ImageIOHandler Class Reference

Base class for all handlers. More...

Inherited by DDSHandler, DefaultHandler, JpegHandler, QPngHandler, and TestHandler.

Public Member Functions
	ImageIOHandler ()
	Creates an ImageIOHandler object.
virtual	~ImageIOHandler ()
	Destroys the ImageIOHandler object.
QIODevice *	device () const
	Returns the device currently assigned to the ImageIOHandler. More...
QMimeType	mimeType () const
	Returns the mime type that is currently assigned to the ImageIOHandler. More...
QByteArray	subType () const
	Returns subType that is used to write an image. More...
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. More...
virtual bool	readHeader (ImageHeader &header)=0
	Read an metadata from the device, and stores it in header. More...
virtual bool	read (ImageContents &contents, const ImageOptions &options)=0
	Read an image data from the device, and stores it in contents. More...
virtual bool	write (const ImageContents &contents, const ImageOptions &options)
	Writes the contents with the given options to the assigned device. More...

Detailed Description

Base class for all handlers.

Member Function Documentation

canRead()

bool ImageIOHandler::canRead ( ) const

pure virtual

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()).

device()

QIODevice * ImageIOHandler::device

(

)

const

Returns the device currently assigned to the ImageIOHandler.

If no device has been assigned, nullptr is returned.

mimeType()

QMimeType ImageIOHandler::mimeType

(

)

const

Returns the mime type that is currently assigned to the ImageIOHandler.

If no mime type has been assigned yet, an empty string is returned.

read()

bool ImageIOHandler::read ( ImageContents &  contents, const ImageOptions &  options  )

pure virtual

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

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

readHeader()

bool ImageIOHandler::readHeader ( ImageHeader &  header )

pure virtual

Read an metadata from the device, and stores it in header.

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

This method is called before read() and should not read actual image data if possible.

subType()

QByteArray ImageIOHandler::subType

(

)

const

Returns subType that is used to write an image.

If no subtype has been assigned, an empty QByteArray is returned.

write()

bool ImageIOHandler::write ( const ImageContents &  contents, const ImageOptions &  options  )

virtual

Writes the contents with the given options to the assigned device.

Returns true on success; otherwise returns false.

The default implementation does nothing, and simply returns false.