diff options
Diffstat (limited to 'doc/html/unicode.html')
| -rw-r--r-- | doc/html/unicode.html | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/doc/html/unicode.html b/doc/html/unicode.html new file mode 100644 index 000000000..6b7873c62 --- /dev/null +++ b/doc/html/unicode.html @@ -0,0 +1,130 @@ +<!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="qtextcodec.html">TQTextCodec</a> and <a href="qtextstream.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="qstring.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="qstring.html">TQString</a> for storing +all user-visible strings, and performing all text file I/O using +<a href="qtextstream.html">TQTextStream</a>. Use <a href="qkeyevent.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="qlabel.html#setText">TQLabel::setText</a>() and a many others, take <tt>const TQString &</tt>s. +<a href="qstring.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="qobject.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="qtranslator.html">TQTranslator</a> objects to do the +mapping. +<p> TQt provides a number of built-in <a href="qtextcodec.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="qfile.html">TQFile</a> f( TQString::<a href="qstring.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> |