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Annotation of qemu/ui/sdl_zoom.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * SDL_zoom - surface scaling
                      3:  * 
                      4:  * Copyright (c) 2009 Citrix Systems, Inc.
                      5:  *
                      6:  * Derived from: SDL_rotozoom,  LGPL (c) A. Schiffler from the SDL_gfx library.
                      7:  * Modifications by Stefano Stabellini.
                      8:  *
                      9:  * This work is licensed under the terms of the GNU GPL version 2.
                     10:  * See the COPYING file in the top-level directory.
                     11:  *
                     12:  */
                     13: 
                     14: #include "sdl_zoom.h"
                     15: #include "osdep.h"
                     16: #include <stdint.h>
                     17: #include <stdio.h>
                     18: 
                     19: static int sdl_zoom_rgb16(SDL_Surface *src, SDL_Surface *dst, int smooth,
                     20:                           SDL_Rect *dst_rect);
                     21: static int sdl_zoom_rgb32(SDL_Surface *src, SDL_Surface *dst, int smooth,
                     22:                           SDL_Rect *dst_rect);
                     23: 
                     24: #define BPP 32
                     25: #include  "sdl_zoom_template.h"
                     26: #undef BPP
                     27: #define BPP 16
                     28: #include  "sdl_zoom_template.h"
                     29: #undef BPP
                     30: 
                     31: int sdl_zoom_blit(SDL_Surface *src_sfc, SDL_Surface *dst_sfc, int smooth,
                     32:                   SDL_Rect *in_rect)
                     33: {
                     34:     SDL_Rect zoom, src_rect;
                     35:     int extra;
                     36: 
                     37:     /* Grow the size of the modified rectangle to avoid edge artefacts */
                     38:     src_rect.x = (in_rect->x > 0) ? (in_rect->x - 1) : 0;
                     39:     src_rect.y = (in_rect->y > 0) ? (in_rect->y - 1) : 0;
                     40: 
                     41:     src_rect.w = in_rect->w + 1;
                     42:     if (src_rect.x + src_rect.w > src_sfc->w)
                     43:         src_rect.w = src_sfc->w - src_rect.x;
                     44: 
                     45:     src_rect.h = in_rect->h + 1;
                     46:     if (src_rect.y + src_rect.h > src_sfc->h)
                     47:         src_rect.h = src_sfc->h - src_rect.y;
                     48: 
                     49:     /* (x,y) : round down */
                     50:     zoom.x = (int)(((float)(src_rect.x * dst_sfc->w)) / (float)(src_sfc->w));
                     51:     zoom.y = (int)(((float)(src_rect.y * dst_sfc->h)) / (float)(src_sfc->h));
                     52: 
                     53:     /* (w,h) : round up */
                     54:     zoom.w = (int)( ((double)((src_rect.w * dst_sfc->w) + (src_sfc->w - 1))) /
                     55:                      (double)(src_sfc->w));
                     56: 
                     57:     zoom.h = (int)( ((double)((src_rect.h * dst_sfc->h) + (src_sfc->h - 1))) /
                     58:                      (double)(src_sfc->h));
                     59: 
                     60:     /* Account for any (x,y) rounding by adding one-source-pixel's worth
                     61:      * of destination pixels and then edge checking.
                     62:      */
                     63: 
                     64:     extra = ((dst_sfc->w-1) / src_sfc->w) + 1;
                     65: 
                     66:     if ((zoom.x + zoom.w) < (dst_sfc->w - extra))
                     67:         zoom.w += extra;
                     68:     else
                     69:         zoom.w = dst_sfc->w - zoom.x;
                     70: 
                     71:     extra = ((dst_sfc->h-1) / src_sfc->h) + 1;
                     72: 
                     73:     if ((zoom.y + zoom.h) < (dst_sfc->h - extra))
                     74:         zoom.h += extra;
                     75:     else
                     76:         zoom.h = dst_sfc->h - zoom.y;
                     77: 
                     78:     /* The rectangle (zoom.x, zoom.y, zoom.w, zoom.h) is the area on the
                     79:      * destination surface that needs to be updated.
                     80:      */
                     81:     if (src_sfc->format->BitsPerPixel == 32)
                     82:         sdl_zoom_rgb32(src_sfc, dst_sfc, smooth, &zoom);
                     83:     else if (src_sfc->format->BitsPerPixel == 16)
                     84:         sdl_zoom_rgb16(src_sfc, dst_sfc, smooth, &zoom);
                     85:     else {
                     86:         fprintf(stderr, "pixel format not supported\n");
                     87:         return -1;
                     88:     }
                     89: 
                     90:     /* Return the rectangle of the update to the caller */
                     91:     *in_rect = zoom;
                     92: 
                     93:     return 0;
                     94: }
                     95: 

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