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 #ifdef __GNUG__
  11 #pragma implementation "imagpng.h"
  12 #endif
  13
  14 // For compilers that support precompilation, includes "wx.h".
  15 #include "wx/wxprec.h"
  16
  17 #ifdef __BORLANDC__
  18   #pragma hdrstop
  19 #endif
  20
  21 #ifndef WX_PRECOMP
  22   #include "wx/defs.h"
  23 #endif
  24
  25 #if wxUSE_IMAGE && wxUSE_LIBPNG
  26
  27 #include "wx/imagpng.h"
  28 #include "wx/bitmap.h"
  29 #include "wx/debug.h"
  30 #include "wx/log.h"
  31 #include "wx/app.h"
  32 #include "png.h"
  33 #include "wx/filefn.h"
  34 #include "wx/wfstream.h"
  35 #include "wx/intl.h"
  36 #include "wx/module.h"
  37
  38 // For memcpy
  39 #include <string.h>
  40
  41 #ifdef __SALFORDC__
  42 #ifdef FAR
  43 #undef FAR
  44 #endif
  45 #endif
  46
  47 #ifdef __WXMSW__
  48 #include <windows.h>
  49 #endif
  50
  51 //-----------------------------------------------------------------------------
  52 // wxPNGHandler
  53 //-----------------------------------------------------------------------------
  54
  55 IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
  56
  57 #if wxUSE_LIBPNG
  58
  59 #ifndef PNGLINKAGEMODE
  60   #define PNGLINKAGEMODE LINKAGEMODE
  61 #endif
  62
  63 static void PNGLINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
  64 {
  65     ((wxInputStream*) png_get_io_ptr( png_ptr )) -> Read(data, length);
  66 }
  67
  68 static void PNGLINKAGEMODE _PNG_stream_writer( png_structp png_ptr, png_bytep data, png_size_t length )
  69 {
  70     ((wxOutputStream*) png_get_io_ptr( png_ptr )) -> Write(data, length);
  71 }
  72
  73 // from pngerror.c
  74 // so that the libpng doesn't send anything on stderr
  75 void
  76 PNGLINKAGEMODE png_silent_error(png_structp png_ptr, png_const_charp WXUNUSED(message))
  77 {
  78 #ifdef USE_FAR_KEYWORD
  79    {
  80       jmp_buf jmpbuf;
  81       png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
  82       longjmp(jmpbuf, 1);
  83    }
  84 #else
  85    longjmp(png_ptr->jmpbuf, 1);
  86 #endif
  87 }
  88
  89 void
  90 PNGLINKAGEMODE png_silent_warning(png_structp WXUNUSED(png_ptr), png_const_charp WXUNUSED(message))
  91 {
  92 }
  93
  94 // temporarily disable the warning C4611 (interaction between '_setjmp' and
  95 // C++ object destruction is non-portable) - I don't see any dtors here
  96 #ifdef __VISUALC__
  97     #pragma warning(disable:4611)
  98 #endif /* VC++ */
  99
 100 bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
 101 {
 102     // VZ: as this function uses setjmp() the only fool proof error handling
 103     //     method is to use goto (setjmp is not really C++ dtors friendly...)
 104
 105     unsigned char **lines;
 106     unsigned int i;
 107     png_infop info_ptr = (png_infop) NULL;
 108
 109     image->Destroy();
 110
 111     png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
 112         (voidp) NULL,
 113         (png_error_ptr) NULL,
 114         (png_error_ptr) NULL );
 115     if (!png_ptr)
 116         goto error_nolines;
 117
 118     // the file example.c explain how to guess if the stream is a png image
 119     if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 120
 121     info_ptr = png_create_info_struct( png_ptr );
 122     if (!info_ptr)
 123         goto error_nolines;
 124
 125     if (setjmp(png_ptr->jmpbuf))
 126         goto error_nolines;
 127
 128     if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
 129         goto error_nolines;
 130
 131     png_set_read_fn( png_ptr, &stream, _PNG_stream_reader);
 132
 133     png_uint_32 width,height;
 134     int bit_depth,color_type,interlace_type;
 135
 136     png_read_info( png_ptr, info_ptr );
 137     png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
 138
 139     if (color_type == PNG_COLOR_TYPE_PALETTE)
 140         png_set_expand( png_ptr );
 141
 142     png_set_strip_16( png_ptr );
 143     png_set_packing( png_ptr );
 144     if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
 145         png_set_expand( png_ptr );
 146     png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
 147
 148     image->Create( (int)width, (int)height );
 149
 150     if (!image->Ok())
 151         goto error_nolines;
 152
 153     lines = (unsigned char **)malloc( (size_t)(height * sizeof(unsigned char *)) );
 154     if (lines == NULL)
 155         goto error_nolines;
 156
 157     for (i = 0; i < height; i++)
 158     {
 159         if ((lines[i] = (unsigned char *)malloc( (size_t)(width * (sizeof(unsigned char) * 4)))) == NULL)
 160         {
 161             for ( unsigned int n = 0; n < i; n++ )
 162                 free( lines[n] );
 163             goto error;
 164         }
 165     }
 166
 167     // loaded successfully!
 168     {
 169         int transp = 0;
 170         png_read_image( png_ptr, lines );
 171         png_read_end( png_ptr, info_ptr );
 172         png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 173         unsigned char *ptr = image->GetData();
 174         if ((color_type == PNG_COLOR_TYPE_GRAY) ||
 175             (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
 176         {
 177             for (unsigned int y = 0; y < height; y++)
 178             {
 179                 unsigned char *ptr2 = lines[y];
 180                 for (unsigned int x = 0; x < width; x++)
 181                 {
 182                     unsigned char r = *ptr2++;
 183                     unsigned char a = *ptr2++;
 184                     if (a < 128)
 185                     {
 186                         *ptr++ = 255;
 187                         *ptr++ = 0;
 188                         *ptr++ = 255;
 189                         transp = 1;
 190                     }
 191                     else
 192                     {
 193                         *ptr++ = r;
 194                         *ptr++ = r;
 195                         *ptr++ = r;
 196                     }
 197                 }
 198             }
 199         }
 200         else
 201         {
 202             for (unsigned int y = 0; y < height; y++)
 203             {
 204                 unsigned char *ptr2 = lines[y];
 205                 for (unsigned int x = 0; x < width; x++)
 206                 {
 207                     unsigned char r = *ptr2++;
 208                     unsigned char g = *ptr2++;
 209                     unsigned char b = *ptr2++;
 210                     unsigned char a = *ptr2++;
 211                     if (a < 128)
 212                     {
 213                         *ptr++ = 255;
 214                         *ptr++ = 0;
 215                         *ptr++ = 255;
 216                         transp = 1;
 217                     }
 218                     else
 219                     {
 220                         if ((r == 255) && (g == 0) && (b == 255)) r = 254;
 221                         *ptr++ = r;
 222                         *ptr++ = g;
 223                         *ptr++ = b;
 224                     }
 225                 }
 226             }
 227         }
 228
 229         for ( unsigned int j = 0; j < height; j++ )
 230             free( lines[j] );
 231         free( lines );
 232
 233         if (transp)
 234         {
 235             image->SetMaskColour( 255, 0, 255 );
 236         }
 237         else
 238         {
 239             image->SetMask( FALSE );
 240         }
 241     }
 242
 243     return TRUE;
 244
 245  error_nolines:
 246     lines = NULL; // called from before it was set
 247  error:
 248     if (verbose)
 249        wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory."));
 250
 251     if ( image->Ok() )
 252     {
 253         image->Destroy();
 254     }
 255
 256     if ( lines )
 257     {
 258         free( lines );
 259     }
 260
 261     if ( png_ptr )
 262     {
 263         if ( info_ptr )
 264         {
 265             png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 266             free(info_ptr);
 267         }
 268         else
 269             png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
 270     }
 271     return FALSE;
 272 }
 273
 274 bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
 275 {
 276     {
 277         png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 278         if (!png_ptr)
 279         {
 280             return FALSE;
 281         }
 282
 283         if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 284
 285         png_infop info_ptr = png_create_info_struct(png_ptr);
 286         if (info_ptr == NULL)
 287         {
 288             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 289             return FALSE;
 290         }
 291
 292         if (setjmp(png_ptr->jmpbuf))
 293         {
 294             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 295             return FALSE;
 296         }
 297
 298         png_set_write_fn( png_ptr, &stream, _PNG_stream_writer, NULL);
 299
 300         png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
 301             PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
 302             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 303
 304         png_color_8 sig_bit;
 305         sig_bit.red = 8;
 306         sig_bit.green = 8;
 307         sig_bit.blue = 8;
 308         sig_bit.alpha = 8;
 309         png_set_sBIT( png_ptr, info_ptr, &sig_bit );
 310         png_write_info( png_ptr, info_ptr );
 311         png_set_shift( png_ptr, &sig_bit );
 312         png_set_packing( png_ptr );
 313
 314         unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
 315         if (!data)
 316         {
 317             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 318             return FALSE;
 319         }
 320
 321         for (int y = 0; y < image->GetHeight(); y++)
 322         {
 323             unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
 324             for (int x = 0; x < image->GetWidth(); x++)
 325             {
 326                 data[(x << 2) + 0] = *ptr++;
 327                 data[(x << 2) + 1] = *ptr++;
 328                 data[(x << 2) + 2] = *ptr++;
 329                 if (( !image->HasMask() ) || \
 330                     (data[(x << 2) + 0] != image->GetMaskRed()) || \
 331                     (data[(x << 2) + 1] != image->GetMaskGreen()) || \
 332                     (data[(x << 2) + 2] != image->GetMaskBlue()))
 333                 {
 334                     data[(x << 2) + 3] = 255;
 335                 }
 336                 else
 337                 {
 338                     data[(x << 2) + 3] = 0;
 339                 }
 340             }
 341             png_bytep row_ptr = data;
 342             png_write_rows( png_ptr, &row_ptr, 1 );
 343         }
 344
 345         free(data);
 346         png_write_end( png_ptr, info_ptr );
 347         png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
 348     }
 349     return TRUE;
 350 }
 351
 352 #ifdef __VISUALC__
 353     #pragma warning(default:4611)
 354 #endif /* VC++ */
 355
 356 bool wxPNGHandler::DoCanRead( wxInputStream& stream )
 357 {
 358     unsigned char hdr[4];
 359
 360     stream.Read(hdr, 4);
 361     stream.SeekI(-4, wxFromCurrent);
 362     return (hdr[0] == 0x89 && hdr[1] == 'P' && hdr[2] == 'N' && hdr[3] == 'G');
 363 }
 364
 365 #endif  // wxUSE_STREAMS
 366
 367 #endif  // wxUSE_LIBPNG