-struct Image::Private
-{
-#ifdef WITH_DEVIL
- unsigned id;
-#endif
-#ifdef WITH_LIBPNG
- PixelFormat fmt;
- unsigned width;
- unsigned height;
- char *data;
-#endif
-
- Private();
-};
-
-Image::Private::Private()
-{
-#ifdef WITH_DEVIL
- id = 0;
-#endif
-#ifdef WITH_LIBPNG
- fmt = RGB;
- width = 0;
- height = 0;
- data = 0;
-#endif
-}
-
-
-namespace {
-
-#ifdef WITH_LIBPNG
-void read(png_struct *png, png_byte *data, png_size_t size)
-{
- IO::Base *in = reinterpret_cast<IO::Base *>(png_get_io_ptr(png));
- in->read(reinterpret_cast<char *>(data), size);
-}
-
-void load_png(IO::Base &in, Image::Private &priv)
-{
- png_struct *png = 0;
- png_info *info = 0;
- priv.data = 0;
-
- try
- {
- png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
- info = png_create_info_struct(png);
-
- if(setjmp(png_jmpbuf(png)))
- throw bad_image_data("PNG error");
-
- png_set_read_fn(png, &in, read);
- png_read_info(png, info);
- png_uint_32 width;
- png_uint_32 height;
- int depth;
- int color;
- png_get_IHDR(png, info, &width, &height, &depth, &color, 0, 0, 0);
- priv.width = width;
- priv.height = height;
- if(depth!=8)
- throw unsupported_image_format("depth!=8");
- switch(color)
- {
- case PNG_COLOR_TYPE_PALETTE: priv.fmt = COLOR_INDEX; break;
- case PNG_COLOR_TYPE_GRAY: priv.fmt = LUMINANCE; break;
- case PNG_COLOR_TYPE_GRAY_ALPHA: priv.fmt = LUMINANCE_ALPHA; break;
- case PNG_COLOR_TYPE_RGB: priv.fmt = RGB; break;
- case PNG_COLOR_TYPE_RGB_ALPHA: priv.fmt = RGBA; break;
- default: throw unsupported_image_format("unknown color type");
- }
-
- unsigned nchans = png_get_channels(png, info);
- if(nchans==4 && priv.fmt==RGB)
- png_set_strip_alpha(png);
-
- unsigned rowstride = priv.width*nchans;
- priv.data = new char[rowstride*priv.height];
- for(unsigned y=0; y<priv.height; ++y)
- png_read_row(png, reinterpret_cast<png_byte *>(priv.data+rowstride*(priv.height-1-y)), 0);
-
- png_read_end(png, 0);
- png_destroy_read_struct(&png, &info, 0);
- }
- catch(...)
- {
- png_destroy_read_struct(&png, &info, 0);
- delete[] priv.data;
- throw;
- }
-}
-#endif