src/common/imagpng.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        imagepng.cpp
   3 // Purpose:     wxImage PNG handler
   4 // Author:      Robert Roebling
   5 // RCS-ID:      $Id$
   6 // Copyright:   (c) Robert Roebling
   7 // Licence:     wxWindows licence
   8 /////////////////////////////////////////////////////////////////////////////
   9
  10 /*
  11    We don't put pragma implement in this file because it is already present in
  12    src/common/image.cpp
  13 */
  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_LIBPNG
  27
  28 #include "wx/image.h"
  29 #include "wx/bitmap.h"
  30 #include "wx/debug.h"
  31 #include "wx/log.h"
  32 #include "wx/app.h"
  33 #include "png.h"
  34 #include "wx/filefn.h"
  35 #include "wx/wfstream.h"
  36 #include "wx/intl.h"
  37 #include "wx/module.h"
  38
  39 // For memcpy
  40 #include <string.h>
  41
  42 #ifdef __SALFORDC__
  43 #ifdef FAR
  44 #undef FAR
  45 #endif
  46 #endif
  47
  48 #ifdef __WXMSW__
  49 #include <windows.h>
  50 #endif
  51
  52 //-----------------------------------------------------------------------------
  53 // wxPNGHandler
  54 //-----------------------------------------------------------------------------
  55
  56 IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
  57
  58 #if wxUSE_LIBPNG
  59
  60 #if defined(__VISAGECPP__)
  61 #define LINKAGEMODE _Optlink
  62 #else
  63 #define LINKAGEMODE
  64 #endif
  65
  66 static void LINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
  67 {
  68     ((wxInputStream*) png_get_io_ptr( png_ptr )) -> Read(data, length);
  69 }
  70
  71 static void LINKAGEMODE _PNG_stream_writer( png_structp png_ptr, png_bytep data, png_size_t length )
  72 {
  73     ((wxOutputStream*) png_get_io_ptr( png_ptr )) -> Write(data, length);
  74 }
  75
  76 // from pngerror.c
  77 // so that the libpng doesn't send anything on stderr
  78 void
  79 LINKAGEMODE png_silent_error(png_structp png_ptr, png_const_charp WXUNUSED(message))
  80 {
  81 #ifdef USE_FAR_KEYWORD
  82    {
  83       jmp_buf jmpbuf;
  84       png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
  85       longjmp(jmpbuf, 1);
  86    }
  87 #else
  88    longjmp(png_ptr->jmpbuf, 1);
  89 #endif
  90 }
  91
  92 void
  93 LINKAGEMODE png_silent_warning(png_structp WXUNUSED(png_ptr), png_const_charp WXUNUSED(message))
  94 {
  95 }
  96
  97 bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
  98 {
  99     // VZ: as this function uses setjmp() the only fool proof error handling
 100     //     method is to use goto (setjmp is not really C++ dtors friendly...)
 101
 102     unsigned char **lines;
 103     unsigned int i;
 104     png_infop info_ptr = (png_infop) NULL;
 105
 106     image->Destroy();
 107
 108     png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
 109         (voidp) NULL,
 110         (png_error_ptr) NULL,
 111         (png_error_ptr) NULL );
 112     if (!png_ptr)
 113         goto error_nolines;
 114
 115     // the file example.c explain how to guess if the stream is a png image
 116     if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 117
 118     info_ptr = png_create_info_struct( png_ptr );
 119     if (!info_ptr)
 120         goto error_nolines;
 121
 122     if (setjmp(png_ptr->jmpbuf))
 123         goto error_nolines;
 124
 125     if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
 126         goto error_nolines;
 127
 128     png_set_read_fn( png_ptr, &stream, _PNG_stream_reader);
 129
 130     png_uint_32 width,height;
 131     int bit_depth,color_type,interlace_type;
 132
 133     png_read_info( png_ptr, info_ptr );
 134     png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
 135
 136     if (color_type == PNG_COLOR_TYPE_PALETTE)
 137         png_set_expand( png_ptr );
 138
 139     png_set_strip_16( png_ptr );
 140     png_set_packing( png_ptr );
 141     if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
 142         png_set_expand( png_ptr );
 143     png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
 144
 145     image->Create( width, height );
 146
 147     if (!image->Ok())
 148         goto error_nolines;
 149
 150     lines = (unsigned char **)malloc( height * sizeof(unsigned char *) );
 151     if (lines == NULL)
 152         goto error_nolines;
 153
 154     for (i = 0; i < height; i++)
 155     {
 156         if ((lines[i] = (unsigned char *)malloc(width * (sizeof(unsigned char) * 4))) == NULL)
 157         {
 158             for ( unsigned int n = 0; n < i; n++ )
 159                 free( lines[n] );
 160             goto error;
 161         }
 162     }
 163
 164     // loaded successfully!
 165     {
 166         int transp = 0;
 167         png_read_image( png_ptr, lines );
 168         png_read_end( png_ptr, info_ptr );
 169         png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 170         unsigned char *ptr = image->GetData();
 171         if ((color_type == PNG_COLOR_TYPE_GRAY) ||
 172             (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
 173         {
 174             for (unsigned int y = 0; y < height; y++)
 175             {
 176                 unsigned char *ptr2 = lines[y];
 177                 for (unsigned int x = 0; x < width; x++)
 178                 {
 179                     unsigned char r = *ptr2++;
 180                     unsigned char a = *ptr2++;
 181                     if (a < 128)
 182                     {
 183                         *ptr++ = 255;
 184                         *ptr++ = 0;
 185                         *ptr++ = 255;
 186                         transp = 1;
 187                     }
 188                     else
 189                     {
 190                         *ptr++ = r;
 191                         *ptr++ = r;
 192                         *ptr++ = r;
 193                     }
 194                 }
 195             }
 196         }
 197         else
 198         {
 199             for (unsigned int y = 0; y < height; y++)
 200             {
 201                 unsigned char *ptr2 = lines[y];
 202                 for (unsigned int x = 0; x < width; x++)
 203                 {
 204                     unsigned char r = *ptr2++;
 205                     unsigned char g = *ptr2++;
 206                     unsigned char b = *ptr2++;
 207                     unsigned char a = *ptr2++;
 208                     if (a < 128)
 209                     {
 210                         *ptr++ = 255;
 211                         *ptr++ = 0;
 212                         *ptr++ = 255;
 213                         transp = 1;
 214                     }
 215                     else
 216                     {
 217                         if ((r == 255) && (g == 0) && (b == 255)) r = 254;
 218                         *ptr++ = r;
 219                         *ptr++ = g;
 220                         *ptr++ = b;
 221                     }
 222                 }
 223             }
 224         }
 225
 226         for ( unsigned int j = 0; j < height; j++ )
 227             free( lines[j] );
 228         free( lines );
 229
 230         if (transp)
 231         {
 232             image->SetMaskColour( 255, 0, 255 );
 233         }
 234         else
 235         {
 236             image->SetMask( FALSE );
 237         }
 238     }
 239
 240     return TRUE;
 241
 242  error_nolines:
 243     lines = NULL; // called from before it was set
 244  error:
 245     if (verbose)
 246        wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory."));
 247
 248     if ( image->Ok() )
 249     {
 250         image->Destroy();
 251     }
 252
 253     if ( lines )
 254     {
 255         free( lines );
 256     }
 257
 258     if ( png_ptr )
 259     {
 260         if ( info_ptr )
 261         {
 262             png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 263             free(info_ptr);
 264         }
 265         else
 266             png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
 267     }
 268     return FALSE;
 269 }
 270
 271
 272 bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
 273 {
 274     {
 275         png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 276         if (!png_ptr)
 277         {
 278             return FALSE;
 279         }
 280
 281         if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 282
 283         png_infop info_ptr = png_create_info_struct(png_ptr);
 284         if (info_ptr == NULL)
 285         {
 286             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 287             return FALSE;
 288         }
 289
 290         if (setjmp(png_ptr->jmpbuf))
 291         {
 292             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 293             return FALSE;
 294         }
 295
 296         png_set_write_fn( png_ptr, &stream, _PNG_stream_writer, NULL);
 297
 298         png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
 299             PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
 300             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 301
 302         png_color_8 sig_bit;
 303         sig_bit.red = 8;
 304         sig_bit.green = 8;
 305         sig_bit.blue = 8;
 306         sig_bit.alpha = 8;
 307         png_set_sBIT( png_ptr, info_ptr, &sig_bit );
 308         png_write_info( png_ptr, info_ptr );
 309         png_set_shift( png_ptr, &sig_bit );
 310         png_set_packing( png_ptr );
 311
 312         unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
 313         if (!data)
 314         {
 315             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 316             return FALSE;
 317         }
 318
 319         for (int y = 0; y < image->GetHeight(); y++)
 320         {
 321             unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
 322             for (int x = 0; x < image->GetWidth(); x++)
 323             {
 324                 data[(x << 2) + 0] = *ptr++;
 325                 data[(x << 2) + 1] = *ptr++;
 326                 data[(x << 2) + 2] = *ptr++;
 327                 if (( !image->HasMask() ) || \
 328                     (data[(x << 2) + 0] != image->GetMaskRed()) || \
 329                     (data[(x << 2) + 1] != image->GetMaskGreen()) || \
 330                     (data[(x << 2) + 2] != image->GetMaskBlue()))
 331                 {
 332                     data[(x << 2) + 3] = 255;
 333                 }
 334                 else
 335                 {
 336                     data[(x << 2) + 3] = 0;
 337                 }
 338             }
 339             png_bytep row_ptr = data;
 340             png_write_rows( png_ptr, &row_ptr, 1 );
 341         }
 342
 343         free(data);
 344         png_write_end( png_ptr, info_ptr );
 345         png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
 346     }
 347     return TRUE;
 348 }
 349
 350 bool wxPNGHandler::DoCanRead( wxInputStream& stream )
 351 {
 352     unsigned char hdr[4];
 353
 354     stream.Read(&hdr, 4);
 355     stream.SeekI(-4, wxFromCurrent);
 356     return (hdr[0] == 0x89 && hdr[1] == 'P' && hdr[2] == 'N' && hdr[3] == 'G');
 357 }
 358
 359 #endif  // wxUSE_STREAMS
 360
 361 #endif  // wxUSE_LIBPNG