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Initial. Don't... just don't ask.

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Ryan McGrath 2011-02-24 00:22:00 -08:00
commit 00bae13bba
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/* Framebuffer Graphics Libary for Linux, Copyright 1993 Harm Hanemaayer */
/* scale.c Scaling routine */
#include <stdlib.h>
#include <vga.h>
#include "inlstring.h" /* include inline string operations */
#include "vgagl.h"
#include "def.h"
static inline int muldiv64(float m1, float m2, float d)
{
return m1 * m2 / d;
}
/* This is a DDA-based algorithm. */
/* Iteration over target bitmap. */
void gl_scalebox(int w1, int h1, void *_dp1, int w2, int h2, void *_dp2)
{
uchar *dp1 = _dp1;
uchar *dp2 = _dp2;
int xfactor;
int yfactor;
if (w2 == 0 || h2 == 0)
return;
xfactor = muldiv64(w1, 65536, w2); /* scaled by 65536 */
yfactor = muldiv64(h1, 65536, h2); /* scaled by 65536 */
switch (BYTESPERPIXEL) {
case 1:
{
int y, sy;
sy = 0;
for (y = 0; y < h2;) {
int sx = 0;
uchar *dp2old = dp2;
int x;
x = 0;
while (x < w2 - 8) {
*(dp2 + x) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 1) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 2) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 3) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 4) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 5) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 6) = *(dp1 + (sx >> 16));
sx += xfactor;
*(dp2 + x + 7) = *(dp1 + (sx >> 16));
sx += xfactor;
x += 8;
}
while (x < w2) {
*(dp2 + x) = *(dp1 + (sx >> 16));
sx += xfactor;
x++;
}
dp2 += w2;
y++;
while (y < h2) {
int l;
int syint = sy >> 16;
sy += yfactor;
if ((sy >> 16) != syint)
break;
/* Copy identical lines. */
l = dp2 - dp2old;
__memcpy(dp2, dp2old, l);
dp2old = dp2;
dp2 += l;
y++;
}
dp1 = _dp1 + (sy >> 16) * w1;
}
}
break;
case 2:
{
int y, sy;
sy = 0;
for (y = 0; y < h2;) {
int sx = 0;
uchar *dp2old = dp2;
int x;
x = 0;
/* This can be greatly optimized with loop */
/* unrolling; omitted to save space. */
while (x < w2) {
*(unsigned short *) (dp2 + x * 2) =
*(unsigned short *) (dp1 + (sx >> 16) * 2);
sx += xfactor;
x++;
}
dp2 += w2 * 2;
y++;
while (y < h2) {
int l;
int syint = sy >> 16;
sy += yfactor;
if ((sy >> 16) != syint)
break;
/* Copy identical lines. */
l = dp2 - dp2old;
__memcpy(dp2, dp2old, l);
dp2old = dp2;
dp2 += l;
y++;
}
dp1 = _dp1 + (sy >> 16) * w1 * 2;
}
}
break;
case 3:
{
int y, sy;
sy = 0;
for (y = 0; y < h2;) {
int sx = 0;
uchar *dp2old = dp2;
int x;
x = 0;
/* This can be greatly optimized with loop */
/* unrolling; omitted to save space. */
while (x < w2) {
*(unsigned short *) (dp2 + x * 3) =
*(unsigned short *) (dp1 + (sx >> 16) * 3);
*(unsigned char *) (dp2 + x * 3 + 2) =
*(unsigned char *) (dp1 + (sx >> 16) * 3 + 2);
sx += xfactor;
x++;
}
dp2 += w2 * 3;
y++;
while (y < h2) {
int l;
int syint = sy >> 16;
sy += yfactor;
if ((sy >> 16) != syint)
break;
/* Copy identical lines. */
l = dp2 - dp2old;
__memcpy(dp2, dp2old, l);
dp2old = dp2;
dp2 += l;
y++;
}
dp1 = _dp1 + (sy >> 16) * w1 * 3;
}
}
break;
case 4:
{
int y, sy;
sy = 0;
for (y = 0; y < h2;) {
int sx = 0;
uchar *dp2old = dp2;
int x;
x = 0;
/* This can be greatly optimized with loop */
/* unrolling; omitted to save space. */
while (x < w2) {
*(unsigned *) (dp2 + x * 4) =
*(unsigned *) (dp1 + (sx >> 16) * 4);
sx += xfactor;
x++;
}
dp2 += w2 * 4;
y++;
while (y < h2) {
int l;
int syint = sy >> 16;
sy += yfactor;
if ((sy >> 16) != syint)
break;
/* Copy identical lines. */
l = dp2 - dp2old;
__memcpy(dp2, dp2old, l);
dp2old = dp2;
dp2 += l;
y++;
}
dp1 = _dp1 + (sy >> 16) * w1 * 4;
}
}
break;
}
}