Stefano Stabellini | c18a2c3 | 2009-06-24 11:58:25 +0100 | [diff] [blame] | 1 | /* |
| 2 | * SDL_zoom_template - 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 | #if BPP == 16 |
| 15 | #define SDL_TYPE Uint16 |
| 16 | #elif BPP == 32 |
| 17 | #define SDL_TYPE Uint32 |
| 18 | #else |
| 19 | #error unsupport depth |
| 20 | #endif |
| 21 | |
| 22 | /* |
| 23 | * Simple helper functions to make the code looks nicer |
| 24 | * |
| 25 | * Assume spf = source SDL_PixelFormat |
| 26 | * dpf = dest SDL_PixelFormat |
| 27 | * |
| 28 | */ |
| 29 | #define getRed(color) (((color) & spf->Rmask) >> spf->Rshift) |
| 30 | #define getGreen(color) (((color) & spf->Gmask) >> spf->Gshift) |
| 31 | #define getBlue(color) (((color) & spf->Bmask) >> spf->Bshift) |
| 32 | #define getAlpha(color) (((color) & spf->Amask) >> spf->Ashift) |
| 33 | |
| 34 | #define setRed(r, pcolor) do { \ |
| 35 | *pcolor = ((*pcolor) & (~(dpf->Rmask))) + \ |
| 36 | (((r) & (dpf->Rmask >> dpf->Rshift)) << dpf->Rshift); \ |
| 37 | } while (0); |
| 38 | |
| 39 | #define setGreen(g, pcolor) do { \ |
| 40 | *pcolor = ((*pcolor) & (~(dpf->Gmask))) + \ |
| 41 | (((g) & (dpf->Gmask >> dpf->Gshift)) << dpf->Gshift); \ |
| 42 | } while (0); |
| 43 | |
| 44 | #define setBlue(b, pcolor) do { \ |
| 45 | *pcolor = ((*pcolor) & (~(dpf->Bmask))) + \ |
| 46 | (((b) & (dpf->Bmask >> dpf->Bshift)) << dpf->Bshift); \ |
| 47 | } while (0); |
| 48 | |
| 49 | #define setAlpha(a, pcolor) do { \ |
| 50 | *pcolor = ((*pcolor) & (~(dpf->Amask))) + \ |
| 51 | (((a) & (dpf->Amask >> dpf->Ashift)) << dpf->Ashift); \ |
| 52 | } while (0); |
| 53 | |
| 54 | static int glue(sdl_zoom_rgb, BPP)(SDL_Surface *src, SDL_Surface *dst, int smooth, |
| 55 | SDL_Rect *dst_rect) |
| 56 | { |
| 57 | int x, y, sx, sy, *sax, *say, *csax, *csay, csx, csy, ex, ey, t1, t2, sstep, sstep_jump; |
| 58 | SDL_TYPE *c00, *c01, *c10, *c11, *sp, *csp, *dp; |
| 59 | int d_gap; |
| 60 | SDL_PixelFormat *spf = src->format; |
| 61 | SDL_PixelFormat *dpf = dst->format; |
| 62 | |
| 63 | if (smooth) { |
| 64 | /* For interpolation: assume source dimension is one pixel. |
| 65 | * Smaller here to avoid overflow on right and bottom edge. |
| 66 | */ |
| 67 | sx = (int) (65536.0 * (float) (src->w - 1) / (float) dst->w); |
| 68 | sy = (int) (65536.0 * (float) (src->h - 1) / (float) dst->h); |
| 69 | } else { |
| 70 | sx = (int) (65536.0 * (float) src->w / (float) dst->w); |
| 71 | sy = (int) (65536.0 * (float) src->h / (float) dst->h); |
| 72 | } |
| 73 | |
| 74 | if ((sax = (int *) malloc((dst->w + 1) * sizeof(Uint32))) == NULL) { |
| 75 | return (-1); |
| 76 | } |
| 77 | if ((say = (int *) malloc((dst->h + 1) * sizeof(Uint32))) == NULL) { |
| 78 | free(sax); |
| 79 | return (-1); |
| 80 | } |
| 81 | |
| 82 | sp = csp = (SDL_TYPE *) src->pixels; |
| 83 | dp = (SDL_TYPE *) (dst->pixels + dst_rect->y * dst->pitch + |
| 84 | dst_rect->x * dst->format->BytesPerPixel); |
| 85 | |
| 86 | csx = 0; |
| 87 | csax = sax; |
| 88 | for (x = 0; x <= dst->w; x++) { |
| 89 | *csax = csx; |
| 90 | csax++; |
| 91 | csx &= 0xffff; |
| 92 | csx += sx; |
| 93 | } |
| 94 | csy = 0; |
| 95 | csay = say; |
| 96 | for (y = 0; y <= dst->h; y++) { |
| 97 | *csay = csy; |
| 98 | csay++; |
| 99 | csy &= 0xffff; |
| 100 | csy += sy; |
| 101 | } |
| 102 | |
| 103 | d_gap = dst->pitch - dst_rect->w * dst->format->BytesPerPixel; |
| 104 | |
| 105 | if (smooth) { |
| 106 | csay = say; |
| 107 | for (y = 0; y < dst_rect->y; y++) { |
| 108 | csay++; |
| 109 | sstep = (*csay >> 16) * src->pitch; |
| 110 | csp = (SDL_TYPE *) ((Uint8 *) csp + sstep); |
| 111 | } |
| 112 | |
| 113 | /* Calculate sstep_jump */ |
| 114 | csax = sax; |
| 115 | sstep_jump = 0; |
| 116 | for (x = 0; x < dst_rect->x; x++) { |
| 117 | csax++; |
| 118 | sstep = (*csax >> 16); |
| 119 | sstep_jump += sstep; |
| 120 | } |
| 121 | |
| 122 | for (y = 0; y < dst_rect->h ; y++) { |
| 123 | /* Setup colour source pointers */ |
| 124 | c00 = csp + sstep_jump; |
| 125 | c01 = c00 + 1; |
| 126 | c10 = (SDL_TYPE *) ((Uint8 *) csp + src->pitch) + sstep_jump; |
| 127 | c11 = c10 + 1; |
| 128 | csax = sax + dst_rect->x; |
| 129 | |
| 130 | for (x = 0; x < dst_rect->w; x++) { |
| 131 | |
| 132 | /* Interpolate colours */ |
| 133 | ex = (*csax & 0xffff); |
| 134 | ey = (*csay & 0xffff); |
| 135 | t1 = ((((getRed(*c01) - getRed(*c00)) * ex) >> 16) + |
| 136 | getRed(*c00)) & (dpf->Rmask >> dpf->Rshift); |
| 137 | t2 = ((((getRed(*c11) - getRed(*c10)) * ex) >> 16) + |
| 138 | getRed(*c10)) & (dpf->Rmask >> dpf->Rshift); |
| 139 | setRed((((t2 - t1) * ey) >> 16) + t1, dp); |
| 140 | t1 = ((((getGreen(*c01) - getGreen(*c00)) * ex) >> 16) + |
| 141 | getGreen(*c00)) & (dpf->Gmask >> dpf->Gshift); |
| 142 | t2 = ((((getGreen(*c11) - getGreen(*c10)) * ex) >> 16) + |
| 143 | getGreen(*c10)) & (dpf->Gmask >> dpf->Gshift); |
| 144 | setGreen((((t2 - t1) * ey) >> 16) + t1, dp); |
| 145 | t1 = ((((getBlue(*c01) - getBlue(*c00)) * ex) >> 16) + |
| 146 | getBlue(*c00)) & (dpf->Bmask >> dpf->Bshift); |
| 147 | t2 = ((((getBlue(*c11) - getBlue(*c10)) * ex) >> 16) + |
| 148 | getBlue(*c10)) & (dpf->Bmask >> dpf->Bshift); |
| 149 | setBlue((((t2 - t1) * ey) >> 16) + t1, dp); |
| 150 | t1 = ((((getAlpha(*c01) - getAlpha(*c00)) * ex) >> 16) + |
| 151 | getAlpha(*c00)) & (dpf->Amask >> dpf->Ashift); |
| 152 | t2 = ((((getAlpha(*c11) - getAlpha(*c10)) * ex) >> 16) + |
| 153 | getAlpha(*c10)) & (dpf->Amask >> dpf->Ashift); |
| 154 | setAlpha((((t2 - t1) * ey) >> 16) + t1, dp); |
| 155 | |
| 156 | /* Advance source pointers */ |
| 157 | csax++; |
| 158 | sstep = (*csax >> 16); |
| 159 | c00 += sstep; |
| 160 | c01 += sstep; |
| 161 | c10 += sstep; |
| 162 | c11 += sstep; |
| 163 | /* Advance destination pointer */ |
| 164 | dp++; |
| 165 | } |
| 166 | /* Advance source pointer */ |
| 167 | csay++; |
| 168 | csp = (SDL_TYPE *) ((Uint8 *) csp + (*csay >> 16) * src->pitch); |
| 169 | /* Advance destination pointers */ |
| 170 | dp = (SDL_TYPE *) ((Uint8 *) dp + d_gap); |
| 171 | } |
| 172 | |
| 173 | |
| 174 | } else { |
| 175 | csay = say; |
| 176 | |
| 177 | for (y = 0; y < dst_rect->y; y++) { |
| 178 | csay++; |
| 179 | sstep = (*csay >> 16) * src->pitch; |
| 180 | csp = (SDL_TYPE *) ((Uint8 *) csp + sstep); |
| 181 | } |
| 182 | |
| 183 | /* Calculate sstep_jump */ |
| 184 | csax = sax; |
| 185 | sstep_jump = 0; |
| 186 | for (x = 0; x < dst_rect->x; x++) { |
| 187 | csax++; |
| 188 | sstep = (*csax >> 16); |
| 189 | sstep_jump += sstep; |
| 190 | } |
| 191 | |
| 192 | for (y = 0 ; y < dst_rect->h ; y++) { |
| 193 | sp = csp + sstep_jump; |
| 194 | csax = sax + dst_rect->x; |
| 195 | |
| 196 | for (x = 0; x < dst_rect->w; x++) { |
| 197 | |
| 198 | /* Draw */ |
| 199 | *dp = *sp; |
| 200 | |
| 201 | /* Advance source pointers */ |
| 202 | csax++; |
| 203 | sstep = (*csax >> 16); |
| 204 | sp += sstep; |
| 205 | |
| 206 | /* Advance destination pointer */ |
| 207 | dp++; |
| 208 | } |
| 209 | /* Advance source pointers */ |
| 210 | csay++; |
| 211 | sstep = (*csay >> 16) * src->pitch; |
| 212 | csp = (SDL_TYPE *) ((Uint8 *) csp + sstep); |
| 213 | |
| 214 | /* Advance destination pointer */ |
| 215 | dp = (SDL_TYPE *) ((Uint8 *) dp + d_gap); |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | free(sax); |
| 220 | free(say); |
| 221 | return (0); |
| 222 | } |
| 223 | |
| 224 | #undef SDL_TYPE |
| 225 | |