- const bool usesAlpha = (image->HasAlpha() || image->HasMask() );
- const int bytesPerPixel = usesAlpha ? 4 : 3;
- png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
- usesAlpha ? PNG_COLOR_TYPE_RGB_ALPHA : PNG_COLOR_TYPE_RGB,
- PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+ const int iColorType = image->HasOption(wxIMAGE_OPTION_PNG_FORMAT)
+ ? image->GetOptionInt(wxIMAGE_OPTION_PNG_FORMAT)
+ : wxPNG_TYPE_COLOUR;
+ const int iBitDepth = image->HasOption(wxIMAGE_OPTION_PNG_BITDEPTH)
+ ? image->GetOptionInt(wxIMAGE_OPTION_PNG_BITDEPTH)
+ : 8;
+
+ wxASSERT_MSG( iBitDepth == 8 || iBitDepth == 16,
+ _T("PNG bit depth must be 8 or 16") );
+
+ bool bHasAlpha = image->HasAlpha();
+ bool bHasMask = image->HasMask();
+ bool bUseAlpha = bHasAlpha || bHasMask;
+
+ int iPngColorType;
+ if ( iColorType==wxPNG_TYPE_COLOUR )
+ {
+ iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_RGB_ALPHA
+ : PNG_COLOR_TYPE_RGB;
+ }
+ else
+ {
+ iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_GRAY_ALPHA
+ : PNG_COLOR_TYPE_GRAY;
+ }
+
+ png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(),
+ iBitDepth, iPngColorType,
+ PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
+ PNG_FILTER_TYPE_BASE);