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Public Member Functions | Static Public Member Functions | List of all members
QGifHandler Class Reference

#include <qgifhandler_p.h>

+ Inheritance diagram for QGifHandler:
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Public Member Functions

 QGifHandler ()
 
 ~QGifHandler ()
 
bool canRead () const override
 Returns true if an image can be read from the device (i.e., the image format is supported, the device can be read from and the initial header information suggests that the image can be read); otherwise returns false.
 
bool read (QImage *image) override
 Read an image from the device, and stores it in image.
 
bool write (const QImage &image) override
 Writes the image image to the assigned device.
 
QVariant option (ImageOption option) const override
 Returns the value assigned to option as a QVariant.
 
void setOption (ImageOption option, const QVariant &value) override
 Sets the option option with the value value.
 
bool supportsOption (ImageOption option) const override
 Returns true if the QImageIOHandler supports the option option; otherwise returns false.
 
int imageCount () const override
 For image formats that support animation, this function returns the number of images in the animation.
 
int loopCount () const override
 For image formats that support animation, this function returns the number of times the animation should loop.
 
int nextImageDelay () const override
 For image formats that support animation, this function returns the number of milliseconds to wait until reading the next image.
 
int currentImageNumber () const override
 For image formats that support animation, this function returns the sequence number of the current image in the animation.
 
- Public Member Functions inherited from QImageIOHandler
 QImageIOHandler ()
 Constructs a QImageIOHandler object.
 
virtual ~QImageIOHandler ()
 Destructs the QImageIOHandler object.
 
void setDevice (QIODevice *device)
 Sets the device of the QImageIOHandler to device.
 
QIODevice * device () const
 Returns the device currently assigned to the QImageIOHandler.
 
void setFormat (const QByteArray &format)
 Sets the format of the QImageIOHandler to format.
 
void setFormat (const QByteArray &format) const
 Sets the format of the QImageIOHandler to format.
 
QByteArray format () const
 Returns the format that is currently assigned to QImageIOHandler.
 
virtual bool canRead () const =0
 Returns true if an image can be read from the device (i.e., the image format is supported, the device can be read from and the initial header information suggests that the image can be read); otherwise returns false.
 
virtual bool read (QImage *image)=0
 Read an image from the device, and stores it in image.
 
virtual bool write (const QImage &image)
 Writes the image image to the assigned device.
 
virtual QVariant option (ImageOption option) const
 Returns the value assigned to option as a QVariant.
 
virtual void setOption (ImageOption option, const QVariant &value)
 Sets the option option with the value value.
 
virtual bool supportsOption (ImageOption option) const
 Returns true if the QImageIOHandler supports the option option; otherwise returns false.
 
virtual bool jumpToNextImage ()
 For image formats that support animation, this function jumps to the next image.
 
virtual bool jumpToImage (int imageNumber)
 For image formats that support animation, this function jumps to the image whose sequence number is imageNumber.
 
virtual int loopCount () const
 For image formats that support animation, this function returns the number of times the animation should loop.
 
virtual int imageCount () const
 For image formats that support animation, this function returns the number of images in the animation.
 
virtual int nextImageDelay () const
 For image formats that support animation, this function returns the number of milliseconds to wait until reading the next image.
 
virtual int currentImageNumber () const
 For image formats that support animation, this function returns the sequence number of the current image in the animation.
 
virtual QRect currentImageRect () const
 Returns the rect of the current image.
 

Static Public Member Functions

static bool canRead (QIODevice *device)
 
- Static Public Member Functions inherited from QImageIOHandler
static bool allocateImage (QSize size, QImage::Format format, QImage *image)
 

Additional Inherited Members

- Public Types inherited from QImageIOHandler
enum  ImageOption {
  Size , ClipRect , Description , ScaledClipRect ,
  ScaledSize , CompressionRatio , Gamma , Quality ,
  Name , SubType , IncrementalReading , Endianness ,
  Animation , BackgroundColor , ImageFormat , SupportedSubTypes ,
  OptimizedWrite , ProgressiveScanWrite , ImageTransformation
}
 This enum describes the different options supported by QImageIOHandler. More...
 
enum  Transformation {
  TransformationNone = 0 , TransformationMirror = 1 , TransformationFlip = 2 , TransformationRotate180 = TransformationMirror | TransformationFlip ,
  TransformationRotate90 = 4 , TransformationMirrorAndRotate90 = TransformationMirror | TransformationRotate90 , TransformationFlipAndRotate90 = TransformationFlip | TransformationRotate90 , TransformationRotate270 = TransformationRotate180 | TransformationRotate90
}
 
- Protected Member Functions inherited from QImageIOHandler
 QImageIOHandler (QImageIOHandlerPrivate &dd)
 
- Protected Attributes inherited from QImageIOHandler
QScopedPointer< QImageIOHandlerPrivate > d_ptr
 

Detailed Description

Definition at line 25 of file qgifhandler_p.h.

Constructor & Destructor Documentation

◆ QGifHandler()

QGifHandler::QGifHandler ( )

Definition at line 1037 of file qgifhandler.cpp.

◆ ~QGifHandler()

QGifHandler::~QGifHandler ( )

Definition at line 1046 of file qgifhandler.cpp.

Member Function Documentation

◆ canRead() [1/2]

bool QGifHandler::canRead ( ) const
overridevirtual

Returns true if an image can be read from the device (i.e., the image format is supported, the device can be read from and the initial header information suggests that the image can be read); otherwise returns false.

When reimplementing canRead(), make sure that the I/O device (device()) is left in its original state (e.g., by using peek() rather than read()).

See also
read(), QIODevice::peek()

Implements QImageIOHandler.

Definition at line 1073 of file qgifhandler.cpp.

References canRead(), QImageIOHandler::device(), and QImageIOHandler::setFormat().

Referenced by canRead(), and QGifPlugin::capabilities().

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◆ canRead() [2/2]

bool QGifHandler::canRead ( QIODevice *  device)
static

Definition at line 1083 of file qgifhandler.cpp.

References QImageIOHandler::device(), QIODevice::peek(), qCWarning, and qstrncmp().

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◆ currentImageNumber()

int QGifHandler::currentImageNumber ( ) const
overridevirtual

For image formats that support animation, this function returns the sequence number of the current image in the animation.

If this function is called before any image is read(), -1 is returned. The number of the first image in the sequence is 0.

If the image format does not support animation, 0 is returned.

See also
read()

Reimplemented from QImageIOHandler.

Definition at line 1196 of file qgifhandler.cpp.

◆ imageCount()

int QGifHandler::imageCount ( ) const
overridevirtual

For image formats that support animation, this function returns the number of images in the animation.

If the image format does not support animation, or if it is unable to determine the number of images, 0 is returned.

The default implementation returns 1 if canRead() returns true; otherwise 0 is returned.

Reimplemented from QImageIOHandler.

Definition at line 1172 of file qgifhandler.cpp.

References QImageIOHandler::device(), QGIFFormat::scan(), and QList< T >::size().

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◆ loopCount()

int QGifHandler::loopCount ( ) const
overridevirtual

For image formats that support animation, this function returns the number of times the animation should loop.

If the image format does not support animation, 0 is returned.

Reimplemented from QImageIOHandler.

Definition at line 1181 of file qgifhandler.cpp.

References QImageIOHandler::device(), and QGIFFormat::scan().

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◆ nextImageDelay()

int QGifHandler::nextImageDelay ( ) const
overridevirtual

For image formats that support animation, this function returns the number of milliseconds to wait until reading the next image.

If the image format does not support animation, 0 is returned.

Reimplemented from QImageIOHandler.

Definition at line 1167 of file qgifhandler.cpp.

◆ option()

QVariant QGifHandler::option ( ImageOption  option) const
overridevirtual

Returns the value assigned to option as a QVariant.

The type of the value depends on the option. For example, option(Size) returns a QSize variant.

See also
setOption(), supportsOption()

Reimplemented from QImageIOHandler.

Definition at line 1140 of file qgifhandler.cpp.

References QImageIOHandler::Animation, QList< T >::at(), QImageIOHandler::device(), QGIFFormat::scan(), QList< T >::size(), and QImageIOHandler::Size.

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◆ read()

bool QGifHandler::read ( QImage *  image)
overridevirtual

Read an image from the device, and stores it in image.

Returns true if the image is successfully read; otherwise returns false.

For image formats that support incremental loading, and for animation formats, the image handler can assume that image points to the previous frame.

See also
canRead()

Implements QImageIOHandler.

Definition at line 1097 of file qgifhandler.cpp.

References QGIFFormat::decode(), QImageIOHandler::device(), QGIFFormat::newFrame, QGIFFormat::partialNewFrame, QIODevice::read(), and QImage::size().

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◆ setOption()

void QGifHandler::setOption ( ImageOption  option,
const QVariant &  value 
)
overridevirtual

Sets the option option with the value value.

See also
option(), ImageOption

Reimplemented from QImageIOHandler.

Definition at line 1161 of file qgifhandler.cpp.

References Q_UNUSED.

◆ supportsOption()

bool QGifHandler::supportsOption ( ImageOption  option) const
overridevirtual

Returns true if the QImageIOHandler supports the option option; otherwise returns false.

For example, if the QImageIOHandler supports the \l Size option, supportsOption(Size) must return true.

See also
setOption(), option()

Reimplemented from QImageIOHandler.

Definition at line 1131 of file qgifhandler.cpp.

References QImageIOHandler::Animation, QImageIOHandler::device(), and QImageIOHandler::Size.

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◆ write()

bool QGifHandler::write ( const QImage &  image)
overridevirtual

Writes the image image to the assigned device.

Returns true on success; otherwise returns false.

The default implementation does nothing, and simply returns false.

Reimplemented from QImageIOHandler.

Definition at line 1125 of file qgifhandler.cpp.

References Q_UNUSED.

The documentation for this class was generated from the following files: