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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>QImageDecoder Class Reference</h1>
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| 33 |
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| 34 | <p>The QImageDecoder class is an incremental image decoder for all supported image formats.
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| 35 | <a href="#details">More...</a>
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| 36 | <p><tt>#include <<a href="qasyncimageio-h.html">qasyncimageio.h</a>></tt>
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| 37 | <p><a href="qimagedecoder-members.html">List of all member functions.</a>
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| 38 | <h2>Public Members</h2>
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| 39 | <ul>
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| 40 | <li class=fn><a href="#QImageDecoder"><b>QImageDecoder</b></a> ( QImageConsumer * c )</li>
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| 41 | <li class=fn><a href="#~QImageDecoder"><b>~QImageDecoder</b></a> ()</li>
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| 42 | <li class=fn>const QImage & <a href="#image"><b>image</b></a> ()</li>
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| 43 | <li class=fn>int <a href="#decode"><b>decode</b></a> ( const uchar * buffer, int length )</li>
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| 44 | </ul>
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| 45 | <h2>Static Public Members</h2>
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| 46 | <ul>
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| 47 | <li class=fn>const char * <a href="#formatName"><b>formatName</b></a> ( const uchar * buffer, int length )</li>
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| 48 | <li class=fn>QImageFormatType * <a href="#format"><b>format</b></a> ( const char * name )</li>
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| 49 | <li class=fn>QStrList <a href="#inputFormats"><b>inputFormats</b></a> ()</li>
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| 50 | <li class=fn>void <a href="#registerDecoderFactory"><b>registerDecoderFactory</b></a> ( QImageFormatType * f )</li>
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| 51 | <li class=fn>void <a href="#unregisterDecoderFactory"><b>unregisterDecoderFactory</b></a> ( QImageFormatType * f )</li>
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| 52 | </ul>
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| 53 | <hr><a name="details"></a><h2>Detailed Description</h2>
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| 54 |
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| 55 |
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| 56 | The QImageDecoder class is an incremental image decoder for all supported image formats.
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| 57 | <p>
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| 58 |
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| 59 |
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| 60 | <p> New formats are installed by creating objects of class
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| 61 | <a href="qimageformattype.html">QImageFormatType</a>; the <a href="qmovie.html">QMovie</a> class can be used for all installed
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| 62 | incremental image formats. QImageDecoder is only useful for
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| 63 | creating new ways of feeding data to an <a href="qimageconsumer.html">QImageConsumer</a>.
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| 64 | <p> A QImageDecoder is a machine that decodes images. It takes encoded
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| 65 | image data via its <a href="#decode">decode</a>() method and expresses its decoding by
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| 66 | supplying information to a QImageConsumer. It implements its
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| 67 | decoding by using a <a href="qimageformat.html">QImageFormat</a> created by one of the
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| 68 | currently-existing QImageFormatType factory objects.
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| 69 | <p> QImageFormatType and QImageFormat are the classes that you might
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| 70 | need to implement support for additional image formats.
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| 71 | <p>
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| 72 | <p> Qt supports GIF reading if it is configured that way during
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| 73 | installation (see qgif.h). If it is, we are required to state that
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| 74 | "The Graphics Interchange Format(c) is the Copyright property of
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| 75 | CompuServe Incorporated. GIF(sm) is a Service Mark property of
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| 76 | CompuServe Incorporated."
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| 77 | <p> <b>Warning:</b> If you are in a country that recognizes software patents
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| 78 | and in which Unisys holds a patent on LZW compression and/or
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| 79 | decompression and you want to use GIF, Unisys may require you to
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| 80 | license that technology. Such countries include Canada, Japan,
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| 81 | the USA, France, Germany, Italy and the UK.
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| 82 | <p> GIF support may be removed completely in a future version of Qt.
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| 83 | We recommend using the MNG or PNG format.
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| 84 | <p>See also <a href="graphics.html">Graphics Classes</a>, <a href="images.html">Image Processing Classes</a>, and <a href="multimedia.html">Multimedia Classes</a>.
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| 85 |
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| 86 | <hr><h2>Member Function Documentation</h2>
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| 87 | <h3 class=fn><a name="QImageDecoder"></a>QImageDecoder::QImageDecoder ( <a href="qimageconsumer.html">QImageConsumer</a> * c )
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| 88 | </h3>
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| 89 | Constructs a QImageDecoder that will send change information to
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| 90 | the <a href="qimageconsumer.html">QImageConsumer</a> <em>c</em>.
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| 91 |
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| 92 | <h3 class=fn><a name="~QImageDecoder"></a>QImageDecoder::~QImageDecoder ()
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| 93 | </h3>
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| 94 | Destroys a QImageDecoder. The image it built is destroyed. The
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| 95 | decoder built by the factory for the file format is destroyed. The
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| 96 | consumer for which it decoded the image is <em>not</em> destroyed.
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| 97 |
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| 98 | <h3 class=fn>int <a name="decode"></a>QImageDecoder::decode ( const uchar * buffer, int length )
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| 99 | </h3>
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| 100 | Call this function to decode some data into image changes. The
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| 101 | data in <em>buffer</em> will be decoded, sending change information to
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| 102 | the <a href="qimageconsumer.html">QImageConsumer</a> of this QImageDecoder until one of the change
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| 103 | functions of the consumer returns FALSE. The length of the data is
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| 104 | given in <em>length</em>.
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| 105 | <p> Returns the number of bytes consumed: 0 if consumption is
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| 106 | complete, and -1 if decoding fails due to invalid data.
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| 107 |
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| 108 | <h3 class=fn><a href="qimageformattype.html">QImageFormatType</a> * <a name="format"></a>QImageDecoder::format ( const char * name )<tt> [static]</tt>
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| 109 | </h3>
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| 110 | Returns a <a href="qimageformattype.html">QImageFormatType</a> by name. This might be used when the
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| 111 | user needs to force data to be interpreted as being in a certain
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| 112 | format. <em>name</em> is one of the formats listed by
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| 113 | <a href="#inputFormats">QImageDecoder::inputFormats</a>(). Note that you will still need to
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| 114 | supply decodable data to result->decoderFor() before you can begin
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| 115 | decoding the data.
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| 116 |
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| 117 | <h3 class=fn>const char * <a name="formatName"></a>QImageDecoder::formatName ( const uchar * buffer, int length )<tt> [static]</tt>
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| 118 | </h3>
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| 119 | Call this function to find the name of the format of the given
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| 120 | header. The returned string is statically allocated. The function
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| 121 | will look at the first <em>length</em> characters in the <em>buffer</em>.
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| 122 | <p> Returns 0 if the format is not recognized.
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| 123 |
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| 124 | <h3 class=fn>const <a href="qimage.html">QImage</a> & <a name="image"></a>QImageDecoder::image ()
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| 125 | </h3>
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| 126 |
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| 127 | <p> Returns the image currently being decoded.
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| 128 |
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| 129 | <h3 class=fn><a href="qstrlist.html">QStrList</a> <a name="inputFormats"></a>QImageDecoder::inputFormats ()<tt> [static]</tt>
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| 130 | </h3>
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| 131 | Returns a sorted list of formats for which asynchronous loading is
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| 132 | supported.
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| 133 |
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| 134 | <h3 class=fn>void <a name="registerDecoderFactory"></a>QImageDecoder::registerDecoderFactory ( <a href="qimageformattype.html">QImageFormatType</a> * f )<tt> [static]</tt>
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| 135 | </h3>
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| 136 | Registers the new <a href="qimageformattype.html">QImageFormatType</a> <em>f</em>. This is not needed in
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| 137 | application code because factories call this themselves.
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| 138 |
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| 139 | <h3 class=fn>void <a name="unregisterDecoderFactory"></a>QImageDecoder::unregisterDecoderFactory ( <a href="qimageformattype.html">QImageFormatType</a> * f )<tt> [static]</tt>
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| 140 | </h3>
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| 141 | Unregisters the <a href="qimageformattype.html">QImageFormatType</a> <em>f</em>. This is not needed in
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| 142 | application code because factories call this themselves.
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| 143 |
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| 144 | <!-- eof -->
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| 145 | <hr><p>
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| 146 | This file is part of the <a href="index.html">Qt toolkit</a>.
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| 147 | Copyright © 1995-2007
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| 148 | <a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
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| 149 | <table width=100% cellspacing=0 border=0><tr>
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| 150 | <td>Copyright © 2007
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| 151 | <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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| 152 | <td align=right><div align=right>Qt 3.3.8</div>
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| 153 | </table></div></address></body>
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| 154 | </html>
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