WebPCompressor Class Reference

Wrapper class to WebP library: Handles 8 and 16 bit PNG as well as alpha transparency. More...

#include <WebPCompressor.h>

Inheritance diagram for WebPCompressor:

Public Member Functions
	WebPCompressor (int compressionLevel)
	Constructor.
void	InitCompression (const RawTile &rawtile, unsigned int strip_height)
	Initialize strip based compression.
unsigned int	CompressStrip (unsigned char *source, unsigned char *output, unsigned int tile_height)
	Compress a strip of image data.
unsigned int	Finish (unsigned char *output)
	Finish the strip based compression and free memory.
unsigned int	Compress (RawTile &t)
	Compress an entire buffer of image data at once in one command.
unsigned int	getHeaderSize () const
	Return the WebP header size.
unsigned char *	getHeader ()
	Return a pointer to the header itself.
const char *	getMimeType () const
	Return the WebP mime type.
const char *	getSuffix () const
	Return the image filename suffix.
CompressionType	getCompressionType () const
	Get compression type.
int	getQuality () const
	Get the current compression level.
void	setQuality (int quality)
	Set the compression level.
Public Member Functions inherited from Compressor
	Compressor (int compressionLevel)
	Constructor.
int	getQuality () const
	Get the current quality level.
void	setResolution (float x, float y, int units)
	Set the physical output resolution.
void	setICCProfile (const std::string &profile)
	Set the ICC profile.
void	setXMPMetadata (const std::string &x)
	Set XMP metadata.
virtual unsigned int	getHeaderSize () const
	Return the image header size.
virtual unsigned char *	getHeader ()
	Return a pointer to the image header itself.
virtual void	InitCompression (const RawTile &rawtile, unsigned int strip_height)
	Initialise strip based compression.
virtual unsigned int	CompressStrip (unsigned char *s, unsigned char *o, unsigned int tile_height)
	Compress a strip of image data.
virtual unsigned int	Finish (unsigned char *output)
	Finish the strip based compression and free memory.
virtual unsigned int	Compress (RawTile &t)
	Compress an entire buffer of image data at once in one command.
virtual void	addXMPMetadata (const std::string &m)
	Add metadata to the image header.
virtual const char *	getMimeType () const
	Get mime type.
virtual const char *	getSuffix () const
	Get file suffix.
virtual CompressionType	getCompressionType () const
	Get compression type.

Additional Inherited Members
virtual void	writeICCProfile ()
	Write ICC profile.
virtual void	writeXMPMetadata ()
	Write XMP metadata.
Protected Attributes inherited from Compressor
int	Q
	Quality or compression level for all image types.
unsigned char *	header
	Pointer to the header data for the output image.
unsigned int	header_size
	Size of the header data.
float	dpi_x
	Physical resolution for X and Y directions.
float	dpi_y
int	dpi_units
	Resolution units.
std::string	icc
	ICC Profile.
std::string	xmp
	XMP metadata.

Detailed Description

Wrapper class to WebP library: Handles 8 and 16 bit PNG as well as alpha transparency.

Constructor & Destructor Documentation

WebPCompressor()

WebPCompressor::WebPCompressor ( int  compressionLevel )

inline

Constructor.

Parameters

compressionLevel

WebP compression level (range 0-100)

References Compressor::Q.

Member Function Documentation

Compress()

unsigned int WebPCompressor::Compress ( RawTile &  t )

virtual

Compress an entire buffer of image data at once in one command.

Parameters

t	tile of image data

Returns

size of compressed data

Reimplemented from Compressor.

CompressStrip()

unsigned int WebPCompressor::CompressStrip ( unsigned char *  source, unsigned char *  output, unsigned int  tile_height  )

virtual

Compress a strip of image data.

Parameters

source	source image data
tile_height	pixel height of the tile we are compressing
output	output_buffer

Returns

size of compressed strip

Reimplemented from Compressor.

Finish()

unsigned int WebPCompressor::Finish ( unsigned char *  output )

virtual

Finish the strip based compression and free memory.

Parameters

output

Output buffer

Returns

size of output generated

Reimplemented from Compressor.

getCompressionType()

CompressionType WebPCompressor::getCompressionType ( ) const

inlinevirtual

Get compression type.

Reimplemented from Compressor.

getHeader()

unsigned char * WebPCompressor::getHeader ( )

inlinevirtual

Return a pointer to the header itself.

Reimplemented from Compressor.

References Compressor::header.

getHeaderSize()

unsigned int WebPCompressor::getHeaderSize ( ) const

inlinevirtual

Return the WebP header size.

Reimplemented from Compressor.

References Compressor::header_size.

getMimeType()

const char * WebPCompressor::getMimeType ( ) const

inlinevirtual

Return the WebP mime type.

Reimplemented from Compressor.

getQuality()

int WebPCompressor::getQuality ( ) const

inline

Get the current compression level.

Returns

compresson level

References Compressor::Q.

getSuffix()

const char * WebPCompressor::getSuffix ( ) const

inlinevirtual

Return the image filename suffix.

Reimplemented from Compressor.

InitCompression()

void WebPCompressor::InitCompression ( const RawTile &  rawtile, unsigned int  strip_height  )

virtual

Initialize strip based compression.

For strip based encoding, we need to first initialize with InitCompression, then compress a single strip at a time using CompressStrip and finally clean up using Finish

Parameters

rawtile	RawTile object containing the image to be compressed
strip_height	height in pixels of the strip we want to compress

Reimplemented from Compressor.

setQuality()

void WebPCompressor::setQuality ( int  quality )

inline

Set the compression level.

Parameters

compression

level: 0-100 with (0 = highest compression)

References Compressor::Q.

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

• WebPCompressor.h