You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
131 lines
6.3 KiB
131 lines
6.3 KiB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/unicode.doc:36 -->
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
|
<title>About Unicode</title>
|
|
<style type="text/css"><!--
|
|
fn { margin-left: 1cm; text-indent: -1cm; }
|
|
a:link { color: #004faf; text-decoration: none }
|
|
a:visited { color: #672967; text-decoration: none }
|
|
body { background: #ffffff; color: black; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
|
|
<table border="0" cellpadding="0" cellspacing="0" width="100%">
|
|
<tr bgcolor="#E5E5E5">
|
|
<td valign=center>
|
|
<a href="index.html">
|
|
<font color="#004faf">Home</font></a>
|
|
| <a href="classes.html">
|
|
<font color="#004faf">All Classes</font></a>
|
|
| <a href="mainclasses.html">
|
|
<font color="#004faf">Main Classes</font></a>
|
|
| <a href="annotated.html">
|
|
<font color="#004faf">Annotated</font></a>
|
|
| <a href="groups.html">
|
|
<font color="#004faf">Grouped Classes</font></a>
|
|
| <a href="functions.html">
|
|
<font color="#004faf">Functions</font></a>
|
|
</td>
|
|
<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>About Unicode</h1>
|
|
|
|
|
|
<p> Unicode is a multi-byte character set, portable across all major
|
|
computing platforms and with decent coverage over most of the world.
|
|
It is also single-locale; it includes no code pages or other
|
|
complexities that make software harder to write and test. There is no
|
|
competing character set that's reasonably multiplatform. For these
|
|
reasons, Trolltech uses Unicode as the native character set for TQt
|
|
(since version 2.0).
|
|
<p> <h2> Information about Unicode on the web.
|
|
</h2>
|
|
<a name="1"></a><p> The <a href="http://www.unicode.org">Unicode Consortium</a>
|
|
has a number of documents available, including
|
|
<p> <ul>
|
|
<p> <li> <a href="http://www.unicode.org/unicode/standard/principles.html">A technical introduction to Unicode</a>
|
|
<li> <a href="http://www.unicode.org/unicode/standard/standard.html">The home page for the standard</a>
|
|
<p> </ul>
|
|
<p> <h2> The Standard
|
|
</h2>
|
|
<a name="2"></a><p> The current version of the standard is 3.2
|
|
<p> <ul>
|
|
<p> <li> <a href="http://www.amazon.com/exec/obidos/ASIN/0201616335/trolltech/t">The Unicode Standard, version 3.2.</a> See also
|
|
<a href="http://www.unicode.org/unicode/standard/versions/">its home page.</a>
|
|
<li> <a href="http://www.amazon.com/exec/obidos/ASIN/0201473459/trolltech/t">The Unicode Standard, version 2.0.</a> See also the
|
|
<a href="http://www.unicode.org/unicode/reports/tr8.html">2.1
|
|
update</a> and
|
|
<a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html#Unicode">2.1.9 the 2.1.9 data files</a> at www.unicode.org.
|
|
<p> </ul>
|
|
<p> <h2> Unicode in TQt
|
|
</h2>
|
|
<a name="3"></a><p> In TQt, and in most applications that use TQt, most or all user-visible
|
|
strings are stored using Unicode. TQt provides:
|
|
<p> <ul>
|
|
<p> <li> Translation to/from legacy encodings for file I/O: see <a href="tqtextcodec.html">TQTextCodec</a> and <a href="tqtextstream.html">TQTextStream</a>.
|
|
<li> Translation from Input Methods and 8-bit keyboard input.
|
|
<li> Translation to legacy character sets for on-screen display.
|
|
<li> A string class, <a href="tqstring.html">TQString</a>, that stores Unicode characters, with
|
|
support for migrating from C strings including fast (cached)
|
|
translation to and from US-ASCII, and all the usual string
|
|
operations.
|
|
<li> Unicode-aware widgets where appropriate.
|
|
<li> Unicode support detection on Windows, so that TQt provides Unicode
|
|
even on Windows platforms that do not support it natively.
|
|
<p> </ul>
|
|
<p> To fully benefit from Unicode, we recommend using <a href="tqstring.html">TQString</a> for storing
|
|
all user-visible strings, and performing all text file I/O using
|
|
<a href="tqtextstream.html">TQTextStream</a>. Use <a href="tqkeyevent.html#text">TQKeyEvent::text</a>() for keyboard input in any custom
|
|
widgets you write; it does not make much difference for slow typists
|
|
in Western Europe or North America, but for fast typists or people
|
|
using special input methods using text() is beneficial.
|
|
<p> All the function arguments in TQt that may be user-visible strings, <a href="tqlabel.html#setText">TQLabel::setText</a>() and a many others, take <tt>const TQString &</tt>s.
|
|
<a href="tqstring.html">TQString</a> provides implicit casting from <tt>const char *</tt>
|
|
so that things like
|
|
<pre>
|
|
myLabel->setText( "Hello, Dolly!" );
|
|
</pre>
|
|
|
|
will work. There is also a function, <a href="tqobject.html#tr">TQObject::tr</a>(), that provides
|
|
translation support, like this:
|
|
<pre>
|
|
myLabel->setText( tr("Hello, Dolly!") );
|
|
</pre>
|
|
|
|
<p> tr() (simplifying somewhat) maps from <tt>const char *</tt> to a
|
|
Unicode string, and uses installable <a href="tqtranslator.html">TQTranslator</a> objects to do the
|
|
mapping.
|
|
<p> TQt provides a number of built-in <a href="tqtextcodec.html">TQTextCodec</a> classes, that is,
|
|
classes that know how to translate between Unicode and legacy
|
|
encodings to support programs that must talk to other programs or
|
|
read/write files in legacy file formats.
|
|
<p> By default, conversion to/from <tt>const char *</tt> uses a
|
|
locale-dependent codec. However, applications can easily find codecs
|
|
for other locales, and set any open file or network connection to use
|
|
a special codec. It is also possible to install new codecs, for
|
|
encodings that the built-in ones do not support. (At the time of
|
|
writing, Vietnamese/VISCII is one such example.)
|
|
<p> Since US-ASCII and ISO-8859-1 are so common, there are also especially
|
|
fast functions for mapping to and from them. For example, to open an
|
|
application's icon one might do this:
|
|
<pre>
|
|
<a href="tqfile.html">TQFile</a> f( TQString::<a href="tqstring.html#fromLatin1">fromLatin1</a>("appicon.png") );
|
|
</pre>
|
|
|
|
<p> Regarding output, TQt will do a best-effort conversion from
|
|
Unicode to whatever encoding the system and fonts provide.
|
|
Depending on operating system, locale, font availability and TQt's
|
|
support for the characters used, this conversion may be good or bad.
|
|
We will extend this in upcoming versions, with emphasis on the most
|
|
common locales first.
|
|
<p>
|
|
<!-- eof -->
|
|
<p><address><hr><div align=center>
|
|
<table width=100% cellspacing=0 border=0><tr>
|
|
<td>Copyright © 2007
|
|
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
|
|
<td align=right><div align=right>TQt 3.3.8</div>
|
|
</table></div></address></body>
|
|
</html>
|