// explanation why this line is mandatory
png_set_write_fn( png_ptr, &wxinfo, wx_PNG_stream_writer, NULL);
- 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);
+ int iElements;
png_color_8 sig_bit;
- sig_bit.red = 8;
- sig_bit.green = 8;
- sig_bit.blue = 8;
- sig_bit.alpha = 8;
+
+ if ( iPngColorType & PNG_COLOR_MASK_COLOR )
+ {
+ sig_bit.red =
+ sig_bit.green =
+ sig_bit.blue = (png_byte)iBitDepth;
+ iElements = 3;
+ }
+ else // grey
+ {
+ sig_bit.gray = (png_byte)iBitDepth;
+ iElements = 1;
+ }
+
+ if ( iPngColorType & PNG_COLOR_MASK_ALPHA )
+ {
+ sig_bit.alpha = (png_byte)iBitDepth;
+ iElements++;
+ }
+
+ if ( iBitDepth == 16 )
+ iElements *= 2;
+
png_set_sBIT( png_ptr, info_ptr, &sig_bit );
png_write_info( png_ptr, info_ptr );
png_set_shift( png_ptr, &sig_bit );
png_set_packing( png_ptr );
- unsigned char *data = (unsigned char *)malloc( image->GetWidth()*bytesPerPixel );
- if (!data)
+ unsigned char *
+ data = (unsigned char *)malloc( image->GetWidth() * iElements );
+ if ( !data )
{
png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
return false;
}
- for (int y = 0; y < image->GetHeight(); y++)
+ unsigned char *
+ pAlpha = (unsigned char *)(bHasAlpha ? image->GetAlpha() : NULL);
+ int iHeight = image->GetHeight();
+ int iWidth = image->GetWidth();
+
+ unsigned char uchMaskRed = 0, uchMaskGreen = 0, uchMaskBlue = 0;
+
+ if ( bHasMask )
+ {
+ uchMaskRed = image->GetMaskRed();
+ uchMaskGreen = image->GetMaskGreen();
+ uchMaskBlue = image->GetMaskBlue();
+ }
+
+ unsigned char *pColors = image->GetData();
+
+ for (int y = 0; y != iHeight; ++y)
{
- unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
- for (int x = 0; x < image->GetWidth(); x++)
+ unsigned char *pData = data;
+ for (int x = 0; x != iWidth; x++)
{
- register const int index = x * bytesPerPixel;
- data[index + 0] = *ptr++;
- data[index + 1] = *ptr++;
- data[index + 2] = *ptr++;
+ unsigned char uchRed = *pColors++;
+ unsigned char uchGreen = *pColors++;
+ unsigned char uchBlue = *pColors++;
- if (usesAlpha)
+ switch ( iColorType )
{
- if ( image->HasAlpha() )
- {
- data[index + 3] = image->GetAlpha(x, y);
- }
- else if ( (data[index + 0] != image->GetMaskRed())
- || (data[index + 1] != image->GetMaskGreen())
- || (data[index + 2] != image->GetMaskBlue()) )
- {
- data[index + 3] = 255;
- }
- else
+ default:
+ wxFAIL_MSG( _T("unknown wxPNG_TYPE_XXX") );
+ // fall through
+
+ case wxPNG_TYPE_COLOUR:
+ *pData++ = uchRed;
+ if ( iBitDepth == 16 )
+ *pData++ = 0;
+ *pData++ = uchGreen;
+ if ( iBitDepth == 16 )
+ *pData++ = 0;
+ *pData++ = uchBlue;
+ if ( iBitDepth == 16 )
+ *pData++ = 0;
+ break;
+
+ case wxPNG_TYPE_GREY:
+ {
+ // where do these coefficients come from? maybe we
+ // should have image options for them as well?
+ unsigned uiColor =
+ (unsigned) (76.544*(unsigned)uchRed +
+ 150.272*(unsigned)uchGreen +
+ 36.864*(unsigned)uchBlue);
+
+ *pData++ = (unsigned char)((uiColor >> 8) & 0xFF);
+ if ( iBitDepth == 16 )
+ *pData++ = (unsigned char)(uiColor & 0xFF);
+ }
+ break;
+
+ case wxPNG_TYPE_GREY_RED:
+ *pData++ = uchRed;
+ if ( iBitDepth == 16 )
+ *pData++ = 0;
+ break;
+ }
+
+ if ( bUseAlpha )
+ {
+ unsigned char uchAlpha = 255;
+ if ( bHasAlpha )
+ uchAlpha = *pAlpha++;
+
+ if ( bHasMask )
{
- data[index + 3] = 0;
+ if ( (uchRed == uchMaskRed)
+ && (uchGreen == uchMaskGreen)
+ && (uchBlue == uchMaskBlue) )
+ uchAlpha = 0;
}
+
+ *pData++ = uchAlpha;
+ if ( iBitDepth == 16 )
+ *pData++ = 0;
}
}
+
png_bytep row_ptr = data;
png_write_rows( png_ptr, &row_ptr, 1 );
}