gnash::image::JpegInput Class Reference

Class for reading JPEG image data. More...

#include <GnashImageJpeg.h>

Inheritance diagram for gnash::image::JpegInput:

List of all members.

Public Member Functions
DSOEXPORT	JpegInput (boost::shared_ptr< IOChannel > in)
	Construct a JpegInput object to read from an IOChannel.
void DSOEXPORT	readHeader (unsigned int maxHeaderBytes)
	Read the JPEG header information only.
	~JpegInput ()
void	read ()
	Begin processing the image data.
DSOEXPORT void	discardPartialBuffer ()
	Discard any data sitting in our input buffer.
void	finishImage ()
	Complete processing the image and clean up.
size_t	getHeight () const
	Get the image's height in pixels.
size_t	getWidth () const
	Get the image's width in pixels.
size_t	getComponents () const
	Get number of components (channels)
void	readScanline (unsigned char *rgbData)
	Read a scanline's worth of image data into the given buffer.
void	errorOccurred (const char *msg)
	This function is called when libjpeg encounters an error.
Static Public Member Functions
static std::auto_ptr< Input >	create (boost::shared_ptr< IOChannel > in)
	Create a JpegInput and transfer ownership to the caller.
static DSOEXPORT std::auto_ptr < GnashImage >	readSWFJpeg2WithTables (JpegInput &loader)
	For reading SWF JPEG2-style image data, using pre-loaded headers stored in the given JpegInput object.
static std::auto_ptr< JpegInput >	createSWFJpeg2HeaderOnly (boost::shared_ptr< IOChannel > in, unsigned int maxHeaderBytes)
	Create a JPEG 'loader' object by reading a JPEG header.

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Detailed Description

Class for reading JPEG image data.

This uses the IJG jpeglib to implement the Input interface.

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Constructor & Destructor Documentation

gnash::image::JpegInput::JpegInput

(

boost::shared_ptr< IOChannel >

in

)

Construct a JpegInput object to read from an IOChannel.

Parameters:

in	The stream to read JPEG data from. Ownership is shared between caller and JpegInput, so it is freed automatically when the last owner is destroyed.

Referenced by create(), and createSWFJpeg2HeaderOnly().

gnash::image::JpegInput::~JpegInput

(

)

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Member Function Documentation

static std::auto_ptr<Input> gnash::image::JpegInput::create

(

boost::shared_ptr< IOChannel >

in

)

[inline, static]

Create a JpegInput and transfer ownership to the caller.

Parameters:

in	The IOChannel to read JPEG data from.

References JpegInput().

Referenced by gnash::image::Input::readImageData().

static std::auto_ptr<JpegInput> gnash::image::JpegInput::createSWFJpeg2HeaderOnly	(	boost::shared_ptr< IOChannel >	in,
		unsigned int	maxHeaderBytes
	)		[inline, static]

Create a JPEG 'loader' object by reading a JPEG header.

This is for reusing the header information for different JPEGs images.

Parameters:

in	The channel to read JPEG header data from.
maxHeaderBytes	The maximum number of bytes to read.

References JpegInput().

Referenced by gnash::SWF::jpeg_tables_loader(), and gnash::image::Input::readSWFJpeg3().

void gnash::image::JpegInput::discardPartialBuffer

(

)

Discard any data sitting in our input buffer.

Use this before/after reading headers or partial image data, to avoid screwing up future reads.

void gnash::image::JpegInput::errorOccurred

(

const char *

msg

)

This function is called when libjpeg encounters an error.

It is needed to avoid memory corruption during stack unwinding by freeing libjpeg resources correctly before throwing an exception.

Parameters:

msg	An error message for logging.

void gnash::image::JpegInput::finishImage

(

)

Complete processing the image and clean up.

This should close / free all resources from libjpeg.

References _.

Referenced by readSWFJpeg2WithTables().

size_t gnash::image::JpegInput::getComponents

(

)

const [virtual]

Get number of components (channels)

Returns:

The number of components, e.g. 3 for RGB

Implements gnash::image::Input.

References assert.

size_t gnash::image::JpegInput::getHeight

(

)

const [virtual]

Get the image's height in pixels.

Returns:

The height of the image in pixels.

Implements gnash::image::Input.

References assert.

Referenced by readSWFJpeg2WithTables().

size_t gnash::image::JpegInput::getWidth

(

)

const [virtual]

Get the image's width in pixels.

Returns:

The width of the image in pixels.

Implements gnash::image::Input.

References assert.

Referenced by readScanline(), and readSWFJpeg2WithTables().

void gnash::image::JpegInput::read

(

)

[virtual]

Begin processing the image data.

Implements gnash::image::Input.

References assert, _, gnash::image::Input::_type, and gnash::image::TYPE_RGB.

Referenced by readSWFJpeg2WithTables().

void gnash::image::JpegInput::readHeader

(

unsigned int

maxHeaderBytes

)

Read the JPEG header information only.

Parameters:

maxHeaderBytes

The maximum number of bytes to read before Stopping. If the header is shorter, we stop early.

References _.

void gnash::image::JpegInput::readScanline

(

unsigned char *

rgbData

)

[virtual]

Read a scanline's worth of image data into the given buffer.

The amount of data read is getWidth() * getComponents().

Parameters:

rgbData

The buffer for writing raw RGB data to.

Implements gnash::image::Input.

References assert, test::w, and getWidth().

Referenced by readSWFJpeg2WithTables().

std::auto_ptr< GnashImage > gnash::image::JpegInput::readSWFJpeg2WithTables

(

JpegInput &

loader

)

[static]

For reading SWF JPEG2-style image data, using pre-loaded headers stored in the given JpegInput object.

Parameters:

loader

The JpegInput object to use for reading the data. This should have been constructed with createSWFJpeg2HeaderOnly().

References read(), getWidth(), getHeight(), y, height, readScanline(), gnash::image::scanline(), and finishImage().

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

• GnashImageJpeg.h
• GnashImageJpeg.cpp