Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4680 | right-hear | 1 | #include "fitz.h" |
| 2 | |||
| 3 | /* |
||
| 4 | |||
| 5 | The functions in this file implement various flavours of Porter-Duff blending. |
||
| 6 | |||
| 7 | We take the following as definitions: |
||
| 8 | |||
| 9 | Cx = Color (from plane x) |
||
| 10 | ax = Alpha (from plane x) |
||
| 11 | cx = Cx.ax = Premultiplied color (from plane x) |
||
| 12 | |||
| 13 | The general PorterDuff blending equation is: |
||
| 14 | |||
| 15 | Blend Z = X op Y cz = Fx.cx + Fy. cy where Fx and Fy depend on op |
||
| 16 | |||
| 17 | The two operations we use in this file are: '(X in Y) over Z' and |
||
| 18 | 'S over Z'. The definitions of the 'over' and 'in' operations are as |
||
| 19 | follows: |
||
| 20 | |||
| 21 | For S over Z, Fs = 1, Fz = 1-as |
||
| 22 | For X in Y, Fx = ay, Fy = 0 |
||
| 23 | |||
| 24 | We have 2 choices; we can either work with premultiplied data, or non |
||
| 25 | premultiplied data. Our |
||
| 26 | |||
| 27 | First the premultiplied case: |
||
| 28 | |||
| 29 | Let S = (X in Y) |
||
| 30 | Let R = (X in Y) over Z = S over Z |
||
| 31 | |||
| 32 | cs = cx.Fx + cy.Fy (where Fx = ay, Fy = 0) |
||
| 33 | = cx.ay |
||
| 34 | as = ax.Fx + ay.Fy |
||
| 35 | = ax.ay |
||
| 36 | |||
| 37 | cr = cs.Fs + cz.Fz (where Fs = 1, Fz = 1-as) |
||
| 38 | = cs + cz.(1-as) |
||
| 39 | = cx.ay + cz.(1-ax.ay) |
||
| 40 | ar = as.Fs + az.Fz |
||
| 41 | = as + az.(1-as) |
||
| 42 | = ax.ay + az.(1-ax.ay) |
||
| 43 | |||
| 44 | This has various nice properties, like not needing any divisions, and |
||
| 45 | being symmetric in color and alpha, so this is what we use. Because we |
||
| 46 | went through the pain of deriving the non premultiplied forms, we list |
||
| 47 | them here too, though they are not used. |
||
| 48 | |||
| 49 | Non Pre-multiplied case: |
||
| 50 | |||
| 51 | Cs.as = Fx.Cx.ax + Fy.Cy.ay (where Fx = ay, Fy = 0) |
||
| 52 | = Cx.ay.ax |
||
| 53 | Cs = (Cx.ay.ax)/(ay.ax) |
||
| 54 | = Cx |
||
| 55 | Cr.ar = Fs.Cs.as + Fz.Cz.az (where Fs = 1, Fz = 1-as) |
||
| 56 | = Cs.as + (1-as).Cz.az |
||
| 57 | = Cx.ax.ay + Cz.az.(1-ax.ay) |
||
| 58 | Cr = (Cx.ax.ay + Cz.az.(1-ax.ay))/(ax.ay + az.(1-ax-ay)) |
||
| 59 | |||
| 60 | Much more complex, it seems. However, if we could restrict ourselves to |
||
| 61 | the case where we were always plotting onto an opaque background (i.e. |
||
| 62 | az = 1), then: |
||
| 63 | |||
| 64 | Cr = Cx.(ax.ay) + Cz.(1-ax.ay) |
||
| 65 | = (Cx-Cz)*(1-ax.ay) + Cz (a single MLA operation) |
||
| 66 | ar = 1 |
||
| 67 | |||
| 68 | Sadly, this is not true in the general case, so we abandon this effort |
||
| 69 | and stick to using the premultiplied form. |
||
| 70 | |||
| 71 | */ |
||
| 72 | |||
| 73 | typedef unsigned char byte; |
||
| 74 | |||
| 75 | /* These are used by the non-aa scan converter */ |
||
| 76 | |||
| 77 | void |
||
| 78 | fz_paint_solid_alpha(byte * restrict dp, int w, int alpha) |
||
| 79 | { |
||
| 80 | int t = FZ_EXPAND(255 - alpha); |
||
| 81 | while (w--) |
||
| 82 | { |
||
| 83 | *dp = alpha + FZ_COMBINE(*dp, t); |
||
| 84 | dp ++; |
||
| 85 | } |
||
| 86 | } |
||
| 87 | |||
| 88 | void |
||
| 89 | fz_paint_solid_color(byte * restrict dp, int n, int w, byte *color) |
||
| 90 | { |
||
| 91 | int n1 = n - 1; |
||
| 92 | int sa = FZ_EXPAND(color[n1]); |
||
| 93 | int k; |
||
| 94 | while (w--) |
||
| 95 | { |
||
| 96 | int ma = FZ_COMBINE(FZ_EXPAND(255), sa); |
||
| 97 | for (k = 0; k < n1; k++) |
||
| 98 | dp[k] = FZ_BLEND(color[k], dp[k], ma); |
||
| 99 | dp[k] = FZ_BLEND(255, dp[k], ma); |
||
| 100 | dp += n; |
||
| 101 | } |
||
| 102 | } |
||
| 103 | |||
| 104 | /* Blend a non-premultiplied color in mask over destination */ |
||
| 105 | |||
| 106 | static inline void |
||
| 107 | fz_paint_span_with_color_2(byte * restrict dp, byte * restrict mp, int w, byte *color) |
||
| 108 | { |
||
| 109 | int sa = FZ_EXPAND(color[1]); |
||
| 110 | int g = color[0]; |
||
| 111 | while (w--) |
||
| 112 | { |
||
| 113 | int ma = *mp++; |
||
| 114 | ma = FZ_COMBINE(FZ_EXPAND(ma), sa); |
||
| 115 | dp[0] = FZ_BLEND(g, dp[0], ma); |
||
| 116 | dp[1] = FZ_BLEND(255, dp[1], ma); |
||
| 117 | dp += 2; |
||
| 118 | } |
||
| 119 | } |
||
| 120 | |||
| 121 | static inline void |
||
| 122 | fz_paint_span_with_color_4(byte * restrict dp, byte * restrict mp, int w, byte *color) |
||
| 123 | { |
||
| 124 | int sa = FZ_EXPAND(color[3]); |
||
| 125 | int r = color[0]; |
||
| 126 | int g = color[1]; |
||
| 127 | int b = color[2]; |
||
| 128 | while (w--) |
||
| 129 | { |
||
| 130 | int ma = *mp++; |
||
| 131 | ma = FZ_COMBINE(FZ_EXPAND(ma), sa); |
||
| 132 | dp[0] = FZ_BLEND(r, dp[0], ma); |
||
| 133 | dp[1] = FZ_BLEND(g, dp[1], ma); |
||
| 134 | dp[2] = FZ_BLEND(b, dp[2], ma); |
||
| 135 | dp[3] = FZ_BLEND(255, dp[3], ma); |
||
| 136 | dp += 4; |
||
| 137 | } |
||
| 138 | } |
||
| 139 | |||
| 140 | static inline void |
||
| 141 | fz_paint_span_with_color_N(byte * restrict dp, byte * restrict mp, int n, int w, byte *color) |
||
| 142 | { |
||
| 143 | int n1 = n - 1; |
||
| 144 | int sa = FZ_EXPAND(color[n1]); |
||
| 145 | int k; |
||
| 146 | while (w--) |
||
| 147 | { |
||
| 148 | int ma = *mp++; |
||
| 149 | ma = FZ_COMBINE(FZ_EXPAND(ma), sa); |
||
| 150 | for (k = 0; k < n1; k++) |
||
| 151 | dp[k] = FZ_BLEND(color[k], dp[k], ma); |
||
| 152 | dp[k] = FZ_BLEND(255, dp[k], ma); |
||
| 153 | dp += n; |
||
| 154 | } |
||
| 155 | } |
||
| 156 | |||
| 157 | void |
||
| 158 | fz_paint_span_with_color(byte * restrict dp, byte * restrict mp, int n, int w, byte *color) |
||
| 159 | { |
||
| 160 | switch (n) |
||
| 161 | { |
||
| 162 | case 2: fz_paint_span_with_color_2(dp, mp, w, color); break; |
||
| 163 | case 4: fz_paint_span_with_color_4(dp, mp, w, color); break; |
||
| 164 | default: fz_paint_span_with_color_N(dp, mp, n, w, color); break; |
||
| 165 | } |
||
| 166 | } |
||
| 167 | |||
| 168 | /* Blend source in mask over destination */ |
||
| 169 | |||
| 170 | static inline void |
||
| 171 | fz_paint_span_with_mask_2(byte * restrict dp, byte * restrict sp, byte * restrict mp, int w) |
||
| 172 | { |
||
| 173 | while (w--) |
||
| 174 | { |
||
| 175 | int masa; |
||
| 176 | int ma = *mp++; |
||
| 177 | ma = FZ_EXPAND(ma); |
||
| 178 | masa = FZ_COMBINE(sp[1], ma); |
||
| 179 | masa = 255 - masa; |
||
| 180 | masa = FZ_EXPAND(masa); |
||
| 181 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 182 | sp++; dp++; |
||
| 183 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 184 | sp++; dp++; |
||
| 185 | } |
||
| 186 | } |
||
| 187 | |||
| 188 | static inline void |
||
| 189 | fz_paint_span_with_mask_4(byte * restrict dp, byte * restrict sp, byte * restrict mp, int w) |
||
| 190 | { |
||
| 191 | while (w--) |
||
| 192 | { |
||
| 193 | int masa; |
||
| 194 | int ma = *mp++; |
||
| 195 | ma = FZ_EXPAND(ma); |
||
| 196 | masa = FZ_COMBINE(sp[3], ma); |
||
| 197 | masa = 255 - masa; |
||
| 198 | masa = FZ_EXPAND(masa); |
||
| 199 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 200 | sp++; dp++; |
||
| 201 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 202 | sp++; dp++; |
||
| 203 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 204 | sp++; dp++; |
||
| 205 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 206 | sp++; dp++; |
||
| 207 | } |
||
| 208 | } |
||
| 209 | |||
| 210 | static inline void |
||
| 211 | fz_paint_span_with_mask_N(byte * restrict dp, byte * restrict sp, byte * restrict mp, int n, int w) |
||
| 212 | { |
||
| 213 | while (w--) |
||
| 214 | { |
||
| 215 | int k = n; |
||
| 216 | int masa; |
||
| 217 | int ma = *mp++; |
||
| 218 | ma = FZ_EXPAND(ma); |
||
| 219 | masa = FZ_COMBINE(sp[n-1], ma); |
||
| 220 | masa = 255-masa; |
||
| 221 | masa = FZ_EXPAND(masa); |
||
| 222 | while (k--) |
||
| 223 | { |
||
| 224 | *dp = FZ_COMBINE2(*sp, ma, *dp, masa); |
||
| 225 | sp++; dp++; |
||
| 226 | } |
||
| 227 | } |
||
| 228 | } |
||
| 229 | |||
| 230 | static void |
||
| 231 | fz_paint_span_with_mask(byte * restrict dp, byte * restrict sp, byte * restrict mp, int n, int w) |
||
| 232 | { |
||
| 233 | switch (n) |
||
| 234 | { |
||
| 235 | case 2: fz_paint_span_with_mask_2(dp, sp, mp, w); break; |
||
| 236 | case 4: fz_paint_span_with_mask_4(dp, sp, mp, w); break; |
||
| 237 | default: fz_paint_span_with_mask_N(dp, sp, mp, n, w); break; |
||
| 238 | } |
||
| 239 | } |
||
| 240 | |||
| 241 | /* Blend source in constant alpha over destination */ |
||
| 242 | |||
| 243 | static inline void |
||
| 244 | fz_paint_span_2_with_alpha(byte * restrict dp, byte * restrict sp, int w, int alpha) |
||
| 245 | { |
||
| 246 | alpha = FZ_EXPAND(alpha); |
||
| 247 | while (w--) |
||
| 248 | { |
||
| 249 | int masa = FZ_COMBINE(sp[1], alpha); |
||
| 250 | *dp = FZ_BLEND(*sp, *dp, masa); |
||
| 251 | dp++; sp++; |
||
| 252 | *dp = FZ_BLEND(*sp, *dp, masa); |
||
| 253 | dp++; sp++; |
||
| 254 | } |
||
| 255 | } |
||
| 256 | |||
| 257 | static inline void |
||
| 258 | fz_paint_span_4_with_alpha(byte * restrict dp, byte * restrict sp, int w, int alpha) |
||
| 259 | { |
||
| 260 | alpha = FZ_EXPAND(alpha); |
||
| 261 | while (w--) |
||
| 262 | { |
||
| 263 | int masa = FZ_COMBINE(sp[3], alpha); |
||
| 264 | *dp = FZ_BLEND(*sp, *dp, masa); |
||
| 265 | sp++; dp++; |
||
| 266 | *dp = FZ_BLEND(*sp, *dp, masa); |
||
| 267 | sp++; dp++; |
||
| 268 | *dp = FZ_BLEND(*sp, *dp, masa); |
||
| 269 | sp++; dp++; |
||
| 270 | *dp = FZ_BLEND(*sp, *dp, masa); |
||
| 271 | sp++; dp++; |
||
| 272 | } |
||
| 273 | } |
||
| 274 | |||
| 275 | static inline void |
||
| 276 | fz_paint_span_N_with_alpha(byte * restrict dp, byte * restrict sp, int n, int w, int alpha) |
||
| 277 | { |
||
| 278 | alpha = FZ_EXPAND(alpha); |
||
| 279 | while (w--) |
||
| 280 | { |
||
| 281 | int masa = FZ_COMBINE(sp[n-1], alpha); |
||
| 282 | int k = n; |
||
| 283 | while (k--) |
||
| 284 | { |
||
| 285 | *dp = FZ_BLEND(*sp++, *dp, masa); |
||
| 286 | dp++; |
||
| 287 | } |
||
| 288 | } |
||
| 289 | } |
||
| 290 | |||
| 291 | /* Blend source over destination */ |
||
| 292 | |||
| 293 | static inline void |
||
| 294 | fz_paint_span_1(byte * restrict dp, byte * restrict sp, int w) |
||
| 295 | { |
||
| 296 | while (w--) |
||
| 297 | { |
||
| 298 | int t = FZ_EXPAND(255 - sp[0]); |
||
| 299 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 300 | dp ++; |
||
| 301 | } |
||
| 302 | } |
||
| 303 | |||
| 304 | static inline void |
||
| 305 | fz_paint_span_2(byte * restrict dp, byte * restrict sp, int w) |
||
| 306 | { |
||
| 307 | while (w--) |
||
| 308 | { |
||
| 309 | int t = FZ_EXPAND(255 - sp[1]); |
||
| 310 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 311 | dp++; |
||
| 312 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 313 | dp++; |
||
| 314 | } |
||
| 315 | } |
||
| 316 | |||
| 317 | static inline void |
||
| 318 | fz_paint_span_4(byte * restrict dp, byte * restrict sp, int w) |
||
| 319 | { |
||
| 320 | while (w--) |
||
| 321 | { |
||
| 322 | int t = FZ_EXPAND(255 - sp[3]); |
||
| 323 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 324 | dp++; |
||
| 325 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 326 | dp++; |
||
| 327 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 328 | dp++; |
||
| 329 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 330 | dp++; |
||
| 331 | } |
||
| 332 | } |
||
| 333 | |||
| 334 | static inline void |
||
| 335 | fz_paint_span_N(byte * restrict dp, byte * restrict sp, int n, int w) |
||
| 336 | { |
||
| 337 | while (w--) |
||
| 338 | { |
||
| 339 | int k = n; |
||
| 340 | int t = FZ_EXPAND(255 - sp[n-1]); |
||
| 341 | while (k--) |
||
| 342 | { |
||
| 343 | *dp = *sp++ + FZ_COMBINE(*dp, t); |
||
| 344 | dp++; |
||
| 345 | } |
||
| 346 | } |
||
| 347 | } |
||
| 348 | |||
| 349 | void |
||
| 350 | fz_paint_span(byte * restrict dp, byte * restrict sp, int n, int w, int alpha) |
||
| 351 | { |
||
| 352 | if (alpha == 255) |
||
| 353 | { |
||
| 354 | switch (n) |
||
| 355 | { |
||
| 356 | case 1: fz_paint_span_1(dp, sp, w); break; |
||
| 357 | case 2: fz_paint_span_2(dp, sp, w); break; |
||
| 358 | case 4: fz_paint_span_4(dp, sp, w); break; |
||
| 359 | default: fz_paint_span_N(dp, sp, n, w); break; |
||
| 360 | } |
||
| 361 | } |
||
| 362 | else if (alpha > 0) |
||
| 363 | { |
||
| 364 | switch (n) |
||
| 365 | { |
||
| 366 | case 2: fz_paint_span_2_with_alpha(dp, sp, w, alpha); break; |
||
| 367 | case 4: fz_paint_span_4_with_alpha(dp, sp, w, alpha); break; |
||
| 368 | default: fz_paint_span_N_with_alpha(dp, sp, n, w, alpha); break; |
||
| 369 | } |
||
| 370 | } |
||
| 371 | } |
||
| 372 | |||
| 373 | /* |
||
| 374 | * Pixmap blending functions |
||
| 375 | */ |
||
| 376 | |||
| 377 | void |
||
| 378 | fz_paint_pixmap_with_rect(fz_pixmap *dst, fz_pixmap *src, int alpha, fz_bbox bbox) |
||
| 379 | { |
||
| 380 | unsigned char *sp, *dp; |
||
| 381 | int x, y, w, h, n; |
||
| 382 | |||
| 383 | assert(dst->n == src->n); |
||
| 384 | |||
| 385 | bbox = fz_intersect_bbox(bbox, fz_bound_pixmap(dst)); |
||
| 386 | bbox = fz_intersect_bbox(bbox, fz_bound_pixmap(src)); |
||
| 387 | |||
| 388 | x = bbox.x0; |
||
| 389 | y = bbox.y0; |
||
| 390 | w = bbox.x1 - bbox.x0; |
||
| 391 | h = bbox.y1 - bbox.y0; |
||
| 392 | if ((w | h) == 0) |
||
| 393 | return; |
||
| 394 | |||
| 395 | n = src->n; |
||
| 396 | sp = src->samples + ((y - src->y) * src->w + (x - src->x)) * src->n; |
||
| 397 | dp = dst->samples + ((y - dst->y) * dst->w + (x - dst->x)) * dst->n; |
||
| 398 | |||
| 399 | while (h--) |
||
| 400 | { |
||
| 401 | fz_paint_span(dp, sp, n, w, alpha); |
||
| 402 | sp += src->w * n; |
||
| 403 | dp += dst->w * n; |
||
| 404 | } |
||
| 405 | } |
||
| 406 | |||
| 407 | void |
||
| 408 | fz_paint_pixmap(fz_pixmap *dst, fz_pixmap *src, int alpha) |
||
| 409 | { |
||
| 410 | unsigned char *sp, *dp; |
||
| 411 | fz_bbox bbox; |
||
| 412 | int x, y, w, h, n; |
||
| 413 | |||
| 414 | assert(dst->n == src->n); |
||
| 415 | |||
| 416 | bbox = fz_bound_pixmap(dst); |
||
| 417 | bbox = fz_intersect_bbox(bbox, fz_bound_pixmap(src)); |
||
| 418 | |||
| 419 | x = bbox.x0; |
||
| 420 | y = bbox.y0; |
||
| 421 | w = bbox.x1 - bbox.x0; |
||
| 422 | h = bbox.y1 - bbox.y0; |
||
| 423 | if ((w | h) == 0) |
||
| 424 | return; |
||
| 425 | |||
| 426 | n = src->n; |
||
| 427 | sp = src->samples + ((y - src->y) * src->w + (x - src->x)) * src->n; |
||
| 428 | dp = dst->samples + ((y - dst->y) * dst->w + (x - dst->x)) * dst->n; |
||
| 429 | |||
| 430 | while (h--) |
||
| 431 | { |
||
| 432 | fz_paint_span(dp, sp, n, w, alpha); |
||
| 433 | sp += src->w * n; |
||
| 434 | dp += dst->w * n; |
||
| 435 | } |
||
| 436 | } |
||
| 437 | |||
| 438 | void |
||
| 439 | fz_paint_pixmap_with_mask(fz_pixmap *dst, fz_pixmap *src, fz_pixmap *msk) |
||
| 440 | { |
||
| 441 | unsigned char *sp, *dp, *mp; |
||
| 442 | fz_bbox bbox; |
||
| 443 | int x, y, w, h, n; |
||
| 444 | |||
| 445 | assert(dst->n == src->n); |
||
| 446 | assert(msk->n == 1); |
||
| 447 | |||
| 448 | bbox = fz_bound_pixmap(dst); |
||
| 449 | bbox = fz_intersect_bbox(bbox, fz_bound_pixmap(src)); |
||
| 450 | bbox = fz_intersect_bbox(bbox, fz_bound_pixmap(msk)); |
||
| 451 | |||
| 452 | x = bbox.x0; |
||
| 453 | y = bbox.y0; |
||
| 454 | w = bbox.x1 - bbox.x0; |
||
| 455 | h = bbox.y1 - bbox.y0; |
||
| 456 | if ((w | h) == 0) |
||
| 457 | return; |
||
| 458 | |||
| 459 | n = src->n; |
||
| 460 | sp = src->samples + ((y - src->y) * src->w + (x - src->x)) * src->n; |
||
| 461 | mp = msk->samples + ((y - msk->y) * msk->w + (x - msk->x)) * msk->n; |
||
| 462 | dp = dst->samples + ((y - dst->y) * dst->w + (x - dst->x)) * dst->n; |
||
| 463 | |||
| 464 | while (h--) |
||
| 465 | { |
||
| 466 | fz_paint_span_with_mask(dp, sp, mp, n, w); |
||
| 467 | sp += src->w * n; |
||
| 468 | dp += dst->w * n; |
||
| 469 | mp += msk->w; |
||
| 470 | } |
||
| 471 | } |