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_STREAMS && 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 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)
  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_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     wxLogError(_("Couldn't load a PNG image - probably file is corrupted."));
 245
 246     if ( image->Ok() )
 247     {
 248         image->Destroy();
 249     }
 250
 251     if ( lines )
 252     {
 253         free( lines );
 254     }
 255
 256     if ( png_ptr )
 257     {
 258         if ( info_ptr )
 259         {
 260             png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 261             free(info_ptr);
 262         }
 263         else
 264             png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
 265     }
 266     return FALSE;
 267 }
 268
 269
 270 bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
 271 {
 272     {
 273         png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 274         if (!png_ptr)
 275         {
 276             return FALSE;
 277         }
 278
 279         if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
 280
 281         png_infop info_ptr = png_create_info_struct(png_ptr);
 282         if (info_ptr == NULL)
 283         {
 284             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 285             return FALSE;
 286         }
 287
 288         if (setjmp(png_ptr->jmpbuf))
 289         {
 290             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 291             return FALSE;
 292         }
 293
 294         png_set_write_fn( png_ptr, &stream, _PNG_stream_writer, NULL);
 295
 296         png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
 297             PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
 298             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 299
 300         png_color_8 sig_bit;
 301         sig_bit.red = 8;
 302         sig_bit.green = 8;
 303         sig_bit.blue = 8;
 304         sig_bit.alpha = 8;
 305         png_set_sBIT( png_ptr, info_ptr, &sig_bit );
 306         png_write_info( png_ptr, info_ptr );
 307         png_set_shift( png_ptr, &sig_bit );
 308         png_set_packing( png_ptr );
 309
 310         unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
 311         if (!data)
 312         {
 313             png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
 314             return FALSE;
 315         }
 316
 317         for (int y = 0; y < image->GetHeight(); y++)
 318         {
 319             unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
 320             for (int x = 0; x < image->GetWidth(); x++)
 321             {
 322                 data[(x << 2) + 0] = *ptr++;
 323                 data[(x << 2) + 1] = *ptr++;
 324                 data[(x << 2) + 2] = *ptr++;
 325                 if ((data[(x << 2) + 0] == image->GetMaskRed()) &&
 326                     (data[(x << 2) + 1] == image->GetMaskGreen()) &&
 327                     (data[(x << 2) + 2] == image->GetMaskBlue()))
 328                 {
 329                     data[(x << 2) + 3] = 0;
 330                 }
 331                 else
 332                 {
 333                     data[(x << 2) + 3] = 255;
 334                 }
 335             }
 336             png_bytep row_ptr = data;
 337             png_write_rows( png_ptr, &row_ptr, 1 );
 338         }
 339
 340         free(data);
 341         png_write_end( png_ptr, info_ptr );
 342         png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
 343     }
 344     return TRUE;
 345 }
 346
 347 bool wxPNGHandler::CanRead( wxInputStream& stream )
 348 {
 349     unsigned char hdr[4];
 350
 351     stream.Read(&hdr, 4);
 352     stream.SeekI(-4, wxFromCurrent);
 353     return (hdr[0] == 0x89 && hdr[1] == 'P' && hdr[2] == 'N' && hdr[3] == 'G');
 354 }
 355
 356 #endif  // wxUSE_STREAMS && wxUSE_LIBPNG
 357