keep the PID file locked for the lifetime of the process
[qemu.git] / ui / sdl_zoom.c
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