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jedi-outcast/utils/roq2/libim/imvfbto.c
Jonathan Gray e4d728c502 ditch dos style newlines
2013-04-22 15:25:59 +10:00

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/**
** $Header: /roq/libim/imvfbto.c 1 11/02/99 4:38p Zaphod $
** Copyright (c) 1989-1995 San Diego Supercomputer Center (SDSC)
** a division of General Atomics, San Diego, California, USA
**
** Users and possessors of this source code are hereby granted a
** nonexclusive, royalty-free copyright and design patent license to
** use this code in individual software. License is not granted for
** commercial resale, in whole or in part, without prior written
** permission from SDSC. This source is provided "AS IS" without express
** or implied warranty of any kind.
**
** For further information contact:
** E-Mail: info@sds.sdsc.edu
**
** Surface Mail: Information Center
** San Diego Supercomputer Center
** P.O. Box 85608
** San Diego, CA 92138-5608
** (619) 534-5000
**/
#define HEADER " $Header: /roq/libim/imvfbto.c 1 11/02/99 4:38p Zaphod $"
/**
** FILE
** imvfbto.c - Image Library VFB depth conversions
**
** PROJECT
** libim - SDSC image manipulation library
**
** DESCRIPTION
** These functions convert images from their current depth to
** images of a specific depth:
** to 24-bit true color
** to 8-bit color index + CLT
** to 16-bit color index + CLT
** to 8-bit grey index
** to 1-bit mono
**
** PUBLIC CONTENTS
** d =defined constant
** f =function
** m =defined macro
** t =typedef/struct/union
** v =variable
** ? =other
**
** ImVfbToRgb f convert a vfb to 24-bit color
** ImVfbToMono f convert to 8-bit monochrome
** ImVfbFSDitherToMono f dither a Vfb to monochrome using
** Floyd-Steinberg dithering
** ImVfbToGray f convert to 8-bit grayscale
** ImVfbToIndex f convert to n-bit color
** ImVfbToIndex8 f convert to 8-bit color
** ImVfbToIndex16 f convert to 8-bit color
**
** PRIVATE CONTENTS
** none
**
** HISTORY
** $Log: /roq/libim/imvfbto.c $
*
* 1 11/02/99 4:38p Zaphod
** Revision 1.18 1995/06/29 00:28:04 bduggan
** updated copyright year
**
** Revision 1.17 1995/06/16 09:01:34 bduggan
** changed bzero to memset. removed some unused vars
**
** Revision 1.16 1995/03/31 05:50:22 bduggan
** Grab the lower 8-bits when converting to index8 from index16
** instead of the upper 8-bits.
**
** Revision 1.15 1995/02/16 21:43:47 bduggan
** Removed threshold variable from dither function
**
** Revision 1.14 1995/01/18 21:49:37 bduggan
** Put in ImCallocRetOnError macro so that -1
** is not returned from a function that's supposed to return
** a pointer
**
** Revision 1.13 1995/01/12 00:36:02 bduggan
** Added dithering support
**
** Revision 1.12 94/10/03 11:29:58 nadeau
** Updated to ANSI C and C++ compatibility.
** Removed all use of register keyword.
** Minimized use of custom SDSC types (e.g., uchar vs. unsigned char)
** Changed all float arguments to double.
** Added forward declarations.
** Added misc. casts to passify SGI and DEC compilers.
** Changed all macros and defined constants to have names
** starting with IM.
** Updated comments.
** Updated indenting on some code.
** Updated copyright message.
**
** Revision 1.11 92/09/18 12:39:07 vle
** Fixed bug in ImVfbToMono() that caused RGB images to be monochromed
** incorrectly.
**
** Revision 1.10 92/09/17 14:58:08 vle
** Added ImVfbToIndex() which converts any VFB type to an N color
** indexed VFB. Modified TryRGB() and TryYUV() to accommadate
** the changes. Fixed bug in ImVfbToIndex16() that caused image
** data to be shifted when it shouldn't be. Updated copyright
** notice.
**
** Revision 1.9 91/10/03 09:23:49 nadeau
** Fixed problem that mapped mono white to (1,1,1) instead
** of (255,255,255) on RGB conversion. Added another decimal
** place to RED/GREEN/BLUE percentages for grayscale conversion.
** Fixed #includes.
**
** Revision 1.8 91/03/13 12:55:43 nadeau
** Typo fixed.
**
** Revision 1.7 91/03/13 12:49:15 nadeau
** Fixed minor CLT grayscale filling bug that always counted to
** 256, whether the CLT was that big or not.
**
** Revision 1.6 91/03/08 14:38:32 nadeau
** Added lots of comments. Added more robust support for the
** various VFB types. Added IMVFBINDEX16 and IMVFBMONO support.
**
** Revision 1.5 91/01/30 18:14:22 nadeau
** Added mono conversion and check and fixed bug in gray conversion.
**
** Revision 1.4 90/10/22 16:40:53 nadeau
** Moved imvfbto8color.c into the file.
**
** Revision 1.3 90/07/23 12:57:12 todd
** Add grayscale (no CLT) to ImVfbTo24()
**
** Revision 1.2 90/07/02 13:23:07 nadeau
** Updated comment and added inclusion of iminternal.h.
**
** Revision 1.1 90/05/11 14:29:07 nadeau
** Initial revision
**
**/
/**
** CODE CREDITS
** Custom development, Dave Nadeau, San Diego Supercomputer Center, 1990.
**/
#include <math.h>
#include "iminternal.h"
#ifdef __STDC__
ImVfb *ImVfbToGray( ImVfb *srcVfb, ImVfb *dstVfb );
#else
ImVfb *ImVfbToGray();
#endif
/*
* FUNCTION
* ImVfbToRgb - convert a vfb to RGB
*
* DESCRIPTION
* Promotion:
* Mono VFB:
* Index8 VFB:
* Index 16 VFB:
* Copied to RGB VFB. CLT used, if any. Otherwise
* grayscale assumed.
*
* No change:
* RGB VFB:
* Copied to RGB VFB.
*
* CLT HANDLING
* When a CLT is not present, the RGB values are generated assuming
* the incoming image is grayscale. Each grayscale index is copied
* to all three channels (red, green, blue) of the RGB VFB. For 16-bit
* index VFB's, the indexes are (unavoidably) truncated to the lower
* 8-bits.
*
* When a CLT is present, the RGB values are generated by looking up
* each VFB index in the CLT and copying the corresponding red, green,
* and blue values to the RGB VFB.
*/
ImVfb * /* Returns changed VFB */
#ifdef __STDC__
ImVfbToRgb( ImVfb *srcVfb, ImVfb *dstVfb )
#else
ImVfbToRgb( srcVfb, dstVfb )
ImVfb *srcVfb; /* input vfb */
ImVfb *dstVfb; /* possibly the output vfb */
#endif
{
ImVfb *rgbVfb; /* the 24-bit vfb */
ImVfbPtr in; /* input pointer into srcVfb */
ImVfbPtr out; /* output pointer into rgbVfb */
ImClt *clt; /* the clt of the source vfb */
ImCltPtr cp; /* pointer into clt */
int fields; /* Input VFB's field mask */
int type; /* Type of input VFB */
ImVfbPtr last; /* Last pointer for input VFB */
int index; /* Color index */
/*
* Create the new VFB, if needed.
*/
if ( dstVfb == IMVFBNEW )
{
if ( (rgbVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBRGB )) == IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
/*
* Confirm the given VFB has an RGB field and that it has
* the same image dimensions.
*/
if ( !(ImVfbQFields( dstVfb ) & IMVFBRGB) )
{
ImErrNo = IMENOTRGB;
return ( IMVFBNULL );
}
if ( ImVfbQWidth( srcVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( srcVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
rgbVfb = dstVfb;
}
/*
* Figure out where to get input colors to be put into the RGB VFB.
*/
clt = ImVfbQClt( srcVfb ); /* Might be IMCLTNULL */
fields = ImVfbQFields( srcVfb );
if ( fields & IMVFBINDEX16 )
type = IMVFBINDEX16; /* 16-bit color index */
else if ( fields & IMVFBINDEX8 )
type = IMVFBINDEX8; /* 8-bit color index */
else if ( fields & IMVFBMONO )
type = IMVFBMONO; /* 1-bit mono */
else if ( fields & IMVFBRGB )
{
if ( srcVfb == dstVfb )
return ( srcVfb ); /* Already RGB */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
ImVfbSRed( rgbVfb, out, ImVfbQRed( srcVfb, in ) );
ImVfbSGreen( rgbVfb, out, ImVfbQGreen( srcVfb, in ) );
ImVfbSBlue( rgbVfb, out, ImVfbQBlue( srcVfb, in ) );
}
return ( rgbVfb );
}
else
{
/*
* No image to convert?
*/
if ( dstVfb != rgbVfb )
ImVfbFree( rgbVfb );
ImErrNo = IMENOTINFO;
return ( IMVFBNULL );
}
if ( clt == IMCLTNULL )
{
/*
* No color table. Assume grayscale.
*/
switch ( type )
{
case IMVFBMONO: /* Monochrome */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
index = (ImVfbQMono( srcVfb, in ) & 0x1);
ImVfbSRed( rgbVfb, out, index * 255 );
ImVfbSGreen( rgbVfb, out, index * 255 );
ImVfbSBlue( rgbVfb, out, index * 255 );
}
return ( rgbVfb );
case IMVFBINDEX8: /* 8-bit color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
index = ImVfbQIndex8( srcVfb, in );
ImVfbSRed( rgbVfb, out, index );
ImVfbSGreen( rgbVfb, out, index );
ImVfbSBlue( rgbVfb, out, index );
}
return ( rgbVfb );
case IMVFBINDEX16: /* 16-bit color */
/*
* Grab the lower 8-bits of each index and treat it
* as a grayscale value.
*/
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
index = ((ImVfbQIndex16( srcVfb, in )) & 0x00FF);
ImVfbSRed( rgbVfb, out, index );
ImVfbSGreen( rgbVfb, out, index );
ImVfbSBlue( rgbVfb, out, index );
}
return ( rgbVfb );
}
}
/*
* Has color table.
*/
switch ( type )
{
case IMVFBMONO: /* Monochrome */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
cp = ImCltQPtr( clt, ImVfbQMono( srcVfb, in ) ) ;
ImVfbSRed( rgbVfb, out, ImCltQRed( cp ) );
ImVfbSGreen( rgbVfb, out, ImCltQGreen( cp ) );
ImVfbSBlue( rgbVfb, out, ImCltQBlue( cp ) );
}
break;
case IMVFBINDEX8: /* 8-bit color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
cp = ImCltQPtr( clt, ImVfbQIndex8( srcVfb, in ) ) ;
ImVfbSRed( rgbVfb, out, ImCltQRed( cp ) );
ImVfbSGreen( rgbVfb, out, ImCltQGreen( cp ) );
ImVfbSBlue( rgbVfb, out, ImCltQBlue( cp ) );
}
break;
case IMVFBINDEX16: /* 16-bit color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(rgbVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(rgbVfb,out) )
{
cp = ImCltQPtr( clt, ImVfbQIndex16( srcVfb, in ) ) ;
ImVfbSRed( rgbVfb, out, ImCltQRed( cp ) );
ImVfbSGreen( rgbVfb, out, ImCltQGreen( cp ) );
ImVfbSBlue( rgbVfb, out, ImCltQBlue( cp ) );
}
break;
}
return ( rgbVfb );
}
/*
* CONSTANTS & MACRO
* *_PERCENT - percent contribution to computation of YIQ gray
* YIQ - compute YIQ grayscale from RGB
*
* DESCRIPTION
* The red, green, and blue components of a color are combined
* to get a gray value via the formula:
*
* gray = 0.30 * red + 0.59 * green + 0.11 * blue + 0.5
*
* This is based upon the NTSC YIQ Y equation that computes the intensity
* value to be used in displaying a color image on a black-n-white TV.
*/
#define IM_RED_PERCENT 0.299
#define IM_GREEN_PERCENT 0.587
#define IM_BLUE_PERCENT 0.114
#define IM_NTSCY( red, green, blue ) \
((int)( IM_RED_PERCENT * (float) (red) + \
IM_GREEN_PERCENT * (float) (green) + \
IM_BLUE_PERCENT * (float) (blue) + 0.5 ))
/*
* FUNCTION
* ImVfbToMono - convert to 1-bit monochrome
*
* DESCRIPTION
* No change:
* Mono VFB:
* Copied to 1-bit mono VFB.
*
* Demotion:
* Index8 VFB:
* Index 16 VFB:
* If no CLT, assumed already grayscale and just
* thresholded and copied. Otherwise pixels converted
* to NTSC Y space to generate grayscale. Those are
* thresholded and copied.
* RGB VFB:
* Pixels converted to NTSC Y space to generate gray.
* Those are thresholded and copied.
*
* NTSC Y SPACE CONVERSION
* The red, green, and blue components of each pixel color are combined
* to get a gray value via the formula:
*
* gray = 0.30 * red + 0.59 * green + 0.11 * blue + 0.5
*
* This is based upon the NTSC YIQ Y equation that computes the intensity
* value to be used in displaying a color image on a black-n-white TV.
*
* MONO THRESHOLD
* Grayscale values less than or equal to the monoThreshold argument
* are considered 'black' and given a mono value of 0. Those above
* the threshold are considered 'white' and given a mono value of 1.
*/
ImVfb * /* Returns mono VFB */
#ifdef __STDC__
ImVfbToMono( ImVfb *srcVfb, int monoThreshold, ImVfb *dstVfb )
#else
ImVfbToMono( srcVfb, monoThreshold, dstVfb )
ImVfb *srcVfb; /* the vfb to change to mono */
int monoThreshold; /* Threshold index */
ImVfb *dstVfb; /* the destination vfb */
#endif
{
int i; /* color index counter */
int g; /* computed gray */
int fields; /* Source fields */
ImVfb *monoVfb; /* the new vfb to create */
ImVfbPtr in; /* input pointer */
ImVfbPtr out; /* output pointer */
ImClt *clt; /* color lookup table */
ImCltPtr cp; /* lookup table pointer */
int glt[256]; /* gray lookup table */
ImVfbPtr last; /* Last pointer for input VFB */
int type; /* Type of VFB */
int index; /* Color index holder */
/*
* Create the new VFB, if needed.
*/
if ( dstVfb == IMVFBNEW )
{
if ( (monoVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBMONO )) == IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
/*
* Confirm the given VFB has a mono field and that it has
* the same image dimensions.
*/
if ( !(ImVfbQFields( dstVfb ) & IMVFBMONO) )
{
ImErrNo = IMENOTMONO;
return ( IMVFBNULL );
}
if ( ImVfbQWidth( srcVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( srcVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
monoVfb = dstVfb;
}
/*
* Figure out where to get input colors to be put into the mono VFB.
*/
clt = ImVfbQClt( srcVfb ); /* Might be IMCLTNULL */
fields = ImVfbQFields( srcVfb );
if ( fields & IMVFBINDEX16 )
type = IMVFBINDEX16; /* 16-bit color index */
else if ( fields & IMVFBINDEX8 )
type = IMVFBINDEX8; /* 8-bit color index */
else if ( fields & IMVFBRGB )
type = IMVFBRGB; /* 24-bit RGB color */
else if ( fields & IMVFBMONO )
{
if ( srcVfb == dstVfb )
return ( srcVfb ); /* Already mono */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(monoVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
ImVfbSMono( monoVfb, out, ImVfbQMono( srcVfb, in ) );
}
return ( monoVfb );
}
else
{
/*
* No image to convert?
*/
if ( dstVfb != monoVfb )
ImVfbFree( monoVfb );
ImErrNo = IMENOTINFO;
return ( IMVFBNULL );
}
if ( clt == IMCLTNULL )
{
/*
* No color table. Assume grayscale.
*/
switch ( type )
{
case IMVFBINDEX8: /* 8-bit color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(monoVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
index = ImVfbQIndex8( srcVfb, in );
if ( index > monoThreshold )
index = 1;
else
index = 0;
ImVfbSMono( monoVfb, out, index );
}
return ( monoVfb );
case IMVFBINDEX16: /* 16-bit color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(monoVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
index = ImVfbQIndex16( srcVfb, in );
if ( index > monoThreshold )
index = 1;
else
index = 0;
ImVfbSMono( monoVfb, out, index );
}
return ( monoVfb );
case IMVFBRGB: /* RGB true-color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst( monoVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
g = IM_NTSCY( ImVfbQRed( srcVfb, in ),
ImVfbQGreen( srcVfb, in ),
ImVfbQBlue( srcVfb, in ) );
if ( g > monoThreshold )
g = 1;
else
g = 0;
ImVfbSMono( monoVfb, out, g );
}
return ( monoVfb );
}
}
/*
* Has color table. Use NTSC Y conversion.
*/
switch ( type )
{
case IMVFBINDEX8: /* 8-bit color */
/*
* Scan the CLT and create a temporary gray
* lookup table. Then scan the image, looking up each
* 8-bit index in the gray (mono) CLT to get a mono value.
*/
for( i=0, cp=ImCltQFirst(clt); i<ImCltQNColors(clt); i++, ImCltSInc(clt,cp) )
{
g = IM_NTSCY( ImCltQRed( cp ), ImCltQGreen( cp ),
ImCltQBlue( cp ) );
if ( g > monoThreshold )
glt[i] = 1;
else
glt[i] = 0;
}
for ( ; i < 256; i++ )
glt[i] = 0;
last = ImVfbQLast( srcVfb );
for( in = ImVfbQFirst(srcVfb), out = ImVfbQFirst( monoVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
g = glt[ ImVfbQIndex8( srcVfb, in ) ];
ImVfbSMono( monoVfb, out, g );
}
return ( monoVfb );
case IMVFBINDEX16: /* 16-bit color */
/*
* 16-bit (or less) index. Creating a temporary CLT
* capable of holding 2^16 = 65535 entries is a bit much.
* So, the image is scanned and each pixel looked up in
* the VFB's CLT, then converted a gray-scale value.
* Slower, but more practical.
*/
last = ImVfbQLast( srcVfb );
for( in = ImVfbQFirst(srcVfb), out = ImVfbQFirst( monoVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
cp = ImCltQPtr( clt, ImVfbQIndex16( srcVfb, in ) );
g = IM_NTSCY( ImCltQRed( cp ), ImCltQGreen( cp ),
ImCltQBlue( cp ) );
if ( g > monoThreshold )
g = 1;
else
g = 0;
ImVfbSMono( monoVfb, out, g );
}
return ( monoVfb );
case IMVFBRGB: /* RGB true-color */
/*
* Don't know what it means to have an RGB VFB with a CLT?
* Ignore the CLT.
*/
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst( monoVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(monoVfb,out) )
{
g = IM_NTSCY( ImVfbQRed( srcVfb, in ),
ImVfbQGreen( srcVfb, in ),
ImVfbQBlue( srcVfb, in ) );
if ( g > monoThreshold )
g = 1;
else
g = 0;
ImVfbSMono( monoVfb, out, g );
}
return ( monoVfb );
}
return IMVFBNULL;
}
/*
* FUNCTION
* ImVfbFSDitherToMono
*
* DESCRIPTION
* Dither a color image to black and white, using the Floyd Steinberg
* algorithm.
*
* FLOYD-STEINBERG ALGORITHM
* First, we convert the image to greyscale. Then we traverse the
* image from top to bottom, and left to right. If a given pixel
* has a value greater than or equal to 255, then this pixel is
* set to white in the outgoing mono vfb, and the error (i.e. how much
* more than 255 this pixel is) is propogated to the surrounding pixels.
*
* Seven-sixteenths of the error propogates to the right neighbor,
* three-sixteenths to the bottom-left, five-sixteenths to the bottom,
* and one-sixteenths to the bottom-right.
*
* ---- xx 7/16
* 3/16 5/16 1/16
*
* The purpose of the algorithm is to enable one to dither an image in
* a single top-bottom, left-right pass.
*
* RETURN VALUE
* The destination VFB, or IMVFBNULL if an error has occurred.
*
*/
ImVfb * /* Returns mono VFB */
#ifdef __STDC__
ImVfbFSDitherToMono(ImVfb *sourceVfb, ImVfb *dstVfb)
#else
ImVfbFSDitherToMono(sourceVfb, dstVfb)
ImVfb *sourceVfb;
ImVfb *dstVfb;
#endif
{
ImVfb *grayVfb; /* VFB to hold grayscale image */
ImVfbPtr vfbptr; /* Ptr into a vfb */
int *dithered; /* Dithered values */
int row, column; /* Loop indices */
int width, height; /* Width, height of image */
int error; /* Error value to propogate */
/*
* Create a new vfb if necessary
*/
if ( dstVfb == IMVFBNEW )
{
if ( (dstVfb = ImVfbAlloc( ImVfbQWidth( sourceVfb ),
ImVfbQHeight( sourceVfb ), IMVFBMONO )) == IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
/*
* Confirm that the given VFB has a mono field and that it
* has the same image dimensions.
*/
if ( !(ImVfbQFields( dstVfb ) & IMVFBMONO) )
{
ImErrNo = IMENOTMONO;
return ( IMVFBNULL );
}
if ( ImVfbQWidth( sourceVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( sourceVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
}
/*
* First, create a Grayscale version of the image with the same
* height and width
*/
width = ImVfbQWidth (sourceVfb);
height = ImVfbQHeight (sourceVfb);
grayVfb = ImVfbAlloc (width, height, IMVFBGRAY);
if (grayVfb == IMVFBNULL)
{
ImErrNo = IMEMALLOC;
return ( IMVFBNULL );
}
/*
* Next create space for the dithered image
*/
ImCallocRetOnError( dithered, int *, (width * height), (sizeof(int)), NULL);
if (dithered == NULL)
{
ImErrNo = IMEMALLOC;
return (IMVFBNULL);
}
/*
* Convert the color image to grayscale and then loop through
* the entire image to pull out the individual grayscale values.
*
* The grayscale values are between 0 and 255, with 0 being black
* and 255 being white.
*/
if ((ImVfbToGray (sourceVfb, grayVfb)) == IMVFBNULL)
{
/* ImErrNo will have been set by ImVfbToGray */
return ( IMVFBNULL );
}
vfbptr = ImVfbQFirst (grayVfb);
for (row = 0; row < height; row++)
{
for (column = 0; column < width; column++)
{
dithered[row*width+column] = ImVfbQGray (grayVfb, vfbptr);
ImVfbSInc (grayVfb, vfbptr);
}
}
ImVfbFree (grayVfb); /* Free the grayscale vfb */
/*
* Loop through the image and set the monochrome vfb to black or
* white depending on the current image value. Then propogate
* the error to the neighboring pixels.
*/
vfbptr = ImVfbQFirst (dstVfb);
for (row = 0; row < height; row++)
{
for (column = 0; column < width; column++)
{
/*
* If the value is over the threshold, then set the pixel
* white, otherwise set it to black
*/
if (dithered[row*width+column] > 255)
{
ImVfbSMono (dstVfb, vfbptr, 1);
error = (dithered[row*width+column]) - 255;
}
else
{
ImVfbSMono (dstVfb, vfbptr, 0);
error = dithered[row*width+column];
}
/*
* Propogate the error to the right neighbor
*/
if (column < width - 1)
dithered[row*width+column+1] += ((7 * error) / 16);
/*
* Propogate the error to the next row
*/
if (row < height - 1)
{
dithered[(row+1)*width+column] += ((5 * error) / 16);
if (column > 0)
dithered[(row+1)*width+column-1] += ((3 * error) / 16);
if (column < width -1)
dithered[(row+1)*width+column+1] += (error / 16);
}
ImVfbSInc (dstVfb, vfbptr);
}
}
/*
* Free the dithered image
*/
free (dithered);
return (dstVfb);
}
/*
* FUNCTION
* ImVfbToGray - convert to 8-bit grayscale
*
* DESCRIPTION
* Promotion:
* Mono VFB:
* Copied to 8-bit gray VFB. CLT copied, if any.
* Otherwise grayscale assumed.
*
* Demotion:
* Index8 VFB:
* If no CLT, assumed already grayscale and just copied.
* Otherwise pixels converted to NTSC Y space to generate
* grayscale.
* Index 16 VFB:
* If no CLT, assumed already grayscale and just copied
* (truncating indexes!). Otherwise pixels converted
* to NTSC Y space to generate grayscale.
* RGB VFB:
* Pixels converted to NTSC Y space to generate gray.
*
* NTSC Y SPACE CONVERSION
* The red, green, and blue components of each pixel color are combined
* to get a gray value via the formula:
*
* gray = 0.30 * red + 0.59 * green + 0.11 * blue + 0.5
*
* This is based upon the NTSC YIQ Y equation that computes the intensity
* value to be used in displaying a color image on a black-n-white TV.
*/
ImVfb * /* Returns gray VFB */
#ifdef __STDC__
ImVfbToGray( ImVfb *srcVfb, ImVfb *dstVfb )
#else
ImVfbToGray( srcVfb, dstVfb )
ImVfb *srcVfb; /* the vfb to change to gray */
ImVfb *dstVfb; /* the destination vfb */
#endif
{
int i; /* color index counter */
int g; /* computed gray */
int fields; /* Source fields */
ImVfb *grayVfb; /* the new vfb to create */
ImVfbPtr in; /* input pointer */
ImVfbPtr out; /* output pointer */
ImClt *clt; /* color lookup table */
ImCltPtr cp; /* lookup table pointer */
int glt[256]; /* gray lookup table */
ImVfbPtr last; /* Last pointer for input VFB */
int type; /* Type of VFB */
int index; /* Color index holder */
/*
* Create the new VFB, if needed.
*/
if ( dstVfb == IMVFBNEW )
{
if ( (grayVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBINDEX8 )) == IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
/*
* Confirm the given VFB has a gray field and that it has
* the same image dimensions.
*/
if ( !(ImVfbQFields( dstVfb ) & IMVFBINDEX8) )
{
ImErrNo = IMENOTINDEX8;
return ( IMVFBNULL );
}
if ( ImVfbQWidth( srcVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( srcVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
grayVfb = dstVfb;
}
/*
* Figure out where to get input colors to be put into the gray VFB.
*/
clt = ImVfbQClt( srcVfb ); /* Might be IMCLTNULL */
fields = ImVfbQFields( srcVfb );
if ( fields & IMVFBINDEX16 )
type = IMVFBINDEX16; /* 16-bit color index */
else if ( fields & IMVFBINDEX8 )
type = IMVFBINDEX8; /* 8-bit color index */
else if ( fields & IMVFBRGB )
type = IMVFBRGB; /* 24-bit RGB color */
else if ( fields & IMVFBMONO )
type = IMVFBMONO; /* 1-bit mono */
else
{
/*
* No image to convert?
*/
if ( dstVfb != grayVfb )
ImVfbFree( grayVfb );
ImErrNo = IMENOTINFO;
return ( IMVFBNULL );
}
if ( clt == IMCLTNULL )
{
/*
* No color table. Assume grayscale.
*/
switch ( type )
{
case IMVFBMONO: /* Monochrome */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(grayVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
index = ImVfbQMono( srcVfb, in );
if ( index == 0 )
ImVfbSIndex8( grayVfb, out, 0 );
else
ImVfbSIndex8( grayVfb, out, 255 );
}
return ( grayVfb );
case IMVFBINDEX8: /* 8-bit color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(grayVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
ImVfbSIndex8( grayVfb, out, ImVfbQIndex8( srcVfb, in ) );
}
return ( grayVfb );
case IMVFBINDEX16: /* 16-bit color */
/*
* Grab the upper 8-bits of each index and treat it
* as a grayscale value.
*/
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(grayVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
index = ((ImVfbQIndex16( srcVfb, in )) & 0xFF00)>>8;
ImVfbSIndex8( grayVfb, out, index );
}
return ( grayVfb );
case IMVFBRGB: /* RGB true-color */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst( grayVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
g = IM_NTSCY( ImVfbQRed( srcVfb, in ),
ImVfbQGreen( srcVfb, in ),
ImVfbQBlue( srcVfb, in ) );
ImVfbSIndex8( grayVfb, out, g );
}
return ( grayVfb );
}
}
/*
* Has color table. Use NTSC Y conversion.
*/
switch ( type )
{
case IMVFBMONO: /* Monochrome */
/*
* Create a 2-entry temporary gray lookup table. Then scan
* the image, looking up each 1-bit index in the gray CLT
* to get a gray scale value.
*/
cp = ImCltQFirst( clt );
glt[0] = IM_NTSCY( ImCltQRed( cp ), ImCltQGreen( cp ),
ImCltQBlue( cp ) );
ImCltSInc( clt, cp );
glt[1] = IM_NTSCY( ImCltQRed( cp ), ImCltQGreen( cp ),
ImCltQBlue( cp ) );
last = ImVfbQLast( srcVfb );
for( in = ImVfbQFirst(srcVfb), out = ImVfbQFirst( grayVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
g = glt[ ((ImVfbQMono( srcVfb, in )) & 0x1) ];
ImVfbSIndex8( grayVfb, out, g );
}
return ( grayVfb );
case IMVFBINDEX8: /* 8-bit color */
/*
* Scan the CLT and create a temporary gray lookup table.
* Then scan the image, looking up each 8-bit index in the
* gray CLT to get a gray scale value.
*/
for( i=0, cp=ImCltQFirst(clt); i<ImCltQNColors(clt); i++, ImCltSInc(clt,cp) )
{
glt[i] = IM_NTSCY( ImCltQRed( cp ), ImCltQGreen( cp ),
ImCltQBlue( cp ) );
}
for ( ; i < 256; i++ )
glt[i] = 0;
last = ImVfbQLast( srcVfb );
for( in = ImVfbQFirst(srcVfb), out = ImVfbQFirst( grayVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
g = glt[ ImVfbQIndex8( srcVfb, in ) ];
ImVfbSIndex8( grayVfb, out, g );
}
return ( grayVfb );
case IMVFBINDEX16: /* 16-bit color */
/*
* 16-bit (or less) index. Creating a temporary CLT
* capable of holding 2^16 = 65536 entries is a
* bit much. So, the image is scanned and each
* pixel looked up in the VFB's CLT, then converted a
* gray-scale value. Slower, but more practical.
*/
last = ImVfbQLast( srcVfb );
for( in = ImVfbQFirst(srcVfb), out = ImVfbQFirst( grayVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
cp = ImCltQPtr( clt, ImVfbQIndex16( srcVfb, in ) );
g = IM_NTSCY( ImCltQRed( cp ), ImCltQGreen( cp ),
ImCltQBlue( cp ) );
ImVfbSIndex8( grayVfb, out, g );
}
return ( grayVfb );
case IMVFBRGB: /* RGB true-color */
/*
* Don't know what it means to have an RGB VFB with a CLT?
* Ignore the CLT.
*/
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst( grayVfb );
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(grayVfb,out) )
{
g = IM_NTSCY( ImVfbQRed( srcVfb, in ),
ImVfbQGreen( srcVfb, in ),
ImVfbQBlue( srcVfb, in ) );
ImVfbSIndex8( grayVfb, out, g );
}
return ( grayVfb );
}
return IMVFBNULL;
}
/* max # bits to mask off when trying RGB: */
#define IM_MAX_BITS_TO_MASK 1
/* range of integer values: */
#define IMVT_MAXR 255
#define IMVT_MAXG 255
#define IMVT_MAXB 255
#define IMVT_MAXY 255
#define IMVT_MAXU 63
#define IMVT_MAXV 63
/* array indices: */
#define IMVT_Y 0
#define IMVT_U 1
#define IMVT_V 2
#define IMVT_R 0
#define IMVT_G 1
#define IMVT_B 2
/**
** helpful information:
**
** Y = 0.30*R + 0.59*G + 0.11*B
** U = B - Y
** V = R - Y
**
**/
/* macro to determine a Freq array index from integer YUV: */
#define IM_INDEX(iy,iu,iv) ( (iy)*(IMVT_MAXU+1)*(IMVT_MAXV+1) + (iu)*(IMVT_MAXV+1) + (iv) )
/* macros to define YUV as functions of RGB: */
#define IM_YFRGB(r,g,b) ( 0.30*(r)/(float)IMVT_MAXR + 0.59*(g)/(float)IMVT_MAXG + 0.11*(b)/(float)IMVT_MAXB )
#define IM_UFRGB(r,g,b) ( -0.30*(r)/(float)IMVT_MAXR - 0.59*(g)/(float)IMVT_MAXG + 0.89*(b)/(float)IMVT_MAXB )
#define IM_VFRGB(r,g,b) ( 0.70*(r)/(float)IMVT_MAXR - 0.59*(g)/(float)IMVT_MAXG - 0.11*(b)/(float)IMVT_MAXB )
/* macros to define RGB as functions of YUV: */
#define IM_RFYUV(y,u,v) (int) ( (float)IMVT_MAXR * ( (y) + (v) ) )
#define IM_GFYUV(y,u,v) (int) ( (float)IMVT_MAXG * ( (0.70-0.11)*(y) + (-0.11)*(u) + (0.70-1.00)*(v) ) / 0.59 )
#define IM_BFYUV(y,u,v) (int) ( (float)IMVT_MAXB * ( (y) + (u) ) )
/* macros to define the integer mappings of YUV: */
#define IM_IYFY(y) ( (int)( (y) * (float)IMVT_MAXY ) )
#define IM_IUFU(u) ( (int)( ( (u)+0.89 ) * ( (float)IMVT_MAXU / (2.*0.89) ) ) )
#define IM_IVFV(v) ( (int)( ( (v)+0.70 ) * ( (float)IMVT_MAXV / (2.*0.70) ) ) )
/* macros to define the floating mappings of YUV: */
#define IM_YFIY(iy) ( (float)(iy) / (float)IMVT_MAXY )
#define IM_UFIU(iu) ( (float)(iu) * ( 2.*0.89/(float)IMVT_MAXU ) - 0.89 )
#define IM_VFIV(iv) ( (float)(iv) * ( 2.*0.70/(float)IMVT_MAXV ) - 0.70 )
/*
* STRUCT
* rgb - unique RGB color holder
* box - range of colors
*/
struct rgb
{
unsigned char r_used; /* != 0: this color is active */
unsigned char r_r, r_g, r_b; /* the color components */
int r_index; /* clt location # */
};
struct box
{
int b_min[3]; /* minimum values */
int b_max[3]; /* maximum values */
int b_maxrange; /* maximum( max - min ) */
int b_mean[3]; /* centroid */
struct box *b_next; /* linked list */
};
/*
* GLOBALS
*/
struct box *Bfree; /* start of box free list */
struct box *Blist; /* start of box list */
struct box *Boxes; /* will become Boxes[n] */
int *Freq; /* will become Freq[y][u][v] */
/**
** function declarations:
**/
#ifdef __STDC__
static void CutBox();
static void FixUp( struct box *bp );
static int Hash8( unsigned char r, unsigned char g, unsigned char b );
static int Hash12( unsigned char r, unsigned char g, unsigned char b );
static void Insert( struct box *b );
static int NColors( struct rgb *rgb, int n, int mask,
int (*hash)( unsigned char r, unsigned char g, unsigned char b), ImVfb *vfb );
static int TryYUV( ImVfb *srcVfb, ImVfb *dstVfb, int maxcolors );
static int TryRGB( ImVfb *srcVfb, ImVfb *dstVfb, int maxcolors );
#else
static void CutBox();
static void FixUp();
static int Hash8();
static int Hash12();
static void Insert();
static int NColors();
static int TryYUV();
static int TryRGB();
#endif
/*
* FUNCTION
* ImVfbToIndex - change a vfb to have n colors
*
* DESCRIPTION
*/
ImVfb * /* Returns converted VFB */
#ifdef __STDC__
ImVfbToIndex( ImVfb *srcVfb, int nColors, ImVfb *dstVfb )
#else
ImVfbToIndex( srcVfb, nColors, dstVfb )
ImVfb *srcVfb; /* Source VFB */
int nColors; /* Number of colors for
Destination VFB */
ImVfb *dstVfb; /* Destination VFB */
#endif
{
int fields; /* vfb field description */
ImClt *dstClt; /* destination CLT */
ImClt *indexClt; /* destination CLT */
ImClt *clt; /* Source CLT */
ImVfbPtr in; /* input pointer */
ImVfbPtr out; /* output pointer */
int type; /* Type of VFB */
int index; /* Color index holder */
ImVfbPtr last; /* Last pointer for input VFB */
ImVfb *indexVfb; /* New 8-bit or 16-bit color
index VFB */
int bitsNeeded; /* number of bits needed for
Ncolors */
/*
* Compute number of bits necessary to display nColors
*/
bitsNeeded = 0;
while( (1 << bitsNeeded) < nColors )
{
++bitsNeeded;
}
if( bitsNeeded > 16 )
{
/* nColors too big */
}
/*
* Create the new VFB, if needed.
*/
if ( dstVfb == IMVFBNEW )
{
if( bitsNeeded < 9 )
{
if ( (indexVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBINDEX8 )) ==
IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
if ( (indexVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBINDEX16 )) ==
IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
}
else
{
/*
* Confirm the given VFB has enough bits for the desired
* number of colors and the same image dimensions.
*/
if( bitsNeeded < 9 )
{
if( ( !(ImVfbQFields( dstVfb ) & IMVFBINDEX8) ) &&
( !(ImVfbQFields( dstVfb ) & IMVFBINDEX16) ) )
{
ImErrNo = IMENOTINDEX8;
return ( IMVFBNULL );
}
}
else
{
if( !(ImVfbQFields( dstVfb ) & IMVFBINDEX16) )
{
ImErrNo = IMENOTINDEX16;
return ( IMVFBNULL );
}
}
if ( ImVfbQWidth( srcVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( srcVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
indexVfb = dstVfb;
}
/*
* Figure out where to get input colors to be put into the Index8 VFB.
*/
clt = ImVfbQClt( srcVfb ); /* Might be IMCLTNULL */
fields = ImVfbQFields( srcVfb );
if ( fields & IMVFBMONO )
{
/* Copy the mono VFB to the index 8 VFB. */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(indexVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(indexVfb,out) )
{
index = ImVfbQMono( srcVfb, in );
if ( index == 0 )
ImVfbSIndex( indexVfb, out, 0 );
else
ImVfbSIndex( indexVfb, out, nColors-1 );
}
if ( clt != IMCLTNULL )
dstClt = ImCltDup( clt );
else
dstClt = ImCltGrayRamp( IMCLTNULL, 0, nColors-1,
0, nColors-1, IMCLTNEW );
if ( dstClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
return ( IMVFBNULL ); /* ImErrNo already set */
}
ImVfbSClt( indexVfb, dstClt );
return ( indexVfb );
}
else if( fields & IMVFBINDEX8 )
type = IMVFBINDEX8; /* 8-bit color index */
else if ( fields & IMVFBINDEX16 )
type = IMVFBINDEX16; /* 16-bit color index */
else if ( fields & IMVFBRGB )
type = IMVFBRGB; /* 24-bit RGB color */
else
{
/*
* No image to convert?
*/
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMENOTINFO;
return ( IMVFBNULL );
}
/*
* At this point we have either an Index8, Index16, or RGB VFB
* to convert.
*/
/*
* If the destination doesn't already have a CLT, add one.
* Remember, the source and destination could be the same VFB.
*/
dstClt = ImVfbQClt( indexVfb );
if ( dstClt == IMCLTNULL )
{
indexClt = ImCltAlloc( nColors-1 );
if ( indexClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
ImVfbSClt( indexVfb, indexClt );
}
else
indexClt = dstClt;
/* Try using masked RGB values. */
if ( TryRGB( srcVfb, indexVfb, nColors-1 ) >= 0 )
return( indexVfb );
/* If that didn't work, cut according to YUV values. */
if ( TryYUV( srcVfb, indexVfb, nColors-1 ) >= 0 )
return( indexVfb );
/* If didn't work (can't think why it wouldn't), return error. */
if ( dstClt != indexClt )
ImCltFree( indexClt );
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMENOTINFO;
return( IMVFBNULL );
}
/*
* FUNCTION
* ImVfbToIndex8 - change a vfb to have 8-bit color
*
* DESCRIPTION
* Promotion:
* Mono VFB:
* Copied to 8-bit VFB. CLT copied, if any. Otherwise
* 2-entry grayscale VFB generated.
* No change:
* Index 8 VFB:
* Copied to 8-bit VFB. CLT copied, if any.
*
* Demotion:
* Index 16 VFB:
* RGB VFB:
* Scanned for number of unique colors in RGB and YUV
* space. If too many, colors are masked to reduce
* their precision and the new number of unique colors
* counted. Continues until we get a reasonable number
* of colors.
*/
ImVfb * /* Returns converted VFB */
#ifdef __STDC__
ImVfbToIndex8( ImVfb *srcVfb, ImVfb *dstVfb )
#else
ImVfbToIndex8( srcVfb, dstVfb )
ImVfb *srcVfb; /* Source VFB */
ImVfb *dstVfb; /* Destination VFB */
#endif
{
int fields; /* vfb field description */
ImClt *dstClt; /* destination CLT */
ImClt *indexClt; /* destination CLT */
ImClt *clt; /* Source CLT */
ImVfbPtr in; /* input pointer */
ImVfbPtr out; /* output pointer */
int type; /* Type of VFB */
int index; /* Color index holder */
ImVfbPtr last; /* Last pointer for input VFB */
ImVfb *indexVfb; /* New 8-bit color index VFB */
/*
* Create the new VFB, if needed.
*/
if ( dstVfb == IMVFBNEW )
{
if ( (indexVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBINDEX8 )) == IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
/*
* Confirm the given VFB has an Index8 field and that it has
* the same image dimensions.
*/
if ( !(ImVfbQFields( dstVfb ) & IMVFBINDEX8) )
{
ImErrNo = IMENOTINDEX8;
return ( IMVFBNULL );
}
if ( ImVfbQWidth( srcVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( srcVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
indexVfb = dstVfb;
}
/*
* Figure out where to get input colors to be put into the Index8 VFB.
*/
clt = ImVfbQClt( srcVfb ); /* Might be IMCLTNULL */
fields = ImVfbQFields( srcVfb );
if ( fields & IMVFBINDEX16 )
type = IMVFBINDEX16; /* 16-bit color index */
else if ( fields & IMVFBRGB )
type = IMVFBRGB; /* 24-bit RGB color */
else if ( fields & IMVFBMONO )
{
/* Copy the mono VFB to the index 8 VFB. */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(indexVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(indexVfb,out) )
{
index = ImVfbQMono( srcVfb, in );
if ( index == 0 )
ImVfbSIndex8( indexVfb, out, 0 );
else
ImVfbSIndex8( indexVfb, out, 255 );
}
if ( clt != IMCLTNULL )
dstClt = ImCltDup( clt );
else
dstClt = ImCltGrayRamp( IMCLTNULL, 0, 255, 0, 255,
IMCLTNEW );
if ( dstClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
return ( IMVFBNULL ); /* ImErrNo already set */
}
ImVfbSClt( indexVfb, dstClt );
return ( indexVfb );
}
else if ( fields & IMVFBINDEX8 )
{
if ( srcVfb == dstVfb )
return ( srcVfb ); /* Already Index8 */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(indexVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(indexVfb,out) )
{
ImVfbSIndex8( indexVfb, out, ImVfbQIndex8( srcVfb, in));
}
if ( clt != IMCLTNULL )
dstClt = ImCltDup( clt );
else
dstClt = ImCltGrayRamp( IMCLTNULL, 0, 255, 0, 255,
IMCLTNEW );
if ( dstClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
return ( IMVFBNULL ); /* ImErrNo already set */
}
ImVfbSClt( indexVfb, dstClt );
return ( indexVfb );
}
else
{
/*
* No image to convert?
*/
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMENOTINFO;
return ( IMVFBNULL );
}
/*
* At this point we have either an RGB or an Index16 VFB to convert.
*/
/*
* If the destination doesn't already have a CLT, add one.
* Remember, the source and destination could be the same VFB.
*/
dstClt = ImVfbQClt( indexVfb );
if ( dstClt == IMCLTNULL )
{
indexClt = ImCltAlloc( 256 );
if ( indexClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
ImVfbSClt( indexVfb, indexClt );
}
else
{
indexClt = dstClt;
}
/* Try using masked RGB values. */
if ( TryRGB( srcVfb, indexVfb, 256 ) >= 0 )
return( indexVfb );
/* If that didn't work, cut according to YUV values. */
if ( TryYUV( srcVfb, indexVfb, 256 ) >= 0 )
return( indexVfb );
/* If didn't work (can't think why it wouldn't), return error. */
if ( dstClt != indexClt )
ImCltFree( indexClt );
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMENOTINFO;
return( IMVFBNULL );
}
/*
* FUNCTION
* ImVfbToIndex16 - change a vfb to have 16-bit color
*
* DESCRIPTION
* Promotion:
* Mono VFB:
* Index8 VFB:
* Copied to 16-bit VFB. CLT copied, if any. Otherwise
* 256-entry grayscale VFB generated.
* No change:
* Index 16 VFB:
* Copied to 16-bit VFB. CLT copied, if any.
*
* Demotion:
* RGB VFB:
* Scanned for number of unique colors in RGB and YUV
* space. If too many, colors are masked to reduce
* their precision and the new number of unique colors
* counted. Continues until we get a reasonable number
* of colors.
*/
ImVfb * /* Returns converted VFB */
#ifdef __STDC__
ImVfbToIndex16( ImVfb *srcVfb, ImVfb *dstVfb )
#else
ImVfbToIndex16( srcVfb, dstVfb )
ImVfb *srcVfb; /* Source VFB */
ImVfb *dstVfb; /* Destination VFB */
#endif
{
int fields; /* vfb field description */
ImClt *dstClt; /* destination CLT */
ImClt *indexClt; /* destination CLT */
ImClt *clt; /* Source CLT */
ImVfbPtr in; /* input pointer */
ImVfbPtr out; /* output pointer */
int index; /* Color index holder */
ImVfbPtr last; /* Last pointer for input VFB */
ImVfb *indexVfb; /* New 8-bit color index VFB */
/*
* Create the new VFB, if needed.
*/
if ( dstVfb == IMVFBNEW )
{
if ( (indexVfb = ImVfbAlloc( ImVfbQWidth( srcVfb ),
ImVfbQHeight( srcVfb ), IMVFBINDEX16 )) == IMVFBNULL )
{
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
}
else
{
/*
* Confirm the given VFB has an Index16 field and that it has
* the same image dimensions.
*/
if ( !(ImVfbQFields( dstVfb ) & IMVFBINDEX16) )
{
ImErrNo = IMENOTINDEX16;
return ( IMVFBNULL );
}
if ( ImVfbQWidth( srcVfb ) != ImVfbQWidth( dstVfb ) )
{
ImErrNo = IMEWIDTH;
return ( IMVFBNULL );
}
if ( ImVfbQHeight( srcVfb ) != ImVfbQHeight( dstVfb ) )
{
ImErrNo = IMEHEIGHT;
return ( IMVFBNULL );
}
indexVfb = dstVfb;
}
/*
* Figure out where to get input colors to be put into the Index16 VFB.
*/
clt = ImVfbQClt( srcVfb ); /* Might be IMCLTNULL */
fields = ImVfbQFields( srcVfb );
if ( fields & IMVFBINDEX16 )
{
if ( srcVfb == dstVfb )
return ( srcVfb ); /* Already Index16 */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(indexVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(indexVfb,out) )
{
ImVfbSIndex16( indexVfb, out, ImVfbQIndex16(srcVfb,in));
}
if ( clt != IMCLTNULL )
dstClt = ImCltDup( clt );
else
dstClt = ImCltGrayRamp( IMCLTNULL, 0, 65535, 0, 65535,
IMCLTNEW );
if ( dstClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
return ( IMVFBNULL ); /* ImErrNo already set */
}
ImVfbSClt( indexVfb, dstClt );
return ( indexVfb );
}
else if ( fields & IMVFBINDEX8 )
{
/* Copy the index 8 VFB to the index 16 VFB. */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(indexVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(indexVfb,out) )
{
ImVfbSIndex16( indexVfb, out,
(ImVfbQIndex8( srcVfb,in) ) );
}
if ( clt != IMCLTNULL )
dstClt = ImCltDup( clt );
else
dstClt = ImCltGrayRamp( IMCLTNULL, 0, 65535, 0, 65535,
IMCLTNEW );
if ( dstClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
return ( IMVFBNULL ); /* ImErrNo already set */
}
ImVfbSClt( indexVfb, dstClt );
return ( indexVfb );
}
else if ( fields & IMVFBMONO )
{
/* Copy the mono VFB to the index 16 VFB. */
last = ImVfbQLast( srcVfb );
for( in=ImVfbQFirst(srcVfb), out=ImVfbQFirst(indexVfb);
in <= last;
ImVfbSInc(srcVfb,in), ImVfbSInc(indexVfb,out) )
{
index = ImVfbQMono( srcVfb, in );
if ( index == 0 )
ImVfbSIndex16( indexVfb, out, 0 );
else
ImVfbSIndex16( indexVfb, out, 65535 );
}
if ( clt != IMCLTNULL )
dstClt = ImCltDup( clt );
else
dstClt = ImCltGrayRamp( IMCLTNULL, 0, 65535, 0, 65535,
IMCLTNEW );
if ( dstClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
return ( IMVFBNULL ); /* ImErrNo already set */
}
ImVfbSClt( indexVfb, dstClt );
return ( indexVfb );
}
else if ( !(fields & IMVFBRGB) )
{
/*
* No image to convert?
*/
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMENOTINFO;
return ( IMVFBNULL );
}
/*
* At this point we have an RGB VFB to convert.
*/
/*
* If the destination doesn't already have a CLT, add one.
* Remember, the source and destination could be the same VFB.
*/
dstClt = ImVfbQClt( indexVfb );
if ( dstClt == IMCLTNULL )
{
indexClt = ImCltAlloc( 65536 );
if ( indexClt == IMCLTNULL )
{
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMEMALLOC;
return( IMVFBNULL );
}
ImVfbSClt( indexVfb, indexClt );
}
else
indexClt = dstClt;
/* Try using masked RGB values. */
if ( TryRGB( srcVfb, indexVfb, 65536 ) >= 0 )
return( indexVfb );
/* If that didn't work, cut according to YUV values. */
if ( TryYUV( srcVfb, indexVfb, 65536 ) >= 0 )
return( indexVfb );
/* If didn't work (can't think why it wouldn't), return error. */
if ( dstClt != indexClt )
ImCltFree( indexClt );
if ( dstVfb != indexVfb )
ImVfbFree( indexVfb );
ImErrNo = IMENOTINFO;
return( IMVFBNULL );
}
/*
* FUNCTION
* CutBox - cut the largest box into 2 boxes
*
* DESCRIPTION
* The largest box is at the top of the Blist
* Cut it in the direction of the largest range
* Cut it on its median
* Put the resulting boxes back in the Blist according to their new
* ranges
*
*/
static void /* Returns nothing */
CutBox( )
{
struct box *bp; /* largest box */
struct box *bpnew; /* new box to be created */
int i, j, k; /* yuv indices */
int i1, i2, i3; /* indices in range order */
int *iy, *iu, *iv; /* where are y,u,v in i,j,k */
int mid; /* mid point (median) of yuv */
int num; /* counter to get to mid */
int in; /* Freq index */
int lastnum; /* shadow of 'num' */
int split; /* where to split the box */
/* pointer to current box and new box: */
bp = Blist; Blist = Blist->b_next;
bpnew = Bfree; Bfree = Bfree->b_next;
*bpnew = *bp; /* identical copy, for now */
/* determine which dimension needs to be cut: */
if ( bp->b_maxrange == bp->b_max[IMVT_Y] - bp->b_min[IMVT_Y] + 1 )
{
i1 = IMVT_Y; i2 = IMVT_U; i3 = IMVT_V;
iy = &i; iu = &j; iv = &k;
#ifdef DEBUG
fprintf( stderr, "Cut along Y: " );
#endif
}
else
{
if ( bp->b_maxrange == bp->b_max[IMVT_U] - bp->b_min[IMVT_U] + 1 )
{
i1 = IMVT_U; i2 = IMVT_Y; i3 = IMVT_V;
iu = &i; iy = &j; iv = &k;
#ifdef DEBUG
fprintf( stderr, "Cut along U: " );
#endif
}
else
{
i1 = IMVT_V; i2 = IMVT_Y; i3 = IMVT_U;
iv = &i; iy = &j; iu = &k;
#ifdef DEBUG
fprintf( stderr, "Cut along V: " );
#endif
}
}
/* determine the median location: */
mid = 0;
for( i = bp->b_min[i1]; i <= bp->b_max[i1]; i++ )
{
for( j = bp->b_min[i2]; j <= bp->b_max[i2]; j++ )
{
for( k = bp->b_min[i3]; k <= bp->b_max[i3]; k++ )
{
in = IM_INDEX( *iy, *iu, *iv );
mid += Freq[in];
}
}
}
mid = mid / 2;
/* find where that median occurred: */
num = 0;
lastnum = -1;
for( i = bp->b_min[i1]; i <= bp->b_max[i1]; i++, lastnum = num )
{
for( j = bp->b_min[i2]; j <= bp->b_max[i2]; j++ )
{
for( k = bp->b_min[i3]; k <= bp->b_max[i3]; k++ )
{
in = IM_INDEX( *iy, *iu, *iv );
num += Freq[in];
}
}
if ( num >= mid )
break;
}
/* determine where to put the split: */
/* divide between 'split' and 'split+1' */
if ( i <= bp->b_min[i1] )
{
split = i;
}
else
{
if ( i >= bp->b_max[i1] )
{
split = i - 1;
}
else
{
if ( num == mid )
split = i;
else
split = i - 1;
}
}
#ifdef DEBUG
fprintf( stderr, "%3d - %3d + %3d - %3d\n",
bp->b_min[i1], split, split+1, bp->b_max[i1] );
#endif
/* make the proper assignments into the 2 box structures: */
bp->b_max[i1] = split;
bpnew->b_min[i1] = split+1;
/* clean-up the 2 box structures: */
FixUp( bp );
FixUp( bpnew );
/* insert the 2 box structures where they belong: */
Insert( bp );
Insert( bpnew );
/* done: */
}
/*
* FUNCTION
* FixUp - cleanup new or changed box structures
*
* DESCRIPTION
* Reset b_min and b_max
* Re-compute b_maxrange
*
*/
static void /* Returns nothing */
#ifdef __STDC__
FixUp( struct box *bp )
#else
FixUp( bp )
struct box *bp; /* the box to fixup */
#endif
{
int iy, iu, iv; /* yuv values */
int in; /* Freq index */
int iymin, iymax; /* y range */
int iumin, iumax; /* u range */
int ivmin, ivmax; /* v range */
int ry, ru, rv; /* yuv ranges */
/* possibly the mins and maxes: */
/* these are most likely more spread out than they need */
/* to be - we will fix that below */
iymin = bp->b_max[IMVT_Y]; iymax = bp->b_min[IMVT_Y];
iumin = bp->b_max[IMVT_U]; iumax = bp->b_min[IMVT_U];
ivmin = bp->b_max[IMVT_V]; ivmax = bp->b_min[IMVT_V];
/* loop through the ranges setting correct mins and maxes: */
for( iy = bp->b_min[IMVT_Y]; iy <= bp->b_max[IMVT_Y]; iy++ )
{
for( iu = bp->b_min[IMVT_U]; iu <= bp->b_max[IMVT_U]; iu++ )
{
for( iv = bp->b_min[IMVT_V]; iv <= bp->b_max[IMVT_V]; iv++ )
{
in = IM_INDEX( iy, iu, iv );
if ( Freq[in] != 0 )
{
if ( iy < iymin ) iymin = iy;
if ( iy > iymax ) iymax = iy;
if ( iu < iumin ) iumin = iu;
if ( iu > iumax ) iumax = iu;
if ( iv < ivmin ) ivmin = iv;
if ( iv > ivmax ) ivmax = iv;
}
}
}
}
/* set the new min and max values: */
bp->b_min[IMVT_Y] = iymin; bp->b_max[IMVT_Y] = iymax;
bp->b_min[IMVT_U] = iumin; bp->b_max[IMVT_U] = iumax;
bp->b_min[IMVT_V] = ivmin; bp->b_max[IMVT_V] = ivmax;
/* determine the maximum range for this box: */
ry = bp->b_max[IMVT_Y] - bp->b_min[IMVT_Y] + 1;
ru = bp->b_max[IMVT_U] - bp->b_min[IMVT_U] + 1;
rv = bp->b_max[IMVT_V] - bp->b_min[IMVT_V] + 1;
bp->b_maxrange = ry;
if ( ru >= ry && ru >= rv )
bp->b_maxrange = ru;
if ( rv >= ry && rv >= ru )
bp->b_maxrange = rv;
/* done: */
}
/*
* FUNCTION
* Hash8 - hash code for an 8-bit color
* Hash12 - hash code for a 12-bit color
* Hash16 - hash code for a 16-bit color
*
*/
static int /* Returns hash code */
#ifdef __STDC__
Hash8( unsigned char r, unsigned char g, unsigned char b )
#else
Hash8( r, g, b )
unsigned char r, g, b;
#endif
{
return( ( r ^ g ^ b ) & 0xff );
}
static int /* Returns hash code */
#ifdef __STDC__
Hash12( unsigned char r, unsigned char g, unsigned char b )
#else
Hash12( r, g, b )
unsigned char r, g, b;
#endif
{
int i1, i2; /* temporary integers */
i1 = ( ( r << 4 ) & 0x0ff0 ) | ( g >> 4 );
i2 = ( ( g << 8 ) & 0x0f00 ) | b;
return( ( i1 ^ i2 ) & 0x0fff );
}
static int /* Returns hash code */
#ifdef __STDC__
Hash16( unsigned char r, unsigned char g, unsigned char b )
#else
Hash16( r, g, b )
unsigned char r, g, b;
#endif
{
int i1, i2; /* temporary integers */
i1 = ( ( r << 4 ) & 0x0ff0 ) | ( g >> 4 );
i2 = ( ( g << 8 ) & 0x0f00 ) | b;
return( ( i1 ^ i2 ) & 0x0fff );
}
/*
* FUNCTION
* Insert - insert a box into the box list
*
*/
static void /* Returns nothing */
#ifdef __STDC__
Insert( struct box *b )
#else
Insert( b )
struct box *b;
#endif
{
struct box *bp; /* box pointer */
struct box *last; /* shadow box pointer */
/* if list is empty, create it with this element: */
if ( Blist == NULL )
{
Blist = b;
b->b_next = NULL;
return;
}
/* otherwise, do an insertion sort: */
for( bp = Blist, last = NULL; bp != NULL; last = bp, bp = bp->b_next )
{
/* loop until bp->b_maxrange gets small enough: */
if ( b->b_maxrange < bp->b_maxrange )
continue;
/* if at first point, make it head of list: */
if ( last == NULL )
{
b->b_next = Blist;
Blist = b;
}
else /* otherwise, link it in */
{
b->b_next = bp;
last->b_next = b;
}
return;
}
/* if got here then add to end of list: */
b->b_next = NULL;
last->b_next = b;
}
/*
* FUNCTION
* NColors - count the # colors that will result if
* the given mask is applied to all RGB values
*
* DESCRIPTION
* This routine looks through all RGB values in the given vfb
* (applying a bitmask to each) and keeps a table of unique
* combinations. If that table overflows, then this mask
* cannot be used to quantize the colors.
*
* A return of -1 indicates that the table overflowed
* A return of >= 0 indicates the number of unique combinations
*/
static int /* Returns # of colors */
#ifdef __STDC__
NColors( struct rgb *rgb, int n, int mask,
int (*hash)(unsigned char r, unsigned char g, unsigned char b), ImVfb *vfb )
#else
NColors( rgb, n, mask, hash, vfb )
struct rgb *rgb; /* rgb array (already alloc'd) */
int n; /* max # colors allowed */
int mask; /* bitmask to apply to all rgb's */
int (*hash)(); /* hash function to index into rgb[] */
ImVfb *vfb; /* the vfb to browse */
#endif
{
int i; /* counter */
int r, g, b; /* rgb values */
int h; /* hash index */
int type; /* type of vfb */
int nunique; /* # unique combinations */
struct rgb *rgbp; /* pointer into rgb[] */
ImVfbPtr p; /* pointer into the vfb */
ImClt *clt; /* clt attached to vfb */
ImCltPtr cp; /* pointer into clt */
/* determine vfb type: */
if ( ImVfbQFields(vfb) & IMVFBRGB )
type = IMVFBRGB;
else
{
if ( ImVfbQFields(vfb) & IMVFBINDEX8 )
type = IMVFBINDEX8;
else
type = IMVFBINDEX16;
clt = ImVfbQClt( vfb );
}
/* set all rgb[].r_used to unused: */
for( i = 0, rgbp = rgb; i < n; i++, rgbp++ )
rgbp->r_used = 0;
/* count the unique values: */
/* if table overflows, return an error */
nunique = 0;
for( p = ImVfbQFirst( vfb ); p <= ImVfbQLast( vfb ); ImVfbSInc( vfb, p ) )
{
if ( type == IMVFBRGB )
{
r = ImVfbQRed( vfb, p ) & mask;
g = ImVfbQGreen( vfb, p ) & mask;
b = ImVfbQBlue( vfb, p ) & mask;
}
else
{
cp = ImCltQPtr( clt, ImVfbQIndex( vfb, p ) );
r = ImCltQRed( cp ) & mask;
g = ImCltQGreen( cp ) & mask;
b = ImCltQBlue( cp ) & mask;
}
h = (*hash)( r, g, b ); /* hash index */
/* find this rgb combo in rgb[]: */
/* if cannot find it, try to create it */
/* if cannot create it, then table is full */
for( i = 0, rgbp = &rgb[h]; i < n; i++, rgbp++ )
{
if ( rgbp >= &rgb[n] )
rgbp = rgb;
/* if find an unused slot, create this rgb: */
if ( rgbp->r_used == 0 )
{
nunique++;
rgbp->r_used = 1;
rgbp->r_r = r;
rgbp->r_g = g;
rgbp->r_b = b;
break;
}
/* if slot is used, see if it matches r, g, and b:*/
if ( rgbp->r_r == r && rgbp->r_g == g && rgbp->r_b == b )
break;
/* if got to here, then haven't found an exact */
/* match, and haven't found an empty slot to */
/* create a new entry in - keep looking */
}
/* if got to here because no more array locations to */
/* look at, table is full and colors cannot be */
/* quantized with this bitmask: */
if ( i >= n )
return( -1 );
/* keep browsing through the vfb: */
}
/* if get here, then colors can be quantized with this bitmask: */
return( nunique );
}
/*
* FUNCTION
* TryRGB - see if an RGB model will work with this
* number of colors
*
* DESCRIPTION
* This routine will see if there are <= N unique RGB combinations
* If not, it will then start to mask off bits from the end of
* the RGB components and see if there are <= N unique combinations
* of those
*
* A return of -1 indicates that the destination vfb is screwy
* A return of -2 indicates that a malloc failed
* A return of -3 indicates that there were too many unique
* combinations and that these colors will need to be quantized further
*/
static int /* REturns status */
#ifdef __STDC__
TryRGB( ImVfb *srcVfb, ImVfb *dstVfb, int maxcolors )
#else
TryRGB( srcVfb, dstVfb, maxcolors )
ImVfb *srcVfb; /* source vfb */
ImVfb *dstVfb; /* destination vfb */
int maxcolors; /* max # colors allowed */
#endif
{
int mask; /* bit mask */
int comp; /* complement to the bitmask */
struct rgb *rgb; /* array of rgb values */
struct rgb *rgbp; /* pointer into rgb array */
int i; /* counter */
int r, g, b; /* rgb values */
int h; /* hash index */
int index; /* index into clt */
int nc; /* return from NColors() */
int type; /* type of frame buffer */
ImVfbPtr psrc, pdst; /* pointers into the vfbs */
ImClt *clt; /* color lookup table */
ImCltPtr cp; /* clt pointer */
#ifdef __STDC__
int (*hash)(unsigned char r, unsigned char g, unsigned char b); /* hash function */
#else
int (*hash)(); /* hash function */
#endif
if( ( maxcolors < 0 ) || ( maxcolors > 65536 ) )
{
return( -1 );
}
else if( maxcolors > 4096 )
{
hash = Hash16;
}
else if( maxcolors > 256 )
{
hash = Hash12;
}
else
{
hash = Hash8;
}
/* allocate rgb array: */
rgb = (struct rgb *) malloc( maxcolors * sizeof( struct rgb ) );
if ( rgb == NULL )
{
return( -2 );
}
/* try to fit all the colors into maxcolors slots: */
for( i=0, comp=0; i <= IM_MAX_BITS_TO_MASK; i++, comp = ( comp << 1 ) | 1 )
{
mask = ~comp;
nc = NColors( rgb, maxcolors, mask, hash, srcVfb );
#ifdef DEBUG
fprintf( stderr, "NColors( rgb, %d, 0x%0x, hash, srcVfb ) = %d\n",
maxcolors, mask, nc );
#endif
if ( nc >= 0 ) /* successful ! */
break;
}
/* if all calls to NColors() failed, return an error: */
if ( nc < 0 )
{
free( (char *) rgb );
return( -3 );
}
/* if a call to NColors() succeeded, fill dstVfb: */
/* first, pack colors in top of clt (point to top anyway): */
for( i = 0, rgbp = &rgb[0], index = 0; i < maxcolors; i++, rgbp++ )
{
if ( rgbp->r_used == 0 )
continue;
rgbp->r_index = index;
index++;
}
/* determine type of vfb the input is: */
if ( ImVfbQFields(srcVfb) & IMVFBRGB )
type = IMVFBRGB;
else
{
if ( ImVfbQFields(srcVfb) & IMVFBINDEX8 )
type = IMVFBINDEX8;
else
type = IMVFBINDEX16;
clt = ImVfbQClt( srcVfb );
}
/* fill the output vfb with correct color indices: */
for( psrc = ImVfbQFirst(srcVfb), pdst = ImVfbQFirst(dstVfb);
psrc <= ImVfbQLast(srcVfb);
ImVfbSInc(srcVfb,psrc), ImVfbSInc(dstVfb,pdst) )
{
if ( type == IMVFBRGB )
{
r = ImVfbQRed( srcVfb, psrc ) & mask;
g = ImVfbQGreen( srcVfb, psrc ) & mask;
b = ImVfbQBlue( srcVfb, psrc ) & mask;
}
else
{
cp = ImCltQPtr( clt, ImVfbQIndex( srcVfb, psrc ) );
r = ImCltQRed( cp ) & mask;
g = ImCltQGreen( cp ) & mask;
b = ImCltQBlue( cp ) & mask;
}
/* locate that RGB combination in the hash table: */
h = (*hash)( r, g, b );
for( i = 0, rgbp = &rgb[h]; i < maxcolors; i++, rgbp++ )
{
if ( rgbp >= &rgb[maxcolors] )
rgbp = rgb;
if ( rgbp->r_used == 0 )
continue;
if ( rgbp->r_r == r && rgbp->r_g == g
&& rgbp->r_b == b )
break;
}
/* we know that this will succeed sooner or later... */
index = rgbp - rgb;
ImVfbSIndex( dstVfb, pdst, rgb[index].r_index );
}
/* fill the new clt: */
clt = ImVfbQClt( dstVfb );
if ( nc != maxcolors )
{
ImCltFree( clt ); /* get rid of full clt */
clt = ImCltAlloc( nc );
ImVfbSClt( dstVfb, clt );
}
for( i = 0, cp = ImCltQFirst(clt), rgbp = rgb;
i < maxcolors;
i++, rgbp++ )
{
if ( rgbp->r_used )
{
ImCltSRed( cp, rgbp->r_r );
ImCltSGreen( cp, rgbp->r_g );
ImCltSBlue( cp, rgbp->r_b );
ImCltSInc( clt, cp );
}
}
/* end game: */
free( (char *) rgb );
return( nc );
}
/*
* FUNCTION
* TryYUV - quantize the colors down with a YUV model
*
* DESCRIPTION
* This routine will see if there are <= N unique YUV combinations
* If not, it will then start to mask off bits from the end of
* the YUV components and see if there are <= N unique combinations
* of those
*
* A return of -1 indicates that the destination vfb is screwy
* A return of -2 indicates that a malloc failed
*/
static int /* Returns status */
#ifdef __STDC__
TryYUV( ImVfb *srcVfb, ImVfb *dstVfb, int maxcolors )
#else
TryYUV( srcVfb, dstVfb, maxcolors )
ImVfb *srcVfb; /* source vfb */
ImVfb *dstVfb; /* destination vfb */
int maxcolors; /* # colors */
#endif
{
int i; /* counter */
int in; /* Freq index */
int iy, iu, iv; /* yuv indices */
int num; /* total # colors */
int r, g, b; /* rgb values */
int iymin, iymax, iumin, iumax, ivmin, ivmax; /* yuv ranges */
int type; /* type of vfb */
int ymean, umean, vmean; /* accumulate avg yuv values */
int denom; /* denominator for the avg yuv values */
struct box *bp; /* box pointer */
ImVfbPtr psrc, pdst; /* vfb pointers */
ImClt *clt; /* clt attached to srcVfb / dstVfb */
ImCltPtr cp; /* clt pointer */
/* # colors to quantize to: */
if ( ( maxcolors < 0 ) || ( maxcolors > 65536 ) )
{
return( -1 );
}
/* allocate the Frequency array: */
Freq = (int *) malloc( (IMVT_MAXY+1)*(IMVT_MAXU+1)*(IMVT_MAXV+1)*sizeof(int) );
if ( Freq == NULL )
return( -2 );
/* allocate Boxes structure: */
Boxes = (struct box *) malloc( maxcolors * sizeof( struct box ) );
if ( Boxes == NULL )
{
free( (char *) Freq );
return( -2 );
}
/* setup used and free lists: */
Blist = NULL;
Bfree = Boxes;
for( i=0; i<maxcolors-1; i++ )
Boxes[i].b_next = &Boxes[i+1];
Boxes[maxcolors-1].b_next = NULL;
/* zero out Frequency array: */
memset( (void *) Freq, 0x00, (IMVT_MAXY+1)*(IMVT_MAXU+1)*(IMVT_MAXV+1)*sizeof(int) );
/* determine vfb type: */
if ( ImVfbQFields(srcVfb) & IMVFBRGB )
type = IMVFBRGB;
else
{
if( ImVfbQFields( srcVfb ) & IMVFBINDEX8 )
type = IMVFBINDEX8;
else
type = IMVFBINDEX16;
clt = ImVfbQClt( srcVfb );
}
/* fill the frequency array and determine range: */
iymin = iumin = ivmin = 100000;
iymax = iumax = ivmax = -100000;
num = 0;
for( psrc = ImVfbQFirst(srcVfb); psrc <= ImVfbQLast(srcVfb); ImVfbSInc(srcVfb,psrc) )
{
if ( type == IMVFBRGB )
{
r = ImVfbQRed( srcVfb, psrc );
g = ImVfbQGreen( srcVfb, psrc );
b = ImVfbQBlue( srcVfb, psrc );
}
else
{
cp = ImCltQPtr( clt, ImVfbQIndex( srcVfb, psrc ) );
r = ImCltQRed( cp );
g = ImCltQGreen( cp );
b = ImCltQBlue( cp );
}
iy = IM_IYFY( IM_YFRGB( r, g, b ) );
iu = IM_IUFU( IM_UFRGB( r, g, b ) );
iv = IM_IVFV( IM_VFRGB( r, g, b ) );
in = IM_INDEX( iy, iu, iv );
if ( Freq[in] == 0 )
num++;
Freq[in]++;
if ( iy < iymin ) iymin = iy;
if ( iy > iymax ) iymax = iy;
if ( iu < iumin ) iumin = iu;
if ( iu > iumax ) iumax = iu;
if ( iv < ivmin ) ivmin = iv;
if ( iv > ivmax ) ivmax = iv;
}
#ifdef DEBUG
fprintf( stderr, "\nYUV bounds on original data:\n" );
fprintf( stderr, "\tY :\t%4d - %4d\n", iymin, iymax );
fprintf( stderr, "\tU :\t%4d - %4d\n", iumin, iumax );
fprintf( stderr, "\tV :\t%4d - %4d\n", ivmin, ivmax );
fprintf( stderr, "%d unique YUV combinations\n", num );
#endif
/* setup the first box: */
Blist = bp = Bfree;
Bfree = Bfree->b_next;
bp->b_next = NULL;
bp->b_min[IMVT_Y] = iymin;
bp->b_max[IMVT_Y] = iymax;
bp->b_min[IMVT_U] = iumin;
bp->b_max[IMVT_U] = iumax;
bp->b_min[IMVT_V] = ivmin;
bp->b_max[IMVT_V] = ivmax;
bp->b_maxrange = iymax - iymin;
if ( iumax - iumin > bp->b_maxrange )
bp->b_maxrange = iumax - iumin;
if ( ivmax - ivmin > bp->b_maxrange )
bp->b_maxrange = ivmax - ivmin;
bp->b_maxrange++; /* range is actually 1 larger */
/* cut the box (n-1) times: */
for( i = 1; i < maxcolors; i++ )
CutBox();
/* re-use the Frequency array to hold index into the box #: */
/* at the same time, compute the RGB mean in each box: */
for( i = 0, bp = Blist; i < maxcolors; i++, bp = bp->b_next )
{
ymean = umean = vmean = 0;
denom = 0;
for( iy = bp->b_min[IMVT_Y]; iy <= bp->b_max[IMVT_Y]; iy++ )
{
for( iu = bp->b_min[IMVT_U]; iu <= bp->b_max[IMVT_U]; iu++ )
{
for( iv = bp->b_min[IMVT_V]; iv <= bp->b_max[IMVT_V]; iv++ )
{
in = IM_INDEX( iy, iu, iv );
if ( Freq[in] > 0 )
{
ymean += iy * Freq[in];
umean += iu * Freq[in];
vmean += iv * Freq[in];
denom += Freq[in];
}
Freq[in] = i;
}
}
}
if ( denom > 0 )
{
ymean /= denom;
umean /= denom;
vmean /= denom;
}
bp->b_mean[IMVT_R] = IM_RFYUV( IM_YFIY(ymean), IM_UFIU(umean), IM_VFIV(vmean) );
bp->b_mean[IMVT_G] = IM_GFYUV( IM_YFIY(ymean), IM_UFIU(umean), IM_VFIV(vmean) );
bp->b_mean[IMVT_B] = IM_BFYUV( IM_YFIY(ymean), IM_UFIU(umean), IM_VFIV(vmean) );
if ( bp->b_mean[IMVT_R] > 255 ) bp->b_mean[IMVT_R] = 255;
if ( bp->b_mean[IMVT_G] > 255 ) bp->b_mean[IMVT_G] = 255;
if ( bp->b_mean[IMVT_B] > 255 ) bp->b_mean[IMVT_B] = 255;
if ( bp->b_mean[IMVT_R] < 0 ) bp->b_mean[IMVT_R] = 0;
if ( bp->b_mean[IMVT_G] < 0 ) bp->b_mean[IMVT_G] = 0;
if ( bp->b_mean[IMVT_B] < 0 ) bp->b_mean[IMVT_B] = 0;
#ifdef DEBUG
fprintf( stderr, "Color %3d: YUV = %4d , %4d , %4d\t\t", i,
ymean, umean, vmean );
fprintf( stderr, "RGB = %3d , %3d , %3d\n",
bp->b_mean[R], bp->b_mean[G], bp->b_mean[B] );
#endif
}
/* insert the indices into the destination vfb: */
for( psrc = ImVfbQFirst(srcVfb), pdst = ImVfbQFirst(dstVfb);
psrc <= ImVfbQLast(srcVfb);
ImVfbSInc(srcVfb,psrc), ImVfbSInc(dstVfb,pdst) )
{
if ( type == IMVFBRGB )
{
r = ImVfbQRed( srcVfb, psrc );
g = ImVfbQGreen( srcVfb, psrc );
b = ImVfbQBlue( srcVfb, psrc );
}
else
{
cp = ImCltQPtr( clt, ImVfbQIndex( srcVfb, psrc ) );
r = ImCltQRed( cp );
g = ImCltQGreen( cp );
b = ImCltQBlue( cp );
}
/* locate that RGB combination in the Freq array: */
iy = IM_IYFY( IM_YFRGB( r, g, b ) );
iu = IM_IUFU( IM_UFRGB( r, g, b ) );
iv = IM_IVFV( IM_VFRGB( r, g, b ) );
in = IM_INDEX( iy, iu, iv );
ImVfbSIndex( dstVfb, pdst, Freq[in] );
}
/* fill the new clt: */
clt = ImVfbQClt( dstVfb );
for( i = 0, cp = ImCltQFirst(clt), bp = Blist;
i < maxcolors;
i++, ImCltSInc(clt,cp), bp = bp->b_next )
{
ImCltSRed( cp, bp->b_mean[IMVT_R] );
ImCltSGreen( cp, bp->b_mean[IMVT_G] );
ImCltSBlue( cp, bp->b_mean[IMVT_B] );
}
/* end game: */
free( (char *) Boxes );
free( (char *) Freq );
return( maxcolors );
}
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