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Club Amiga de Montreal - CAM
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dith.c
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C/C++ Source or Header
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1986-11-10
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4KB
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167 lines
#include <graphics/gfxbase.h>
#include <graphics/display.h>
#include <intuition/intuition.h>
#include <stdio.h>
struct GfxBase *GfxBase; /* Export the library pointers */
struct IntuitionBase *IntuitionBase;
struct RastPort *rp; /* Graphics structures */
struct ViewPort *vp;
struct Window *w; /* Intuition structures */
struct Screen *screen;
struct NewScreen ns = {
0, 0, /* start position */
640, 400, 4, /* width, height, depth */
15, 0, /* detail pen, block pen */
HIRES|INTERLACE, /* Hires ViewMode */
CUSTOMSCREEN, /* screen type */
NULL, /* font to use */
" Dither Tester ", /* default title for screen */
NULL /* pointer to additional gadgets */
};
struct NewWindow nw = {
0, 11, /* start position */
640, 386, /* width, height */
15, 0, /* detail pen, block pen */
NULL, /* IDCMP flags */
BORDERLESS, /* window flags */
NULL, /* pointer to first user gadget */
NULL, /* pointer to user checkmark */
NULL, /* window title */
NULL, /* pointer to screen (set below) */
NULL, /* pointer to superbitmap */
0, 0, 640, 386, /* ignored since not sizeable */
CUSTOMSCREEN /* type of screen desired */
};
FILE *in;
main(argc, argv)
int argc;
char **argv;
{
char wait[10];
if ( !(GfxBase=(struct GfxBase *)OpenLibrary("graphics.library") ) ) {
cleanup();
exit(103);
}
if ( !( IntuitionBase
=(struct IntuitionBase *)OpenLibrary("intuition.library") )
) {
cleanup();
exit(103);
}
if ( !(screen = (struct Screen *)OpenScreen(&ns) ) ) {
cleanup();
exit(103);
}
nw.Screen = screen; /* Open window in our new screen */
if ( ! (w = (struct Window *)OpenWindow(&nw) ) ) {
cleanup();
exit(103);
}
vp = &screen->ViewPort; /* Set colors in screen's VP */
rp = w->RPort; /* Render into the window's RP */
/* Set the color registers */
SetRGB4(vp, 0, 00, 00, 00);
SetRGB4(vp, 1, 01, 00, 01);
SetRGB4(vp, 2, 02, 01, 02);
SetRGB4(vp, 3, 03, 02, 03);
SetRGB4(vp, 4, 04, 03, 04);
SetRGB4(vp, 5, 05, 04, 05);
SetRGB4(vp, 6, 06, 05, 06);
SetRGB4(vp, 7, 07, 06, 07);
SetRGB4(vp, 8, 08, 07, 08);
SetRGB4(vp, 9, 09, 08, 09);
SetRGB4(vp,10, 10, 09, 10);
SetRGB4(vp,11, 11, 10, 11);
SetRGB4(vp,12, 12, 11, 12);
SetRGB4(vp,13, 13, 12, 13);
SetRGB4(vp,14, 14, 13, 14);
SetRGB4(vp,15, 15, 14, 15);
show();
gets(wait);
cleanup();
}
cleanup()
{
if (w)
CloseWindow(w);
if (screen)
CloseScreen(screen);
if (IntuitionBase)
CloseLibrary(IntuitionBase);
if (GfxBase)
CloseLibrary(GfxBase);
}
show()
{
int x, y, color=0;
for(y=0; y<=0x0F; y++)
for(x=0; x<=0x0F; x++)
box( (x*17)+30, (y*17)+30, color++);
}
box(x, y, color)
int x, y, color;
{
int i, j;
for (i=0; i<=0x0F; i++)
for (j=0; j<=0x0F; j++) {
SetAPen(rp, dither(x+i, x+j, color) );
WritePixel(rp, x+i, y+j);
}
}
#define dithsize 7
/* 8 x 8 dithering matrix */
static int matrix[dithsize+1][dithsize+1] = {
{ 0, 128, 32, 160, 8, 136, 40, 168 },
{ 192, 64, 224, 96, 200, 72, 232, 104 },
{ 48, 176, 16, 144, 56, 184, 24, 152 },
{ 240, 112, 208, 80, 248, 120, 216, 88 },
{ 12, 140, 44, 174, 4, 132, 36, 164 },
{ 204, 76, 236, 108, 196, 68, 228, 100 },
{ 60, 188, 28, 156, 52, 180, 20, 148 },
{ 252, 124, 210, 92, 244, 116, 212, 84 }
};
/*
dithering by area access to matrix by using
the MOD function on the x and y coordinates
*/
dither(x, y, level) /* dithering function */
register int x, y, level;
{
register int base, dith;
base = level >> 4;
if (base == 0x0F)
return(base);
dith = (level & 0x0F) << 4;
if ( dith > matrix [x%dithsize] [y%dithsize] )
return(base+1);
return(base);
}