qimagedecoder(3qt)

1QImageDecoder(3qt)                                          QImageDecoder(3qt)
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NAME

6       QImageDecoder - Incremental image decoder for all supported image
7       formats
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SYNOPSIS

10       #include <qasyncimageio.h>
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12   Public Members
13       QImageDecoder ( QImageConsumer * c )
14       ~QImageDecoder ()
15       const QImage & image ()
16       int decode ( const uchar * buffer, int length )
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18   Static Public Members
19       const char * formatName ( const uchar * buffer, int length )
20       QImageFormatType * format ( const char * name )
21       QStrList inputFormats ()
22       void registerDecoderFactory ( QImageFormatType * f )
23       void unregisterDecoderFactory ( QImageFormatType * f )
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DESCRIPTION

26       The QImageDecoder class is an incremental image decoder for all
27       supported image formats.
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29       New formats are installed by creating objects of class
30       QImageFormatType; the QMovie class can be used for all installed
31       incremental image formats. QImageDecoder is only useful for creating
32       new ways of feeding data to an QImageConsumer.
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34       A QImageDecoder is a machine that decodes images. It takes encoded
35       image data via its decode() method and expresses its decoding by
36       supplying information to a QImageConsumer. It implements its decoding
37       by using a QImageFormat created by one of the currently-existing
38       QImageFormatType factory objects.
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40       QImageFormatType and QImageFormat are the classes that you might need
41       to implement support for additional image formats.
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43       Qt supports GIF reading if it is configured that way during
44       installation (see qgif.h). If it is, we are required to state that" The
45       Graphics Interchange Format(c) is the Copyright property of CompuServe
46       Incorporated. GIF(sm) is a Service Mark property of CompuServe
47       Incorporated."
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49       Warning: If you are in a country that recognizes software patents and
50       in which Unisys holds a patent on LZW compression and/or decompression
51       and you want to use GIF, Unisys may require you to license that
52       technology. Such countries include Canada, Japan, the USA, France,
53       Germany, Italy and the UK.
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55       GIF support may be removed completely in a future version of Qt. We
56       recommend using the MNG or PNG format.
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58       See also Graphics Classes, Image Processing Classes, and Multimedia
59       Classes.
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MEMBER FUNCTION DOCUMENTATION

QImageDecoder::QImageDecoder ( QImageConsumer * c )

63       Constructs a QImageDecoder that will send change information to the
64       QImageConsumer c.
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QImageDecoder::~QImageDecoder ()

67       Destroys a QImageDecoder. The image it built is destroyed. The decoder
68       built by the factory for the file format is destroyed. The consumer for
69       which it decoded the image is not destroyed.
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int QImageDecoder::decode ( const uchar * buffer, int length )

72       Call this function to decode some data into image changes. The data in
73       buffer will be decoded, sending change information to the
74       QImageConsumer of this QImageDecoder until one of the change functions
75       of the consumer returns FALSE. The length of the data is given in
76       length.
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78       Returns the number of bytes consumed: 0 if consumption is complete, and
79       -1 if decoding fails due to invalid data.
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QImageFormatType * QImageDecoder::format ( const char * name ) [static]

82       Returns a QImageFormatType by name. This might be used when the user
83       needs to force data to be interpreted as being in a certain format.
84       name is one of the formats listed by QImageDecoder::inputFormats().
85       Note that you will still need to supply decodable data to
86       result->decoderFor() before you can begin decoding the data.
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const char * QImageDecoder::formatName ( const uchar * buffer, int length )

89       [static]
90       Call this function to find the name of the format of the given header.
91       The returned string is statically allocated. The function will look at
92       the first length characters in the buffer.
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94       Returns 0 if the format is not recognized.
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const QImage & QImageDecoder::image ()

97       Returns the image currently being decoded.
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QStrList QImageDecoder::inputFormats () [static]

100       Returns a sorted list of formats for which asynchronous loading is
101       supported.
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void QImageDecoder::registerDecoderFactory ( QImageFormatType * f ) [static]

104       Registers the new QImageFormatType f. This is not needed in application
105       code because factories call this themselves.
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void QImageDecoder::unregisterDecoderFactory ( QImageFormatType * f ) [static]

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109       Unregisters the QImageFormatType f. This is not needed in application
110       code because factories call this themselves.
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COPYRIGHT

118       Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com.  See the
119       license file included in the distribution for a complete license
120       statement.
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AUTHOR

123       Generated automatically from the source code.
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BUGS

126       If you find a bug in Qt, please report it as described in
127       http://doc.trolltech.com/bughowto.html.  Good bug reports help us to
128       help you. Thank you.
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130       The definitive Qt documentation is provided in HTML format; it is
131       located at $QTDIR/doc/html and can be read using Qt Assistant or with a
132       web browser. This man page is provided as a convenience for those users
133       who prefer man pages, although this format is not officially supported
134       by Trolltech.
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136       If you find errors in this manual page, please report them to qt-
137       bugs@trolltech.com.  Please include the name of the manual page
138       (qimagedecoder.3qt) and the Qt version (3.3.8).
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142Trolltech AS                    2 February 2007             QImageDecoder(3qt)