Dogcows Code - chaz/openbox/blob - render/gradient.c

   1 /* -*- indent-tabs-mode: nil; tab-width: 4; c-basic-offset: 4; -*-
   2
   3    gradient.c for the Openbox window manager
   4    Copyright (c) 2006        Mikael Magnusson
   5    Copyright (c) 2003        Ben Jansens
   6    Copyright (c) 2003        Derek Foreman
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    See the COPYING file for a copy of the GNU General Public License.
  19 */
  20
  21 #include "render.h"
  22 #include "gradient.h"
  23 #include "color.h"
  24 #include <glib.h>
  25
  26 static void highlight(RrPixel32 *x, RrPixel32 *y, gboolean raised);
  27 static void gradient_solid(RrAppearance *l, gint w, gint h);
  28 static void gradient_splitvertical(RrAppearance *a, gint w, gint h);
  29 static void gradient_vertical(RrSurface *sf, gint w, gint h);
  30 static void gradient_horizontal(RrSurface *sf, gint w, gint h);
  31 static void gradient_mirrorhorizontal(RrSurface *sf, gint w, gint h);
  32 static void gradient_diagonal(RrSurface *sf, gint w, gint h);
  33 static void gradient_crossdiagonal(RrSurface *sf, gint w, gint h);
  34 static void gradient_pyramid(RrSurface *sf, gint inw, gint inh);
  35
  36 void RrRender(RrAppearance *a, gint w, gint h)
  37 {
  38     RrPixel32 *data = a->surface.pixel_data;
  39     RrPixel32 current;
  40     guint r,g,b;
  41     gint off, x;
  42
  43     switch (a->surface.grad) {
  44     case RR_SURFACE_SOLID:
  45         gradient_solid(a, w, h);
  46         break;
  47     case RR_SURFACE_SPLIT_VERTICAL:
  48         gradient_splitvertical(a, w, h);
  49         break;
  50     case RR_SURFACE_VERTICAL:
  51         gradient_vertical(&a->surface, w, h);
  52         break;
  53     case RR_SURFACE_HORIZONTAL:
  54         gradient_horizontal(&a->surface, w, h);
  55         break;
  56     case RR_SURFACE_MIRROR_HORIZONTAL:
  57         gradient_mirrorhorizontal(&a->surface, w, h);
  58         break;
  59     case RR_SURFACE_DIAGONAL:
  60         gradient_diagonal(&a->surface, w, h);
  61         break;
  62     case RR_SURFACE_CROSS_DIAGONAL:
  63         gradient_crossdiagonal(&a->surface, w, h);
  64         break;
  65     case RR_SURFACE_PYRAMID:
  66         gradient_pyramid(&a->surface, w, h);
  67         break;
  68     default:
  69         g_assert_not_reached(); /* unhandled gradient */
  70         return;
  71     }
  72
  73     if (a->surface.interlaced) {
  74         gint i;
  75         RrPixel32 *p;
  76
  77         r = a->surface.interlace_color->r;
  78         g = a->surface.interlace_color->g;
  79         b = a->surface.interlace_color->b;
  80         current = (r << RrDefaultRedOffset)
  81             + (g << RrDefaultGreenOffset)
  82             + (b << RrDefaultBlueOffset);
  83         p = data;
  84         for (i = 0; i < h; i += 2, p += w)
  85             for (x = 0; x < w; ++x, ++p)
  86                 *p = current;
  87     }
  88
  89     if (a->surface.relief == RR_RELIEF_FLAT && a->surface.border) {
  90         r = a->surface.border_color->r;
  91         g = a->surface.border_color->g;
  92         b = a->surface.border_color->b;
  93         current = (r << RrDefaultRedOffset)
  94             + (g << RrDefaultGreenOffset)
  95             + (b << RrDefaultBlueOffset);
  96         for (off = 0, x = 0; x < w; ++x, off++) {
  97             *(data + off) = current;
  98             *(data + off + ((h-1) * w)) = current;
  99         }
 100         for (off = 0, x = 0; x < h; ++x, off++) {
 101             *(data + (off * w)) = current;
 102             *(data + (off * w) + w - 1) = current;
 103         }
 104     }
 105
 106     if (a->surface.relief != RR_RELIEF_FLAT) {
 107         if (a->surface.bevel == RR_BEVEL_1) {
 108             for (off = 1, x = 1; x < w - 1; ++x, off++)
 109                 highlight(data + off,
 110                           data + off + (h-1) * w,
 111                           a->surface.relief==RR_RELIEF_RAISED);
 112             for (off = 0, x = 0; x < h; ++x, off++)
 113                 highlight(data + off * w,
 114                           data + off * w + w - 1,
 115                           a->surface.relief==RR_RELIEF_RAISED);
 116         }
 117
 118         if (a->surface.bevel == RR_BEVEL_2) {
 119             for (off = 2, x = 2; x < w - 2; ++x, off++)
 120                 highlight(data + off + w,
 121                           data + off + (h-2) * w,
 122                           a->surface.relief==RR_RELIEF_RAISED);
 123             for (off = 1, x = 1; x < h-1; ++x, off++)
 124                 highlight(data + off * w + 1,
 125                           data + off * w + w - 2,
 126                           a->surface.relief==RR_RELIEF_RAISED);
 127         }
 128     }
 129 }
 130
 131 static void highlight(RrPixel32 *x, RrPixel32 *y, gboolean raised)
 132 {
 133     gint r, g, b;
 134
 135     RrPixel32 *up, *down;
 136     if (raised) {
 137         up = x;
 138         down = y;
 139     } else {
 140         up = y;
 141         down = x;
 142     }
 143     r = (*up >> RrDefaultRedOffset) & 0xFF;
 144     r += r >> 1;
 145     g = (*up >> RrDefaultGreenOffset) & 0xFF;
 146     g += g >> 1;
 147     b = (*up >> RrDefaultBlueOffset) & 0xFF;
 148     b += b >> 1;
 149     if (r > 0xFF) r = 0xFF;
 150     if (g > 0xFF) g = 0xFF;
 151     if (b > 0xFF) b = 0xFF;
 152     *up = (r << RrDefaultRedOffset) + (g << RrDefaultGreenOffset)
 153         + (b << RrDefaultBlueOffset);
 154
 155     r = (*down >> RrDefaultRedOffset) & 0xFF;
 156     r = (r >> 1) + (r >> 2);
 157     g = (*down >> RrDefaultGreenOffset) & 0xFF;
 158     g = (g >> 1) + (g >> 2);
 159     b = (*down >> RrDefaultBlueOffset) & 0xFF;
 160     b = (b >> 1) + (b >> 2);
 161     *down = (r << RrDefaultRedOffset) + (g << RrDefaultGreenOffset)
 162         + (b << RrDefaultBlueOffset);
 163 }
 164
 165 static void create_bevel_colors(RrAppearance *l)
 166 {
 167     gint r, g, b;
 168
 169     /* light color */
 170     r = l->surface.primary->r;
 171     r += r >> 1;
 172     g = l->surface.primary->g;
 173     g += g >> 1;
 174     b = l->surface.primary->b;
 175     b += b >> 1;
 176     if (r > 0xFF) r = 0xFF;
 177     if (g > 0xFF) g = 0xFF;
 178     if (b > 0xFF) b = 0xFF;
 179     g_assert(!l->surface.bevel_light);
 180     l->surface.bevel_light = RrColorNew(l->inst, r, g, b);
 181
 182     /* dark color */
 183     r = l->surface.primary->r;
 184     r = (r >> 1) + (r >> 2);
 185     g = l->surface.primary->g;
 186     g = (g >> 1) + (g >> 2);
 187     b = l->surface.primary->b;
 188     b = (b >> 1) + (b >> 2);
 189     g_assert(!l->surface.bevel_dark);
 190     l->surface.bevel_dark = RrColorNew(l->inst, r, g, b);
 191 }
 192
 193 static void gradient_solid(RrAppearance *l, gint w, gint h)
 194 {
 195     gint i;
 196     RrPixel32 pix;
 197     RrPixel32 *data = l->surface.pixel_data;
 198     RrSurface *sp = &l->surface;
 199     gint left = 0, top = 0, right = w - 1, bottom = h - 1;
 200
 201     pix = (sp->primary->r << RrDefaultRedOffset)
 202         + (sp->primary->g << RrDefaultGreenOffset)
 203         + (sp->primary->b << RrDefaultBlueOffset);
 204
 205     for (i = 0; i < w * h; i++)
 206         *data++ = pix;
 207
 208     if (sp->interlaced)
 209         return;
 210
 211     XFillRectangle(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->primary),
 212                    0, 0, w, h);
 213
 214     switch (sp->relief) {
 215     case RR_RELIEF_RAISED:
 216         if (!sp->bevel_dark)
 217             create_bevel_colors(l);
 218
 219         switch (sp->bevel) {
 220         case RR_BEVEL_1:
 221             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 222                       left, bottom, right, bottom);
 223             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 224                       right, bottom, right, top);
 225
 226             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 227                       left, top, right, top);
 228             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 229                       left, bottom, left, top);
 230             break;
 231         case RR_BEVEL_2:
 232             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 233                       left + 2, bottom - 1, right - 2, bottom - 1);
 234             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 235                       right - 1, bottom - 1, right - 1, top + 1);
 236
 237             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 238                       left + 2, top + 1, right - 2, top + 1);
 239             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 240                       left + 1, bottom - 1, left + 1, top + 1);
 241             break;
 242         default:
 243             g_assert_not_reached(); /* unhandled BevelType */
 244         }
 245         break;
 246     case RR_RELIEF_SUNKEN:
 247         if (!sp->bevel_dark)
 248             create_bevel_colors(l);
 249
 250         switch (sp->bevel) {
 251         case RR_BEVEL_1:
 252             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 253                       left, bottom, right, bottom);
 254             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 255                       right, bottom, right, top);
 256
 257             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 258                       left, top, right, top);
 259             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 260                       left, bottom, left, top);
 261             break;
 262         case RR_BEVEL_2:
 263             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 264                       left + 2, bottom - 1, right - 2, bottom - 1);
 265             XDrawLine(RrDisplay(l->inst), l->pixmap,RrColorGC(sp->bevel_light),
 266                       right - 1, bottom - 1, right - 1, top + 1);
 267
 268             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 269                       left + 2, top + 1, right - 2, top + 1);
 270             XDrawLine(RrDisplay(l->inst), l->pixmap, RrColorGC(sp->bevel_dark),
 271                       left + 1, bottom - 1, left + 1, top + 1);
 272             break;
 273         default:
 274             g_assert_not_reached(); /* unhandled BevelType */
 275         }
 276         break;
 277     case RR_RELIEF_FLAT:
 278         if (sp->border) {
 279             XDrawRectangle(RrDisplay(l->inst), l->pixmap,
 280                            RrColorGC(sp->border_color),
 281                            left, top, right, bottom);
 282         }
 283         break;
 284     default:
 285         g_assert_not_reached(); /* unhandled ReliefType */
 286     }
 287 }
 288
 289 /* * * * * * * * * * * * * * GRADIENT MAGIC WOOT * * * * * * * * * * * * * * */
 290
 291 #define VARS(x)                                                     \
 292     guint color##x[3];                                       \
 293     gint len##x, cdelta##x[3], error##x[3] = { 0, 0, 0 }, inc##x[3]; \
 294     gboolean bigslope##x[3] /* color slope > 1 */
 295
 296 #define SETUP(x, from, to, w)         \
 297     len##x = w;                       \
 298                                       \
 299     color##x[0] = from->r;            \
 300     color##x[1] = from->g;            \
 301     color##x[2] = from->b;            \
 302                                       \
 303     cdelta##x[0] = to->r - from->r;   \
 304     cdelta##x[1] = to->g - from->g;   \
 305     cdelta##x[2] = to->b - from->b;   \
 306                                       \
 307     if (cdelta##x[0] < 0) {           \
 308         cdelta##x[0] = -cdelta##x[0]; \
 309         inc##x[0] = -1;               \
 310     } else                            \
 311         inc##x[0] = 1;                \
 312     if (cdelta##x[1] < 0) {           \
 313         cdelta##x[1] = -cdelta##x[1]; \
 314         inc##x[1] = -1;               \
 315     } else                            \
 316         inc##x[1] = 1;                \
 317     if (cdelta##x[2] < 0) {           \
 318         cdelta##x[2] = -cdelta##x[2]; \
 319         inc##x[2] = -1;               \
 320     } else                            \
 321         inc##x[2] = 1;                \
 322     bigslope##x[0] = cdelta##x[0] > w;\
 323     bigslope##x[1] = cdelta##x[1] > w;\
 324     bigslope##x[2] = cdelta##x[2] > w
 325
 326 #define COLOR_RR(x, c)                       \
 327     c->r = color##x[0];                      \
 328     c->g = color##x[1];                      \
 329     c->b = color##x[2]
 330
 331 #define COLOR(x)                             \
 332     ((color##x[0] << RrDefaultRedOffset) +   \
 333      (color##x[1] << RrDefaultGreenOffset) + \
 334      (color##x[2] << RrDefaultBlueOffset))
 335
 336 #define INCREMENT(x, i) \
 337     (inc##x[i])
 338
 339 #define NEXT(x)                                           \
 340 {                                                         \
 341     gint i;                                                \
 342     for (i = 2; i >= 0; --i) {                            \
 343         if (!cdelta##x[i]) continue;                      \
 344                                                           \
 345         if (!bigslope##x[i]) {                            \
 346             /* Y (color) is dependant on X */             \
 347             error##x[i] += cdelta##x[i];                  \
 348             if ((error##x[i] << 1) >= len##x) {           \
 349                 color##x[i] += INCREMENT(x, i);           \
 350                 error##x[i] -= len##x;                    \
 351             }                                             \
 352         } else {                                          \
 353             /* X is dependant on Y (color) */             \
 354             while (1) {                                   \
 355                 color##x[i] += INCREMENT(x, i);           \
 356                 error##x[i] += len##x;                    \
 357                 if ((error##x[i] << 1) >= cdelta##x[i]) { \
 358                     error##x[i] -= cdelta##x[i];          \
 359                     break;                                \
 360                 }                                         \
 361             }                                             \
 362         }                                                 \
 363     }                                                     \
 364 }
 365
 366 static void gradient_splitvertical(RrAppearance *a, gint w, gint h)
 367 {
 368     gint x, y1, y3, r, g, b;
 369     RrSurface *sf = &a->surface;
 370     RrPixel32 *data = sf->pixel_data;
 371     RrPixel32 current;
 372     RrColor *primary_light, *secondary_light;
 373
 374     VARS(y1);
 375     VARS(y3);
 376
 377     r = sf->primary->r;
 378     r += r >> 2;
 379     g = sf->primary->g;
 380     g += g >> 2;
 381     b = sf->primary->b;
 382     b += b >> 2;
 383     if (r > 0xFF) r = 0xFF;
 384     if (g > 0xFF) g = 0xFF;
 385     if (b > 0xFF) b = 0xFF;
 386       primary_light = RrColorNew(a->inst, r, g, b);
 387
 388     r = sf->secondary->r;
 389     r += r >> 4;
 390     g = sf->secondary->g;
 391     g += g >> 4;
 392     b = sf->secondary->b;
 393     b += b >> 4;
 394     if (r > 0xFF) r = 0xFF;
 395     if (g > 0xFF) g = 0xFF;
 396     if (b > 0xFF) b = 0xFF;
 397     secondary_light = RrColorNew(a->inst, r, g, b);
 398
 399     SETUP(y1, primary_light, sf->primary, (h / 2) -1);
 400     SETUP(y3, sf->secondary, secondary_light,  (h / 2) -1);
 401
 402     for (y1 = h - 1; y1 > (h / 2) -1; --y1) {  /* 0 -> h-1 */
 403         current = COLOR(y1);
 404         for (x = w - 1; x >= 0; --x)  /* 0 -> w */
 405             *(data++) = current;
 406
 407         NEXT(y1);
 408     }
 409
 410
 411     for (y3 = (h / 2) - 1; y3 > 0; --y3) {
 412         current = COLOR(y3);
 413         for (x = w - 1; x >= 0; --x)
 414             *(data++) = current;
 415
 416         NEXT(y3);
 417     }
 418
 419     current = COLOR(y3);
 420     for (x = w - 1; x >= 0; --x)  /* 0 -> w */
 421         *(data++) = current;
 422
 423     RrColorFree(primary_light);
 424     RrColorFree(secondary_light);
 425 }
 426
 427 static void gradient_horizontal(RrSurface *sf, gint w, gint h)
 428 {
 429     gint x, y;
 430     RrPixel32 *data = sf->pixel_data, *datav;
 431     RrPixel32 current;
 432
 433     VARS(x);
 434     SETUP(x, sf->primary, sf->secondary, w);
 435
 436     for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 437         current = COLOR(x);
 438         datav = data;
 439         for (y = h - 1; y >= 0; --y) {  /* 0 -> h */
 440             *datav = current;
 441             datav += w;
 442         }
 443         ++data;
 444
 445         NEXT(x);
 446     }
 447     current = COLOR(x);
 448     for (y = h - 1; y >= 0; --y)  /* 0 -> h */
 449         *(data + y * w) = current;
 450 }
 451
 452 static void gradient_mirrorhorizontal(RrSurface *sf, gint w, gint h)
 453 {
 454     gint x, y;
 455     RrPixel32 *data = sf->pixel_data, *datav;
 456     RrPixel32 current;
 457
 458     VARS(x);
 459     SETUP(x, sf->primary, sf->secondary, w/2);
 460
 461     if (w > 1) {
 462         for (x = w - 1; x > w/2-1; --x) {  /* 0 -> w-1 */
 463             current = COLOR(x);
 464             datav = data;
 465             for (y = h - 1; y >= 0; --y) {  /* 0 -> h */
 466                 *datav = current;
 467                 datav += w;
 468             }
 469             ++data;
 470
 471             NEXT(x);
 472         }
 473         SETUP(x, sf->secondary, sf->primary, w/2);
 474         for (x = w/2 - 1; x > 0; --x) {  /* 0 -> w-1 */
 475             current = COLOR(x);
 476             datav = data;
 477             for (y = h - 1; y >= 0; --y) {  /* 0 -> h */
 478                 *datav = current;
 479                 datav += w;
 480             }
 481             ++data;
 482
 483             NEXT(x);
 484         }
 485     }
 486     current = COLOR(x);
 487     for (y = h - 1; y >= 0; --y)  /* 0 -> h */
 488         *(data + y * w) = current;
 489 }
 490
 491 static void gradient_vertical(RrSurface *sf, gint w, gint h)
 492 {
 493     gint x, y;
 494     RrPixel32 *data = sf->pixel_data;
 495     RrPixel32 current;
 496
 497     VARS(y);
 498     SETUP(y, sf->primary, sf->secondary, h);
 499
 500     for (y = h - 1; y > 0; --y) {  /* 0 -> h-1 */
 501         current = COLOR(y);
 502         for (x = w - 1; x >= 0; --x)  /* 0 -> w */
 503             *(data++) = current;
 504
 505         NEXT(y);
 506     }
 507     current = COLOR(y);
 508     for (x = w - 1; x >= 0; --x)  /* 0 -> w */
 509         *(data++) = current;
 510 }
 511
 512
 513 static void gradient_diagonal(RrSurface *sf, gint w, gint h)
 514 {
 515     gint x, y;
 516     RrPixel32 *data = sf->pixel_data;
 517     RrColor left, right;
 518     RrColor extracorner;
 519
 520     VARS(lefty);
 521     VARS(righty);
 522     VARS(x);
 523
 524     extracorner.r = (sf->primary->r + sf->secondary->r) / 2;
 525     extracorner.g = (sf->primary->g + sf->secondary->g) / 2;
 526     extracorner.b = (sf->primary->b + sf->secondary->b) / 2;
 527
 528     SETUP(lefty, sf->primary, (&extracorner), h);
 529     SETUP(righty, (&extracorner), sf->secondary, h);
 530
 531     for (y = h - 1; y > 0; --y) {  /* 0 -> h-1 */
 532         COLOR_RR(lefty, (&left));
 533         COLOR_RR(righty, (&right));
 534
 535         SETUP(x, (&left), (&right), w);
 536
 537         for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 538             *(data++) = COLOR(x);
 539
 540             NEXT(x);
 541         }
 542         *(data++) = COLOR(x);
 543
 544         NEXT(lefty);
 545         NEXT(righty);
 546     }
 547     COLOR_RR(lefty, (&left));
 548     COLOR_RR(righty, (&right));
 549
 550     SETUP(x, (&left), (&right), w);
 551
 552     for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 553         *(data++) = COLOR(x);
 554
 555         NEXT(x);
 556     }
 557     *data = COLOR(x);
 558 }
 559
 560 static void gradient_crossdiagonal(RrSurface *sf, gint w, gint h)
 561 {
 562     gint x, y;
 563     RrPixel32 *data = sf->pixel_data;
 564     RrColor left, right;
 565     RrColor extracorner;
 566
 567     VARS(lefty);
 568     VARS(righty);
 569     VARS(x);
 570
 571     extracorner.r = (sf->primary->r + sf->secondary->r) / 2;
 572     extracorner.g = (sf->primary->g + sf->secondary->g) / 2;
 573     extracorner.b = (sf->primary->b + sf->secondary->b) / 2;
 574
 575     SETUP(lefty, (&extracorner), sf->secondary, h);
 576     SETUP(righty, sf->primary, (&extracorner), h);
 577
 578     for (y = h - 1; y > 0; --y) {  /* 0 -> h-1 */
 579         COLOR_RR(lefty, (&left));
 580         COLOR_RR(righty, (&right));
 581
 582         SETUP(x, (&left), (&right), w);
 583
 584         for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 585             *(data++) = COLOR(x);
 586
 587             NEXT(x);
 588         }
 589         *(data++) = COLOR(x);
 590
 591         NEXT(lefty);
 592         NEXT(righty);
 593     }
 594     COLOR_RR(lefty, (&left));
 595     COLOR_RR(righty, (&right));
 596
 597     SETUP(x, (&left), (&right), w);
 598
 599     for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 600         *(data++) = COLOR(x);
 601
 602         NEXT(x);
 603     }
 604     *data = COLOR(x);
 605 }
 606
 607 static void gradient_pyramid(RrSurface *sf, gint inw, gint inh)
 608 {
 609     gint x, y, w = (inw >> 1) + 1, h = (inh >> 1) + 1;
 610     RrPixel32 *data = sf->pixel_data;
 611     RrPixel32 *end = data + inw*inh - 1;
 612     RrPixel32 current;
 613     RrColor left, right;
 614     RrColor extracorner;
 615
 616     VARS(lefty);
 617     VARS(righty);
 618     VARS(x);
 619
 620     extracorner.r = (sf->primary->r + sf->secondary->r) / 2;
 621     extracorner.g = (sf->primary->g + sf->secondary->g) / 2;
 622     extracorner.b = (sf->primary->b + sf->secondary->b) / 2;
 623
 624     SETUP(lefty, (&extracorner), sf->secondary, h);
 625     SETUP(righty, sf->primary, (&extracorner), h);
 626
 627     for (y = h - 1; y > 0; --y) {  /* 0 -> h-1 */
 628         COLOR_RR(lefty, (&left));
 629         COLOR_RR(righty, (&right));
 630
 631         SETUP(x, (&left), (&right), w);
 632
 633         for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 634             current = COLOR(x);
 635             *(data+x) = current;
 636             *(data+inw-x) = current;
 637             *(end-x) = current;
 638             *(end-(inw-x)) = current;
 639
 640             NEXT(x);
 641         }
 642         current = COLOR(x);
 643         *(data+x) = current;
 644         *(data+inw-x) = current;
 645         *(end-x) = current;
 646         *(end-(inw-x)) = current;
 647
 648         data+=inw;
 649         end-=inw;
 650
 651         NEXT(lefty);
 652         NEXT(righty);
 653     }
 654     COLOR_RR(lefty, (&left));
 655     COLOR_RR(righty, (&right));
 656
 657     SETUP(x, (&left), (&right), w);
 658
 659     for (x = w - 1; x > 0; --x) {  /* 0 -> w-1 */
 660         current = COLOR(x);
 661         *(data+x) = current;
 662         *(data+inw-x) = current;
 663         *(end-x) = current;
 664         *(end-(inw-x)) = current;
 665
 666         NEXT(x);
 667     }
 668     current = COLOR(x);
 669     *(data+x) = current;
 670     *(data+inw-x) = current;
 671     *(end-x) = current;
 672     *(end-(inw-x)) = current;
 673 }
 674