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 /*
  12    We don't put pragma implement in this file because it is already present in
  13    src/common/image.cpp
  14 */
  15
  16 // For compilers that support precompilation, includes "wx.h".
  17 #include "wx/wxprec.h"
  18
  19 #ifdef __BORLANDC__
  20 #pragma hdrstop
  21 #endif
  22
  23 #ifndef WX_PRECOMP
  24 #  include "wx/defs.h"
  25 #endif
  26
  27 #if wxUSE_STREAMS && wxUSE_PCX
  28
  29 #include "wx/image.h"
  30 #include "wx/wfstream.h"
  31 #include "wx/module.h"
  32 #include "wx/log.h"
  33
  34
  35 //-----------------------------------------------------------------------------
  36 // PCX decoding
  37 //-----------------------------------------------------------------------------
  38
  39 void RLEencode(unsigned char *WXUNUSED(p), unsigned int WXUNUSED(size), wxOutputStream& WXUNUSED(s))
  40 {
  41 }
  42
  43 void RLEdecode(unsigned char *p, unsigned int size, wxInputStream& s)
  44 {
  45     unsigned int i, data, cont;
  46
  47     // Read 'size' bytes. The PCX official specs say there will be
  48     // a decoding break at the end of each scanline (but not at the
  49     // end of each plane inside a scanline). Only use this function
  50     // to read one or more _complete_ scanlines. Else, more than
  51     // 'size' bytes might be read and the buffer might overflow.
  52     //
  53     while (size > 0)
  54     {
  55         data = (unsigned char)s.GetC();
  56
  57         // If ((data & 0xC0) != 0xC0), then the value read is a data
  58         // byte. Else, it is a counter (cont = val & 0x3F) and the
  59         // next byte is the data byte.
  60         //
  61         if ((data & 0xC0) != 0xC0)
  62         {
  63             *(p++) = data;
  64             size--;
  65         }
  66         else
  67         {
  68             cont = data & 0x3F;
  69             data = (unsigned char)s.GetC();
  70             for (i = 1; i <= cont; i++)
  71                 *(p++) = data;
  72             size -= cont;
  73         }
  74     }
  75 }
  76
  77
  78 /* PCX header */
  79 #define HDR_VERSION         1
  80 #define HDR_ENCODING        2
  81 #define HDR_BITSPERPIXEL    3
  82 #define HDR_XMIN            4
  83 #define HDR_YMIN            6
  84 #define HDR_XMAX            8
  85 #define HDR_YMAX            10
  86 #define HDR_NPLANES         65
  87 #define HDR_BYTESPERLINE    66
  88
  89 /* image formats */
  90 #define IMAGE_8BIT  0       // 8 bpp, 1 plane (8 bit)
  91 #define IMAGE_24BIT 1       // 8 bpp, 3 planes (24 bit)
  92
  93 /* error codes */
  94 #define E_OK        0       // everything was OK
  95 #define E_FORMATO   1       // error in pcx file format
  96 #define E_MEMORIA   2       // error allocating memory
  97 #define E_VERSION   3       // error in pcx version number
  98
  99
 100 // ReadPCX:
 101 //  Loads a PCX file into the wxImage object pointed by image.
 102 //  Returns E_OK on success, or an error code otherwise (see
 103 //  above for error codes)
 104 //
 105 int ReadPCX(wxImage *image, wxInputStream& stream)
 106 {
 107     unsigned char hdr[128];         // PCX header
 108     unsigned char pal[768];         // palette for 8 bit images
 109     unsigned char *p;               // space to store one scanline
 110     unsigned char *dst;             // pointer into wxImage data
 111     unsigned int width, height;     // size of the image
 112     unsigned int bytesperline;      // bytes per line (each plane)
 113     int bitsperpixel;               // bits per pixel (each plane)
 114     int nplanes;                    // number of planes
 115     int encoding;                   // is the image RLE encoded?
 116     int format;                     // image format (8 bit, 24 bit)
 117     unsigned int i;
 118     off_t pos;
 119
 120     // Read PCX header and check the version number (it must
 121     // be at least 5 or higher for 8 bit and 24 bit images).
 122     //
 123     stream.Read(hdr, 128);
 124
 125     if (hdr[HDR_VERSION] < 5) return E_VERSION;
 126
 127     // Extract all image info from the PCX header.
 128     //
 129     encoding     = hdr[HDR_ENCODING];
 130     nplanes      = hdr[HDR_NPLANES];
 131     bitsperpixel = hdr[HDR_BITSPERPIXEL];
 132     bytesperline = hdr[HDR_BYTESPERLINE] + 256 * hdr[HDR_BYTESPERLINE + 1];
 133     width        = (hdr[HDR_XMAX] + 256 * hdr[HDR_XMAX + 1]) -
 134                    (hdr[HDR_XMIN] + 256 * hdr[HDR_XMIN + 1]) + 1;
 135     height       = (hdr[HDR_YMAX] + 256 * hdr[HDR_YMAX + 1]) -
 136                    (hdr[HDR_YMIN] + 256 * hdr[HDR_YMIN + 1]) + 1;
 137
 138     // Check image format. Currently supported formats are
 139     // 8 bits (8 bpp, 1 plane) and 24 bits (8 bpp, 3 planes).
 140     //
 141     if ((nplanes == 3) && (bitsperpixel == 8))
 142         format = IMAGE_24BIT;
 143     else if ((nplanes == 1) && (bitsperpixel == 8))
 144         format = IMAGE_8BIT;
 145     else
 146         return E_FORMATO;
 147
 148     // If the image is of type IMAGE_8BIT, then there is a
 149     // palette at the end of the file. Read it now before
 150     // proceeding.
 151     //
 152     if (format == IMAGE_8BIT)
 153     {
 154         pos = stream.TellI();
 155         stream.SeekI(-769, wxFromEnd);
 156
 157         if (stream.GetC() != 12)
 158             return E_FORMATO;
 159
 160         stream.Read(pal, 768);
 161         stream.SeekI(pos, wxFromStart);
 162     }
 163
 164     // Allocate memory for a scanline and resize the image.
 165     //
 166     image->Create(width, height);
 167
 168     if (!image->Ok())
 169         return E_MEMORIA;
 170
 171     if ((p = (unsigned char *) malloc(bytesperline * nplanes)) == NULL)
 172         return E_MEMORIA;
 173
 174     // Now start reading the file, line by line, and store
 175     // the data in the format required by wxImage.
 176     //
 177     dst = image->GetData();
 178
 179     for (; height; height--)
 180     {
 181         if (encoding)
 182             RLEdecode(p, bytesperline * nplanes, stream);
 183         else
 184             stream.Read(p, bytesperline * nplanes);
 185
 186         switch (format)
 187         {
 188             case IMAGE_8BIT:
 189             {
 190                 for (i = 0; i < width; i++)
 191                 {
 192                     *(dst++) = pal[ 3 * (p[i]) ];
 193                     *(dst++) = pal[ 3 * (p[i]) + 1];
 194                     *(dst++) = pal[ 3 * (p[i]) + 2];
 195                 }
 196                 break;
 197             }
 198             case IMAGE_24BIT:
 199             {
 200                 for (i = 0; i < width; i++)
 201                 {
 202                     *(dst++) = p[i];
 203                     *(dst++) = p[i + bytesperline];
 204                     *(dst++) = p[i + 2 * bytesperline];
 205                 }
 206                 break;
 207             }
 208         }
 209     }
 210
 211     free(p);
 212
 213     return E_OK;
 214 }
 215
 216
 217 //-----------------------------------------------------------------------------
 218 // wxPCXHandler
 219 //-----------------------------------------------------------------------------
 220
 221 #if !USE_SHARED_LIBRARIES
 222 IMPLEMENT_DYNAMIC_CLASS(wxPCXHandler,wxImageHandler)
 223 #endif
 224
 225 bool wxPCXHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose )
 226 {
 227     int error;
 228
 229     if (!CanRead(stream))
 230     {
 231         if (verbose)
 232             wxLogError(wxT("wxPCXHandler: this is not a PCX file"));
 233
 234         return FALSE;
 235     }
 236
 237     image->Destroy();
 238
 239     if ((error = ReadPCX(image, stream)) != E_OK)
 240     {
 241         if (verbose)
 242         {
 243             switch (error)
 244             {
 245                 case E_FORMATO: wxLogError(wxT("wxPCXHandler: image format unsupported")); break;
 246                 case E_MEMORIA: wxLogError(wxT("wxPCXHandler: couldn't allocate memory")); break;
 247                 case E_VERSION: wxLogError(wxT("wxPCXHandler: version number too low")); break;
 248                 default:        wxLogError(wxT("wxPCXHandler: unknown error !!!"));
 249             }
 250         }
 251         image->Destroy();
 252         return FALSE;
 253     }
 254
 255     return TRUE;
 256 }
 257
 258 bool wxPCXHandler::SaveFile( wxImage *WXUNUSED(image), wxOutputStream& WXUNUSED(stream), bool verbose )
 259 {
 260     if (verbose)
 261         wxLogError(wxT("wxPCXHandler::SaveFile still not implemented"));
 262
 263     return FALSE;
 264 }
 265
 266 bool wxPCXHandler::DoCanRead( wxInputStream& stream )
 267 {
 268     unsigned char c;
 269     off_t pos;
 270
 271     pos = stream.TellI();
 272     stream.SeekI(0, wxFromStart);
 273     c = stream.GetC();
 274     stream.SeekI(pos, wxFromStart);
 275
 276     // not very safe, but this is all we can get from PCX header :-(
 277     return (c == 10);
 278 }
 279
 280 #endif // wxUSE_STREAMS && wxUSE_PCX
 281