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# include "bitmapConfig.h"
# include "bmintern.h"
# include <string.h>
# include <appDebugon.h>
/************************************************************************/
/* */
/* Map a color image to grayscale. */
/* */
/************************************************************************/
# define F_R 77
# define F_G 150
# define F_B 29
/************************************************************************/
/* */
/* Free memory in a grayscale allocator. */
/* */
/************************************************************************/
static void bmGrayCleanupAllocator( ColorAllocator * ca )
{
if ( ca->caSystemPrivate )
{ free( ca->caSystemPrivate ); }
return;
}
/************************************************************************/
/* */
/* Set resources in a grayscale allocator, depending on the number of */
/* bits. */
/* */
/************************************************************************/
static int bmGraySetAllocator( ColorAllocator * ca,
int bitsPerPixel,
SystemAllocator sysAllocator )
{
unsigned int * fresh;
unsigned int mask;
unsigned int divi;
mask= ( 1 << bitsPerPixel )- 1;
divi= ( 255* 256 )/mask;
fresh= (unsigned int *)realloc( ca->caSystemPrivate, 2* sizeof(int) );
if ( ! fresh )
{ XDEB(fresh); return -1; }
ca->caSystemPrivate= fresh;
fresh[0]= divi;
fresh[1]= mask;
ca->caSystemAllocator= sysAllocator;
ca->caSystemCleanup= bmGrayCleanupAllocator;
ca->caAllocationType= CA_ALLOCATOR;
return 0;
}
/************************************************************************/
/* */
/* Allocate a grayscale color: */
/* */
/* WB: White on Black i.e. White is maximum. */
/* BW: Black on White i.e. Black is maximum. */
/* */
/************************************************************************/
static int bmToGrayAllocateWBColor( AllocatorColor * ac,
ColorAllocator * ca,
unsigned int r,
unsigned int g,
unsigned int b )
{
const unsigned int * pars= (unsigned int *)ca->caSystemPrivate;
unsigned int divi= pars[0];
long val;
val= ( F_R* r+ F_G* g+ F_B* b )/ divi;
ac->acRed= 257* r;
ac->acGreen= 257* g;
ac->acBlue= 257* b;
ac->acColorNumber= val;
return 0;
}
static int bmToGrayAllocateBWColor( AllocatorColor * ac,
ColorAllocator * ca,
unsigned int r,
unsigned int g,
unsigned int b )
{
const unsigned int * pars= (unsigned int *)ca->caSystemPrivate;
unsigned int divi= pars[0];
unsigned int mask= pars[1];
long val;
val= ( F_R* r+ F_G* g+ F_B* b )/ divi;
ac->acRed= 257* r;
ac->acGreen= 257* g;
ac->acBlue= 257* b;
ac->acColorNumber= mask- val;
return 0;
}
/************************************************************************/
/* */
/* Choose an allocator for colors in a grayscale image. */
/* */
/* WB: White on Black i.e. White is maximum. */
/* BW: Black on White i.e. Black is maximum. */
/* */
/************************************************************************/
int bmSetColorAllocatorForBWImage( ColorAllocator * ca,
const BitmapDescription * bd )
{
switch( bd->bdBitsPerPixel )
{
case 8:
case 4:
case 2:
case 1:
if ( bmGraySetAllocator( ca, bd->bdBitsPerPixel,
bmToGrayAllocateBWColor ) )
{ LDEB(bd->bdBitsPerPixel); return -1; }
return 0;
default:
LDEB(bd->bdBitsPerPixel); return -1;
}
}
int bmSetColorAllocatorForWBImage( ColorAllocator * ca,
const BitmapDescription * bd )
{
switch( bd->bdBitsPerPixel )
{
case 8:
case 4:
case 2:
case 1:
if ( bmGraySetAllocator( ca, bd->bdBitsPerPixel,
bmToGrayAllocateWBColor ) )
{ LDEB(bd->bdBitsPerPixel); return -1; }
return 0;
default:
LDEB(bd->bdBitsPerPixel); return -1;
}
}
/************************************************************************/
/* */
/* Convert an image to grayscale. */
/* */
/* 1) Check input format. */
/* 2) Derive properties of output bitmap from input. */
/* 3) Choose grayscale color allocator. */
/* 4) Allocate output buffer. */
/* 5) Fill it. */
/* 6) Return outputs. */
/* 7) Cleanup. */
/* */
/************************************************************************/
int bmToGrayscale( BitmapDescription * bdOut,
const BitmapDescription * bdIn,
unsigned char ** pBufOut,
const unsigned char * bufferIn,
int ignoredInt )
{
int rval= 0;
BitmapDescription bd;
unsigned char * buffer= (unsigned char *)0;
ColorAllocator ca;
int bitmapUnit= 0;
int swapBitmapBytes= 0;
int swapBitmapBits= 0;
const int dither= 0;
bmInitDescription( &bd );
bmInitColorAllocator( &ca );
/* 1 */
switch( bdIn->bdColorEncoding )
{
case BMcoRGB:
break;
case BMcoBLACKWHITE:
case BMcoWHITEBLACK:
case BMcoRGB8PALETTE:
default:
LDEB(bdIn->bdColorEncoding);
rval= -1; goto ready;
}
switch( bdIn->bdBitsPerSample )
{
case 8:
break;
default:
LDEB(bdIn->bdBitsPerSample);
rval= -1; goto ready;
}
/* 2 */
bmCopyDescription( &bd, bdIn );
bd.bdColorEncoding= BMcoWHITEBLACK;
bd.bdBitsPerSample= 8;
if ( bmCalculateSizes( &bd ) )
{ LDEB(1); rval= -1; goto ready; }
/* 3 */
if ( bmGraySetAllocator( &ca, bd.bdBitsPerPixel,
bmToGrayAllocateWBColor ) )
{ LDEB(bd.bdBitsPerPixel); rval= -1; goto ready; }
/* 4 */
buffer= (unsigned char *)malloc( bd.bdBufferLength );
if ( ! buffer )
{ LLDEB(bd.bdBufferLength,buffer); rval= -1; goto ready; }
/* 5 */
if ( bmFillImage( &ca, bitmapUnit, swapBitmapBytes, swapBitmapBits,
dither, buffer, bufferIn, &bd, bdIn ) )
{ LDEB(1); rval= -1; goto ready; }
/* 6 */
if ( bmCopyDescription( bdOut, &bd ) )
{ LDEB(1); rval= -1; goto ready; }
/* steal */
*pBufOut= buffer; buffer= (unsigned char *)0;
ready:
/* 7 */
if ( buffer )
{ free( buffer ); }
bmCleanDescription( &bd );
bmCleanColorAllocator( &ca );
return rval;
}
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