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