Detailed Description
The QImageFormatType class is a factory that makes QImageFormat objects.
Whereas the QImageIO class allows for complete loading of
images, QImageFormatType allows for incremental loading of
images.
New image file formats are installed by creating objects of
derived classes of QImageFormatType. They must implement
decoderFor() and formatName().
QImageFormatType is a very simple class. Its only task is to
recognize image data in some format and make a new object,
subclassed from QImageFormat, which can decode that format.
The factories for formats built into Qt are automatically defined
before any other factory is initialized. If two factories would
recognize an image format, the factory created last will override
the earlier one; you can thus override current and future built-in
formats.
See also Graphics Classes, Image Processing Classes, and Multimedia Classes.
Member Function Documentation
QImageFormatType::QImageFormatType () [protected]
Constructs a factory. It automatically registers itself with
QImageDecoder.
QImageFormatType::~QImageFormatType () [virtual]
Destroys a factory. It automatically unregisters itself from
QImageDecoder.
QImageFormat * QImageFormatType::decoderFor ( const uchar * buffer, int length ) [pure virtual]
Returns a decoder for decoding an image that starts with the bytes
in buffer. The length of the data is given in length. This
function should only return a decoder if it is certain that the
decoder applies to data with the given header. Returns 0 if there
is insufficient data in the header to make a positive
identification or if the data is not recognized.
const char * QImageFormatType::formatName () const [pure virtual]
Returns the name of the format supported by decoders from this
factory. The string is statically allocated.
This file is part of the Qt toolkit.
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Trolltech. All Rights Reserved.
