translations can come from any
360source you choose.
361<p> <a name="qt-itself"></a>
362Qt itself contains over 400 strings that will also need to be
363translated into the languages that you are targeting. You will find
364translation files for French and German in <tt>$QTDIR/translations</tt> as
365well as a template for translating to other languages. (This directory
366also contains some additional unsupported translations which may be
367useful.)
368<p> Typically, your application's main() function will look like this:
369<pre>
370 int main( int argc, char **argv )
371 {
372 <a href="qapplication.html">QApplication</a> app( argc, argv );
373
374 // translation file for Qt
375 <a href="qtranslator.html">QTranslator</a> qt( 0 );
376 qt.<a href="qtranslator.html#load">load</a>( QString( "qt_" ) + QTextCodec::locale(), "." );
377 app.<a href="qapplication.html#installTranslator">installTranslator</a>( &amp;qt );
378
379 // translation file for application strings
380 <a href="qtranslator.html">QTranslator</a> myapp( 0 );
381 myapp.<a href="qtranslator.html#load">load</a>( QString( "myapp_" ) + QTextCodec::locale(), "." );
382 app.<a href="qapplication.html#installTranslator">installTranslator</a>( &amp;myapp );
383
384 ...
385
386 return app.<a href="qapplication.html#exec">exec</a>();
387 }
388</pre>
389
390<p> <h3> Support for Encodings
391</h3>
392<a name="1-6"></a><p> The <a href="qtextcodec.html">QTextCodec</a> class and the facilities in <a href="qtextstream.html">QTextStream</a> make it easy to
393support many input and output encodings for your users' data. When an
394application starts, the locale of the machine will determine the 8-bit
395encoding used when dealing with 8-bit data: such as for font
396selection, text display, 8-bit text I/O and character input.
397<p> The application may occasionally require encodings other than the
398default local 8-bit encoding. For example, an application in a
399Cyrillic KOI8-R locale (the de-facto standard locale in Russia) might
400need to output Cyrillic in the ISO 8859-5 encoding. Code for this
401would be:
402<p> <pre>
403 <a href="qstring.html">QString</a> string = ...; // some Unicode text
404
405 <a href="qtextcodec.html">QTextCodec</a>* codec = QTextCodec::<a href="qtextcodec.html#codecForName">codecForName</a>( "ISO 8859-5" );
406 <a href="qcstring.html">QCString</a> encoded_string = codec-&gt;<a href="qtextcodec.html#fromUnicode">fromUnicode</a>( string );
407
408 ...; // use encoded_string in 8-bit operations
409</pre>
410
411<p> For converting Unicode to local 8-bit encodings, a shortcut is
412available: the <a href="qstring.html#local8Bit">local8Bit</a>() method
413of <a href="qstring.html">QString</a> returns such 8-bit data. Another useful shortcut is the
414<a href="qstring.html#utf8">utf8</a>() method, which returns text in the
4158-bit UTF-8 encoding: this perfectly preserves Unicode information
416while looking like plain US-ASCII if the text is wholly US-ASCII.
417<p> For converting the other way, there are the <a href="qstring.html#fromUtf8">QString::fromUtf8</a>() and
418<a href="qstring.html#fromLocal8Bit">QString::fromLocal8Bit</a>() convenience functions, or the general code,
419demonstrated by this conversion from ISO 8859-5 Cyrillic to Unicode
420conversion:
421<p> <pre>
422 <a href="qcstring.html">QCString</a> encoded_string = ...; // Some ISO 8859-5 encoded text.
423
424 <a href="qtextcodec.html">QTextCodec</a>* codec = QTextCodec::<a href="qtextcodec.html#codecForName">codecForName</a>("ISO 8859-5");
425 <a href="qstring.html">QString</a> string = codec-&gt;<a href="qtextcodec.html#toUnicode">toUnicode</a>(encoded_string);
426
427 ...; // Use string in all of Qt's QString operations.
428</pre>
429
430<p> Ideally Unicode I/O should be used as this maximizes the portability
431of documents between users around the world, but in reality it is
432useful to support all the appropriate encodings that your users will
433need to process existing documents. In general, Unicode (UTF-16 or
434UTF-8) is best for information transferred between arbitrary people,
435while within a language or national group, a local standard is often
436more appropriate. The most important encoding to support is the one
437returned by <a href="qtextcodec.html#codecForLocale">QTextCodec::codecForLocale</a>(), as this is the one the user
438is most likely to need for communicating with other people and
439applications (this is the codec used by local8Bit()).
440<p> Qt supports most of the more frequently used encodings natively. For a
441complete list of supported encodings see the <a href="qtextcodec.html">QTextCodec</a>
442documentation.
443<p> In some cases and for less frequently used encodings it may be
444necessary to write your own <a href="qtextcodec.html">QTextCodec</a> subclass. Depending on the
445urgency, it may be useful to contact Trolltech technical support or
446ask on the <tt>qt-interest</tt> mailing list to see if someone else is
447already working on supporting the encoding. A useful interim measure
448can be to use the <a href="qtextcodec.html#loadCharmapFile">QTextCodec::loadCharmapFile</a>() function to build a
449data-driven codec, although this approach has a memory and speed
450penalty, especially with dynamically loaded libraries. For details of
451writing your own QTextCodec, see the main QTextCodec class
452documentation.
453<p> <!-- index localization --><a name="localization"></a>
454<p> <h3> Localize
455</h3>
456<a name="1-7"></a><p> Localization is the process of adapting to local conventions, for
457example presenting dates and times using the locally preferred
458formats. Such localizations can be accomplished using appropriate tr()
459strings.
460<p> <pre>
461 void Clock::setTime(const <a href="qtime.html">QTime</a>&amp; t)
462 {
463 if ( tr("AMPM") == "AMPM" ) {
464 // 12-hour clock
465 } else {
466 // 24-hour clock
467 }
468 }
469</pre>
470
471<p> In the example, for the US we would leave the translation of "AMPM" as
472it is and thereby use the 12-hour clock branch; but in Europe we would
473translate it as something else (anything else, e.g. "EU") and this
474will make the code use the 24-hour clock branch.
475<p> Localizing images is not recommended. Choose clear icons that are
476appropriate for all localities, rather than relying on local puns or
477stretched metaphors.
478<p> <h2> Dynamic Translation
479</h2>
480<a name="2"></a><p> Some applications, such as Qt Linguist, must be able to support changes
481to the user's language settings while they are still running. To make
482widgets aware of changes to the system language, implement a public
483slot called <tt>languageChange()</tt> in each widget that needs to be notified.
484In this slot, you should update the text displayed by widgets using the
485<a href="qobject.html#tr">QObject::tr</a>(){tr()} function in the usual way; for example:
486<p> <pre>
487void MyWidget::languageChange()
488{
489 titleLabel-&gt;setText(tr("Document Title"));
490 ...
491 okPushButton-&gt;setText(tr("&amp;OK"));
492}
493</pre>
494
495<p> The default event handler for <a href="qwidget.html">QWidget</a> subclasses responds to the
496<a href="qevent.html#Type-enum">LanguageChange</a> event, and will call this slot
497when necessary; other application components can also connect signals
498to this slot to force widgets to update themselves.
499<p> <h2> System Support
500</h2>
501<a name="3"></a><p> Some of the operating systems and windowing systems that Qt runs on
502only have limited support for Unicode. The level of support available
503in the underlying system has some influence on the support that Qt can
504provide on those platforms, although in general Qt applications need
505not be too concerned with platform-specific limitations.
506<p> <h3> Unix/X11
507</h3>
508<a name="3-1"></a><p> <ul>
509<li> Locale-oriented fonts and input methods. Qt hides these and
510provides Unicode input and output.
511<li> Filesystem conventions such as
512<a href="http://www.ietf.org/rfc/rfc2279.txt">UTF-8</a>
513are under development
514in some Unix variants. All Qt file functions allow Unicode,
515but convert filenames to the local 8-bit encoding, as
516this is the Unix convention
517(see <a href="qfile.html#setEncodingFunction">QFile::setEncodingFunction</a>()
518to explore alternative encodings).
519<li> File I/O defaults to the local 8-bit encoding,
520with Unicode options in <a href="qtextstream.html">QTextStream</a>.
521</ul>
522<p> <h3> Windows
523</h3>
524<a name="3-2"></a><p> <ul>
525<li> Qt provides full Unicode support, including input methods, fonts,
526clipboard, drag-and-drop and file names.
527<li> File I/O defaults to Latin-1, with Unicode options in QTextStream.
528Note that some Windows programs do not understand big-endian
529Unicode text files even though that is the order prescribed by
530the Unicode Standard in the absence of higher-level protocols.
531<li> Unlike programs written with MFC or plain winlib, Qt programs
532are portable between Windows 95/98 and Windows NT.
533<em>You do not need different binaries to support Unicode.</em>
534</ul>
535<p> <h2> Note about Locales on X11
536</h2>
537<a name="4"></a><p> Many Unix distributions contain only partial support for some locales.
538For example, if you have a <tt>/usr/share/locale/ja_JP.EUC</tt> directory,
539this does not necessarily mean you can display Japanese text; you also
540need JIS encoded fonts (or Unicode fonts), and the <tt>/usr/share/locale/ja_JP.EUC</tt> directory needs to be complete. For best
541results, use complete locales from your system vendor.
542<p> <h2> Relevant Qt Classes
543</h2>
544<a name="5"></a><p> These classes are relevant to internationalizing Qt applications.
545
546<p><table width="100%">
547<tr bgcolor=#f0f0f0><td><b><a href="qbig5codec.html">QBig5Codec</a></b><td>Conversion to and from the Big5 encoding
548<tr bgcolor=#f0f0f0><td><b><a href="qeucjpcodec.html">QEucJpCodec</a></b><td>Conversion to and from EUC-JP character sets
549<tr bgcolor=#f0f0f0><td><b><a href="qeuckrcodec.html">QEucKrCodec</a></b><td>Conversion to and from EUC-KR character sets
550<tr bgcolor=#f0f0f0><td><b><a href="qgb18030codec.html">QGb18030Codec</a></b><td>Conversion to and from the Chinese GB18030/GBK/GB2312 encoding
551<tr bgcolor=#f0f0f0><td><b><a href="qgb2312codec.html">QGb2312Codec</a></b><td>Conversion to and from the Chinese GB2312 encoding
552<tr bgcolor=#f0f0f0><td><b><a href="qgbkcodec.html">QGbkCodec</a></b><td>Conversion to and from the Chinese GBK encoding
553<tr bgcolor=#f0f0f0><td><b><a href="qhebrewcodec.html">QHebrewCodec</a></b><td>Conversion to and from visually ordered Hebrew
554<tr bgcolor=#f0f0f0><td><b><a href="qjiscodec.html">QJisCodec</a></b><td>Conversion to and from JIS character sets
555<tr bgcolor=#f0f0f0><td><b><a href="qsjiscodec.html">QSjisCodec</a></b><td>Conversion to and from Shift-JIS
556<tr bgcolor=#f0f0f0><td><b><a href="qtextcodec.html">QTextCodec</a></b><td>Conversion between text encodings
557<tr bgcolor=#f0f0f0><td><b><a href="qtextdecoder.html">QTextDecoder</a></b><td>State-based decoder
558<tr bgcolor=#f0f0f0><td><b><a href="qtextencoder.html">QTextEncoder</a></b><td>State-based encoder
559<tr bgcolor=#f0f0f0><td><b><a href="qtranslator.html">QTranslator</a></b><td>Internationalization support for text output
560<tr bgcolor=#f0f0f0><td><b><a href="qtranslatormessage.html">QTranslatorMessage</a></b><td>Translator message and its properties
561<tr bgcolor=#f0f0f0><td><b><a href="qtsciicodec.html">QTsciiCodec</a></b><td>Conversion to and from the Tamil TSCII encoding
562</table>
563<!-- eof -->
564<p><address><hr><div align=center>
565<table width=100% cellspacing=0 border=0><tr>
566<td>Copyright &copy; 2007
567<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
568<td align=right><div align=right>Qt 3.3.8</div>
569</table></div></address></body>
570</html>
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