cvr::ioJPEG Class Reference

Class to read and write images store in the Joint Picture Expert Group file format (JPEG). More...

#include <cvrIOJPEG.h>

Inheritance diagram for cvr::ioJPEG:

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Collaboration diagram for cvr::ioJPEG:

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List of all members.

Classes
class	parameters
	Parameter class of ioJPEG. More...
Public Member Functions
	ioJPEG ()
	ioJPEG (const parameters &other)
	ioJPEG (const ioJPEG &other)
	~ioJPEG ()
const parameters &	getParameters () const
virtual const std::string &	name () const
virtual ioJPEG *	clone () const
virtual ioJPEG *	newInstance () const
virtual bool	load (const std::string &filename, image &theImage)
virtual bool	load (const std::string &filename, matrix< ubyte > &theImage, palette &colors)
virtual bool	load (const std::string &filename, matrix< ubyte > &chnl)
virtual bool	load (const std::string &filename, matrix< float > &chnl)
virtual bool	load (const std::string &filename, matrix< int32 > &chnl, palette &pal)
virtual bool	load (const std::string &filename, matrix< int32 > &chnl)
bool	checkHeader (const std::string &filename, headerInformation &info)
virtual bool	save (const std::string &filename, const image &theImage)
virtual bool	save (const std::string &filename, const matrix< ubyte > &theChannel, const cvr::palette &colors)
virtual bool	save (const std::string &filename, const matrix< ubyte > &theChannel)
bool	save (const std::string &filename, const matrix< float > &theChannel)
virtual bool	save (const std::string &filename, const matrix< int32 > &chnl, const palette &pal)
virtual bool	save (const std::string &filename, const matrix< int32 > &chnl)
Additional methods not in ioImageInterface
bool	load (const std::string &filename, image &theImage, bool &isGray)

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Detailed Description

Class to read and write images store in the Joint Picture Expert Group file format (JPEG).

It is NOT thread save, this means, the SAME instance can not be used from different threads or processes at the same time. If this occurs an unpredictible behaviour must be expected!. If this is required, just use a different instance of the functor for each thread, or use mutexes to avoid parallel accesses.

Example:

 cvr::image anImg;                      // an image
 ...
 cvr::ioJPEG loader;                     // the load/save class
 loader.load("~/tmp/theFile.jpeg",img); // load the image.

Exceptions:

BadJpegStream

is thrown when the Stream is corrupted.

See also:

ioImage

There are two implementations of this functor.

• The first one uses the C++ JPEG interface from Miano (at Colosseum Builders C++ Image Library), for which several files are required. These are published under another licence and therefore are not included in the default CVR-Lib . You can use them in non-commercial applications and get them from ltilib.sourceforge.net. See file ltilib/src/io/jpeg/00readme.txt for more information. If the file cvrJPEGFunctor.cpp and the directory jpeg/ are found in ltilib/src/io, and HAVE_LIBJPEG is not defined in basis/cvrConfig.h, this will be the implementation used.

• The second implementation uses the standard JPEG Library, which is usually installed in all Linux distributions, but not for Windows. The implementation is included in the standard CVR-Lib , (file is called cvrJPEGLibFunctor.cpp). The autoconf script (./configure) will automatically detect if you have the libjpeg installed, and activate this implementation if possible. (see http://www.ijg.org/files/ and http://freealter.org/doc_distrib/libgr-2.0.13/jpeg/Libjpeg.html)

We recomend to use the libjpeg, it is more robust against not 100% correct JPEG-files, and it is faster. Mianos' implementation is mainly for windows users who do not want to install the jpeglib.

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Constructor & Destructor Documentation

cvr::ioJPEG::ioJPEG

(

)

Default constructor.

cvr::ioJPEG::ioJPEG

(

const parameters &

other

)

Constructor with parameters.

cvr::ioJPEG::ioJPEG

(

const ioJPEG &

other

)

Copy constructor.

cvr::ioJPEG::~ioJPEG

(

)

Destructor.

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Member Function Documentation

bool cvr::ioJPEG::checkHeader	(	const std::string &	filename,
		headerInformation &	info
	)			[virtual]

Returns the essential image information.

This function will search the file for all chunks with essential picture information. Scanning stops before the first StartOfScan-Block. That is, all comments that follow the image data are not read!

Parameters:

	filename	name of the file to check
	info	contains the header data

Returns:

true if file and header are ok

Implements cvr::ioImageInterface.

virtual ioJPEG* cvr::ioJPEG::clone

(

)

const [virtual]

Returns a pointer to a clone of this functor.

Implements cvr::ioImageInterface.

const parameters& cvr::ioJPEG::getParameters

(

)

const

Returns current parameters.

Reimplemented from cvr::ioImageInterface.

bool cvr::ioJPEG::load	(	const std::string &	filename,
		image &	theImage,
		bool &	isGray
	)

Load image with image type.

Parameters:

	filename	name of the file to read
	theImage	variable where the image is stored
	isGray	will be set with true if the image contains only gray values.

virtual bool cvr::ioJPEG::load	(	const std::string &	filename,
		matrix< int32 > &	chnl
	)			[virtual]

Load the contents as a integer mask.

Default implementation discards the palette of the other matrix<int32> method.

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::load	(	const std::string &	filename,
		matrix< int32 > &	chnl,
		palette &	pal
	)			[virtual]

Load the contents as a integer mask.

Default implementation returns the casting of the channel8 related method.

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::load	(	const std::string &	filename,
		matrix< float > &	chnl
	)			[virtual]

Load a floating point channel.

Not many file formats support floating point channels, so the default implementation just casts a channel8 into the float.

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::load	(	const std::string &	filename,
		matrix< ubyte > &	chnl
	)			[virtual]

Load the contents as a gray channel.

Default implementation just discards the palette of load(const std::string&,matrix<ubyte>&,palette&)

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::load	(	const std::string &	filename,
		matrix< ubyte > &	theImage,
		palette &	colors
	)			[virtual]

Load indexed image.

Implements cvr::ioImageInterface.

virtual bool cvr::ioJPEG::load	(	const std::string &	filename,
		image &	theImage
	)			[virtual]

Load true-color image.

Parameters:

	filename	name of the file to read
	theImage	variable where the image is stored

Implements cvr::ioImageInterface.

virtual const std::string& cvr::ioJPEG::name

(

)

const [virtual]

Returns the name of this class.

Reimplemented from cvr::ioImageInterface.

virtual ioJPEG* cvr::ioJPEG::newInstance

(

)

const [virtual]

Returns a pointer to a new instance of this functor.

Implements cvr::ioImageInterface.

virtual bool cvr::ioJPEG::save	(	const std::string &	filename,
		const matrix< int32 > &	chnl
	)			[virtual]

Save the contents as a integer mask.

Default implementation discards the palette of the other matrix<int32> method.

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::save	(	const std::string &	filename,
		const matrix< int32 > &	chnl,
		const palette &	pal
	)			[virtual]

Save the contents as a integer mask.

Default implementation returns the casting of the channel8 related method.

Reimplemented from cvr::ioImageInterface.

bool cvr::ioJPEG::save	(	const std::string &	filename,
		const matrix< float > &	theChannel
	)			[virtual]

Save a channel as a gray valued JPEG.

Parameters:

	filename	name of the file to save
	theChannel	the channel to be saved

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::save	(	const std::string &	filename,
		const matrix< ubyte > &	theChannel
	)			[virtual]

shortcut for load JPEG

Parameters:

	filename	name of the file to save
	theChannel	the channel to be saved

Reimplemented from cvr::ioImageInterface.

virtual bool cvr::ioJPEG::save	(	const std::string &	filename,
		const matrix< ubyte > &	theChannel,
		const cvr::palette &	colors
	)			[virtual]

Save an "indexed" image contained in the given channel8 (indices) and the given color palette.

Implements cvr::ioImageInterface.

virtual bool cvr::ioJPEG::save	(	const std::string &	filename,
		const image &	theImage
	)			[virtual]

Save an image in JPEG format.

Parameters:

	filename	name of the file to save
	theImage	the image to be saved

Implements cvr::ioImageInterface.

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

• cvrIOJPEG.h