granicus.if.org Git - imagemagick/blob - coders/dib.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %                            DDDD   IIIII  BBBB                               %
   7 %                            D   D    I    B   B                              %
   8 %                            D   D    I    BBBB                               %
   9 %                            D   D    I    B   B                              %
  10 %                            DDDD   IIIII  BBBB                               %
  11 %                                                                             %
  12 %                                                                             %
  13 %                   Read/Write Windows DIB Image Format                       %
  14 %                                                                             %
  15 %                              Software Design                                %
  16 %                                John Cristy                                  %
  17 %                                 July 1992                                   %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2012 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  28 %  Unless required by applicable law or agreed to in writing, software        %
  29 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  30 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  31 %  See the License for the specific language governing permissions and        %
  32 %  limitations under the License.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  36 %
  37 */
  38 \f
  39 /*
  40   Include declarations.
  41 */
  42 #include "MagickCore/studio.h"
  43 #include "MagickCore/attribute.h"
  44 #include "MagickCore/blob.h"
  45 #include "MagickCore/blob-private.h"
  46 #include "MagickCore/cache.h"
  47 #include "MagickCore/color.h"
  48 #include "MagickCore/color-private.h"
  49 #include "MagickCore/colormap.h"
  50 #include "MagickCore/colormap-private.h"
  51 #include "MagickCore/colorspace.h"
  52 #include "MagickCore/colorspace-private.h"
  53 #include "MagickCore/draw.h"
  54 #include "MagickCore/exception.h"
  55 #include "MagickCore/exception-private.h"
  56 #include "MagickCore/geometry.h"
  57 #include "MagickCore/image.h"
  58 #include "MagickCore/image-private.h"
  59 #include "MagickCore/list.h"
  60 #include "MagickCore/log.h"
  61 #include "MagickCore/magick.h"
  62 #include "MagickCore/memory_.h"
  63 #include "MagickCore/monitor.h"
  64 #include "MagickCore/monitor-private.h"
  65 #include "MagickCore/pixel-accessor.h"
  66 #include "MagickCore/quantum-private.h"
  67 #include "MagickCore/static.h"
  68 #include "MagickCore/string_.h"
  69 #include "MagickCore/module.h"
  70 #include "MagickCore/transform.h"
  71 \f
  72 /*
  73   Typedef declarations.
  74 */
  75 typedef struct _DIBInfo
  76 {
  77   size_t
  78     size;
  79
  80   ssize_t
  81     width,
  82     height;
  83
  84   unsigned short
  85     planes,
  86     bits_per_pixel;
  87
  88   size_t
  89     compression,
  90     image_size,
  91     x_pixels,
  92     y_pixels,
  93     number_colors,
  94     red_mask,
  95     green_mask,
  96     blue_mask,
  97     alpha_mask,
  98     colors_important;
  99
 100   ssize_t
 101     colorspace;
 102
 103   PointInfo
 104     red_primary,
 105     green_primary,
 106     blue_primary,
 107     gamma_scale;
 108 } DIBInfo;
 109 \f
 110 /*
 111   Forward declarations.
 112 */
 113 static MagickBooleanType
 114   WriteDIBImage(const ImageInfo *,Image *,ExceptionInfo *);
 115 \f
 116 /*
 117 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 118 %                                                                             %
 119 %                                                                             %
 120 %                                                                             %
 121 %   D e c o d e I m a g e                                                     %
 122 %                                                                             %
 123 %                                                                             %
 124 %                                                                             %
 125 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 126 %
 127 %  DecodeImage unpacks the packed image pixels into runlength-encoded
 128 %  pixel packets.
 129 %
 130 %  The format of the DecodeImage method is:
 131 %
 132 %      MagickBooleanType DecodeImage(Image *image,
 133 %        const MagickBooleanType compression,unsigned char *pixels)
 134 %
 135 %  A description of each parameter follows:
 136 %
 137 %    o image: the address of a structure of type Image.
 138 %
 139 %    o compression:  A value of 1 means the compressed pixels are runlength
 140 %      encoded for a 256-color bitmap.  A value of 2 means a 16-color bitmap.
 141 %
 142 %    o pixels:  The address of a byte (8 bits) array of pixel data created by
 143 %      the decoding process.
 144 %
 145 */
 146
 147 static inline size_t MagickMin(const size_t x,const size_t y)
 148 {
 149   if (x < y)
 150     return(x);
 151   return(y);
 152 }
 153
 154 static MagickBooleanType DecodeImage(Image *image,
 155   const MagickBooleanType compression,unsigned char *pixels)
 156 {
 157 #if !defined(MAGICKCORE_WINDOWS_SUPPORT) || defined(__MINGW32__)
 158 #define BI_RGB  0
 159 #define BI_RLE8  1
 160 #define BI_RLE4  2
 161 #define BI_BITFIELDS  3
 162 #endif
 163
 164   int
 165     count;
 166
 167   ssize_t
 168     y;
 169
 170   register ssize_t
 171     i,
 172     x;
 173
 174   register unsigned char
 175     *p,
 176     *q;
 177
 178   unsigned char
 179     byte;
 180
 181   assert(image != (Image *) NULL);
 182   assert(image->signature == MagickSignature);
 183   if (image->debug != MagickFalse)
 184     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 185   assert(pixels != (unsigned char *) NULL);
 186   (void) ResetMagickMemory(pixels,0,(size_t) image->columns*image->rows*
 187     sizeof(*pixels));
 188   byte=0;
 189   x=0;
 190   p=pixels;
 191   q=pixels+(size_t) image->columns*image->rows;
 192   for (y=0; y < (ssize_t) image->rows; )
 193   {
 194     if ((p < pixels) || (p >= q))
 195       break;
 196     count=ReadBlobByte(image);
 197     if (count == EOF)
 198       break;
 199     if (count != 0)
 200       {
 201         count=(int) MagickMin((size_t) count,(size_t) (q-p));
 202         /*
 203           Encoded mode.
 204         */
 205         byte=(unsigned char) ReadBlobByte(image);
 206         if (compression == BI_RLE8)
 207           {
 208             for (i=0; i < count; i++)
 209               *p++=(unsigned char) byte;
 210           }
 211         else
 212           {
 213             for (i=0; i < count; i++)
 214               *p++=(unsigned char)
 215                 ((i & 0x01) != 0 ? (byte & 0x0f) : ((byte >> 4) & 0x0f));
 216           }
 217         x+=count;
 218       }
 219     else
 220       {
 221         /*
 222           Escape mode.
 223         */
 224         count=ReadBlobByte(image);
 225         if (count == 0x01)
 226           return(MagickTrue);
 227         switch (count)
 228         {
 229           case 0x00:
 230           {
 231             /*
 232               End of line.
 233             */
 234             x=0;
 235             y++;
 236             p=pixels+y*image->columns;
 237             break;
 238           }
 239           case 0x02:
 240           {
 241             /*
 242               Delta mode.
 243             */
 244             x+=ReadBlobByte(image);
 245             y+=ReadBlobByte(image);
 246             p=pixels+y*image->columns+x;
 247             break;
 248           }
 249           default:
 250           {
 251             /*
 252               Absolute mode.
 253             */
 254             count=(int) MagickMin((size_t) count,(size_t) (q-p));
 255             if (compression == BI_RLE8)
 256               for (i=0; i < count; i++)
 257                 *p++=(unsigned char) ReadBlobByte(image);
 258             else
 259               for (i=0; i < count; i++)
 260               {
 261                 if ((i & 0x01) == 0)
 262                   byte=(unsigned char) ReadBlobByte(image);
 263                 *p++=(unsigned char)
 264                   ((i & 0x01) != 0 ? (byte & 0x0f) : ((byte >> 4) & 0x0f));
 265               }
 266             x+=count;
 267             /*
 268               Read pad byte.
 269             */
 270             if (compression == BI_RLE8)
 271               {
 272                 if ((count & 0x01) != 0)
 273                   (void) ReadBlobByte(image);
 274               }
 275             else
 276               if (((count & 0x03) == 1) || ((count & 0x03) == 2))
 277                 (void) ReadBlobByte(image);
 278             break;
 279           }
 280         }
 281       }
 282     if (SetImageProgress(image,LoadImageTag,y,image->rows) == MagickFalse)
 283       break;
 284   }
 285   (void) ReadBlobByte(image);  /* end of line */
 286   (void) ReadBlobByte(image);
 287   return(MagickTrue);
 288 }
 289 \f
 290 /*
 291 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 292 %                                                                             %
 293 %                                                                             %
 294 %                                                                             %
 295 %   E n c o d e I m a g e                                                     %
 296 %                                                                             %
 297 %                                                                             %
 298 %                                                                             %
 299 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 300 %
 301 %  EncodeImage compresses pixels using a runlength encoded format.
 302 %
 303 %  The format of the EncodeImage method is:
 304 %
 305 %    static MagickBooleanType EncodeImage(Image *image,
 306 %      const size_t bytes_per_line,const unsigned char *pixels,
 307 %      unsigned char *compressed_pixels)
 308 %
 309 %  A description of each parameter follows:
 310 %
 311 %    o image:  The image.
 312 %
 313 %    o bytes_per_line: the number of bytes in a scanline of compressed pixels
 314 %
 315 %    o pixels:  The address of a byte (8 bits) array of pixel data created by
 316 %      the compression process.
 317 %
 318 %    o compressed_pixels:  The address of a byte (8 bits) array of compressed
 319 %      pixel data.
 320 %
 321 */
 322 static size_t EncodeImage(Image *image,const size_t bytes_per_line,
 323   const unsigned char *pixels,unsigned char *compressed_pixels)
 324 {
 325   ssize_t
 326     y;
 327
 328   register const unsigned char
 329     *p;
 330
 331   register ssize_t
 332     i,
 333     x;
 334
 335   register unsigned char
 336     *q;
 337
 338   /*
 339     Runlength encode pixels.
 340   */
 341   assert(image != (Image *) NULL);
 342   assert(image->signature == MagickSignature);
 343   if (image->debug != MagickFalse)
 344     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
 345   assert(pixels != (const unsigned char *) NULL);
 346   assert(compressed_pixels != (unsigned char *) NULL);
 347   p=pixels;
 348   q=compressed_pixels;
 349   i=0;
 350   for (y=0; y < (ssize_t) image->rows; y++)
 351   {
 352     for (x=0; x < (ssize_t) bytes_per_line; x+=i)
 353     {
 354       /*
 355         Determine runlength.
 356       */
 357       for (i=1; ((x+i) < (ssize_t) bytes_per_line); i++)
 358         if ((*(p+i) != *p) || (i == 255))
 359           break;
 360       *q++=(unsigned char) i;
 361       *q++=(*p);
 362       p+=i;
 363     }
 364     /*
 365       End of line.
 366     */
 367     *q++=0x00;
 368     *q++=0x00;
 369     if (SetImageProgress(image,LoadImageTag,y,image->rows) == MagickFalse)
 370       break;
 371   }
 372   /*
 373     End of bitmap.
 374   */
 375   *q++=0;
 376   *q++=0x01;
 377   return((size_t) (q-compressed_pixels));
 378 }
 379 \f
 380 /*
 381 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 382 %                                                                             %
 383 %                                                                             %
 384 %                                                                             %
 385 %   I s D I B                                                                 %
 386 %                                                                             %
 387 %                                                                             %
 388 %                                                                             %
 389 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 390 %
 391 %  IsDIB() returns MagickTrue if the image format type, identified by the
 392 %  magick string, is DIB.
 393 %
 394 %  The format of the IsDIB method is:
 395 %
 396 %      MagickBooleanType IsDIB(const unsigned char *magick,const size_t length)
 397 %
 398 %  A description of each parameter follows:
 399 %
 400 %    o magick: compare image format pattern against these bytes.
 401 %
 402 %    o length: Specifies the length of the magick string.
 403 %
 404 */
 405 static MagickBooleanType IsDIB(const unsigned char *magick,const size_t length)
 406 {
 407   if (length < 2)
 408     return(MagickFalse);
 409   if (memcmp(magick,"\050\000",2) == 0)
 410     return(MagickTrue);
 411   return(MagickFalse);
 412 }
 413 \f
 414 /*
 415 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 416 %                                                                             %
 417 %                                                                             %
 418 %                                                                             %
 419 %   R e a d D I B I m a g e                                                   %
 420 %                                                                             %
 421 %                                                                             %
 422 %                                                                             %
 423 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 424 %
 425 %  ReadDIBImage() reads a Microsoft Windows bitmap image file and
 426 %  returns it.  It allocates the memory necessary for the new Image structure
 427 %  and returns a pointer to the new image.
 428 %
 429 %  The format of the ReadDIBImage method is:
 430 %
 431 %      image=ReadDIBImage(image_info)
 432 %
 433 %  A description of each parameter follows:
 434 %
 435 %    o image_info: the image info.
 436 %
 437 %    o exception: return any errors or warnings in this structure.
 438 %
 439 */
 440
 441 static inline ssize_t MagickAbsoluteValue(const ssize_t x)
 442 {
 443   if (x < 0)
 444     return(-x);
 445   return(x);
 446 }
 447
 448 static inline size_t MagickMax(const size_t x,const size_t y)
 449 {
 450   if (x > y)
 451     return(x);
 452   return(y);
 453 }
 454
 455 static Image *ReadDIBImage(const ImageInfo *image_info,ExceptionInfo *exception)
 456 {
 457   DIBInfo
 458     dib_info;
 459
 460   Image
 461     *image;
 462
 463   MagickBooleanType
 464     status;
 465
 466   Quantum
 467     index;
 468
 469   register ssize_t
 470     x;
 471
 472   register Quantum
 473     *q;
 474
 475   register ssize_t
 476     i;
 477
 478   register unsigned char
 479     *p;
 480
 481   size_t
 482     bytes_per_line,
 483     length;
 484
 485   ssize_t
 486     bit,
 487     count,
 488     y;
 489
 490
 491   unsigned char
 492     *pixels;
 493
 494   /*
 495     Open image file.
 496   */
 497   assert(image_info != (const ImageInfo *) NULL);
 498   assert(image_info->signature == MagickSignature);
 499   if (image_info->debug != MagickFalse)
 500     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
 501       image_info->filename);
 502   assert(exception != (ExceptionInfo *) NULL);
 503   assert(exception->signature == MagickSignature);
 504   image=AcquireImage(image_info,exception);
 505   status=OpenBlob(image_info,image,ReadBinaryBlobMode,exception);
 506   if (status == MagickFalse)
 507     {
 508       image=DestroyImageList(image);
 509       return((Image *) NULL);
 510     }
 511   /*
 512     Determine if this a DIB file.
 513   */
 514   (void) ResetMagickMemory(&dib_info,0,sizeof(dib_info));
 515   dib_info.size=ReadBlobLSBLong(image);
 516   if (dib_info.size!=40)
 517     ThrowReaderException(CorruptImageError,"ImproperImageHeader");
 518   /*
 519     Microsoft Windows 3.X DIB image file.
 520   */
 521   dib_info.width=(short) ReadBlobLSBLong(image);
 522   dib_info.height=(short) ReadBlobLSBLong(image);
 523   dib_info.planes=ReadBlobLSBShort(image);
 524   dib_info.bits_per_pixel=ReadBlobLSBShort(image);
 525   dib_info.compression=ReadBlobLSBLong(image);
 526   dib_info.image_size=ReadBlobLSBLong(image);
 527   dib_info.x_pixels=ReadBlobLSBLong(image);
 528   dib_info.y_pixels=ReadBlobLSBLong(image);
 529   dib_info.number_colors=ReadBlobLSBLong(image);
 530   dib_info.colors_important=ReadBlobLSBLong(image);
 531   if ((dib_info.compression == BI_BITFIELDS) &&
 532       ((dib_info.bits_per_pixel == 16) || (dib_info.bits_per_pixel == 32)))
 533     {
 534       dib_info.red_mask=ReadBlobLSBLong(image);
 535       dib_info.green_mask=ReadBlobLSBLong(image);
 536       dib_info.blue_mask=ReadBlobLSBLong(image);
 537     }
 538   image->matte=dib_info.bits_per_pixel == 32 ? MagickTrue : MagickFalse;
 539   image->columns=(size_t) MagickAbsoluteValue(dib_info.width);
 540   image->rows=(size_t) MagickAbsoluteValue(dib_info.height);
 541   image->depth=8;
 542   if ((dib_info.number_colors != 0) || (dib_info.bits_per_pixel < 16))
 543     {
 544       size_t
 545         one;
 546
 547       image->storage_class=PseudoClass;
 548       image->colors=dib_info.number_colors;
 549       one=1;
 550       if (image->colors == 0)
 551         image->colors=one << dib_info.bits_per_pixel;
 552     }
 553   if (image_info->size)
 554     {
 555       RectangleInfo
 556         geometry;
 557
 558       MagickStatusType
 559         flags;
 560
 561       flags=ParseAbsoluteGeometry(image_info->size,&geometry);
 562       if (flags & WidthValue)
 563         if ((geometry.width != 0) && (geometry.width < image->columns))
 564           image->columns=geometry.width;
 565       if (flags & HeightValue)
 566         if ((geometry.height != 0) && (geometry.height < image->rows))
 567           image->rows=geometry.height;
 568     }
 569   if (image->storage_class == PseudoClass)
 570     {
 571       size_t
 572         length,
 573         packet_size;
 574
 575       unsigned char
 576         *dib_colormap;
 577
 578       /*
 579         Read DIB raster colormap.
 580       */
 581       if (AcquireImageColormap(image,image->colors,exception) == MagickFalse)
 582         ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
 583       length=(size_t) image->colors;
 584       dib_colormap=(unsigned char *) AcquireQuantumMemory(length,
 585         4*sizeof(*dib_colormap));
 586       if (dib_colormap == (unsigned char *) NULL)
 587         ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
 588       packet_size=4;
 589       count=ReadBlob(image,packet_size*image->colors,dib_colormap);
 590       if (count != (ssize_t) (packet_size*image->colors))
 591         ThrowReaderException(CorruptImageError,"InsufficientImageDataInFile");
 592       p=dib_colormap;
 593       for (i=0; i < (ssize_t) image->colors; i++)
 594       {
 595         image->colormap[i].blue=ScaleCharToQuantum(*p++);
 596         image->colormap[i].green=ScaleCharToQuantum(*p++);
 597         image->colormap[i].red=ScaleCharToQuantum(*p++);
 598         if (packet_size == 4)
 599           p++;
 600       }
 601       dib_colormap=(unsigned char *) RelinquishMagickMemory(dib_colormap);
 602     }
 603   /*
 604     Read image data.
 605   */
 606   if (dib_info.compression == BI_RLE4)
 607     dib_info.bits_per_pixel<<=1;
 608   bytes_per_line=4*((image->columns*dib_info.bits_per_pixel+31)/32);
 609   length=bytes_per_line*image->rows;
 610   pixels=(unsigned char *) AcquireQuantumMemory((size_t) image->rows,
 611     MagickMax(bytes_per_line,image->columns+256UL)*sizeof(*pixels));
 612   if (pixels == (unsigned char *) NULL)
 613     ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
 614   if ((dib_info.compression == BI_RGB) ||
 615       (dib_info.compression == BI_BITFIELDS))
 616     {
 617       count=ReadBlob(image,length,pixels);
 618       if (count != (ssize_t) (length))
 619         ThrowReaderException(CorruptImageError,"InsufficientImageDataInFile");
 620     }
 621   else
 622     {
 623       /*
 624         Convert run-length encoded raster pixels.
 625       */
 626       status=DecodeImage(image,dib_info.compression ? MagickTrue : MagickFalse,
 627         pixels);
 628       if (status == MagickFalse)
 629         ThrowReaderException(CorruptImageError,"UnableToRunlengthDecodeImage");
 630     }
 631   /*
 632     Initialize image structure.
 633   */
 634   image->units=PixelsPerCentimeterResolution;
 635   image->resolution.x=(double) dib_info.x_pixels/100.0;
 636   image->resolution.y=(double) dib_info.y_pixels/100.0;
 637   /*
 638     Convert DIB raster image to pixel packets.
 639   */
 640   switch (dib_info.bits_per_pixel)
 641   {
 642     case 1:
 643     {
 644       /*
 645         Convert bitmap scanline.
 646       */
 647       for (y=(ssize_t) image->rows-1; y >= 0; y--)
 648       {
 649         p=pixels+(image->rows-y-1)*bytes_per_line;
 650         q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
 651         if (q == (Quantum *) NULL)
 652           break;
 653         for (x=0; x < ((ssize_t) image->columns-7); x+=8)
 654         {
 655           for (bit=0; bit < 8; bit++)
 656           {
 657             index=(Quantum) ((*p) & (0x80 >> bit) ? 0x01 : 0x00);
 658             SetPixelIndex(image,index,q);
 659             q+=GetPixelChannels(image);
 660           }
 661           p++;
 662         }
 663         if ((image->columns % 8) != 0)
 664           {
 665             for (bit=0; bit < (ssize_t) (image->columns % 8); bit++)
 666             {
 667               index=(Quantum) ((*p) & (0x80 >> bit) ? 0x01 : 0x00);
 668               SetPixelIndex(image,index,q);
 669               q+=GetPixelChannels(image);
 670             }
 671             p++;
 672           }
 673         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 674           break;
 675         if (image->previous == (Image *) NULL)
 676           {
 677             status=SetImageProgress(image,LoadImageTag,image->rows-y-1,
 678               image->rows);
 679             if (status == MagickFalse)
 680               break;
 681           }
 682       }
 683       (void) SyncImage(image,exception);
 684       break;
 685     }
 686     case 4:
 687     {
 688       /*
 689         Convert PseudoColor scanline.
 690       */
 691       for (y=(ssize_t) image->rows-1; y >= 0; y--)
 692       {
 693         p=pixels+(image->rows-y-1)*bytes_per_line;
 694         q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
 695         if (q == (Quantum *) NULL)
 696           break;
 697         for (x=0; x < ((ssize_t) image->columns-1); x+=2)
 698         {
 699           index=ConstrainColormapIndex(image,(*p >> 4) & 0xf,exception);
 700           SetPixelIndex(image,index,q);
 701           q+=GetPixelChannels(image);
 702           index=ConstrainColormapIndex(image,*p & 0xf,exception);
 703           SetPixelIndex(image,index,q);
 704           p++;
 705           q+=GetPixelChannels(image);
 706         }
 707         if ((image->columns % 2) != 0)
 708           {
 709             index=ConstrainColormapIndex(image,(*p >> 4) & 0xf,exception);
 710             SetPixelIndex(image,index,q);
 711             q+=GetPixelChannels(image);
 712             p++;
 713           }
 714         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 715           break;
 716         if (image->previous == (Image *) NULL)
 717           {
 718             status=SetImageProgress(image,LoadImageTag,image->rows-y-1,
 719               image->rows);
 720             if (status == MagickFalse)
 721               break;
 722           }
 723       }
 724       (void) SyncImage(image,exception);
 725       break;
 726     }
 727     case 8:
 728     {
 729       /*
 730         Convert PseudoColor scanline.
 731       */
 732       if ((dib_info.compression == BI_RLE8) ||
 733           (dib_info.compression == BI_RLE4))
 734         bytes_per_line=image->columns;
 735       for (y=(ssize_t) image->rows-1; y >= 0; y--)
 736       {
 737         p=pixels+(image->rows-y-1)*bytes_per_line;
 738         q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
 739         if (q == (Quantum *) NULL)
 740           break;
 741         for (x=0; x < (ssize_t) image->columns; x++)
 742         {
 743           index=ConstrainColormapIndex(image,*p,exception);
 744           SetPixelIndex(image,index,q);
 745           p++;
 746           q+=GetPixelChannels(image);
 747         }
 748         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 749           break;
 750         if (image->previous == (Image *) NULL)
 751           {
 752             status=SetImageProgress(image,LoadImageTag,image->rows-y-1,
 753               image->rows);
 754             if (status == MagickFalse)
 755               break;
 756           }
 757       }
 758       (void) SyncImage(image,exception);
 759       break;
 760     }
 761     case 16:
 762     {
 763       unsigned short
 764         word;
 765
 766       /*
 767         Convert PseudoColor scanline.
 768       */
 769       image->storage_class=DirectClass;
 770       if (dib_info.compression == BI_RLE8)
 771         bytes_per_line=2*image->columns;
 772       for (y=(ssize_t) image->rows-1; y >= 0; y--)
 773       {
 774         p=pixels+(image->rows-y-1)*bytes_per_line;
 775         q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
 776         if (q == (Quantum *) NULL)
 777           break;
 778         for (x=0; x < (ssize_t) image->columns; x++)
 779         {
 780           word=(*p++);
 781           word|=(*p++ << 8);
 782           if (dib_info.red_mask == 0)
 783             {
 784               SetPixelRed(image,ScaleCharToQuantum(ScaleColor5to8(
 785                 (unsigned char) ((word >> 10) & 0x1f))),q);
 786               SetPixelGreen(image,ScaleCharToQuantum(ScaleColor5to8(
 787                 (unsigned char) ((word >> 5) & 0x1f))),q);
 788               SetPixelBlue(image,ScaleCharToQuantum(ScaleColor5to8(
 789                 (unsigned char) (word & 0x1f))),q);
 790             }
 791           else
 792             {
 793               SetPixelRed(image,ScaleCharToQuantum(ScaleColor5to8(
 794                 (unsigned char) ((word >> 11) & 0x1f))),q);
 795               SetPixelGreen(image,ScaleCharToQuantum(ScaleColor6to8(
 796                 (unsigned char) ((word >> 5) & 0x3f))),q);
 797               SetPixelBlue(image,ScaleCharToQuantum(ScaleColor5to8(
 798                 (unsigned char) (word & 0x1f))),q);
 799             }
 800           q+=GetPixelChannels(image);
 801         }
 802         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 803           break;
 804         if (image->previous == (Image *) NULL)
 805           {
 806             status=SetImageProgress(image,LoadImageTag,image->rows-y-1,
 807               image->rows);
 808             if (status == MagickFalse)
 809               break;
 810           }
 811       }
 812       break;
 813     }
 814     case 24:
 815     case 32:
 816     {
 817       /*
 818         Convert DirectColor scanline.
 819       */
 820       for (y=(ssize_t) image->rows-1; y >= 0; y--)
 821       {
 822         p=pixels+(image->rows-y-1)*bytes_per_line;
 823         q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
 824         if (q == (Quantum *) NULL)
 825           break;
 826         for (x=0; x < (ssize_t) image->columns; x++)
 827         {
 828           SetPixelBlue(image,ScaleCharToQuantum(*p++),q);
 829           SetPixelGreen(image,ScaleCharToQuantum(*p++),q);
 830           SetPixelRed(image,ScaleCharToQuantum(*p++),q);
 831           if (image->matte != MagickFalse)
 832             SetPixelAlpha(image,ScaleCharToQuantum(*p++),q);
 833           q+=GetPixelChannels(image);
 834         }
 835         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 836           break;
 837         if (image->previous == (Image *) NULL)
 838           {
 839             status=SetImageProgress(image,LoadImageTag,image->rows-y-1,
 840               image->rows);
 841             if (status == MagickFalse)
 842               break;
 843           }
 844       }
 845       break;
 846     }
 847     default:
 848       ThrowReaderException(CorruptImageError,"ImproperImageHeader");
 849   }
 850   pixels=(unsigned char *) RelinquishMagickMemory(pixels);
 851   if (EOFBlob(image) != MagickFalse)
 852     ThrowFileException(exception,CorruptImageError,"UnexpectedEndOfFile",
 853       image->filename);
 854   if (dib_info.height < 0)
 855     {
 856       Image
 857         *flipped_image;
 858
 859       /*
 860         Correct image orientation.
 861       */
 862       flipped_image=FlipImage(image,exception);
 863       if (flipped_image != (Image *) NULL)
 864         {
 865           DuplicateBlob(flipped_image,image);
 866           image=DestroyImage(image);
 867           image=flipped_image;
 868         }
 869     }
 870   (void) CloseBlob(image);
 871   return(GetFirstImageInList(image));
 872 }
 873 \f
 874 /*
 875 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 876 %                                                                             %
 877 %                                                                             %
 878 %                                                                             %
 879 %   R e g i s t e r D I B I m a g e                                           %
 880 %                                                                             %
 881 %                                                                             %
 882 %                                                                             %
 883 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 884 %
 885 %  RegisterDIBImage() adds attributes for the DIB image format to
 886 %  the list of supported formats.  The attributes include the image format
 887 %  tag, a method to read and/or write the format, whether the format
 888 %  supports the saving of more than one frame to the same file or blob,
 889 %  whether the format supports native in-memory I/O, and a brief
 890 %  description of the format.
 891 %
 892 %  The format of the RegisterDIBImage method is:
 893 %
 894 %      size_t RegisterDIBImage(void)
 895 %
 896 */
 897 ModuleExport size_t RegisterDIBImage(void)
 898 {
 899   MagickInfo
 900     *entry;
 901
 902   entry=SetMagickInfo("DIB");
 903   entry->decoder=(DecodeImageHandler *) ReadDIBImage;
 904   entry->encoder=(EncodeImageHandler *) WriteDIBImage;
 905   entry->magick=(IsImageFormatHandler *) IsDIB;
 906   entry->adjoin=MagickFalse;
 907   entry->stealth=MagickTrue;
 908   entry->description=ConstantString(
 909     "Microsoft Windows 3.X Packed Device-Independent Bitmap");
 910   entry->module=ConstantString("DIB");
 911   (void) RegisterMagickInfo(entry);
 912   return(MagickImageCoderSignature);
 913 }
 914 \f
 915 /*
 916 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 917 %                                                                             %
 918 %                                                                             %
 919 %                                                                             %
 920 %   U n r e g i s t e r D I B I m a g e                                       %
 921 %                                                                             %
 922 %                                                                             %
 923 %                                                                             %
 924 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 925 %
 926 %  UnregisterDIBImage() removes format registrations made by the
 927 %  DIB module from the list of supported formats.
 928 %
 929 %  The format of the UnregisterDIBImage method is:
 930 %
 931 %      UnregisterDIBImage(void)
 932 %
 933 */
 934 ModuleExport void UnregisterDIBImage(void)
 935 {
 936   (void) UnregisterMagickInfo("DIB");
 937 }
 938 \f
 939 /*
 940 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 941 %                                                                             %
 942 %                                                                             %
 943 %                                                                             %
 944 %   W r i t e D I B I m a g e                                                 %
 945 %                                                                             %
 946 %                                                                             %
 947 %                                                                             %
 948 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 949 %
 950 %  WriteDIBImage() writes an image in Microsoft Windows bitmap encoded
 951 %  image format.
 952 %
 953 %  The format of the WriteDIBImage method is:
 954 %
 955 %      MagickBooleanType WriteDIBImage(const ImageInfo *image_info,
 956 %        Image *image,ExceptionInfo *exception)
 957 %
 958 %  A description of each parameter follows.
 959 %
 960 %    o image_info: the image info.
 961 %
 962 %    o image:  The image.
 963 %
 964 %    o exception: return any errors or warnings in this structure.
 965 %
 966 */
 967 static MagickBooleanType WriteDIBImage(const ImageInfo *image_info,Image *image,
 968   ExceptionInfo *exception)
 969 {
 970   DIBInfo
 971     dib_info;
 972
 973   MagickBooleanType
 974     status;
 975
 976   register const Quantum
 977     *p;
 978
 979   register ssize_t
 980     i,
 981     x;
 982
 983   register unsigned char
 984     *q;
 985
 986   size_t
 987     bytes_per_line;
 988
 989   ssize_t
 990     y;
 991
 992   unsigned char
 993     *dib_data,
 994     *pixels;
 995
 996   /*
 997     Open output image file.
 998   */
 999   assert(image_info != (const ImageInfo *) NULL);
1000   assert(image_info->signature == MagickSignature);
1001   assert(image != (Image *) NULL);
1002   assert(image->signature == MagickSignature);
1003   if (image->debug != MagickFalse)
1004     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1005   assert(exception != (ExceptionInfo *) NULL);
1006   assert(exception->signature == MagickSignature);
1007   status=OpenBlob(image_info,image,WriteBinaryBlobMode,exception);
1008   if (status == MagickFalse)
1009     return(status);
1010   /*
1011     Initialize DIB raster file header.
1012   */
1013   if (IssRGBColorspace(image->colorspace) == MagickFalse)
1014     (void) TransformImageColorspace(image,sRGBColorspace,exception);
1015   if (image->storage_class == DirectClass)
1016     {
1017       /*
1018         Full color DIB raster.
1019       */
1020       dib_info.number_colors=0;
1021       dib_info.bits_per_pixel=(unsigned short) (image->matte ? 32 : 24);
1022     }
1023   else
1024     {
1025       /*
1026         Colormapped DIB raster.
1027       */
1028       dib_info.bits_per_pixel=8;
1029       if (image_info->depth > 8)
1030         dib_info.bits_per_pixel=16;
1031       if (IsImageMonochrome(image,exception) != MagickFalse)
1032         dib_info.bits_per_pixel=1;
1033       dib_info.number_colors=(dib_info.bits_per_pixel == 16) ? 0 :
1034         (1UL << dib_info.bits_per_pixel);
1035     }
1036   bytes_per_line=4*((image->columns*dib_info.bits_per_pixel+31)/32);
1037   dib_info.size=40;
1038   dib_info.width=(ssize_t) image->columns;
1039   dib_info.height=(ssize_t) image->rows;
1040   dib_info.planes=1;
1041   dib_info.compression=(size_t) (dib_info.bits_per_pixel == 16 ?
1042     BI_BITFIELDS : BI_RGB);
1043   dib_info.image_size=bytes_per_line*image->rows;
1044   dib_info.x_pixels=75*39;
1045   dib_info.y_pixels=75*39;
1046   switch (image->units)
1047   {
1048     case UndefinedResolution:
1049     case PixelsPerInchResolution:
1050     {
1051       dib_info.x_pixels=(size_t) (100.0*image->resolution.x/2.54);
1052       dib_info.y_pixels=(size_t) (100.0*image->resolution.y/2.54);
1053       break;
1054     }
1055     case PixelsPerCentimeterResolution:
1056     {
1057       dib_info.x_pixels=(size_t) (100.0*image->resolution.x);
1058       dib_info.y_pixels=(size_t) (100.0*image->resolution.y);
1059       break;
1060     }
1061   }
1062   dib_info.colors_important=dib_info.number_colors;
1063   /*
1064     Convert MIFF to DIB raster pixels.
1065   */
1066   pixels=(unsigned char *) AcquireQuantumMemory(dib_info.image_size,
1067     sizeof(*pixels));
1068   if (pixels == (unsigned char *) NULL)
1069     ThrowWriterException(ResourceLimitError,"MemoryAllocationFailed");
1070   (void) ResetMagickMemory(pixels,0,dib_info.image_size);
1071   switch (dib_info.bits_per_pixel)
1072   {
1073     case 1:
1074     {
1075       register unsigned char
1076         bit,
1077         byte;
1078
1079       /*
1080         Convert PseudoClass image to a DIB monochrome image.
1081       */
1082       for (y=0; y < (ssize_t) image->rows; y++)
1083       {
1084         p=GetVirtualPixels(image,0,y,image->columns,1,exception);
1085         if (p == (const Quantum *) NULL)
1086           break;
1087         q=pixels+(image->rows-y-1)*bytes_per_line;
1088         bit=0;
1089         byte=0;
1090         for (x=0; x < (ssize_t) image->columns; x++)
1091         {
1092           byte<<=1;
1093           byte|=GetPixelIndex(image,p) != 0 ? 0x01 : 0x00;
1094           bit++;
1095           if (bit == 8)
1096             {
1097               *q++=byte;
1098               bit=0;
1099               byte=0;
1100             }
1101            p+=GetPixelChannels(image);
1102          }
1103          if (bit != 0)
1104            {
1105              *q++=(unsigned char) (byte << (8-bit));
1106              x++;
1107            }
1108         for (x=(ssize_t) (image->columns+7)/8; x < (ssize_t) bytes_per_line; x++)
1109           *q++=0x00;
1110         status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
1111           image->rows);
1112         if (status == MagickFalse)
1113           break;
1114       }
1115       break;
1116     }
1117     case 8:
1118     {
1119       /*
1120         Convert PseudoClass packet to DIB pixel.
1121       */
1122       for (y=0; y < (ssize_t) image->rows; y++)
1123       {
1124         p=GetVirtualPixels(image,0,y,image->columns,1,exception);
1125         if (p == (const Quantum *) NULL)
1126           break;
1127         q=pixels+(image->rows-y-1)*bytes_per_line;
1128         for (x=0; x < (ssize_t) image->columns; x++)
1129         {
1130           *q++=(unsigned char) GetPixelIndex(image,p);
1131           p+=GetPixelChannels(image);
1132         }
1133         for ( ; x < (ssize_t) bytes_per_line; x++)
1134           *q++=0x00;
1135         status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
1136           image->rows);
1137         if (status == MagickFalse)
1138           break;
1139       }
1140       break;
1141     }
1142     case 16:
1143     {
1144       unsigned short
1145         word;
1146       /*
1147         Convert PseudoClass packet to DIB pixel.
1148       */
1149       for (y=0; y < (ssize_t) image->rows; y++)
1150       {
1151         p=GetVirtualPixels(image,0,y,image->columns,1,exception);
1152         if (p == (const Quantum *) NULL)
1153           break;
1154         q=pixels+(image->rows-y-1)*bytes_per_line;
1155         for (x=0; x < (ssize_t) image->columns; x++)
1156         {
1157           word=(unsigned short) ((ScaleColor8to5((unsigned char)
1158             ScaleQuantumToChar(GetPixelRed(image,p))) << 11) | (ScaleColor8to6(
1159             (unsigned char) ScaleQuantumToChar(GetPixelGreen(image,p))) << 5) |
1160             (ScaleColor8to5((unsigned char) ScaleQuantumToChar((unsigned char)
1161             GetPixelBlue(image,p)) << 0)));
1162           *q++=(unsigned char)(word & 0xff);
1163           *q++=(unsigned char)(word >> 8);
1164           p+=GetPixelChannels(image);
1165         }
1166         for (x=(ssize_t) (2*image->columns); x < (ssize_t) bytes_per_line; x++)
1167           *q++=0x00;
1168         status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
1169           image->rows);
1170         if (status == MagickFalse)
1171           break;
1172       }
1173       break;
1174     }
1175     case 24:
1176     case 32:
1177     {
1178       /*
1179         Convert DirectClass packet to DIB RGB pixel.
1180       */
1181       for (y=0; y < (ssize_t) image->rows; y++)
1182       {
1183         p=GetVirtualPixels(image,0,y,image->columns,1,exception);
1184         if (p == (const Quantum *) NULL)
1185           break;
1186         q=pixels+(image->rows-y-1)*bytes_per_line;
1187         for (x=0; x < (ssize_t) image->columns; x++)
1188         {
1189           *q++=ScaleQuantumToChar(GetPixelBlue(image,p));
1190           *q++=ScaleQuantumToChar(GetPixelGreen(image,p));
1191           *q++=ScaleQuantumToChar(GetPixelRed(image,p));
1192           if (image->matte != MagickFalse)
1193             *q++=ScaleQuantumToChar(GetPixelAlpha(image,p));
1194           p+=GetPixelChannels(image);
1195         }
1196         if (dib_info.bits_per_pixel == 24)
1197           for (x=(ssize_t) (3*image->columns); x < (ssize_t) bytes_per_line; x++)
1198             *q++=0x00;
1199         status=SetImageProgress(image,SaveImageTag,(MagickOffsetType) y,
1200           image->rows);
1201         if (status == MagickFalse)
1202           break;
1203       }
1204       break;
1205     }
1206   }
1207   if (dib_info.bits_per_pixel == 8)
1208     if (image_info->compression != NoCompression)
1209       {
1210         size_t
1211           length;
1212
1213         /*
1214           Convert run-length encoded raster pixels.
1215         */
1216         length=2UL*(bytes_per_line+2UL)+2UL;
1217         dib_data=(unsigned char *) AcquireQuantumMemory(length,
1218           (image->rows+2UL)*sizeof(*dib_data));
1219         if (pixels == (unsigned char *) NULL)
1220           {
1221             pixels=(unsigned char *) RelinquishMagickMemory(pixels);
1222             ThrowWriterException(ResourceLimitError,"MemoryAllocationFailed");
1223           }
1224         dib_info.image_size=(size_t) EncodeImage(image,bytes_per_line,
1225           pixels,dib_data);
1226         pixels=(unsigned char *) RelinquishMagickMemory(pixels);
1227         pixels=dib_data;
1228         dib_info.compression = BI_RLE8;
1229       }
1230   /*
1231     Write DIB header.
1232   */
1233   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.size);
1234   (void) WriteBlobLSBLong(image,dib_info.width);
1235   (void) WriteBlobLSBLong(image,(unsigned short) dib_info.height);
1236   (void) WriteBlobLSBShort(image,(unsigned short) dib_info.planes);
1237   (void) WriteBlobLSBShort(image,dib_info.bits_per_pixel);
1238   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.compression);
1239   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.image_size);
1240   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.x_pixels);
1241   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.y_pixels);
1242   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.number_colors);
1243   (void) WriteBlobLSBLong(image,(unsigned int) dib_info.colors_important);
1244   if (image->storage_class == PseudoClass)
1245     {
1246       if (dib_info.bits_per_pixel <= 8)
1247         {
1248           unsigned char
1249             *dib_colormap;
1250
1251           /*
1252             Dump colormap to file.
1253           */
1254           dib_colormap=(unsigned char *) AcquireQuantumMemory((size_t)
1255             (1UL << dib_info.bits_per_pixel),4*sizeof(dib_colormap));
1256           if (dib_colormap == (unsigned char *) NULL)
1257             ThrowWriterException(ResourceLimitError,"MemoryAllocationFailed");
1258           q=dib_colormap;
1259           for (i=0; i < (ssize_t) MagickMin(image->colors,dib_info.number_colors); i++)
1260           {
1261             *q++=ScaleQuantumToChar(image->colormap[i].blue);
1262             *q++=ScaleQuantumToChar(image->colormap[i].green);
1263             *q++=ScaleQuantumToChar(image->colormap[i].red);
1264             *q++=(Quantum) 0x0;
1265           }
1266           for ( ; i < (ssize_t) (1L << dib_info.bits_per_pixel); i++)
1267           {
1268             *q++=(Quantum) 0x0;
1269             *q++=(Quantum) 0x0;
1270             *q++=(Quantum) 0x0;
1271             *q++=(Quantum) 0x0;
1272           }
1273           (void) WriteBlob(image,(size_t) (4*(1 << dib_info.bits_per_pixel)),
1274             dib_colormap);
1275           dib_colormap=(unsigned char *) RelinquishMagickMemory(dib_colormap);
1276         }
1277       else
1278         if ((dib_info.bits_per_pixel == 16) &&
1279             (dib_info.compression == BI_BITFIELDS))
1280           {
1281             (void) WriteBlobLSBLong(image,0xf800);
1282             (void) WriteBlobLSBLong(image,0x07e0);
1283             (void) WriteBlobLSBLong(image,0x001f);
1284           }
1285     }
1286   (void) WriteBlob(image,dib_info.image_size,pixels);
1287   pixels=(unsigned char *) RelinquishMagickMemory(pixels);
1288   (void) CloseBlob(image);
1289   return(MagickTrue);
1290 }