src/common/imagpcx.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/imagpcx.cpp
   3 // Purpose:     wxImage PCX handler
   4 // Author:      Guillermo Rodriguez Garcia <guille@iies.es>
   5 // Version:     1.1
   6 // CVS-ID:      $Id$
   7 // Copyright:   (c) 1999 Guillermo Rodriguez Garcia
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // For compilers that support precompilation, includes "wx.h".
  12 #include "wx/wxprec.h"
  13
  14 #ifdef __BORLANDC__
  15     #pragma hdrstop
  16 #endif
  17
  18 #if wxUSE_IMAGE && wxUSE_PCX
  19
  20 #ifndef WX_PRECOMP
  21     #include "wx/object.h"
  22     #include "wx/log.h"
  23     #include "wx/intl.h"
  24     #include "wx/palette.h"
  25 #endif
  26
  27 #include "wx/imagpcx.h"
  28 #include "wx/wfstream.h"
  29 #include "wx/module.h"
  30
  31 #include "wx/hash.h"
  32 #include "wx/list.h"
  33
  34 //-----------------------------------------------------------------------------
  35 // wxPCXHandler
  36 //-----------------------------------------------------------------------------
  37
  38 IMPLEMENT_DYNAMIC_CLASS(wxPCXHandler,wxImageHandler)
  39
  40 #if wxUSE_STREAMS
  41
  42 //-----------------------------------------------------------------------------
  43 // RLE encoding and decoding
  44 //-----------------------------------------------------------------------------
  45
  46 void RLEencode(unsigned char *p, unsigned int size, wxOutputStream& s)
  47 {
  48     unsigned int data, last, cont;
  49
  50     // Write 'size' bytes. The PCX official specs say there will be
  51     // a decoding break at the end of each scanline, so in order to
  52     // force this decoding break use this function to write, at most,
  53     // _one_ complete scanline at a time.
  54
  55     last = (unsigned char) *(p++);
  56     cont = 1;
  57     size--;
  58
  59     while (size-- > 0)
  60     {
  61         data = (unsigned char) *(p++);
  62
  63         // Up to 63 bytes with the same value can be stored using
  64         // a single { cont, value } pair.
  65         //
  66         if ((data == last) && (cont < 63))
  67         {
  68             cont++;
  69         }
  70         else
  71         {
  72             // need to write a 'counter' byte?
  73             if ((cont > 1) || ((last & 0xC0) == 0xC0))
  74                 s.PutC((char) (cont | 0xC0));
  75
  76             s.PutC((char) last);
  77             last = data;
  78             cont = 1;
  79         }
  80     }
  81
  82     // write the last one and return;
  83     if ((cont > 1) || ((last & 0xC0) == 0xC0))
  84         s.PutC((char) (cont | 0xC0));
  85
  86     s.PutC((char) last);
  87 }
  88
  89 void RLEdecode(unsigned char *p, unsigned int size, wxInputStream& s)
  90 {
  91     unsigned int i, data, cont;
  92
  93     // Read 'size' bytes. The PCX official specs say there will be
  94     // a decoding break at the end of each scanline (but not at the
  95     // end of each plane inside a scanline). Only use this function
  96     // to read one or more _complete_ scanlines. Else, more than
  97     // 'size' bytes might be read and the buffer might overflow.
  98
  99     while (size > 0)
 100     {
 101         data = (unsigned char)s.GetC();
 102
 103         // If ((data & 0xC0) != 0xC0), then the value read is a data
 104         // byte. Else, it is a counter (cont = val & 0x3F) and the
 105         // next byte is the data byte.
 106
 107         if ((data & 0xC0) != 0xC0)
 108         {
 109             *(p++) = (unsigned char)data;
 110             size--;
 111         }
 112         else
 113         {
 114             cont = data & 0x3F;
 115             data = (unsigned char)s.GetC();
 116             for (i = 1; i <= cont; i++)
 117                 *(p++) = (unsigned char)data;
 118             size -= cont;
 119         }
 120     }
 121 }
 122
 123
 124 //-----------------------------------------------------------------------------
 125 // PCX reading and saving
 126 //-----------------------------------------------------------------------------
 127
 128 // PCX header
 129 #define HDR_MANUFACTURER    0
 130 #define HDR_VERSION         1
 131 #define HDR_ENCODING        2
 132 #define HDR_BITSPERPIXEL    3
 133 #define HDR_XMIN            4
 134 #define HDR_YMIN            6
 135 #define HDR_XMAX            8
 136 #define HDR_YMAX            10
 137 #define HDR_NPLANES         65
 138 #define HDR_BYTESPERLINE    66
 139 #define HDR_PALETTEINFO     68
 140
 141 // image formats
 142 enum {
 143     wxPCX_8BIT,             // 8 bpp, 1 plane (8 bit)
 144     wxPCX_24BIT             // 8 bpp, 3 planes (24 bit)
 145 };
 146
 147 // error codes
 148 enum {
 149     wxPCX_OK = 0,           // everything was OK
 150     wxPCX_INVFORMAT = 1,    // error in pcx file format
 151     wxPCX_MEMERR = 2,       // error allocating memory
 152     wxPCX_VERERR = 3        // error in pcx version number
 153 };
 154
 155
 156 // ReadPCX:
 157 //  Loads a PCX file into the wxImage object pointed by image.
 158 //  Returns wxPCX_OK on success, or an error code otherwise
 159 //  (see above for error codes)
 160 //
 161 int ReadPCX(wxImage *image, wxInputStream& stream)
 162 {
 163     unsigned char hdr[128];         // PCX header
 164     unsigned char pal[768];         // palette for 8 bit images
 165     unsigned char *p;               // space to store one scanline
 166     unsigned char *dst;             // pointer into wxImage data
 167     unsigned int width, height;     // size of the image
 168     unsigned int bytesperline;      // bytes per line (each plane)
 169     int bitsperpixel;               // bits per pixel (each plane)
 170     int nplanes;                    // number of planes
 171     int encoding;                   // is the image RLE encoded?
 172     int format;                     // image format (8 bit, 24 bit)
 173     unsigned int i, j;
 174
 175     // Read PCX header and check the version number (it must
 176     // be at least 5 or higher for 8 bit and 24 bit images).
 177
 178     stream.Read(hdr, 128);
 179
 180     if (hdr[HDR_VERSION] < 5) return wxPCX_VERERR;
 181
 182     // Extract all image info from the PCX header.
 183
 184     encoding     = hdr[HDR_ENCODING];
 185     nplanes      = hdr[HDR_NPLANES];
 186     bitsperpixel = hdr[HDR_BITSPERPIXEL];
 187     bytesperline = hdr[HDR_BYTESPERLINE] + 256 * hdr[HDR_BYTESPERLINE + 1];
 188     width        = (hdr[HDR_XMAX] + 256 * hdr[HDR_XMAX + 1]) -
 189                    (hdr[HDR_XMIN] + 256 * hdr[HDR_XMIN + 1]) + 1;
 190     height       = (hdr[HDR_YMAX] + 256 * hdr[HDR_YMAX + 1]) -
 191                    (hdr[HDR_YMIN] + 256 * hdr[HDR_YMIN + 1]) + 1;
 192
 193     // Check image format. Currently supported formats are
 194     // 8 bits (8 bpp, 1 plane) and 24 bits (8 bpp, 3 planes).
 195
 196     if ((nplanes == 3) && (bitsperpixel == 8))
 197         format = wxPCX_24BIT;
 198     else if ((nplanes == 1) && (bitsperpixel == 8))
 199         format = wxPCX_8BIT;
 200     else
 201         return wxPCX_INVFORMAT;
 202
 203     // If the image is of type wxPCX_8BIT, then there is
 204     // a palette at the end of the image data. If we were
 205     // working with a file, we could seek at the end to the
 206     // end (SeekI(-769, wxFromEnd) and read the palette
 207     // before proceeding. Unfortunately, this would prevent
 208     // loading several PCXs in a single stream, so we can't
 209     // do it. Thus, 8-bit images will have to be decoded in
 210     // two passes: one to read and decode the image data,
 211     // and another to replace 'colour indexes' with RGB
 212     // values.
 213
 214     // Resize the image and allocate memory for a scanline.
 215
 216     image->Create(width, height);
 217
 218     if (!image->Ok())
 219         return wxPCX_MEMERR;
 220
 221     if ((p = (unsigned char *) malloc(bytesperline * nplanes)) == NULL)
 222         return wxPCX_MEMERR;
 223
 224     // Now start reading the file, line by line, and store
 225     // the data in the format required by wxImage.
 226
 227     dst = image->GetData();
 228
 229     for (j = height; j; j--)
 230     {
 231         if (encoding)
 232             RLEdecode(p, bytesperline * nplanes, stream);
 233         else
 234             stream.Read(p, bytesperline * nplanes);
 235
 236         switch (format)
 237         {
 238             case wxPCX_8BIT:
 239             {
 240                 for (i = 0; i < width; i++)
 241                 {
 242                     // first pass, just store the colour index
 243                     *dst = p[i];
 244                     dst += 3;
 245                 }
 246                 break;
 247             }
 248             case wxPCX_24BIT:
 249             {
 250                 for (i = 0; i < width; i++)
 251                 {
 252                     *(dst++) = p[i];
 253                     *(dst++) = p[i + bytesperline];
 254                     *(dst++) = p[i + 2 * bytesperline];
 255                 }
 256                 break;
 257             }
 258         }
 259     }
 260
 261     free(p);
 262
 263     // For 8 bit images, we read the palette, and then do a second
 264     // pass replacing indexes with their RGB values;
 265
 266     if (format == wxPCX_8BIT)
 267     {
 268         unsigned char index;
 269
 270         if (stream.GetC() != 12)
 271             return wxPCX_INVFORMAT;
 272
 273         stream.Read(pal, 768);
 274
 275         p = image->GetData();
 276         for (unsigned long k = height * width; k; k--)
 277         {
 278             index = *p;
 279             *(p++) = pal[3 * index];
 280             *(p++) = pal[3 * index + 1];
 281             *(p++) = pal[3 * index + 2];
 282         }
 283
 284 #if wxUSE_PALETTE
 285         unsigned char r[256];
 286         unsigned char g[256];
 287         unsigned char b[256];
 288         for (i = 0; i < 256; i++)
 289         {
 290             r[i] = pal[3*i + 0];
 291             g[i] = pal[3*i + 1];
 292             b[i] = pal[3*i + 2];
 293         }
 294         image->SetPalette(wxPalette(256, r, g, b));
 295 #endif // wxUSE_PALETTE
 296     }
 297
 298     return wxPCX_OK;
 299 }
 300
 301 // SavePCX:
 302 //  Saves a PCX file into the wxImage object pointed by image.
 303 //  Returns wxPCX_OK on success, or an error code otherwise
 304 //  (see above for error codes). Will try to save as 8-bit
 305 //  PCX if possible, and then fall back to 24-bit if there
 306 //  are more than 256 different colours.
 307 //
 308 int SavePCX(wxImage *image, wxOutputStream& stream)
 309 {
 310     unsigned char hdr[128];         // PCX header
 311     unsigned char pal[768];         // palette for 8 bit images
 312     unsigned char *p;               // space to store one scanline
 313     unsigned char *src;             // pointer into wxImage data
 314     unsigned int width, height;     // size of the image
 315     unsigned int bytesperline;      // bytes per line (each plane)
 316     unsigned char nplanes = 3;      // number of planes
 317     int format = wxPCX_24BIT;       // image format (8 bit, 24 bit)
 318     wxImageHistogram histogram;     // image histogram
 319     unsigned long key;              // key in the hashtable
 320     unsigned int i;
 321
 322     // See if we can save as 8 bit.
 323
 324     if (image->CountColours(256) <= 256)
 325     {
 326         image->ComputeHistogram(histogram);
 327         format = wxPCX_8BIT;
 328         nplanes = 1;
 329     }
 330
 331     // Get image dimensions, calculate bytesperline (must be even,
 332     // according to PCX specs) and allocate space for one complete
 333     // scanline.
 334
 335     if (!image->Ok())
 336         return wxPCX_INVFORMAT;
 337
 338     width = image->GetWidth();
 339     height = image->GetHeight();
 340     bytesperline = width;
 341     if (bytesperline % 2)
 342         bytesperline++;
 343
 344     if ((p = (unsigned char *) malloc(bytesperline * nplanes)) == NULL)
 345         return wxPCX_MEMERR;
 346
 347     // Build header data and write it to the stream. Initially,
 348     // set all bytes to zero (most values default to zero).
 349
 350     memset(hdr, 0, sizeof(hdr));
 351
 352     hdr[HDR_MANUFACTURER]     = 10;
 353     hdr[HDR_VERSION]          = 5;
 354     hdr[HDR_ENCODING]         = 1;
 355     hdr[HDR_NPLANES]          = nplanes;
 356     hdr[HDR_BITSPERPIXEL]     = 8;
 357     hdr[HDR_BYTESPERLINE]     = (unsigned char)(bytesperline % 256);
 358     hdr[HDR_BYTESPERLINE + 1] = (unsigned char)(bytesperline / 256);
 359     hdr[HDR_XMAX]             = (unsigned char)((width - 1)  % 256);
 360     hdr[HDR_XMAX + 1]         = (unsigned char)((width - 1)  / 256);
 361     hdr[HDR_YMAX]             = (unsigned char)((height - 1) % 256);
 362     hdr[HDR_YMAX + 1]         = (unsigned char)((height - 1) / 256);
 363     hdr[HDR_PALETTEINFO]      = 1;
 364
 365     stream.Write(hdr, 128);
 366
 367     // Encode image data line by line and write it to the stream
 368
 369     src = image->GetData();
 370
 371     for (; height; height--)
 372     {
 373         switch (format)
 374         {
 375             case wxPCX_8BIT:
 376             {
 377                 unsigned char r, g, b;
 378
 379                 for (i = 0; i < width; i++)
 380                 {
 381                     r = *(src++);
 382                     g = *(src++);
 383                     b = *(src++);
 384                     key = (r << 16) | (g << 8) | b;
 385
 386                     p[i] = (unsigned char)histogram[key].index;
 387                 }
 388                 break;
 389             }
 390             case wxPCX_24BIT:
 391             {
 392                 for (i = 0; i < width; i++)
 393                 {
 394                     p[i] = *(src++);
 395                     p[i + bytesperline] = *(src++);
 396                     p[i + 2 * bytesperline] = *(src++);
 397                 }
 398                 break;
 399             }
 400         }
 401
 402         RLEencode(p, bytesperline * nplanes, stream);
 403     }
 404
 405     free(p);
 406
 407     // For 8 bit images, build the palette and write it to the stream:
 408     if (format == wxPCX_8BIT)
 409     {
 410         // zero unused colours
 411         memset(pal, 0, sizeof(pal));
 412
 413         unsigned long index;
 414
 415         for (wxImageHistogram::iterator entry = histogram.begin();
 416              entry != histogram.end(); ++entry )
 417         {
 418             key = entry->first;
 419             index = entry->second.index;
 420             pal[3 * index]     = (unsigned char)(key >> 16);
 421             pal[3 * index + 1] = (unsigned char)(key >> 8);
 422             pal[3 * index + 2] = (unsigned char)(key);
 423         }
 424
 425         stream.PutC(12);
 426         stream.Write(pal, 768);
 427     }
 428
 429     return wxPCX_OK;
 430 }
 431
 432 //-----------------------------------------------------------------------------
 433 // wxPCXHandler
 434 //-----------------------------------------------------------------------------
 435
 436 bool wxPCXHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
 437 {
 438     int error;
 439
 440     if (!CanRead(stream))
 441     {
 442         if (verbose)
 443             wxLogError(_("PCX: this is not a PCX file."));
 444
 445         return false;
 446     }
 447
 448     image->Destroy();
 449
 450     if ((error = ReadPCX(image, stream)) != wxPCX_OK)
 451     {
 452         if (verbose)
 453         {
 454             switch (error)
 455             {
 456                 case wxPCX_INVFORMAT: wxLogError(_("PCX: image format unsupported")); break;
 457                 case wxPCX_MEMERR:    wxLogError(_("PCX: couldn't allocate memory")); break;
 458                 case wxPCX_VERERR:    wxLogError(_("PCX: version number too low")); break;
 459                 default:              wxLogError(_("PCX: unknown error !!!"));
 460             }
 461         }
 462         image->Destroy();
 463         return false;
 464     }
 465
 466     return true;
 467 }
 468
 469 bool wxPCXHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
 470 {
 471     int error;
 472
 473     if ((error = SavePCX(image, stream)) != wxPCX_OK)
 474     {
 475         if (verbose)
 476         {
 477             switch (error)
 478             {
 479                 case wxPCX_INVFORMAT: wxLogError(_("PCX: invalid image")); break;
 480                 case wxPCX_MEMERR:    wxLogError(_("PCX: couldn't allocate memory")); break;
 481                 default:              wxLogError(_("PCX: unknown error !!!"));
 482             }
 483         }
 484     }
 485
 486     return (error == wxPCX_OK);
 487 }
 488
 489 bool wxPCXHandler::DoCanRead( wxInputStream& stream )
 490 {
 491     unsigned char c = stream.GetC();
 492     if ( !stream )
 493         return false;
 494
 495     // not very safe, but this is all we can get from PCX header :-(
 496     return c == 10;
 497 }
 498
 499 #endif // wxUSE_STREAMS
 500
 501 #endif // wxUSE_IMAGE && wxUSE_PCX