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 #if defined(__VISAGECPP__)
  60 #define PNGLINKAGEMODE _Optlink
  61 #elif defined(__WATCOMC__)
  62 #define PNGLINKAGEMODE _cdecl
  63 #else
  64 #define PNGLINKAGEMODE
  65 #endif
  66
  67 static void PNGLINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
  68 {
  69     ((wxInputStream*) png_get_io_ptr( png_ptr )) -> Read(data, length);
  70 }
  71
  72 static void PNGLINKAGEMODE _PNG_stream_writer( png_structp png_ptr, png_bytep data, png_size_t length )
  73 {
  74     ((wxOutputStream*) png_get_io_ptr( png_ptr )) -> Write(data, length);
  75 }
  76
  77 // from pngerror.c
  78 // so that the libpng doesn't send anything on stderr
  79 void
  80 PNGLINKAGEMODE png_silent_error(png_structp png_ptr, png_const_charp WXUNUSED(message))
  81 {
  82 #ifdef USE_FAR_KEYWORD
  83    {
  84       jmp_buf jmpbuf;
  85       png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
  86       longjmp(jmpbuf, 1);
  87    }
  88 #else
  89    longjmp(png_ptr->jmpbuf, 1);
  90 #endif
  91 }
  92
  93 void
  94 PNGLINKAGEMODE png_silent_warning(png_structp WXUNUSED(png_ptr), png_const_charp WXUNUSED(message))
  95 {
  96 }
  97
  98 // temporarily disable the warning C4611 (interaction between '_setjmp' and
  99 // C++ object destruction is non-portable) - I don't see any dtors here
 100 #ifdef __VISUALC__
 101     #pragma warning(disable:4611)
 102 #endif /* VC++ */
 103
 104 bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
 105 {
 106     // VZ: as this function uses setjmp() the only fool proof error handling
 107     //     method is to use goto (setjmp is not really C++ dtors friendly...)
 108
 109     unsigned char **lines;
 110     unsigned int i;
 111     png_infop info_ptr = (png_infop) NULL;
 112
 113     image->Destroy();
 114
 115     png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
 116         (voidp) NULL,
 117         (png_error_ptr) NULL,
 118         (png_error_ptr) NULL );
 119     if (!png_ptr)
 120         goto error_nolines;
 121
 122     // the file example.c explain how to guess if the stream is a png image
 123     if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 124
 125     info_ptr = png_create_info_struct( png_ptr );
 126     if (!info_ptr)
 127         goto error_nolines;
 128
 129     if (setjmp(png_ptr->jmpbuf))
 130         goto error_nolines;
 131
 132     if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
 133         goto error_nolines;
 134
 135     png_set_read_fn( png_ptr, &stream, _PNG_stream_reader);
 136
 137     png_uint_32 width,height;
 138     int bit_depth,color_type,interlace_type;
 139
 140     png_read_info( png_ptr, info_ptr );
 141     png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
 142
 143     if (color_type == PNG_COLOR_TYPE_PALETTE)
 144         png_set_expand( png_ptr );
 145
 146     png_set_strip_16( png_ptr );
 147     png_set_packing( png_ptr );
 148     if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
 149         png_set_expand( png_ptr );
 150     png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
 151
 152     image->Create( (int)width, (int)height );
 153
 154     if (!image->Ok())
 155         goto error_nolines;
 156
 157     lines = (unsigned char **)malloc( (size_t)(height * sizeof(unsigned char *)) );
 158     if (lines == NULL)
 159         goto error_nolines;
 160
 161     for (i = 0; i < height; i++)
 162     {
 163         if ((lines[i] = (unsigned char *)malloc( (size_t)(width * (sizeof(unsigned char) * 4)))) == NULL)
 164         {
 165             for ( unsigned int n = 0; n < i; n++ )
 166                 free( lines[n] );
 167             goto error;
 168         }
 169     }
 170
 171     // loaded successfully!
 172     {
 173         int transp = 0;
 174         png_read_image( png_ptr, lines );
 175         png_read_end( png_ptr, info_ptr );
 176         png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 177         unsigned char *ptr = image->GetData();
 178         if ((color_type == PNG_COLOR_TYPE_GRAY) ||
 179             (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
 180         {
 181             for (unsigned int y = 0; y < height; y++)
 182             {
 183                 unsigned char *ptr2 = lines[y];
 184                 for (unsigned int x = 0; x < width; x++)
 185                 {
 186                     unsigned char r = *ptr2++;
 187                     unsigned char a = *ptr2++;
 188                     if (a < 128)
 189                     {
 190                         *ptr++ = 255;
 191                         *ptr++ = 0;
 192                         *ptr++ = 255;
 193                         transp = 1;
 194                     }
 195                     else
 196                     {
 197                         *ptr++ = r;
 198                         *ptr++ = r;
 199                         *ptr++ = r;
 200                     }
 201                 }
 202             }
 203         }
 204         else
 205         {
 206             for (unsigned int y = 0; y < height; y++)
 207             {
 208                 unsigned char *ptr2 = lines[y];
 209                 for (unsigned int x = 0; x < width; x++)
 210                 {
 211                     unsigned char r = *ptr2++;
 212                     unsigned char g = *ptr2++;
 213                     unsigned char b = *ptr2++;
 214                     unsigned char a = *ptr2++;
 215                     if (a < 128)
 216                     {
 217                         *ptr++ = 255;
 218                         *ptr++ = 0;
 219                         *ptr++ = 255;
 220                         transp = 1;
 221                     }
 222                     else
 223                     {
 224                         if ((r == 255) && (g == 0) && (b == 255)) r = 254;
 225                         *ptr++ = r;
 226                         *ptr++ = g;
 227                         *ptr++ = b;
 228                     }
 229                 }
 230             }
 231         }
 232
 233         for ( unsigned int j = 0; j < height; j++ )
 234             free( lines[j] );
 235         free( lines );
 236
 237         if (transp)
 238         {
 239             image->SetMaskColour( 255, 0, 255 );
 240         }
 241         else
 242         {
 243             image->SetMask( FALSE );
 244         }
 245     }
 246
 247     return TRUE;
 248
 249  error_nolines:
 250     lines = NULL; // called from before it was set
 251  error:
 252     if (verbose)
 253        wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory."));
 254
 255     if ( image->Ok() )
 256     {
 257         image->Destroy();
 258     }
 259
 260     if ( lines )
 261     {
 262         free( lines );
 263     }
 264
 265     if ( png_ptr )
 266     {
 267         if ( info_ptr )
 268         {
 269             png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 270             free(info_ptr);
 271         }
 272         else
 273             png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
 274     }
 275     return FALSE;
 276 }
 277
 278 bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
 279 {
 280     {
 281         png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 282         if (!png_ptr)
 283         {
 284             return FALSE;
 285         }
 286
 287         if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 288
 289         png_infop info_ptr = png_create_info_struct(png_ptr);
 290         if (info_ptr == NULL)
 291         {
 292             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 293             return FALSE;
 294         }
 295
 296         if (setjmp(png_ptr->jmpbuf))
 297         {
 298             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 299             return FALSE;
 300         }
 301
 302         png_set_write_fn( png_ptr, &stream, _PNG_stream_writer, NULL);
 303
 304         png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
 305             PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
 306             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 307
 308         png_color_8 sig_bit;
 309         sig_bit.red = 8;
 310         sig_bit.green = 8;
 311         sig_bit.blue = 8;
 312         sig_bit.alpha = 8;
 313         png_set_sBIT( png_ptr, info_ptr, &sig_bit );
 314         png_write_info( png_ptr, info_ptr );
 315         png_set_shift( png_ptr, &sig_bit );
 316         png_set_packing( png_ptr );
 317
 318         unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
 319         if (!data)
 320         {
 321             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 322             return FALSE;
 323         }
 324
 325         for (int y = 0; y < image->GetHeight(); y++)
 326         {
 327             unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
 328             for (int x = 0; x < image->GetWidth(); x++)
 329             {
 330                 data[(x << 2) + 0] = *ptr++;
 331                 data[(x << 2) + 1] = *ptr++;
 332                 data[(x << 2) + 2] = *ptr++;
 333                 if (( !image->HasMask() ) || \
 334                     (data[(x << 2) + 0] != image->GetMaskRed()) || \
 335                     (data[(x << 2) + 1] != image->GetMaskGreen()) || \
 336                     (data[(x << 2) + 2] != image->GetMaskBlue()))
 337                 {
 338                     data[(x << 2) + 3] = 255;
 339                 }
 340                 else
 341                 {
 342                     data[(x << 2) + 3] = 0;
 343                 }
 344             }
 345             png_bytep row_ptr = data;
 346             png_write_rows( png_ptr, &row_ptr, 1 );
 347         }
 348
 349         free(data);
 350         png_write_end( png_ptr, info_ptr );
 351         png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
 352     }
 353     return TRUE;
 354 }
 355
 356 #ifdef __VISUALC__
 357     #pragma warning(default:4611)
 358 #endif /* VC++ */
 359
 360 bool wxPNGHandler::DoCanRead( wxInputStream& stream )
 361 {
 362     unsigned char hdr[4];
 363
 364     stream.Read(hdr, 4);
 365     stream.SeekI(-4, wxFromCurrent);
 366     return (hdr[0] == 0x89 && hdr[1] == 'P' && hdr[2] == 'N' && hdr[3] == 'G');
 367 }
 368
 369 #endif  // wxUSE_STREAMS
 370
 371 #endif  // wxUSE_LIBPNG