Sweden-Number/objects/dither.c

141 lines
3.8 KiB
C

/*
* Dithering functions
*
* Copyright 1994 Alexandre Julliard
*/
static char Copyright[] = "Copyright Alexandre Julliard, 1994";
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include "gdi.h"
#include "bitmap.h"
/* Levels of each primary */
#define PRIMARY_LEVELS 3
#define TOTAL_LEVELS (PRIMARY_LEVELS*PRIMARY_LEVELS*PRIMARY_LEVELS)
/* Dithering matrix size */
#define MATRIX_SIZE 8
#define MATRIX_SIZE_2 (MATRIX_SIZE*MATRIX_SIZE)
/* Total number of possible levels for a dithered primary color */
#define DITHER_LEVELS (MATRIX_SIZE_2 * (PRIMARY_LEVELS-1) + 1)
/* Dithering matrix */
static const int dither_matrix[MATRIX_SIZE_2] =
{
0, 32, 8, 40, 2, 34, 10, 42,
48, 16, 56, 24, 50, 18, 58, 26,
12, 44, 4, 36, 14, 46, 6, 38,
60, 28, 52, 20, 62, 30, 54, 22,
3, 35, 11, 43, 1, 33, 9, 41,
51, 19, 59, 27, 49, 17, 57, 25,
15, 47, 7, 39, 13, 45, 5, 37,
63, 31, 55, 23, 61, 29, 53, 21
};
/* Mapping between (R,G,B) triples and EGA colors */
static const int EGAmapping[TOTAL_LEVELS] =
{
0, /* 000000 -> 000000 */
4, /* 00007f -> 000080 */
12, /* 0000ff -> 0000ff */
2, /* 007f00 -> 008000 */
6, /* 007f7f -> 008080 */
6, /* 007fff -> 008080 */
10, /* 00ff00 -> 00ff00 */
6, /* 00ff7f -> 008080 */
14, /* 00ffff -> 00ffff */
1, /* 7f0000 -> 800000 */
5, /* 7f007f -> 800080 */
5, /* 7f00ff -> 800080 */
3, /* 7f7f00 -> 808000 */
8, /* 7f7f7f -> 808080 */
7, /* 7f7fff -> c0c0c0 */
3, /* 7fff00 -> 808000 */
7, /* 7fff7f -> c0c0c0 */
7, /* 7fffff -> c0c0c0 */
9, /* ff0000 -> ff0000 */
5, /* ff007f -> 800080 */
13, /* ff00ff -> ff00ff */
3, /* ff7f00 -> 808000 */
7, /* ff7f7f -> c0c0c0 */
7, /* ff7fff -> c0c0c0 */
11, /* ffff00 -> ffff00 */
7, /* ffff7f -> c0c0c0 */
15 /* ffffff -> ffffff */
};
/* Map an EGA index (0..15) to a pixel value */
extern int COLOR_mapEGAPixel[16]; /* in color.c */
#define PIXEL_VALUE(r,g,b) \
COLOR_mapEGAPixel[EGAmapping[((r)*PRIMARY_LEVELS+(g))*PRIMARY_LEVELS+(b)]]
/* X image for building dithered pixmap */
static XImage *ditherImage = NULL;
static char *imageData = NULL;
/***********************************************************************
* DITHER_Init
*
* Create the X image used for dithering.
*/
BOOL DITHER_Init()
{
int bytes_per_line = (screenDepth * MATRIX_SIZE + 7) / 8;
if (!(imageData = (char *) malloc( bytes_per_line * MATRIX_SIZE )))
return FALSE;
ditherImage = XCreateImage( display, DefaultVisualOfScreen(screen),
screenDepth, ZPixmap, 0, imageData,
MATRIX_SIZE, MATRIX_SIZE, 8, bytes_per_line );
return (ditherImage != NULL);
}
/***********************************************************************
* DITHER_DitherColor
*/
Pixmap DITHER_DitherColor( DC *dc, COLORREF color )
{
static COLORREF prevColor = 0xffffffff;
unsigned int x, y;
Pixmap pixmap;
/* printf( "Dither: %x\n", color ); */
if (color != prevColor)
{
int r = GetRValue( color ) * DITHER_LEVELS;
int g = GetGValue( color ) * DITHER_LEVELS;
int b = GetBValue( color ) * DITHER_LEVELS;
const int *pmatrix = dither_matrix;
WORD *mapping = (WORD *) GDI_HEAP_ADDR( dc->u.x.pal.hMapping );
for (y = 0; y < MATRIX_SIZE; y++)
{
for (x = 0; x < MATRIX_SIZE; x++)
{
int d = *pmatrix++ * 256;
int dr = ((r + d) / MATRIX_SIZE_2) / 256;
int dg = ((g + d) / MATRIX_SIZE_2) / 256;
int db = ((b + d) / MATRIX_SIZE_2) / 256;
XPutPixel( ditherImage, x, y, PIXEL_VALUE(dr,dg,db) );
}
}
prevColor = color;
}
pixmap = XCreatePixmap( display, rootWindow,
MATRIX_SIZE, MATRIX_SIZE, screenDepth );
XPutImage( display, pixmap, BITMAP_colorGC, ditherImage, 0, 0,
0, 0, MATRIX_SIZE, MATRIX_SIZE );
return pixmap;
}