pagespeed::image_compression::PngScanlineReader Class Reference

#include "png_optimizer.h"

Inheritance diagram for pagespeed::image_compression::PngScanlineReader:

Public Member Functions
	PngScanlineReader (MessageHandler *handler)
jmp_buf *	GetJmpBuf ()
virtual bool	Reset ()
bool	InitializeRead (const PngReaderInterface &reader, const GoogleString &in)
	Initializes the read structures with the given input.
bool	InitializeRead (const PngReaderInterface &reader, const GoogleString &in, bool *is_opaque)
virtual size_t	GetBytesPerScanline ()
	Returns number of bytes that required to store a scanline.
virtual bool	HasMoreScanLines ()
	Returns true if there are more scanlines to read.
virtual ScanlineStatus	ReadNextScanlineWithStatus (void **out_scanline_bytes)
virtual size_t	GetImageHeight ()
	Returns the height of the image.
virtual size_t	GetImageWidth ()
	Returns the width of the image.
virtual PixelFormat	GetPixelFormat ()
	Returns the pixel format that need to be used by writer.
virtual bool	IsProgressive ()
void	set_transform (int transform)
void	set_require_opaque (bool require_opaque)
int	GetColorType ()
bool	GetBackgroundColor (unsigned char *red, unsigned char *green, unsigned char *blue)
virtual ScanlineStatus	InitializeWithStatus (const void *image_buffer, size_t buffer_length)
	This is a no-op and should not be called.
Public Member Functions inherited from pagespeed::image_compression::ScanlineReaderInterface
bool	Initialize (const void *image_buffer, size_t buffer_length)
bool	ReadNextScanline (void **out_scanline_bytes)

Detailed Description

Reader for PNG-encoded data. This is sample code on how someone can use the scanline reader interface. bool func() { if (setjmp(*GetJmpBuf())) { return false; }

InitializeRead(...) while (HasMoreScanlines()) { Scanline line; ReadNextScanline(line); .... .... } }

Member Function Documentation

virtual bool pagespeed::image_compression::PngScanlineReader::IsProgressive ( )

virtual

Returns true if the original image was encoded progressively by the origin site, so that it could be progressively rendered while the image contents were being transferred

Implements pagespeed::image_compression::ScanlineReaderInterface.

virtual ScanlineStatus pagespeed::image_compression::PngScanlineReader::ReadNextScanlineWithStatus ( void **  out_scanline_bytes )

virtual

Reads the next available scanline. Returns the ScanlineStatus of the conversion.

Implements pagespeed::image_compression::ScanlineReaderInterface.

virtual bool pagespeed::image_compression::PngScanlineReader::Reset ( )

virtual

This will only return false as a result of a longjmp due to an unhandled libpng error.

Implements pagespeed::image_compression::ScanlineReaderInterface.

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

• pagespeed/kernel/image/png_optimizer.h