IlvQuantizer Class Reference

Quantizer base class. More...

#include <ilviews/bitmaps/quantize.h>

Inheritance diagram for IlvQuantizer:

List of all members.

Public Member Functions
virtual IlvColorMap *	computeColorMap (const IlvBitmapData *data, IlUInt numcols)=0
	Computes the colormap from the original true color bitmap data.
virtual IlBoolean	hasDithering () const
	Returns whether the instance uses Floyd-Steinberg dithering.
virtual IlvIndexedBitmapData *	quantize (const IlvBitmapData *data, IlUInt numcols)
	Creates indexed bitmap data from true color bitmap data using the requested number of colors (this number can be ignored by the actual quantizer). The default implementation calls computeColorMap and then remap.
virtual IlvIndexedBitmapData *	remap (const IlvBitmapData *data, const IlvColorMap *colormap, IlBoolean fsdither=((IlBoolean) 1))
	Remaps the true colors to the indexed colors.
void	setDithering (IlBoolean dither)
	Sets whether the instance uses Floyd-Steinberg dithering.

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Detailed Description

Quantizer base class.

Library: display

This class provides methods to convert true color images to indexed images. This is a virtual class that must be subclassed. This class knows how to remap true colors to indexed colors using a dithering method called Floyd-Steinberg diffusion, leading to high quality images, even with few colors.

See also:

IlvFixedQuantizer, IlvQuickQuantizer, IlvWUQuantizer, IlvNetscapeQuantizer

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Member Function Documentation

virtual IlvColorMap* IlvQuantizer::computeColorMap	(	const IlvBitmapData *	data,
		IlUInt	numcols
	)			[pure virtual]

Computes the colormap from the original true color bitmap data.

Parameters:

	data	The original true color bitmap data.
	numcols	The requested number of colors.

Returns:

The computed colormap.

Implemented in IlvFixedQuantizer, and IlvWUQuantizer.

virtual IlBoolean IlvQuantizer::hasDithering

(

)

const [virtual]

Returns whether the instance uses Floyd-Steinberg dithering.

Returns:

IlTrue if the instance uses Floyd-Steinberg dithering.

virtual IlvIndexedBitmapData* IlvQuantizer::quantize	(	const IlvBitmapData *	data,
		IlUInt	numcols
	)			[virtual]

Creates indexed bitmap data from true color bitmap data using the requested number of colors (this number can be ignored by the actual quantizer). The default implementation calls computeColorMap and then remap.

Parameters:

	data	The true color bitmap data.
	numcols	The requested number of colors.

Returns:

The computed indexed bitmap data.

virtual IlvIndexedBitmapData* IlvQuantizer::remap	(	const IlvBitmapData *	data,
		const IlvColorMap *	colormap,
		IlBoolean	fsdither = ((IlBoolean) 1)
	)			[virtual]

Remaps the true colors to the indexed colors.

Parameters:

	data	The original true color bitmap data.
	colormap	The colormap to remap the bitmap data to.
	fsdither	An IlBoolean value to indicate whether or not to use Floyd-Steinberg error diffusion.

Returns:

The computed indexed bitmap data.

Reimplemented in IlvQuickQuantizer.

void IlvQuantizer::setDithering

(

IlBoolean

dither

)

Sets whether the instance uses Floyd-Steinberg dithering.

Parameters:

dither

An IlBoolean indicating whether dithering is performed.