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c18a2c36 SS |
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> | |
22d091b3 | 17 | #include <stdio.h> |
c18a2c36 SS |
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 |