rgb2ind.c File Reference

Convert a truecolor RGB image to an indexed image. More...

#include <stdio.h>
#include <string.h>
#include "rgb2ind.h"

Go to the source code of this file.

Data Structures
struct	bbox
	Bounding box struct for median cut color quantization. More...

Functions
static long	BoxVolume (bbox Box)
	Compute the volume of a bbox.
static void	MedianSplit (bbox *NewBox, bbox *SplitBox, const unsigned char *RgbImage, long NumPixels)
	Split a bbox along its longest dimension at the median.
int	Rgb2Ind (unsigned char *Dest, unsigned char *Palette, int NumColors, const unsigned char *RgbImage, long NumPixels)
	Convert a truecolor RGB image to an indexed image. More...

Detailed Description

Convert a truecolor RGB image to an indexed image.

Author

Pascal Getreuer getre.nosp@m.uer@.nosp@m.gmail.nosp@m..com

Copyright (c) 2011, Pascal Getreuer All rights reserved.

This program is free software: you can redistribute it and/or modify it under, at your option, the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version, or the terms of the simplified BSD license.

You should have received a copy of these licenses along with this program. If not, see http://www.gnu.org/licenses/ and http://www.opensource.org/licenses/bsd-license.html.

Definition in file rgb2ind.c.

Function Documentation

int Rgb2Ind	(	unsigned char *	Dest,
		unsigned char *	Palette,
		int	NumColors,
		const unsigned char *	RgbImage,
		long	NumPixels
	)

Convert a truecolor RGB image to an indexed image.

Parameters

Dest	where to store the indexed image
Palette	where to store the palette
NumColors	maximum number of colors to use
RgbImage	the input RGB image
NumPixels	number of pixels in RgbImage

Returns

1 on success, 0 on failure

This routine quantizes the colors of the input RgbImage to an indexed image Dest using at most NumColors distinct colors. RgbImage should be a contiguous array of RGB triples,

ImageRgb[3*i + 0] = Red component of the ith pixel,
ImageRgb[3*i + 1] = Green component of the ith pixel,
ImageRgb[3*i + 2] = Blue component of the ith pixel.

Dest should be an array with space for at least NumPixels elements, and Palette should have space for at least 3*NumColors elements. Dest and Palette are filled such that the quantized image is

Palette[3*Dest[i] + 0] = Red component of the ith pixel,
Palette[3*Dest[i] + 1] = Green component of the ith pixel,
Palette[3*Dest[i] + 2] = Blue component of the ith pixel.

The quantized image should approximate RgbImage.

The quantization is performed using the median cut algorithm. No dithering is performed.

Definition at line 70 of file rgb2ind.c.