<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- /tmp/qt-4.2.1-harald-1161357942206/qt-x11-opensource-src-4.2.1/src/gui/image/qpicture.cpp -->
<head>
<title>Qt 4.2: QPictureIO Class Reference</title>
<link href="classic.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="left" valign="top" width="32"><a href="http://www.trolltech.com/products/qt"><img src="images/qt-logo.png" align="left" width="32" height="32" border="0" /></a></td>
<td width="1"> </td><td class="postheader" 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="groups.html"><font color="#004faf">Grouped Classes</font></a> · <a href="modules.html"><font color="#004faf">Modules</font></a> · <a href="functions.html"><font color="#004faf">Functions</font></a></td>
<td align="right" valign="top" width="230"><a href="http://www.trolltech.com"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></a></td></tr></table><h1 align="center">QPictureIO Class Reference<br /><sup><sup>[<a href="qtgui.html">QtGui</a> module]</sup></sup></h1>
<p>The QPictureIO class contains parameters for loading and saving pictures. <a href="#details">More...</a></p>
<pre> #include <QPictureIO></pre><ul>
<li><a href="qpictureio-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="public-functions"></a>
<h3>Public Functions</h3>
<ul>
<li><div class="fn"/><b><a href="qpictureio.html#QPictureIO">QPictureIO</a></b> ()</li>
<li><div class="fn"/><b><a href="qpictureio.html#QPictureIO-2">QPictureIO</a></b> ( QIODevice * <i>ioDevice</i>, const char * <i>format</i> )</li>
<li><div class="fn"/><b><a href="qpictureio.html#QPictureIO-3">QPictureIO</a></b> ( const QString & <i>fileName</i>, const char * <i>format</i> )</li>
<li><div class="fn"/><b><a href="qpictureio.html#dtor.QPictureIO">~QPictureIO</a></b> ()</li>
<li><div class="fn"/>QString <b><a href="qpictureio.html#description">description</a></b> () const</li>
<li><div class="fn"/>QString <b><a href="qpictureio.html#fileName">fileName</a></b> () const</li>
<li><div class="fn"/>const char * <b><a href="qpictureio.html#format">format</a></b> () const</li>
<li><div class="fn"/>float <b><a href="qpictureio.html#gamma">gamma</a></b> () const</li>
<li><div class="fn"/>QIODevice * <b><a href="qpictureio.html#ioDevice">ioDevice</a></b> () const</li>
<li><div class="fn"/>const char * <b><a href="qpictureio.html#parameters">parameters</a></b> () const</li>
<li><div class="fn"/>const QPicture & <b><a href="qpictureio.html#picture">picture</a></b> () const</li>
<li><div class="fn"/>int <b><a href="qpictureio.html#quality">quality</a></b> () const</li>
<li><div class="fn"/>bool <b><a href="qpictureio.html#read">read</a></b> ()</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setDescription">setDescription</a></b> ( const QString & <i>description</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setFileName">setFileName</a></b> ( const QString & <i>fileName</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setFormat">setFormat</a></b> ( const char * <i>format</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setGamma">setGamma</a></b> ( float <i>gamma</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setIODevice">setIODevice</a></b> ( QIODevice * <i>ioDevice</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setParameters">setParameters</a></b> ( const char * <i>parameters</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setPicture">setPicture</a></b> ( const QPicture & <i>picture</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setQuality">setQuality</a></b> ( int <i>q</i> )</li>
<li><div class="fn"/>void <b><a href="qpictureio.html#setStatus">setStatus</a></b> ( int <i>status</i> )</li>
<li><div class="fn"/>int <b><a href="qpictureio.html#status">status</a></b> () const</li>
<li><div class="fn"/>bool <b><a href="qpictureio.html#write">write</a></b> ()</li>
</ul>
<a name="static-public-members"></a>
<h3>Static Public Members</h3>
<ul>
<li><div class="fn"/>void <b><a href="qpictureio.html#defineIOHandler">defineIOHandler</a></b> ( const char * <i>format</i>, const char * <i>header</i>, const char * <i>flags</i>, picture_io_handler <i>readPicture</i>, picture_io_handler <i>writePicture</i> )</li>
<li><div class="fn"/>QList<QByteArray> <b><a href="qpictureio.html#inputFormats">inputFormats</a></b> ()</li>
<li><div class="fn"/>QList<QByteArray> <b><a href="qpictureio.html#outputFormats">outputFormats</a></b> ()</li>
<li><div class="fn"/>QByteArray <b><a href="qpictureio.html#pictureFormat">pictureFormat</a></b> ( const QString & <i>fileName</i> )</li>
<li><div class="fn"/>QByteArray <b><a href="qpictureio.html#pictureFormat-2">pictureFormat</a></b> ( QIODevice * <i>d</i> )</li>
</ul>
<a name="details"></a>
<hr />
<h2>Detailed Description</h2>
<p>The QPictureIO class contains parameters for loading and saving pictures.</p>
<p>QPictureIO contains a <a href="qiodevice.html">QIODevice</a> object that is used for picture data I/O. The programmer can install new picture file formats in addition to those that Qt provides.</p>
<p>You don't normally need to use this class; <a href="qpicture.html#load">QPicture::load</a>(), <a href="qpicture.html#save">QPicture::save</a>().</p>
<p>See also <a href="qpicture.html">QPicture</a>, <a href="qpixmap.html">QPixmap</a>, and <a href="qfile.html">QFile</a>.</p>
<hr />
<h2>Member Function Documentation</h2>
<h3 class="fn"><a name="QPictureIO"></a>QPictureIO::QPictureIO ()</h3>
<p>Constructs a <a href="qpictureio.html">QPictureIO</a> object with all parameters set to zero.</p>
<h3 class="fn"><a name="QPictureIO-2"></a>QPictureIO::QPictureIO ( <a href="qiodevice.html">QIODevice</a> * <i>ioDevice</i>, const char * <i>format</i> )</h3>
<p>Constructs a <a href="qpictureio.html">QPictureIO</a> object with the I/O device <i>ioDevice</i> and a <i>format</i> tag.</p>
<h3 class="fn"><a name="QPictureIO-3"></a>QPictureIO::QPictureIO ( const <a href="qstring.html">QString</a> & <i>fileName</i>, const char * <i>format</i> )</h3>
<p>Constructs a <a href="qpictureio.html">QPictureIO</a> object with the file name <i>fileName</i> and a <i>format</i> tag.</p>
<h3 class="fn"><a name="dtor.QPictureIO"></a>QPictureIO::~QPictureIO ()</h3>
<p>Destroys the object and all related data.</p>
<h3 class="fn"><a name="defineIOHandler"></a>void QPictureIO::defineIOHandler ( const char * <i>format</i>, const char * <i>header</i>, const char * <i>flags</i>, picture_io_handler <i>readPicture</i>, picture_io_handler <i>writePicture</i> ) <tt> [static]</tt></h3>
<p>Defines a picture I/O handler for the picture format called <i>format</i>, which is recognized using the regular expression defined in <i>header</i>, read using <i>readPicture</i> and written using <i>writePicture</i>.</p>
<p><i>flags</i> is a string of single-character flags for this format. The only flag defined currently is T (upper case), so the only legal value for <i>flags</i> are "T" and the empty string. The "T" flag means that the picture file is a text file, and Qt should treat all newline conventions as equivalent. (XPM files and some PPM files are text files for example.)</p>
<p><i>format</i> is used to select a handler to write a <a href="qpicture.html">QPicture</a>; <i>header</i> is used to select a handler to read an picture file.</p>
<p>If <i>readPicture</i> is a null pointer, the <a href="qpictureio.html">QPictureIO</a> will not be able to read pictures in <i>format</i>. If <i>writePicture</i> is a null pointer, the <a href="qpictureio.html">QPictureIO</a> will not be able to write pictures in <i>format</i>. If both are null, the <a href="qpictureio.html">QPictureIO</a> object is valid but useless.</p>
<p>Example:</p>
<pre> void readSVG(QPictureIO *picture)
{
<span class="comment">// read the picture using the picture->ioDevice()</span>
}
void writeSVG(QPictureIO *picture)
{
<span class="comment">// write the picture using the picture->ioDevice()</span>
}
<span class="comment">// add the SVG picture handler</span>
<span class="comment">// ...</span></pre>
<p>Before the regulare expression test, all the 0 bytes in the file header are converted to 1 bytes. This is done because when Qt was ASCII-based, <a href="qregexp.html">QRegExp</a> could not handle 0 bytes in strings.</p>
<p>The regexp is only applied on the first 14 bytes of the file.</p>
<p>(Note that if one handlerIO supports writing a format and another supports reading it, Qt supports both reading and writing. If two handlers support the same operation, Qt chooses one arbitrarily.)</p>
<h3 class="fn"><a name="description"></a><a href="qstring.html">QString</a> QPictureIO::description () const</h3>
<p>Returns the picture description string.</p>
<p>See also <a href="qpictureio.html#setDescription">setDescription</a>().</p>
<h3 class="fn"><a name="fileName"></a><a href="qstring.html">QString</a> QPictureIO::fileName () const</h3>
<p>Returns the file name currently set.</p>
<p>See also <a href="qpictureio.html#setFileName">setFileName</a>().</p>
<h3 class="fn"><a name="format"></a>const char * QPictureIO::format () const</h3>
<p>Returns the picture format string or 0 if no format has been explicitly set.</p>
<p>See also <a href="qpictureio.html#setFormat">setFormat</a>().</p>
<h3 class="fn"><a name="gamma"></a>float QPictureIO::gamma () const</h3>
<p>Returns the gamma value at which the picture will be viewed.</p>
<p>See also <a href="qpictureio.html#setGamma">setGamma</a>().</p>
<h3 class="fn"><a name="inputFormats"></a><a href="qlist.html">QList</a><<a href="qbytearray.html">QByteArray</a>> QPictureIO::inputFormats () <tt> [static]</tt></h3>
<p>Returns a sorted list of picture formats that are supported for picture input.</p>
<h3 class="fn"><a name="ioDevice"></a><a href="qiodevice.html">QIODevice</a> * QPictureIO::ioDevice () const</h3>
<p>Returns the IO device currently set.</p>
<p>See also <a href="qpictureio.html#setIODevice">setIODevice</a>().</p>
<h3 class="fn"><a name="outputFormats"></a><a href="qlist.html">QList</a><<a href="qbytearray.html">QByteArray</a>> QPictureIO::outputFormats () <tt> [static]</tt></h3>
<p>Returns a sorted list of picture formats that are supported for picture output.</p>
<h3 class="fn"><a name="parameters"></a>const char * QPictureIO::parameters () const</h3>
<p>Returns the picture's parameters string.</p>
<p>See also <a href="qpictureio.html#setParameters">setParameters</a>().</p>
<h3 class="fn"><a name="picture"></a>const <a href="qpicture.html">QPicture</a> & QPictureIO::picture () const</h3>
<p>Returns the picture currently set.</p>
<p>See also <a href="qpictureio.html#setPicture">setPicture</a>().</p>
<h3 class="fn"><a name="pictureFormat"></a><a href="qbytearray.html">QByteArray</a> QPictureIO::pictureFormat ( const <a href="qstring.html">QString</a> & <i>fileName</i> ) <tt> [static]</tt></h3>
<p>Returns a string that specifies the picture format of the file <i>fileName</i>, or null if the file cannot be read or if the format is not recognized.</p>
<h3 class="fn"><a name="pictureFormat-2"></a><a href="qbytearray.html">QByteArray</a> QPictureIO::pictureFormat ( <a href="qiodevice.html">QIODevice</a> * <i>d</i> ) <tt> [static]</tt></h3>
<p>This is an overloaded member function, provided for convenience.</p>
<p>Returns a string that specifies the picture format of the picture read from IO device <i>d</i>, or 0 if the device cannot be read or if the format is not recognized.</p>
<p>Make sure that <i>d</i> is at the right position in the device (for example, at the beginning of the file).</p>
<p>See also <a href="qiodevice-qt3.html#at">QIODevice::at</a>().</p>
<h3 class="fn"><a name="quality"></a>int QPictureIO::quality () const</h3>
<p>Returns the quality of the written picture, related to the compression ratio.</p>
<p>See also <a href="qpictureio.html#setQuality">setQuality</a>() and <a href="qpicture.html#save">QPicture::save</a>().</p>
<h3 class="fn"><a name="read"></a>bool QPictureIO::read ()</h3>
<p>Reads an picture into memory and returns true if the picture was successfully read; otherwise returns false.</p>
<p>Before reading an picture you must set an IO device or a file name. If both an IO device and a file name have been set, the IO device will be used.</p>
<p>Setting the picture file format string is optional.</p>
<p>Note that this function does <i>not</i> set the <a href="qpictureio.html#format">format</a> used to read the picture. If you need that information, use the <a href="qpictureio.html#pictureFormat">pictureFormat</a>() static functions.</p>
<p>Example:</p>
<pre> QPictureIO iio;
QPixmap pixmap;
iio.setFileName("vegeburger.bmp");
if (iio.read()) { <span class="comment">// OK</span>
QPicture picture = iio.picture();
QPainter painter(&pixmap);
painter.drawPicture(0, 0, picture);
}</pre>
<p>See also <a href="qpictureio.html#setIODevice">setIODevice</a>(), <a href="qpictureio.html#setFileName">setFileName</a>(), <a href="qpictureio.html#setFormat">setFormat</a>(), <a href="qpictureio.html#write">write</a>(), and <a href="qpixmap.html#load">QPixmap::load</a>().</p>
<h3 class="fn"><a name="setDescription"></a>void QPictureIO::setDescription ( const <a href="qstring.html">QString</a> & <i>description</i> )</h3>
<p>Sets the picture description string for picture handlers that support picture descriptions to <i>description</i>.</p>
<p>Currently, no picture format supported by Qt uses the description string.</p>
<p>See also <a href="qpictureio.html#description">description</a>().</p>
<h3 class="fn"><a name="setFileName"></a>void QPictureIO::setFileName ( const <a href="qstring.html">QString</a> & <i>fileName</i> )</h3>
<p>Sets the name of the file to read or write an picture from to <i>fileName</i>.</p>
<p>See also <a href="qpictureio.html#fileName">fileName</a>() and <a href="qpictureio.html#setIODevice">setIODevice</a>().</p>
<h3 class="fn"><a name="setFormat"></a>void QPictureIO::setFormat ( const char * <i>format</i> )</h3>
<p>Sets the picture format to <i>format</i> for the picture to be read or written.</p>
<p>It is necessary to specify a format before writing an picture, but it is not necessary to specify a format before reading an picture.</p>
<p>If no format has been set, Qt guesses the picture format before reading it. If a format is set the picture will only be read if it has that format.</p>
<p>See also <a href="qpictureio.html#read">read</a>(), <a href="qpictureio.html#write">write</a>(), and <a href="qpictureio.html#format">format</a>().</p>
<h3 class="fn"><a name="setGamma"></a>void QPictureIO::setGamma ( float <i>gamma</i> )</h3>
<p>Sets the gamma value at which the picture will be viewed to <i>gamma</i>. If the picture format stores a gamma value for which the picture is intended to be used, then this setting will be used to modify the picture. Setting to 0.0 will disable gamma correction (i.e. any specification in the file will be ignored).</p>
<p>The default value is 0.0.</p>
<p>See also <a href="qpictureio.html#gamma">gamma</a>().</p>
<h3 class="fn"><a name="setIODevice"></a>void QPictureIO::setIODevice ( <a href="qiodevice.html">QIODevice</a> * <i>ioDevice</i> )</h3>
<p>Sets the IO device to be used for reading or writing an picture.</p>
<p>Setting the IO device allows pictures to be read/written to any block-oriented <a href="qiodevice.html">QIODevice</a>.</p>
<p>If <i>ioDevice</i> is not null, this IO device will override file name settings.</p>
<p>See also <a href="qpictureio.html#setFileName">setFileName</a>().</p>
<h3 class="fn"><a name="setParameters"></a>void QPictureIO::setParameters ( const char * <i>parameters</i> )</h3>
<p>Sets the picture's parameter string to <i>parameters</i>. This is for picture handlers that require special parameters.</p>
<p>Although the current picture formats supported by Qt ignore the parameters string, it may be used in future extensions or by contributions (for example, JPEG).</p>
<p>See also <a href="qpictureio.html#parameters">parameters</a>().</p>
<h3 class="fn"><a name="setPicture"></a>void QPictureIO::setPicture ( const <a href="qpicture.html">QPicture</a> & <i>picture</i> )</h3>
<p>Sets the picture to <i>picture</i>.</p>
<p>See also <a href="qpictureio.html#picture">picture</a>().</p>
<h3 class="fn"><a name="setQuality"></a>void QPictureIO::setQuality ( int <i>q</i> )</h3>
<p>Sets the quality of the written picture to <i>q</i>, related to the compression ratio.</p>
<p><i>q</i> must be in the range -1..100. Specify 0 to obtain small compressed files, 100 for large uncompressed files. (-1 signifies the default compression.)</p>
<p>See also <a href="qpictureio.html#quality">quality</a>() and <a href="qpicture.html#save">QPicture::save</a>().</p>
<h3 class="fn"><a name="setStatus"></a>void QPictureIO::setStatus ( int <i>status</i> )</h3>
<p>Sets the picture IO status to <i>status</i>. A non-zero value indicates an error, whereas 0 means that the IO operation was successful.</p>
<p>See also <a href="qpictureio.html#status">status</a>().</p>
<h3 class="fn"><a name="status"></a>int QPictureIO::status () const</h3>
<p>Returns the picture's IO status. A non-zero value indicates an error, whereas 0 means that the IO operation was successful.</p>
<p>See also <a href="qpictureio.html#setStatus">setStatus</a>().</p>
<h3 class="fn"><a name="write"></a>bool QPictureIO::write ()</h3>
<p>Writes an picture to an IO device and returns true if the picture was successfully written; otherwise returns false.</p>
<p>Before writing an picture you must set an IO device or a file name. If both an IO device and a file name have been set, the IO device will be used.</p>
<p>The picture will be written using the specified picture format.</p>
<p>Example:</p>
<pre> QPictureIO iio;
QPicture picture;
QPainter painter(&picture);
painter.drawPixmap(0, 0, pixmap);
iio.setPicture(picture);
iio.setFileName("vegeburger.bmp");
iio.setFormat("BMP");
if (iio.write())
return true; <span class="comment">// returned true if written successfully</span></pre>
<p>See also <a href="qpictureio.html#setIODevice">setIODevice</a>(), <a href="qpictureio.html#setFileName">setFileName</a>(), <a href="qpictureio.html#setFormat">setFormat</a>(), <a href="qpictureio.html#read">read</a>(), and <a href="qpixmap.html#save">QPixmap::save</a>().</p>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="30%">Copyright © 2006 <a href="trolltech.html">Trolltech</a></td>
<td width="40%" align="center"><a href="trademarks.html">Trademarks</a></td>
<td width="30%" align="right"><div align="right">Qt 4.2.1</div></td>
</tr></table></div></address></body>
</html>
