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/*
* SDL_zoom - surface scaling
*
* Copyright (c) 2009 Citrix Systems, Inc.
*
* Derived from: SDL_rotozoom, LGPL (c) A. Schiffler from the SDL_gfx library.
* Modifications by Stefano Stabellini.
*
* This work is licensed under the terms of the GNU GPL version 2.
* See the COPYING file in the top-level directory.
*
*/
#include "sdl_zoom.h"
#include "osdep.h"
#include <stdint.h>
static int sdl_zoom_rgb16(SDL_Surface *src, SDL_Surface *dst, int smooth,
SDL_Rect *dst_rect);
static int sdl_zoom_rgb32(SDL_Surface *src, SDL_Surface *dst, int smooth,
SDL_Rect *dst_rect);
#define BPP 32
#include "sdl_zoom_template.h"
#undef BPP
#define BPP 16
#include "sdl_zoom_template.h"
#undef BPP
int sdl_zoom_blit(SDL_Surface *src_sfc, SDL_Surface *dst_sfc, int smooth,
SDL_Rect *in_rect)
{
SDL_Rect zoom, src_rect;
int extra;
/* Grow the size of the modified rectangle to avoid edge artefacts */
src_rect.x = (in_rect->x > 0) ? (in_rect->x - 1) : 0;
src_rect.y = (in_rect->y > 0) ? (in_rect->y - 1) : 0;
src_rect.w = in_rect->w + 1;
if (src_rect.x + src_rect.w > src_sfc->w)
src_rect.w = src_sfc->w - src_rect.x;
src_rect.h = in_rect->h + 1;
if (src_rect.y + src_rect.h > src_sfc->h)
src_rect.h = src_sfc->h - src_rect.y;
/* (x,y) : round down */
zoom.x = (int)(((float)(src_rect.x * dst_sfc->w)) / (float)(src_sfc->w));
zoom.y = (int)(((float)(src_rect.y * dst_sfc->h)) / (float)(src_sfc->h));
/* (w,h) : round up */
zoom.w = (int)( ((double)((src_rect.w * dst_sfc->w) + (src_sfc->w - 1))) /
(double)(src_sfc->w));
zoom.h = (int)( ((double)((src_rect.h * dst_sfc->h) + (src_sfc->h - 1))) /
(double)(src_sfc->h));
/* Account for any (x,y) rounding by adding one-source-pixel's worth
* of destination pixels and then edge checking.
*/
extra = ((dst_sfc->w-1) / src_sfc->w) + 1;
if ((zoom.x + zoom.w) < (dst_sfc->w - extra))
zoom.w += extra;
else
zoom.w = dst_sfc->w - zoom.x;
extra = ((dst_sfc->h-1) / src_sfc->h) + 1;
if ((zoom.y + zoom.h) < (dst_sfc->h - extra))
zoom.h += extra;
else
zoom.h = dst_sfc->h - zoom.y;
/* The rectangle (zoom.x, zoom.y, zoom.w, zoom.h) is the area on the
* destination surface that needs to be updated.
*/
if (src_sfc->format->BitsPerPixel == 32)
sdl_zoom_rgb32(src_sfc, dst_sfc, smooth, &zoom);
else if (src_sfc->format->BitsPerPixel == 16)
sdl_zoom_rgb16(src_sfc, dst_sfc, smooth, &zoom);
else {
fprintf(stderr, "pixel format not supported\n");
return -1;
}
/* Return the rectangle of the update to the caller */
*in_rect = zoom;
return 0;
}
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