/* * 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> #include <stdio.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; }