JPEGEXT Class Reference

Base class for JPEG image access. More...

#include <mi32/jpegext.h>

Inheritance diagram for JPEGEXT:

[legend]

List of all members.

Public Types
enum	COLORSPACE { CS_Grayscale, CS_RGB, CS_CMYK }
enum	DCTMETHOD {   DCT_ISLOW, DCT_IFAST, DCT_FLOAT, DCT_DEFAULT,   DCT_FASTEST }
Public Member Functions
virtual	~JPEGEXT ()
COLORSPACE	GetColorSpace () const
INT64	GetCompressedSize () const
const Exiv2::ExifData *	GetExifData () const
UINT32	GetHeight () const
bool	GetMetadata (MISTRING &string)
UINT16	GetNumComponents () const
UINT32	GetWidth () const
	MAKEPARMS (UINT32 width=0, UINT32 height=0, UINT32 quality=75)
ERRVALUE	ReadLines (void *buffer, UINT32 numlines)
ERRVALUE	Rewind ()
void	SetColorSpace (COLORSPACE colorspace)
void	SetDCTMethod (DCTMETHOD method)
void	SetNumComponents (UINT16 components)
ERRVALUE	SetZoom (double zoom)
ERRVALUE	WriteLines (const void *buffer, UINT32 numlines)
Protected Types
enum	OPENMODE { OPENMODE_Read = 0, OPENMODE_Write = 1 }
Protected Member Functions
	JPEGEXT (PRIV *pPriv)

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Detailed Description

Base class for JPEG image access.

Parameters for making a new JPEG.

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Member Enumeration Documentation

enum JPEGEXT::COLORSPACE

Enumerator:

CS_Grayscale
CS_RGB
CS_CMYK

enum JPEGEXT::DCTMETHOD

Enumerator:

DCT_ISLOW
DCT_IFAST	Slow but accurate integer algorithm.
DCT_FLOAT	faster, less accurate integer method
DCT_DEFAULT	floating-point method
DCT_FASTEST	default method (normally DCT_ISLOW) fastest method (normally DCT_IFAST)

enum JPEGEXT::OPENMODE [protected]

Enumerator:

OPENMODE_Read
OPENMODE_Write

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Constructor & Destructor Documentation

virtual JPEGEXT::~JPEGEXT

(

)

[virtual]

Destructor.

JPEGEXT::JPEGEXT

(

PRIV *

pPriv

)

[protected]

Base class, cannot be constructed directly.

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Member Function Documentation

COLORSPACE JPEGEXT::GetColorSpace

(

)

const

Get the color space of an existing JPEG.

INT64 JPEGEXT::GetCompressedSize

(

)

const

Get the current size of the compressed JPEG if opened for writing.

Do not use if opened for reading.

const Exiv2::ExifData* JPEGEXT::GetExifData

(

)

const

Get the Exif data for an existing JPEG.

Will return NULL if the Exif header could not be read.

UINT32 JPEGEXT::GetHeight

(

)

const

Get the height of an existing JPEG.

Result is affected by use of SetZoom.

bool JPEGEXT::GetMetadata

(

MISTRING &

string

)

Get the Exif data for an existing JPEG as a formatted text.

Does NOT clear the string first Returns true if there was Exif data, false if not

UINT16 JPEGEXT::GetNumComponents

(

)

const

Get the number of components of an existing JPEG.

UINT32 JPEGEXT::GetWidth

(

)

const

Get the width of an existing JPEG.

Result is affected by use of SetZoom.

JPEGEXT::MAKEPARMS	(	UINT32	width = 0,
		UINT32	height = 0,
		UINT32	quality = 75
	)

Constructor.

ERRVALUE JPEGEXT::ReadLines	(	void *	buffer,
		UINT32	numlines
	)

Read lines.

Returns EBadFuncParm if this is opened for writing.

Parameters:

	buffer	Buffer to contain pixels
	numlines	Number of scanlines to read

ERRVALUE JPEGEXT::Rewind

(

)

Rewind reader to beginning.

void JPEGEXT::SetColorSpace

(

COLORSPACE

colorspace

)

Set the input color space.

void JPEGEXT::SetDCTMethod

(

DCTMETHOD

method

)

Set the algorithm used for the DCT step.

void JPEGEXT::SetNumComponents

(

UINT16

components

)

ERRVALUE JPEGEXT::SetZoom

(

double

zoom

)

Set zoom value for decompression.

Must be used after Open or Rewind before ReadLines. Will affect result of GetHeight and GetWidth

Parameters:

zoom

Zoom value, must be 1, 1/2, 1/4 or 1/8

ERRVALUE JPEGEXT::WriteLines	(	const void *	buffer,
		UINT32	numlines
	)

Parameters:

	buffer	Buffer containing pixels to write
	numlines	Number of lines to write

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

• mi32/jpegext.h