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gstreamer/gst/videoscale/videoscale.c
David Schleef 2936894898 Fix silly typo 
Original commit message from CVS:
Fix silly typo
2004-01-02 10:02:37 +00:00

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/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#define DEBUG_ENABLED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#include <stdlib.h>
#include <math.h>
#include <videoscale.h>
#include <string.h>
#include "gstvideoscale.h"
#undef HAVE_CPU_I386
#ifdef HAVE_CPU_I386
#include "videoscale_x86.h"
#endif
/* scalers */
static void gst_videoscale_scale_nearest (GstVideoscale *scale, unsigned char *dest, unsigned char *src,
int sw, int sh, int dw, int dh);
#if 0
static void gst_videoscale_scale_plane_slow (GstVideoscale *scale, unsigned char *src, unsigned char *dest,
int sw, int sh, int dw, int dh);
static void gst_videoscale_scale_point_sample (GstVideoscale *scale, unsigned char *src, unsigned char *dest,
int sw, int sh, int dw, int dh);
/* filters */
static unsigned char gst_videoscale_bilinear (unsigned char *src, double x, double y, int sw, int sh);
static unsigned char gst_videoscale_bicubic (unsigned char *src, double x, double y, int sw, int sh);
#endif
static void gst_videoscale_planar411 (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_planar400 (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_packed422 (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_packed422rev (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_32bit (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_24bit (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_16bit (GstVideoscale *scale, unsigned char *dest, unsigned char *src);
static void gst_videoscale_scale_nearest_str2 (GstVideoscale *scale,
unsigned char *dest, unsigned char *src, int sw, int sh, int dw, int dh);
static void gst_videoscale_scale_nearest_str4 (GstVideoscale *scale,
unsigned char *dest, unsigned char *src, int sw, int sh, int dw, int dh);
static void gst_videoscale_scale_nearest_32bit (GstVideoscale *scale,
unsigned char *dest, unsigned char *src, int sw, int sh, int dw, int dh);
static void gst_videoscale_scale_nearest_24bit (GstVideoscale *scale,
unsigned char *dest, unsigned char *src, int sw, int sh, int dw, int dh);
static void gst_videoscale_scale_nearest_16bit (GstVideoscale *scale,
unsigned char *dest, unsigned char *src, int sw, int sh, int dw, int dh);
#define fourcc_YUY2 GST_MAKE_FOURCC('Y','U','Y','2')
#define fourcc_UYVY GST_MAKE_FOURCC('U','Y','V','Y')
#define fourcc_Y422 GST_MAKE_FOURCC('Y','4','2','2')
#define fourcc_UYNV GST_MAKE_FOURCC('U','Y','N','V')
#define fourcc_YVYU GST_MAKE_FOURCC('Y','V','Y','U')
#define fourcc_YV12 GST_MAKE_FOURCC('Y','V','1','2')
#define fourcc_I420 GST_MAKE_FOURCC('I','4','2','0')
#define fourcc_Y800 GST_MAKE_FOURCC('Y','8','0','0')
#define fourcc_RGB_ GST_MAKE_FOURCC('R','G','B',' ')
struct videoscale_format_struct videoscale_formats[] = {
/* packed */
{ fourcc_YUY2, 16, gst_videoscale_packed422, },
{ fourcc_UYVY, 16, gst_videoscale_packed422rev, },
{ fourcc_Y422, 16, gst_videoscale_packed422rev, },
{ fourcc_UYNV, 16, gst_videoscale_packed422rev, },
{ fourcc_YVYU, 16, gst_videoscale_packed422, },
/* planar */
{ fourcc_YV12, 12, gst_videoscale_planar411, },
{ fourcc_I420, 12, gst_videoscale_planar411, },
{ fourcc_Y800, 8, gst_videoscale_planar400, },
/* RGB */
{ fourcc_RGB_, 32, gst_videoscale_32bit, 24, G_BIG_ENDIAN, 0x00ff0000, 0x0000ff00, 0x000000ff },
{ fourcc_RGB_, 32, gst_videoscale_32bit, 24, G_BIG_ENDIAN, 0x000000ff, 0x0000ff00, 0x00ff0000 },
{ fourcc_RGB_, 32, gst_videoscale_32bit, 24, G_BIG_ENDIAN, 0xff000000, 0x00ff0000, 0x0000ff00 },
{ fourcc_RGB_, 32, gst_videoscale_32bit, 24, G_BIG_ENDIAN, 0x0000ff00, 0x00ff0000, 0xff000000 },
{ fourcc_RGB_, 24, gst_videoscale_24bit, 24, G_BIG_ENDIAN, 0xff0000, 0x00ff00, 0x0000ff },
{ fourcc_RGB_, 24, gst_videoscale_24bit, 24, G_BIG_ENDIAN, 0x0000ff, 0x00ff00, 0xff0000 },
{ fourcc_RGB_, 16, gst_videoscale_16bit, 16, G_BYTE_ORDER, 0xf800, 0x07e0, 0x001f },
{ fourcc_RGB_, 16, gst_videoscale_16bit, 15, G_BYTE_ORDER, 0x7c00, 0x03e0, 0x001f },
};
int videoscale_n_formats = sizeof(videoscale_formats)/sizeof(videoscale_formats[0]);
GstStructure *
videoscale_get_structure (struct videoscale_format_struct *format)
{
GstStructure *structure;
if(format->scale==NULL)
return NULL;
if(format->depth){
structure = gst_structure_new ("video/x-raw-rgb",
"depth", G_TYPE_INT, format->depth,
"bpp", G_TYPE_INT, format->bpp,
"endianness", G_TYPE_INT, format->endianness,
"red_mask", G_TYPE_INT, format->red_mask,
"green_mask", G_TYPE_INT, format->green_mask,
"blue_mask", G_TYPE_INT, format->blue_mask,
NULL);
}else{
structure = gst_structure_new ("video/x-raw-yuv",
"format", GST_TYPE_FOURCC, format->fourcc, NULL);
}
gst_structure_set(structure,
"width", GST_TYPE_INT_RANGE, 100, G_MAXINT,
"height", GST_TYPE_INT_RANGE, 100, G_MAXINT,
"framerate", GST_TYPE_DOUBLE_RANGE, 0.0, G_MAXDOUBLE,
NULL);
return structure;
}
struct videoscale_format_struct *
videoscale_find_by_structure(GstStructure *structure)
{
int i;
gboolean ret;
struct videoscale_format_struct *format;
GST_DEBUG ("finding %s",gst_structure_to_string(structure));
g_return_val_if_fail(structure != NULL, NULL);
if(strcmp(gst_structure_get_name(structure),"video/x-raw-yuv")==0){
unsigned int fourcc;
ret = gst_structure_get_fourcc (structure, "format", &fourcc);
if(!ret) return NULL;
for (i = 0; i < videoscale_n_formats; i++){
format = videoscale_formats + i;
if(format->depth==0 && format->fourcc == fourcc){
return format;
}
}
}else{
int bpp;
int depth;
int endianness;
int red_mask;
int green_mask;
int blue_mask;
ret = gst_structure_get_int (structure, "bpp", &bpp);
ret &= gst_structure_get_int (structure, "depth", &depth);
ret &= gst_structure_get_int (structure, "endianness", &endianness);
ret &= gst_structure_get_int (structure, "red_mask", &red_mask);
ret &= gst_structure_get_int (structure, "green_mask", &green_mask);
ret &= gst_structure_get_int (structure, "blue_mask", &blue_mask);
if(!ret) return NULL;
for (i = 0; i < videoscale_n_formats; i++){
format = videoscale_formats + i;
if(format->bpp == bpp && format->depth == depth &&
format->endianness == endianness && format->red_mask == red_mask &&
format->green_mask == green_mask && format->blue_mask == blue_mask) {
return format;
}
}
}
return NULL;
}
void
gst_videoscale_setup (GstVideoscale *videoscale)
{
g_return_if_fail (GST_IS_VIDEOSCALE (videoscale));
g_return_if_fail (videoscale->format != NULL);
GST_DEBUG ("format=%p " GST_FOURCC_FORMAT " from %dx%d to %dx%d",
videoscale->format, GST_FOURCC_ARGS(videoscale->format->fourcc),
videoscale->from_width, videoscale->from_height,
videoscale->to_width, videoscale->to_height);
if(videoscale->to_width==0 || videoscale->to_height==0 ||
videoscale->from_width==0 || videoscale->from_height==0){
g_critical ("bad sizes %dx%d %dx%d",
videoscale->from_width, videoscale->from_height,
videoscale->to_width, videoscale->to_height);
return;
}
if(videoscale->to_width == videoscale->from_width &&
videoscale->to_height == videoscale->from_height){
GST_DEBUG ("videoscale: using passthru");
videoscale->passthru = TRUE;
videoscale->inited = TRUE;
return;
}
GST_DEBUG ("videoscale: scaling method POINT_SAMPLE");
videoscale->from_buf_size = (videoscale->from_width * videoscale->from_height
* videoscale->format->bpp) / 8;
videoscale->to_buf_size = (videoscale->to_width * videoscale->to_height
* videoscale->format->bpp) / 8;
videoscale->passthru = FALSE;
videoscale->inited = TRUE;
}
#if 0
static void
gst_videoscale_scale_rgb (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling RGB %dx%d to %dx%d", sw, sh, dw, dh);
switch (scale->scale_bytes) {
case 2:
dw = ((dw + 1) & ~1) << 1;
sw = sw<<1;
break;
case 4:
dw = ((dw + 2) & ~3) << 2;
sw = sw<<2;
break;
default:
break;
}
GST_DEBUG ("videoscale: %p %p", src, dest);
//scale->scaler(scale, src, dest, sw, sh, dw, dh);
}
#endif
static void
gst_videoscale_planar411 (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling planar 4:1:1 %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest(scale, dest, src, sw, sh, dw, dh);
src += sw*sh;
dest += dw*dh;
dh = dh>>1;
dw = dw>>1;
sh = sh>>1;
sw = sw>>1;
gst_videoscale_scale_nearest(scale, dest, src, sw, sh, dw, dh);
src += sw*sh;
dest += dw*dh;
gst_videoscale_scale_nearest(scale, dest, src, sw, sh, dw, dh);
}
static void
gst_videoscale_planar400 (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling Y-only %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest(scale, dest, src, sw, sh, dw, dh);
}
static void
gst_videoscale_packed422 (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling 4:2:2 %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest_str2(scale, dest, src, sw, sh, dw, dh);
gst_videoscale_scale_nearest_str4(scale, dest+1, src+1, sw/2, sh, dw/2, dh);
gst_videoscale_scale_nearest_str4(scale, dest+3, src+3, sw/2, sh, dw/2, dh);
}
static void
gst_videoscale_packed422rev (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling 4:2:2 %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest_str2(scale, dest+1, src, sw, sh, dw, dh);
gst_videoscale_scale_nearest_str4(scale, dest, src+1, sw/2, sh, dw/2, dh);
gst_videoscale_scale_nearest_str4(scale, dest+2, src+3, sw/2, sh, dw/2, dh);
}
static void
gst_videoscale_32bit (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling 32bit %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest_32bit(scale, dest, src, sw, sh, dw, dh);
}
static void
gst_videoscale_24bit (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling 24bit %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest_24bit(scale, dest, src, sw, sh, dw, dh);
}
static void
gst_videoscale_16bit (GstVideoscale *scale, unsigned char *dest, unsigned char *src)
{
int sw = scale->from_width;
int sh = scale->from_height;
int dw = scale->to_width;
int dh = scale->to_height;
GST_DEBUG ("videoscale: scaling 16bit %dx%d to %dx%d", sw, sh, dw, dh);
gst_videoscale_scale_nearest_16bit(scale, dest, src, sw, sh, dw, dh);
}
#if 0
#define RC(x,y) *(src+(int)(x)+(int)((y)*sw))
static unsigned char
gst_videoscale_bilinear (unsigned char *src, double x, double y, int sw, int sh)
{
int j=floor(x);
int k=floor(y);
double a=x-j;
double b=y-k;
double dest;
int color;
GST_DEBUG ("videoscale: scaling bilinear %f %f %dx%d", x, y, sw, sh);
dest=(1-a)*(1-b)*RC(j,k)+
a*(1-b)*RC(j+1,k);
k = MIN(sh-1, k);
dest+= b*(1-a)*RC(j,k+1)+
a*b*RC(j+1,k+1);
color=rint(dest);
if (color<0) color=abs(color); /* cannot have negative values ! */
/*if (color<0) color=0; // cannot have negative values ! */
if (color>255) color=255;
return (unsigned char) color;
}
static unsigned char
gst_videoscale_bicubic (unsigned char *src, double x, double y, int sw, int sh)
{
int j=floor(x);
int k=floor(y), k2;
double a=x-j;
double b=y-k;
double dest;
int color;
double t1, t2, t3, t4;
double a1, a2, a3, a4;
GST_DEBUG ("videoscale: scaling bicubic %dx%d", sw, sh);
a1 = -a*(1-a)*(1-a);
a2 = (1-2*a*a+a*a*a);
a3 = a*(1+a-a*a);
a4 = a*a*(1-a);
k2 = MAX(0, k-1);
t1=a1*RC(j-1,k2)+ a2*RC(j,k2)+ a3*RC(j+1,k2)- a4*RC(j+2,k2);
t2=a1*RC(j-1,k)+ a2*RC(j,k)+ a3*RC(j+1,k)- a4*RC(j+2,k);
k2 = MIN(sh, k+1);
t3=a1*RC(j-1,k2)+ a2*RC(j,k2)+ a3*RC(j+1,k2)- a4*RC(j+2,k2);
k2 = MIN(sh, k+2);
t4=a1*RC(j-1,k2)+ a2*RC(j,k2)+ a3*RC(j+1,k2)- a4*RC(j+2,k2);
dest= -b*(1-b)*(1-b)*t1+ (1-2*b*b+b*b*b)*t2+ b*(1+b-b*b)*t3+ b*b*(b-1)*t4;
color=rint(dest);
if (color<0) color=abs(color); /* cannot have negative values ! */
if (color>255) color=255;
return (unsigned char) color;
}
static void
gst_videoscale_scale_plane_slow (GstVideoscale *scale, unsigned char *src, unsigned char *dest,
int sw, int sh, int dw, int dh)
{
double zoomx = ((double)dw)/(double)sw;
double zoomy = ((double)dh)/(double)sh;
double xr, yr;
int x, y;
GST_DEBUG ("videoscale: scale plane slow %dx%d %dx%d %g %g %p %p", sw, sh, dw, dh, zoomx, zoomy, src, dest);
for (y=0; y<dh; y++) {
yr = ((double)y)/zoomy;
for (x=0; x<dw; x++) {
xr = ((double)x)/zoomx;
GST_DEBUG ("videoscale: scale plane slow %g %g %p", xr, yr, (src+(int)(x)+(int)((y)*sw)));
if (floor(xr) == xr && floor(yr) == yr){
GST_DEBUG ("videoscale: scale plane %g %g %p %p", xr, yr, (src+(int)(x)+(int)((y)*sw)), dest);
*dest++ = RC(xr, yr);
}
else {
*dest++ = scale->filter(src, xr, yr, sw, sh);
/**dest++ = gst_videoscale_bicubic(src, xr, yr, sw, sh); */
}
}
}
}
#endif
#if 0
static void
gst_videoscale_scale_point_sample (GstVideoscale *scale, unsigned char *src, unsigned char *dest,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
int sum, xcount, ycount, loop;
unsigned char *srcp, *srcp2;
GST_DEBUG ("videoscale: scaling nearest point sample %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
ycount = 1;
srcp = src;
while (ypos >0x10000) {
ycount++;
ypos-=0x10000;
src += sw;
}
xpos = 0x10000;
for ( x=dw; x; x-- ) {
xcount = 0;
sum=0;
while ( xpos >= 0x10000L ) {
loop = ycount;
srcp2 = srcp;
while (loop--) {
sum += *srcp2;
srcp2 += sw;
}
srcp++;
xcount++;
xpos -= 0x10000L;
}
*dest++ = sum/(xcount*ycount);
xpos += xinc;
}
ypos += yinc;
}
}
#endif
static void
gst_videoscale_scale_nearest (GstVideoscale *scale,
unsigned char *dest,
unsigned char *src,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
guchar *destp = dest;
guchar *srcp = src;
GST_DEBUG ("videoscale: scaling nearest %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
while (ypos >0x10000) {
ypos-=0x10000;
src += sw;
}
xpos = 0x10000;
srcp = src;
destp = dest;
for ( x=dw; x; x-- ) {
while ( xpos >= 0x10000L ) {
srcp++;
xpos -= 0x10000L;
}
*destp++ = *srcp;
xpos += xinc;
}
dest += dw;
ypos += yinc;
}
}
static void
gst_videoscale_scale_nearest_str2 (GstVideoscale *scale,
unsigned char *dest,
unsigned char *src,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
guchar *destp = dest;
guchar *srcp = src;
GST_DEBUG ("videoscale: scaling nearest %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
while (ypos >0x10000) {
ypos-=0x10000;
src += sw*2;
}
xpos = 0x10000;
srcp = src;
destp = dest;
for ( x=dw; x; x-- ) {
while ( xpos >= 0x10000L ) {
srcp+=2;
xpos -= 0x10000L;
}
*destp = *srcp;
destp+=2;
xpos += xinc;
}
dest += dw*2;
ypos += yinc;
}
}
static void
gst_videoscale_scale_nearest_str4 (GstVideoscale *scale,
unsigned char *dest,
unsigned char *src,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
guchar *destp = dest;
guchar *srcp = src;
GST_DEBUG ("videoscale: scaling nearest %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
while (ypos >0x10000) {
ypos-=0x10000;
src += sw*4;
}
xpos = 0x10000;
srcp = src;
destp = dest;
for ( x=dw; x; x-- ) {
while ( xpos >= 0x10000L ) {
srcp+=4;
xpos -= 0x10000L;
}
*destp = *srcp;
destp+=4;
xpos += xinc;
}
dest += dw*4;
ypos += yinc;
}
}
static void
gst_videoscale_scale_nearest_32bit (GstVideoscale *scale,
unsigned char *dest,
unsigned char *src,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
guchar *destp = dest;
guchar *srcp = src;
GST_DEBUG ("videoscale: scaling nearest %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
while (ypos >0x10000) {
ypos-=0x10000;
src += sw*4;
}
xpos = 0x10000;
srcp = src;
destp = dest;
for ( x=dw; x; x-- ) {
while ( xpos >= 0x10000L ) {
srcp+=4;
xpos -= 0x10000L;
}
*(guint32 *)destp = *(guint32 *)srcp;
destp+=4;
xpos += xinc;
}
dest += dw*4;
ypos += yinc;
}
}
static void
gst_videoscale_scale_nearest_24bit (GstVideoscale *scale,
unsigned char *dest,
unsigned char *src,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
guchar *destp = dest;
guchar *srcp = src;
GST_DEBUG ("videoscale: scaling nearest %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
while (ypos >0x10000) {
ypos-=0x10000;
src += sw*3;
}
xpos = 0x10000;
srcp = src;
destp = dest;
for ( x=dw; x; x-- ) {
while ( xpos >= 0x10000L ) {
srcp+=3;
xpos -= 0x10000L;
}
destp[0] = srcp[0];
destp[1] = srcp[1];
destp[2] = srcp[2];
destp+=3;
xpos += xinc;
}
dest += dw*3;
ypos += yinc;
}
}
static void
gst_videoscale_scale_nearest_16bit (GstVideoscale *scale,
unsigned char *dest,
unsigned char *src,
int sw, int sh, int dw, int dh)
{
int ypos, yinc, y;
int xpos, xinc, x;
guchar *destp = dest;
guchar *srcp = src;
GST_DEBUG ("videoscale: scaling nearest %p %p %d", src, dest, dw);
ypos = 0x10000;
yinc = (sh<<16)/dh;
xinc = (sw<<16)/dw;
for (y = dh; y; y--) {
while (ypos >0x10000) {
ypos-=0x10000;
src += sw*2;
}
xpos = 0x10000;
srcp = src;
destp = dest;
for ( x=dw; x; x-- ) {
while ( xpos >= 0x10000L ) {
srcp+=2;
xpos -= 0x10000L;
}
destp[0] = srcp[0];
destp[1] = srcp[1];
destp+=2;
xpos += xinc;
}
dest += dw*2;
ypos += yinc;
}
}
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