src/common/imagpcx.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        imagpcx.cpp
   3 // Purpose:     wxImage PCX handler
   4 // Author:      Guillermo Rodriguez Garcia <guille@iies.es>
   5 // Version:     1.00
   6 // CVS-ID:      $Id$
   7 // Copyright:   (c) 1999 Guillermo Rodriguez Garcia
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 #ifdef __GNUG__
  12 #pragma implementation "imagpcx.h"
  13 #endif
  14
  15 // For compilers that support precompilation, includes "wx.h".
  16 #include "wx/wxprec.h"
  17
  18 #ifdef __BORLANDC__
  19 #pragma hdrstop
  20 #endif
  21
  22 #ifndef WX_PRECOMP
  23 #  include "wx/defs.h"
  24 #endif
  25
  26 #if wxUSE_STREAMS && wxUSE_PCX
  27
  28 #include "wx/imagpcx.h"
  29 #include "wx/wfstream.h"
  30 #include "wx/module.h"
  31 #include "wx/log.h"
  32 #include "wx/intl.h"
  33
  34 #include "wx/hash.h"
  35 #include "wx/list.h"
  36 #include "wx/object.h"
  37
  38 //-----------------------------------------------------------------------------
  39 // RLE encoding and decoding
  40 //-----------------------------------------------------------------------------
  41
  42 void RLEencode(unsigned char *p, unsigned int size, wxOutputStream& s)
  43 {
  44     unsigned int data, last, cont;
  45
  46     // Write 'size' bytes. The PCX official specs say there will be
  47     // a decoding break at the end of each scanline, so in order to
  48     // force this decoding break use this function to write, at most,
  49     // _one_ complete scanline at a time.
  50
  51     last = (unsigned char) *(p++);
  52     cont = 1;
  53     size--;
  54
  55     while (size-- > 0)
  56     {
  57         data = (unsigned char) *(p++);
  58
  59         // Up to 63 bytes with the same value can be stored using a
  60         // single { cont, value } pair.
  61         //
  62         if ((data == last) && (cont < 63))
  63         {
  64             cont++;
  65         }
  66         else
  67         {
  68             // Need to write a 'counter' byte?
  69             //
  70             if ((cont > 1) || ((last & 0xC0) == 0xC0))
  71                 s.PutC((char) (cont | 0xC0));
  72
  73             s.PutC((char) last);
  74             last = data;
  75             cont = 1;
  76         }
  77     }
  78
  79     // Write the last one and return;
  80     //
  81     if ((cont > 1) || ((last & 0xC0) == 0xC0))
  82         s.PutC((char) (cont | 0xC0));
  83
  84     s.PutC((char) last);
  85 }
  86
  87 void RLEdecode(unsigned char *p, unsigned int size, wxInputStream& s)
  88 {
  89     unsigned int i, data, cont;
  90
  91     // Read 'size' bytes. The PCX official specs say there will be
  92     // a decoding break at the end of each scanline (but not at the
  93     // end of each plane inside a scanline). Only use this function
  94     // to read one or more _complete_ scanlines. Else, more than
  95     // 'size' bytes might be read and the buffer might overflow.
  96     //
  97     while (size > 0)
  98     {
  99         data = (unsigned char)s.GetC();
 100
 101         // If ((data & 0xC0) != 0xC0), then the value read is a data
 102         // byte. Else, it is a counter (cont = val & 0x3F) and the
 103         // next byte is the data byte.
 104         //
 105         if ((data & 0xC0) != 0xC0)
 106         {
 107             *(p++) = data;
 108             size--;
 109         }
 110         else
 111         {
 112             cont = data & 0x3F;
 113             data = (unsigned char)s.GetC();
 114             for (i = 1; i <= cont; i++)
 115                 *(p++) = data;
 116             size -= cont;
 117         }
 118     }
 119 }
 120
 121
 122 //-----------------------------------------------------------------------------
 123 // PCX reading and saving
 124 //-----------------------------------------------------------------------------
 125
 126 // PCX header
 127 #define HDR_MANUFACTURER    0
 128 #define HDR_VERSION         1
 129 #define HDR_ENCODING        2
 130 #define HDR_BITSPERPIXEL    3
 131 #define HDR_XMIN            4
 132 #define HDR_YMIN            6
 133 #define HDR_XMAX            8
 134 #define HDR_YMAX            10
 135 #define HDR_NPLANES         65
 136 #define HDR_BYTESPERLINE    66
 137 #define HDR_PALETTEINFO     68
 138
 139 // image formats
 140 enum {
 141     wxPCX_8BIT,             // 8 bpp, 1 plane (8 bit)
 142     wxPCX_24BIT             // 8 bpp, 3 planes (24 bit)
 143 };
 144
 145 // error codes
 146 enum {
 147     wxPCX_OK = 0,           // everything was OK
 148     wxPCX_INVFORMAT = 1,    // error in pcx file format
 149     wxPCX_MEMERR = 2,       // error allocating memory
 150     wxPCX_VERERR = 3        // error in pcx version number
 151 };
 152
 153
 154 // ReadPCX:
 155 //  Loads a PCX file into the wxImage object pointed by image.
 156 //  Returns wxPCX_OK on success, or an error code otherwise
 157 //  (see above for error codes)
 158 //
 159 int ReadPCX(wxImage *image, wxInputStream& stream)
 160 {
 161     unsigned char hdr[128];         // PCX header
 162     unsigned char pal[768];         // palette for 8 bit images
 163     unsigned char *p;               // space to store one scanline
 164     unsigned char *dst;             // pointer into wxImage data
 165     unsigned int width, height;     // size of the image
 166     unsigned int bytesperline;      // bytes per line (each plane)
 167     int bitsperpixel;               // bits per pixel (each plane)
 168     int nplanes;                    // number of planes
 169     int encoding;                   // is the image RLE encoded?
 170     int format;                     // image format (8 bit, 24 bit)
 171     unsigned int i;
 172     off_t pos;
 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 a
 203     // palette at the end of the file. Read it now before
 204     // proceeding.
 205     //
 206     if (format == wxPCX_8BIT)
 207     {
 208         pos = stream.TellI();
 209         stream.SeekI(-769, wxFromEnd);
 210
 211         if (stream.GetC() != 12)
 212             return wxPCX_INVFORMAT;
 213
 214         stream.Read(pal, 768);
 215         stream.SeekI(pos, wxFromStart);
 216     }
 217
 218     // Allocate memory for a scanline and resize the image.
 219     //
 220     image->Create(width, height);
 221
 222     if (!image->Ok())
 223         return wxPCX_MEMERR;
 224
 225     if ((p = (unsigned char *) malloc(bytesperline * nplanes)) == NULL)
 226         return wxPCX_MEMERR;
 227
 228     // Now start reading the file, line by line, and store
 229     // the data in the format required by wxImage.
 230     //
 231     dst = image->GetData();
 232
 233     for (; height; height--)
 234     {
 235         if (encoding)
 236             RLEdecode(p, bytesperline * nplanes, stream);
 237         else
 238             stream.Read(p, bytesperline * nplanes);
 239
 240         switch (format)
 241         {
 242             case wxPCX_8BIT:
 243             {
 244                 for (i = 0; i < width; i++)
 245                 {
 246                     *(dst++) = pal[ 3 * (p[i]) ];
 247                     *(dst++) = pal[ 3 * (p[i]) + 1];
 248                     *(dst++) = pal[ 3 * (p[i]) + 2];
 249                 }
 250                 break;
 251             }
 252             case wxPCX_24BIT:
 253             {
 254                 for (i = 0; i < width; i++)
 255                 {
 256                     *(dst++) = p[i];
 257                     *(dst++) = p[i + bytesperline];
 258                     *(dst++) = p[i + 2 * bytesperline];
 259                 }
 260                 break;
 261             }
 262         }
 263     }
 264
 265     free(p);
 266
 267     return wxPCX_OK;
 268 }
 269
 270 // SavePCX:
 271 //  Saves a PCX file into the wxImage object pointed by image.
 272 //  Returns wxPCX_OK on success, or an error code otherwise
 273 //  (see above for error codes). Currently, always saves images
 274 //  in 24 bit format. XXX
 275 //
 276 int SavePCX(wxImage *image, wxOutputStream& stream)
 277 {
 278     unsigned char hdr[128];         // PCX header
 279     unsigned char pal[768];         // palette for 8 bit images
 280     unsigned char *p;               // space to store one scanline
 281     unsigned char *src;             // pointer into wxImage data
 282     unsigned int width, height;     // size of the image
 283     unsigned int bytesperline;      // bytes per line (each plane)
 284     int nplanes = 3;                // number of planes
 285     int format = wxPCX_24BIT;       // image format (8 bit, 24 bit)
 286     wxHashTable h(wxKEY_INTEGER);   // image histogram
 287     unsigned long key;              // key in the hashtable
 288     unsigned int i;
 289
 290     // See if we can save as 8 bit.
 291     //
 292     if (image->CountColours(256) <= 256)
 293     {
 294         image->ComputeHistogram(h);
 295         format = wxPCX_8BIT;
 296         nplanes = 1;
 297     }
 298
 299     // Get image dimensions, calculate bytesperline (must be even,
 300     // according to PCX specs) and allocate space for one complete
 301     // scanline.
 302     //
 303     if (!image->Ok())
 304         return wxPCX_INVFORMAT;
 305
 306     width = image->GetWidth();
 307     height = image->GetHeight();
 308     bytesperline = width;
 309     if (bytesperline % 2)
 310         bytesperline++;
 311
 312     if ((p = (unsigned char *) malloc(bytesperline * nplanes)) == NULL)
 313         return wxPCX_MEMERR;
 314
 315     // Build header data and write it to the stream. Initially,
 316     // set all bytes to zero (most values default to zero).
 317     //
 318     memset(hdr, 0, sizeof(hdr));
 319
 320     hdr[HDR_MANUFACTURER]     = 10;
 321     hdr[HDR_VERSION]          = 5;
 322     hdr[HDR_ENCODING]         = 1;
 323     hdr[HDR_NPLANES]          = nplanes;
 324     hdr[HDR_BITSPERPIXEL]     = 8;
 325     hdr[HDR_BYTESPERLINE]     = bytesperline % 256;
 326     hdr[HDR_BYTESPERLINE + 1] = bytesperline / 256;
 327     hdr[HDR_XMAX]             = (width - 1)  % 256;
 328     hdr[HDR_XMAX + 1]         = (width - 1)  / 256;
 329     hdr[HDR_YMAX]             = (height - 1) % 256;
 330     hdr[HDR_YMAX + 1]         = (height - 1) / 256;
 331     hdr[HDR_PALETTEINFO]      = 1;
 332
 333     stream.Write(hdr, 128);
 334
 335     // Encode image data line by line and write it to the stream
 336     //
 337     src = image->GetData();
 338
 339     for (; height; height--)
 340     {
 341         switch (format)
 342         {
 343             case wxPCX_8BIT:
 344             {
 345                 unsigned char r, g, b;
 346                 wxHNode *hnode;
 347
 348                 for (i = 0; i < width; i++)
 349                 {
 350                     r = *(src++);
 351                     g = *(src++);
 352                     b = *(src++);
 353                     key = (r << 16) | (g << 8) | b;
 354
 355                     hnode = (wxHNode *) h.Get(key);
 356                     p[i] = hnode->index;
 357                 }
 358                 break;
 359             }
 360             case wxPCX_24BIT:
 361             {
 362                 for (i = 0; i < width; i++)
 363                 {
 364                     p[i] = *(src++);
 365                     p[i + bytesperline] = *(src++);
 366                     p[i + 2 * bytesperline] = *(src++);
 367                 }
 368                 break;
 369             }
 370         }
 371
 372         RLEencode(p, bytesperline * nplanes, stream);
 373     }
 374
 375     free(p);
 376
 377     // For 8 bit images, build the palette and write it to the stream
 378     //
 379     if (format == wxPCX_8BIT)
 380     {
 381         wxNode *node;
 382         wxHNode *hnode;
 383
 384         // zero unused colours
 385         memset(pal, 0, sizeof(pal));
 386
 387         h.BeginFind();
 388         while ((node = h.Next()) != NULL)
 389         {
 390             key = node->GetKeyInteger();
 391             hnode = (wxHNode *) node->GetData();
 392
 393             pal[3 * hnode->index]     = (unsigned char)(key >> 16);
 394             pal[3 * hnode->index + 1] = (unsigned char)(key >> 8);
 395             pal[3 * hnode->index + 2] = (unsigned char)(key);
 396             delete hnode;
 397         }
 398
 399         stream.PutC(12);
 400         stream.Write(pal, 768);
 401     }
 402
 403     return wxPCX_OK;
 404 }
 405
 406 //-----------------------------------------------------------------------------
 407 // wxPCXHandler
 408 //-----------------------------------------------------------------------------
 409
 410 IMPLEMENT_DYNAMIC_CLASS(wxPCXHandler,wxImageHandler)
 411
 412 bool wxPCXHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
 413 {
 414     int error;
 415
 416     if (!CanRead(stream))
 417     {
 418         if (verbose)
 419             wxLogError(_("PCX: this is not a PCX file."));
 420
 421         return FALSE;
 422     }
 423
 424     image->Destroy();
 425
 426     if ((error = ReadPCX(image, stream)) != wxPCX_OK)
 427     {
 428         if (verbose)
 429         {
 430             switch (error)
 431             {
 432                 case wxPCX_INVFORMAT: wxLogError(_("wxPCXHandler: image format unsupported")); break;
 433                 case wxPCX_MEMERR:    wxLogError(_("wxPCXHandler: couldn't allocate memory")); break;
 434                 case wxPCX_VERERR:    wxLogError(_("wxPCXHandler: version number too low")); break;
 435                 default:              wxLogError(_("wxPCXHandler: unknown error !!!"));
 436             }
 437         }
 438         image->Destroy();
 439         return FALSE;
 440     }
 441
 442     return TRUE;
 443 }
 444
 445 bool wxPCXHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
 446 {
 447     int error;
 448
 449     if ((error = SavePCX(image, stream)) != wxPCX_OK)
 450     {
 451         if (verbose)
 452         {
 453             switch (error)
 454             {
 455                 case wxPCX_INVFORMAT: wxLogError(_("wxPCXHandler: invalid image")); break;
 456                 case wxPCX_MEMERR:    wxLogError(_("wxPCXHandler: couldn't allocate memory")); break;
 457                 default:              wxLogError(_("wxPCXHandler: unknown error !!!"));
 458             }
 459         }
 460     }
 461
 462     return (error == wxPCX_OK);
 463 }
 464
 465 bool wxPCXHandler::DoCanRead( wxInputStream& stream )
 466 {
 467     unsigned char c;
 468
 469     c = stream.GetC();
 470     stream.SeekI(-1, wxFromCurrent);
 471
 472     // not very safe, but this is all we can get from PCX header :-(
 473     return (c == 10);
 474 }
 475
 476 #endif // wxUSE_STREAMS && wxUSE_PCX
 477