Exiv2::Internal::PngChunk Class Reference

Stateless parser class for data in PNG chunk format. Images use this class to decode and encode PNG-based data. More...

#include <pngchunk_int.hpp>

List of all members.

Public Types
enum	TxtChunkType { tEXt_Chunk = 0, zTXt_Chunk = 1, iTXt_Chunk = 2 }
	Text Chunk types.
Static Public Member Functions
static void	decodeIHDRChunk (const DataBuf &data, int *outWidth, int *outHeight)
	Decode PNG IHDR chunk data from a data buffer data and return image size to outWidth and outHeight.
static void	decodeTXTChunk (Image *pImage, const DataBuf &data, TxtChunkType type)
	Decode PNG tEXt, zTXt, or iTXt chunk data from pImage passed by data buffer data and extract Comment, Exif, Iptc, Xmp metadata accordingly.
static DataBuf	keyTXTChunk (const DataBuf &data, bool stripHeader=false)
	Return PNG TXT chunk key as data buffer.
static std::string	makeMetadataChunk (const std::string &metadata, MetadataId type)
	Return a complete PNG chunk data compressed or not as buffer. Data returned is formated accordingly with metadata type to host passed by metadata.

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Detailed Description

Stateless parser class for data in PNG chunk format. Images use this class to decode and encode PNG-based data.

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Member Function Documentation

void Exiv2::Internal::PngChunk::decodeIHDRChunk	(	const DataBuf &	data,
		int *	outWidth,
		int *	outHeight
	)			[static]

Decode PNG IHDR chunk data from a data buffer data and return image size to outWidth and outHeight.

Parameters:

	data	PNG Chunk data buffer.
	outWidth	Integer pointer to be set to the width of the image.
	outHeight	Integer pointer to be set to the height of the image.

Referenced by decodeTXTChunk(), and Exiv2::PngImage::readMetadata().

void Exiv2::Internal::PngChunk::decodeTXTChunk	(	Image *	pImage,
		const DataBuf &	data,
		TxtChunkType	type
	)			[static]

Decode PNG tEXt, zTXt, or iTXt chunk data from pImage passed by data buffer data and extract Comment, Exif, Iptc, Xmp metadata accordingly.

Parameters:

	pImage	Pointer to the image to hold the metadata
	data	PNG Chunk data buffer.
	type	PNG Chunk TXT type.

References decodeIHDRChunk().

Referenced by Exiv2::PngImage::readMetadata().

DataBuf Exiv2::Internal::PngChunk::keyTXTChunk	(	const DataBuf &	data,
		bool	stripHeader = false
	)			[static]

Return PNG TXT chunk key as data buffer.

Parameters:

	data	PNG Chunk data buffer.
	stripHeader	Set true if chunk data start with header bytes, else false (default).

References Exiv2::getLong(), and Exiv2::DataBuf::pData_.

std::string Exiv2::Internal::PngChunk::makeMetadataChunk	(	const std::string &	metadata,
		MetadataId	type
	)			[static]

Return a complete PNG chunk data compressed or not as buffer. Data returned is formated accordingly with metadata type to host passed by metadata.

Parameters:

	metadata	metadata buffer.
	type	metadata type.

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

• pngchunk_int.hpp
• pngchunk.cpp