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