wrlib/convert.c

   1 /* convert.c - convert RImage to Pixmap
   2  *
   3  *  Raster graphics library
   4  *
   5  *  Copyright (c) 1997 Alfredo K. Kojima
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Library General Public
   9  *  License as published by the Free Software Foundation; either
  10  *  version 2 of the License, or (at your option) any later version.
  11  *
  12  *  This library is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  Library General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Library General Public
  18  *  License along with this library; if not, write to the Free
  19  *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21 #include <config.h>
  22
  23 /* AIX requires this to be the first thing in the file.  */
  24 #ifdef __GNUC__
  25 # define alloca __builtin_alloca
  26 #else
  27 # if HAVE_ALLOCA_H
  28 #  include <alloca.h>
  29 # else
  30 #  ifdef _AIX
  31 #   pragma alloca
  32 #  else
  33 #   ifndef alloca /* predefined by HP cc +Olibcalls */
  34 char *alloca ();
  35 #   endif
  36 #  endif
  37 # endif
  38 #endif
  39
  40
  41 #include <X11/Xlib.h>
  42 #include <X11/Xutil.h>
  43 #include <stdlib.h>
  44 #include <stdio.h>
  45 #include <string.h>
  46
  47 #include <assert.h>
  48
  49 #include "wraster.h"
  50
  51 #ifdef XSHM
  52 Pixmap R_CreateXImageMappedPixmap(RContext *context, RXImage *ximage);
  53
  54 #endif
  55
  56
  57 typedef struct RConversionTable {
  58     unsigned short table[256];
  59     unsigned short index;
  60     struct RConversionTable *next;
  61 } RConversionTable;
  62
  63
  64 static RConversionTable *conversionTable = NULL;
  65
  66
  67 static unsigned short*
  68 computeTable(unsigned short mask)
  69 {
  70     RConversionTable *tmp = conversionTable;
  71     int i;
  72
  73     while (tmp) {
  74         if (tmp->index == mask)
  75             break;
  76         tmp = tmp->next;
  77     }
  78
  79     if (tmp)
  80         return tmp->table;
  81
  82     tmp = (RConversionTable *)malloc(sizeof(RConversionTable));
  83     if (tmp == NULL)
  84         return NULL;
  85
  86     for (i=0;i<256;i++)
  87         tmp->table[i] = (i*mask + 0x7f)/0xff;
  88
  89     tmp->index = mask;
  90     tmp->next = conversionTable;
  91     conversionTable = tmp;
  92     return tmp->table;
  93 }
  94
  95
  96 static RXImage*
  97 image2TrueColor(RContext *ctx, RImage *image)
  98 {
  99     RXImage *ximg;
 100     register int x, y, r, g, b;
 101     unsigned char *red, *grn, *blu;
 102     unsigned long pixel;
 103     unsigned short rmask, gmask, bmask;
 104     unsigned short roffs, goffs, boffs;
 105     unsigned short *rtable, *gtable, *btable;
 106     int ofs;
 107
 108     ximg = RCreateXImage(ctx, ctx->depth, image->width, image->height);
 109     if (!ximg) {
 110         return NULL;
 111     }
 112
 113     red = image->data[0];
 114     grn = image->data[1];
 115     blu = image->data[2];
 116
 117     roffs = ctx->red_offset;
 118     goffs = ctx->green_offset;
 119     boffs = ctx->blue_offset;
 120
 121     rmask = ctx->visual->red_mask >> roffs;
 122     gmask = ctx->visual->green_mask >> goffs;
 123     bmask = ctx->visual->blue_mask >> boffs;
 124
 125 #if 0
 126     /* this do not seem to increase speed. Only 0.06 second faster in
 127      * rendering a 800x600 image to pixmap. 1.12 sec instead of 1.18.
 128      * But does not require a 256*256*256 lookup table.
 129      */
 130     if (ctx->depth==24) {
 131 #ifdef DEBUG
 132         puts("true color match for 24bpp");
 133 #endif
 134         for (y=0; y < image->height; y++) {
 135             for (x=0; x < image->width; x++) {
 136                 pixel = (*(red++)<<roffs) | (*(grn++)<<goffs) | (*(blu++)<<boffs);
 137                 XPutPixel(ximg->image, x, y, pixel);
 138             }
 139         }
 140         return ximg;
 141     }
 142 #endif
 143
 144     rtable = computeTable(rmask);
 145     gtable = computeTable(gmask);
 146     btable = computeTable(bmask);
 147
 148     if (rtable==NULL || gtable==NULL || btable==NULL) {
 149         RErrorCode = RERR_NOMEMORY;
 150         RDestroyXImage(ctx, ximg);
 151         return NULL;
 152     }
 153
 154     if (ctx->attribs->render_mode==RM_MATCH) {
 155         /* fake match */
 156 #ifdef DEBUG
 157         puts("true color match");
 158 #endif
 159         for (y=0, ofs=0; y < image->height; y++) {
 160             for (x=0; x < image->width; x++, ofs++) {
 161                 /* reduce pixel */
 162                 r = rtable[red[ofs]];
 163                 g = gtable[grn[ofs]];
 164                 b = btable[blu[ofs]];
 165                 pixel = (r<<roffs) | (g<<goffs) | (b<<boffs);
 166                 XPutPixel(ximg->image, x, y, pixel);
 167             }
 168         }
 169     } else {
 170         /* dither */
 171         short *rerr, *gerr, *berr;
 172         short *nrerr, *ngerr, *nberr;
 173         short *terr;
 174         int rer, ger, ber;
 175         const int dr=0xff/rmask;
 176         const int dg=0xff/gmask;
 177         const int db=0xff/bmask;
 178
 179 #ifdef DEBUG
 180         puts("true color dither");
 181 #endif
 182         rerr = (short*)alloca((image->width+2)*sizeof(short));
 183         gerr = (short*)alloca((image->width+2)*sizeof(short));
 184         berr = (short*)alloca((image->width+2)*sizeof(short));
 185         nrerr = (short*)alloca((image->width+2)*sizeof(short));
 186         ngerr = (short*)alloca((image->width+2)*sizeof(short));
 187         nberr = (short*)alloca((image->width+2)*sizeof(short));
 188         if (!rerr || !gerr || !berr || !nrerr || !ngerr || !nberr) {
 189             RErrorCode = RERR_NOMEMORY;
 190             RDestroyXImage(ctx, ximg);
 191             return NULL;
 192         }
 193         for (x=0; x<image->width; x++) {
 194             rerr[x] = red[x];
 195             gerr[x] = grn[x];
 196             berr[x] = blu[x];
 197         }
 198         rerr[x] = gerr[x] = berr[x] = 0;
 199         /* convert and dither the image to XImage */
 200         for (y=0, ofs=0; y<image->height; y++) {
 201             if (y<image->height-1) {
 202                 int x1;
 203                 for (x=0, x1=ofs+image->width; x<image->width; x++, x1++) {
 204                     nrerr[x] = red[x1];
 205                     ngerr[x] = grn[x1];
 206                     nberr[x] = blu[x1];
 207                 }
 208                 /* last column */
 209                 x1--;
 210                 nrerr[x] = red[x1];
 211                 ngerr[x] = grn[x1];
 212                 nberr[x] = blu[x1];
 213             }
 214             for (x=0; x<image->width; x++) {
 215                 /* reduce pixel */
 216                 if (rerr[x]>0xff) rerr[x]=0xff; else if (rerr[x]<0) rerr[x]=0;
 217                 if (gerr[x]>0xff) gerr[x]=0xff; else if (gerr[x]<0) gerr[x]=0;
 218                 if (berr[x]>0xff) berr[x]=0xff; else if (berr[x]<0) berr[x]=0;
 219
 220                 r = rtable[rerr[x]];
 221                 g = gtable[gerr[x]];
 222                 b = btable[berr[x]];
 223
 224                 pixel = (r<<roffs) | (g<<goffs) | (b<<boffs);
 225                 XPutPixel(ximg->image, x, y, pixel);
 226                 /* calc error */
 227                 rer = rerr[x] - r*dr;
 228                 ger = gerr[x] - g*dg;
 229                 ber = berr[x] - b*db;
 230
 231                 /* distribute error */
 232                 r = (rer*3)/8;
 233                 g = (ger*3)/8;
 234                 b = (ber*3)/8;
 235                 /* x+1, y */
 236                 rerr[x+1]+=r;
 237                 gerr[x+1]+=g;
 238                 berr[x+1]+=b;
 239                 /* x, y+1 */
 240                 nrerr[x]+=r;
 241                 ngerr[x]+=g;
 242                 nberr[x]+=b;
 243                 /* x+1, y+1 */
 244                 nrerr[x+1]+=rer-2*r;
 245                 ngerr[x+1]+=ger-2*g;
 246                 nberr[x+1]+=ber-2*b;
 247             }
 248             ofs+=image->width;
 249             /* skip to next line */
 250             terr = rerr;
 251             rerr = nrerr;
 252             nrerr = terr;
 253
 254             terr = gerr;
 255             gerr = ngerr;
 256             ngerr = terr;
 257
 258             terr = berr;
 259             berr = nberr;
 260             nberr = terr;
 261         }
 262     }
 263     return ximg;
 264 }
 265
 266
 267 static RXImage*
 268 image2PseudoColor(RContext *ctx, RImage *image)
 269 {
 270     RXImage *ximg;
 271     register int x, y, r, g, b;
 272     unsigned char *red, *grn, *blu;
 273     unsigned long pixel;
 274     const int cpc=ctx->attribs->colors_per_channel;
 275     const unsigned short rmask = cpc-1; /* different sizes could be used */
 276     const unsigned short gmask = rmask; /* for r,g,b */
 277     const unsigned short bmask = rmask;
 278     unsigned short *rtable, *gtable, *btable;
 279     const int cpccpc = cpc*cpc;
 280     unsigned char *data;
 281     int ofs;
 282     /*register unsigned char maxrgb = 0xff;*/
 283
 284     ximg = RCreateXImage(ctx, ctx->depth, image->width, image->height);
 285     if (!ximg) {
 286         return NULL;
 287     }
 288
 289     red = image->data[0];
 290     grn = image->data[1];
 291     blu = image->data[2];
 292
 293     data = ximg->image->data;
 294
 295     /* Tables are same at the moment because rmask==gmask==bmask. */
 296     rtable = computeTable(rmask);
 297     gtable = computeTable(gmask);
 298     btable = computeTable(bmask);
 299
 300     if (rtable==NULL || gtable==NULL || btable==NULL) {
 301         RErrorCode = RERR_NOMEMORY;
 302         RDestroyXImage(ctx, ximg);
 303         return NULL;
 304     }
 305
 306     if (ctx->attribs->render_mode == RM_MATCH) {
 307         /* fake match */
 308 #ifdef DEBUG
 309         printf("pseudo color match with %d colors per channel\n", cpc);
 310 #endif
 311         for (y=0, ofs = 0; y<image->height; y++) {
 312             for (x=0; x<image->width; x++, ofs++) {
 313                 /* reduce pixel */
 314                 r = rtable[red[ofs]];
 315                 g = gtable[grn[ofs]];
 316                 b = btable[blu[ofs]];
 317                 pixel = r*cpccpc + g*cpc + b;
 318                 /*data[ofs] = ctx->colors[pixel].pixel;*/
 319                 XPutPixel(ximg->image, x, y, ctx->colors[pixel].pixel);
 320             }
 321         }
 322     } else {
 323         /* dither */
 324         short *rerr, *gerr, *berr;
 325         short *nrerr, *ngerr, *nberr;
 326         short *terr;
 327         int rer, ger, ber;
 328         const int dr=0xff/rmask;
 329         const int dg=0xff/gmask;
 330         const int db=0xff/bmask;
 331
 332 #ifdef DEBUG
 333         printf("pseudo color dithering with %d colors per channel\n", cpc);
 334 #endif
 335         rerr = (short*)alloca((image->width+2)*sizeof(short));
 336         gerr = (short*)alloca((image->width+2)*sizeof(short));
 337         berr = (short*)alloca((image->width+2)*sizeof(short));
 338         nrerr = (short*)alloca((image->width+2)*sizeof(short));
 339         ngerr = (short*)alloca((image->width+2)*sizeof(short));
 340         nberr = (short*)alloca((image->width+2)*sizeof(short));
 341         if (!rerr || !gerr || !berr || !nrerr || !ngerr || !nberr) {
 342             RErrorCode = RERR_NOMEMORY;
 343             RDestroyXImage(ctx, ximg);
 344             return NULL;
 345         }
 346         for (x=0; x<image->width; x++) {
 347             rerr[x] = red[x];
 348             gerr[x] = grn[x];
 349             berr[x] = blu[x];
 350         }
 351         rerr[x] = gerr[x] = berr[x] = 0;
 352         /* convert and dither the image to XImage */
 353         for (y=0, ofs=0; y<image->height; y++) {
 354             if (y<image->height-1) {
 355                 int x1;
 356                 for (x=0, x1=ofs+image->width; x<image->width; x++, x1++) {
 357                     nrerr[x] = red[x1];
 358                     ngerr[x] = grn[x1];
 359                     nberr[x] = blu[x1];
 360                 }
 361                 /* last column */
 362                 x1--;
 363                 nrerr[x] = red[x1];
 364                 ngerr[x] = grn[x1];
 365                 nberr[x] = blu[x1];
 366             }
 367             for (x=0; x<image->width; x++, ofs++) {
 368                 /* reduce pixel */
 369                 if (rerr[x]>0xff) rerr[x]=0xff; else if (rerr[x]<0) rerr[x]=0;
 370                 if (gerr[x]>0xff) gerr[x]=0xff; else if (gerr[x]<0) gerr[x]=0;
 371                 if (berr[x]>0xff) berr[x]=0xff; else if (berr[x]<0) berr[x]=0;
 372
 373                 r = rtable[rerr[x]];
 374                 g = gtable[gerr[x]];
 375                 b = btable[berr[x]];
 376
 377                 pixel = r*cpccpc + g*cpc + b;
 378                 /*data[ofs] = ctx->colors[pixel].pixel;*/
 379                 XPutPixel(ximg->image, x, y, ctx->colors[pixel].pixel);
 380
 381                 /* calc error */
 382                 rer = rerr[x] - r*dr;
 383                 ger = gerr[x] - g*dg;
 384                 ber = berr[x] - b*db;
 385
 386                 /* distribute error */
 387                 rerr[x+1]+=(rer*7)/16;
 388                 gerr[x+1]+=(ger*7)/16;
 389                 berr[x+1]+=(ber*7)/16;
 390
 391                 nrerr[x]+=(rer*5)/16;
 392                 ngerr[x]+=(ger*5)/16;
 393                 nberr[x]+=(ber*5)/16;
 394
 395                 if (x>0) {
 396                     nrerr[x-1]+=(rer*3)/16;
 397                     ngerr[x-1]+=(ger*3)/16;
 398                     nberr[x-1]+=(ber*3)/16;
 399                 }
 400
 401                 nrerr[x+1]+=rer/16;
 402                 ngerr[x+1]+=ger/16;
 403                 nberr[x+1]+=ber/16;
 404 #if 0
 405                 /* distribute error */
 406                 r = (rer*3)/8;
 407                 g = (ger*3)/8;
 408                 b = (ber*3)/8;
 409                 /* x+1, y */
 410                 rerr[x+1]+=r;
 411                 gerr[x+1]+=g;
 412                 berr[x+1]+=b;
 413                 /* x, y+1 */
 414                 nrerr[x]+=r;
 415                 ngerr[x]+=g;
 416                 nberr[x]+=b;
 417                 /* x+1, y+1 */
 418                 nrerr[x+1]+=rer-2*r;
 419                 ngerr[x+1]+=ger-2*g;
 420                 nberr[x+1]+=ber-2*b;
 421 #endif
 422             }
 423             /* skip to next line */
 424             terr = rerr;
 425             rerr = nrerr;
 426             nrerr = terr;
 427
 428             terr = gerr;
 429             gerr = ngerr;
 430             ngerr = terr;
 431
 432             terr = berr;
 433             berr = nberr;
 434             nberr = terr;
 435         }
 436     }
 437     ximg->image->data = (char*)data;
 438
 439     return ximg;
 440 }
 441
 442
 443 static RXImage*
 444 image2GrayScale(RContext *ctx, RImage *image)
 445 {
 446     RXImage *ximg;
 447     register int x, y, g;
 448     unsigned char *red, *grn, *blu;
 449     const int cpc=ctx->attribs->colors_per_channel;
 450     unsigned short gmask;
 451     unsigned short *table;
 452     unsigned char *data;
 453     int ofs;
 454     /*register unsigned char maxrgb = 0xff;*/
 455
 456     ximg = RCreateXImage(ctx, ctx->depth, image->width, image->height);
 457     if (!ximg) {
 458         return NULL;
 459     }
 460
 461     red = image->data[0];
 462     grn = image->data[1];
 463     blu = image->data[2];
 464
 465     data = ximg->image->data;
 466
 467     if (ctx->vclass == StaticGray)
 468         gmask = (1<<ctx->depth) - 1; /* use all grays */
 469     else
 470         gmask  = cpc*cpc*cpc-1;
 471
 472     table = computeTable(gmask);
 473
 474     if (table==NULL) {
 475         RErrorCode = RERR_NOMEMORY;
 476         RDestroyXImage(ctx, ximg);
 477         return NULL;
 478     }
 479
 480     if (ctx->attribs->render_mode == RM_MATCH) {
 481         /* fake match */
 482 #ifdef DEBUG
 483         printf("grayscale match with %d colors per channel\n", cpc);
 484 #endif
 485         for (y=0, ofs = 0; y<image->height; y++) {
 486             for (x=0; x<image->width; x++, ofs++) {
 487                 /* reduce pixel */
 488                 g = table[(red[ofs]*30+grn[ofs]*59+blu[ofs]*11)/100];
 489
 490                 /*data[ofs] = ctx->colors[g].pixel;*/
 491                 XPutPixel(ximg->image, x, y, ctx->colors[g].pixel);
 492             }
 493         }
 494     } else {
 495         /* dither */
 496         short *gerr;
 497         short *ngerr;
 498         short *terr;
 499         int ger;
 500         const int dg=0xff/gmask;
 501
 502 #ifdef DEBUG
 503         printf("grayscale dither with %d colors per channel\n", cpc);
 504 #endif
 505         gerr = (short*)alloca((image->width+2)*sizeof(short));
 506         ngerr = (short*)alloca((image->width+2)*sizeof(short));
 507         if (!gerr || !ngerr) {
 508             RErrorCode = RERR_NOMEMORY;
 509             RDestroyXImage(ctx, ximg);
 510             return NULL;
 511         }
 512         for (x=0; x<image->width; x++) {
 513             gerr[x] = (red[x]*30 + grn[x]*59 + blu[x]*11)/100;
 514         }
 515         gerr[x] = 0;
 516         /* convert and dither the image to XImage */
 517         for (y=0, ofs=0; y<image->height; y++) {
 518             if (y<image->height-1) {
 519                 int x1;
 520                 for (x=0, x1=ofs+image->width; x<image->width; x++, x1++) {
 521                     ngerr[x] = (red[x1]*30 + grn[x1]*59 + blu[x1]*11)/100;
 522                 }
 523                 /* last column */
 524                 x1--;
 525                 ngerr[x] = (red[x1]*30 + grn[x1]*59 + blu[x1]*11)/100;
 526             }
 527             for (x=0; x<image->width; x++, ofs++) {
 528                 /* reduce pixel */
 529                 if (gerr[x]>0xff) gerr[x]=0xff; else if (gerr[x]<0) gerr[x]=0;
 530
 531                 g = table[gerr[x]];
 532
 533                 /*data[ofs] = ctx->colors[g].pixel;*/
 534                 XPutPixel(ximg->image, x, y, ctx->colors[g].pixel);
 535                 /* calc error */
 536                 ger = gerr[x] - g*dg;
 537
 538                 /* distribute error */
 539                 g = (ger*3)/8;
 540                 /* x+1, y */
 541                 gerr[x+1]+=g;
 542                 /* x, y+1 */
 543                 ngerr[x]+=g;
 544                 /* x+1, y+1 */
 545                 ngerr[x+1]+=ger-2*g;
 546             }
 547             /* skip to next line */
 548             terr = gerr;
 549             gerr = ngerr;
 550             ngerr = terr;
 551         }
 552     }
 553     ximg->image->data = (char*)data;
 554
 555     return ximg;
 556 }
 557
 558
 559 static RXImage*
 560 image2Bitmap(RContext *ctx, RImage *image, int threshold)
 561 {
 562     RXImage *ximg;
 563     unsigned char *alpha;
 564     int x, y;
 565
 566     ximg = RCreateXImage(ctx, 1, image->width, image->height);
 567     if (!ximg) {
 568         return NULL;
 569     }
 570     alpha = image->data[3];
 571
 572     for (y = 0; y < image->height; y++) {
 573         for (x = 0; x < image->width; x++) {
 574             XPutPixel(ximg->image, x, y, (*alpha <= threshold ? 0 : 1));
 575             alpha++;
 576         }
 577     }
 578
 579     return ximg;
 580 }
 581
 582
 583
 584 int
 585 RConvertImage(RContext *context, RImage *image, Pixmap *pixmap)
 586 {
 587     RXImage *ximg=NULL;
 588 #ifdef XSHM
 589     Pixmap tmp;
 590 #endif
 591
 592     assert(context!=NULL);
 593     assert(image!=NULL);
 594     assert(pixmap!=NULL);
 595
 596     /* clear error message */
 597     if (context->vclass == TrueColor)
 598       ximg = image2TrueColor(context, image);
 599     else if (context->vclass == PseudoColor || context->vclass == StaticColor)
 600       ximg = image2PseudoColor(context, image);
 601     else if (context->vclass == GrayScale || context->vclass == StaticGray)
 602       ximg = image2GrayScale(context, image);
 603
 604     if (!ximg) {
 605 #ifdef C_ALLOCA
 606         alloca(0);
 607 #endif
 608         return False;
 609     }
 610
 611
 612     *pixmap = XCreatePixmap(context->dpy, context->drawable, image->width,
 613                             image->height, context->depth);
 614
 615 #ifdef XSHM
 616     tmp = R_CreateXImageMappedPixmap(context, ximg);
 617     if (tmp) {
 618         /*
 619          * We have to copy the shm Pixmap into a normal Pixmap because
 620          * otherwise, we would have to control when Pixmaps are freed so
 621          * that we can detach their shm segments. This is a problem if the
 622          * program crash, leaving stale shared memory segments in the
 623          * system (lots of them). But with some work, we can optimize
 624          * things and remove this XCopyArea. This will require
 625          * explicitly freeing all pixmaps when exiting or restarting
 626          * wmaker.
 627          */
 628         XCopyArea(context->dpy, tmp, *pixmap, context->copy_gc, 0, 0,
 629                   image->width, image->height, 0, 0);
 630         XFreePixmap(context->dpy, tmp);
 631     } else {
 632         RPutXImage(context, *pixmap, context->copy_gc, ximg, 0, 0, 0, 0,
 633                    image->width, image->height);
 634     }
 635 #else /* !XSHM */
 636     RPutXImage(context, *pixmap, context->copy_gc, ximg, 0, 0, 0, 0,
 637                image->width, image->height);
 638 #endif /* !XSHM */
 639
 640     RDestroyXImage(context, ximg);
 641
 642 #ifdef C_ALLOCA
 643     alloca(0);
 644 #endif
 645     return True;
 646 }
 647
 648
 649 int
 650 RConvertImageMask(RContext *context, RImage *image, Pixmap *pixmap,
 651                   Pixmap *mask, int threshold)
 652 {
 653     GC gc;
 654     XGCValues gcv;
 655     RXImage *ximg=NULL;
 656
 657     assert(context!=NULL);
 658     assert(image!=NULL);
 659     assert(pixmap!=NULL);
 660     assert(mask!=NULL);
 661
 662     if (!RConvertImage(context, image, pixmap))
 663         return False;
 664
 665     if (image->data[3]==NULL) {
 666         *mask = None;
 667         return True;
 668     }
 669
 670     ximg = image2Bitmap(context, image, threshold);
 671
 672     if (!ximg) {
 673 #ifdef C_ALLOCA
 674         alloca(0);
 675 #endif
 676         return False;
 677     }
 678     *mask = XCreatePixmap(context->dpy, context->drawable, image->width,
 679                           image->height, 1);
 680     gcv.foreground = context->black;
 681     gcv.background = context->white;
 682     gcv.graphics_exposures = False;
 683     gc = XCreateGC(context->dpy, *mask, GCForeground|GCBackground
 684                    |GCGraphicsExposures, &gcv);
 685     RPutXImage(context, *mask, gc, ximg, 0, 0, 0, 0,
 686                image->width, image->height);
 687     RDestroyXImage(context, ximg);
 688
 689 #ifdef C_ALLOCA
 690     alloca(0);
 691 #endif
 692     return True;
 693 }
 694
 695
 696 Bool
 697 RGetClosestXColor(RContext *context, RColor *color, XColor *retColor)
 698 {
 699     if (context->vclass == TrueColor) {
 700         unsigned short rmask, gmask, bmask;
 701         unsigned short roffs, goffs, boffs;
 702         unsigned short *rtable, *gtable, *btable;
 703
 704         roffs = context->red_offset;
 705         goffs = context->green_offset;
 706         boffs = context->blue_offset;
 707
 708         rmask = context->visual->red_mask >> roffs;
 709         gmask = context->visual->green_mask >> goffs;
 710         bmask = context->visual->blue_mask >> boffs;
 711
 712         rtable = computeTable(rmask);
 713         gtable = computeTable(gmask);
 714         btable = computeTable(bmask);
 715
 716         retColor->pixel = (rtable[color->red]<<roffs) |
 717             (rtable[color->green]<<goffs) | (rtable[color->blue]<<boffs);
 718
 719         retColor->red = rtable[color->red] << 8;
 720         retColor->green = rtable[color->green] << 8;
 721         retColor->blue = rtable[color->blue] << 8;
 722         retColor->flags = DoRed|DoGreen|DoBlue;
 723
 724     } else if (context->vclass == PseudoColor || context->vclass == StaticColor) {
 725         const int cpc=context->attribs->colors_per_channel;
 726         const unsigned short rmask = cpc-1; /* different sizes could be used */
 727         const unsigned short gmask = rmask; /* for r,g,b */
 728         const unsigned short bmask = rmask;
 729         unsigned short *rtable, *gtable, *btable;
 730         const int cpccpc = cpc*cpc;
 731         int index;
 732
 733         rtable = computeTable(rmask);
 734         gtable = computeTable(gmask);
 735         btable = computeTable(bmask);
 736
 737         if (rtable==NULL || gtable==NULL || btable==NULL) {
 738             RErrorCode = RERR_NOMEMORY;
 739             return False;
 740         }
 741         index = rtable[color->red]*cpccpc + gtable[color->green]*cpc
 742             + btable[color->blue];
 743         *retColor = context->colors[index];
 744     } else if (context->vclass == GrayScale || context->vclass == StaticGray) {
 745
 746         const int cpc = context->attribs->colors_per_channel;
 747         unsigned short gmask;
 748         unsigned short *table;
 749         int index;
 750
 751         if (context->vclass == StaticGray)
 752             gmask = (1<<context->depth) - 1; /* use all grays */
 753         else
 754             gmask  = cpc*cpc*cpc-1;
 755
 756         table = computeTable(gmask);
 757         if (!table)
 758             return False;
 759
 760         index = table[(color->red*30 + color->green*59 + color->blue*11)/100];
 761
 762         *retColor = context->colors[index];
 763     } else {
 764         RErrorCode = RERR_INTERNAL;
 765         return False;
 766     }
 767
 768     return True;
 769 }