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 #if !USE_SHARED_LIBRARIES
  57 IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
  58 #endif
  59
  60 #if wxUSE_STREAMS
  61
  62 #if defined(__VISAGECPP__)
  63 #define LINKAGEMODE _Optlink
  64 #else
  65 #define LINKAGEMODE
  66 #endif
  67
  68 static void LINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
  69 {
  70     ((wxInputStream*) png_get_io_ptr( png_ptr )) -> Read(data, length);
  71 }
  72
  73 static void LINKAGEMODE _PNG_stream_writer( png_structp png_ptr, png_bytep data, png_size_t length )
  74 {
  75     ((wxOutputStream*) png_get_io_ptr( png_ptr )) -> Write(data, length);
  76 }
  77
  78 // from pngerror.c
  79 // so that the libpng doesn't send anything on stderr
  80 void
  81 png_silent_error(png_structp png_ptr, png_const_charp WXUNUSED(message))
  82 {
  83 #ifdef USE_FAR_KEYWORD
  84    {
  85       jmp_buf jmpbuf;
  86       png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
  87       longjmp(jmpbuf, 1);
  88    }
  89 #else
  90    longjmp(png_ptr->jmpbuf, 1);
  91 #endif
  92 }
  93
  94 void
  95 png_silent_warning(png_structp WXUNUSED(png_ptr), png_const_charp WXUNUSED(message))
  96 {
  97 }
  98
  99 bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose)
 100 {
 101     // VZ: as this function uses setjmp() the only fool proof error handling
 102     //     method is to use goto (setjmp is not really C++ dtors friendly...)
 103
 104     unsigned char **lines;
 105     unsigned int i;
 106     png_infop info_ptr = (png_infop) NULL;
 107
 108     image->Destroy();
 109
 110     png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
 111         (voidp) NULL,
 112         (png_error_ptr) NULL,
 113         (png_error_ptr) NULL );
 114     if (!png_ptr)
 115         goto error_nolines;
 116
 117     // the file example.c explain how to guess if the stream is a png image
 118     if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 119
 120     info_ptr = png_create_info_struct( png_ptr );
 121     if (!info_ptr)
 122         goto error_nolines;
 123
 124     if (setjmp(png_ptr->jmpbuf))
 125         goto error_nolines;
 126
 127     if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
 128         goto error_nolines;
 129
 130     png_set_read_fn( png_ptr, &stream, _PNG_stream_reader);
 131
 132     png_uint_32 width,height;
 133     int bit_depth,color_type,interlace_type;
 134
 135     png_read_info( png_ptr, info_ptr );
 136     png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
 137
 138     if (color_type == PNG_COLOR_TYPE_PALETTE)
 139         png_set_expand( png_ptr );
 140
 141     png_set_strip_16( png_ptr );
 142     png_set_packing( png_ptr );
 143     if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
 144         png_set_expand( png_ptr );
 145     png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
 146
 147     image->Create( width, height );
 148
 149     if (!image->Ok())
 150         goto error_nolines;
 151
 152     lines = (unsigned char **)malloc( height * sizeof(unsigned char *) );
 153     if (lines == NULL)
 154         goto error_nolines;
 155
 156     for (i = 0; i < height; i++)
 157     {
 158         if ((lines[i] = (unsigned char *)malloc(width * (sizeof(unsigned char) * 4))) == NULL)
 159         {
 160             for ( unsigned int n = 0; n < i; n++ )
 161                 free( lines[n] );
 162             goto error;
 163         }
 164     }
 165
 166     // loaded successfully!
 167     {
 168         int transp = 0;
 169         png_read_image( png_ptr, lines );
 170         png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 171         unsigned char *ptr = image->GetData();
 172         if ((color_type == PNG_COLOR_TYPE_GRAY) ||
 173             (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
 174         {
 175             for (unsigned int y = 0; y < height; y++)
 176             {
 177                 unsigned char *ptr2 = lines[y];
 178                 for (unsigned int x = 0; x < width; x++)
 179                 {
 180                     unsigned char r = *ptr2++;
 181                     unsigned char a = *ptr2++;
 182                     if (a < 128)
 183                     {
 184                         *ptr++ = 255;
 185                         *ptr++ = 0;
 186                         *ptr++ = 255;
 187                         transp = 1;
 188                     }
 189                     else
 190                     {
 191                         *ptr++ = r;
 192                         *ptr++ = r;
 193                         *ptr++ = r;
 194                     }
 195                 }
 196             }
 197         }
 198         else
 199         {
 200             for (unsigned int y = 0; y < height; y++)
 201             {
 202                 unsigned char *ptr2 = lines[y];
 203                 for (unsigned int x = 0; x < width; x++)
 204                 {
 205                     unsigned char r = *ptr2++;
 206                     unsigned char g = *ptr2++;
 207                     unsigned char b = *ptr2++;
 208                     unsigned char a = *ptr2++;
 209                     if (a < 128)
 210                     {
 211                         *ptr++ = 255;
 212                         *ptr++ = 0;
 213                         *ptr++ = 255;
 214                         transp = 1;
 215                     }
 216                     else
 217                     {
 218                         if ((r == 255) && (g == 0) && (b == 255)) r = 254;
 219                         *ptr++ = r;
 220                         *ptr++ = g;
 221                         *ptr++ = b;
 222                     }
 223                 }
 224             }
 225         }
 226
 227         for ( unsigned int j = 0; j < height; j++ )
 228             free( lines[j] );
 229         free( lines );
 230
 231         if (transp)
 232         {
 233             image->SetMaskColour( 255, 0, 255 );
 234         }
 235         else
 236         {
 237             image->SetMask( FALSE );
 238         }
 239     }
 240
 241     return TRUE;
 242
 243  error_nolines:
 244     lines = NULL; // called from before it was set
 245  error:
 246     wxLogError(_("Couldn't load a PNG image - probably file is corrupted."));
 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 ((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] = 0;
 332                 }
 333                 else
 334                 {
 335                     data[(x << 2) + 3] = 255;
 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::CanRead( 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
 359   // wxUSE_STREAMS
 360
 361 #endif
 362   // wxUSE_LIBPNG
 363