added support for saving grey and grey-red PNG images (patch 985447)
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@32414 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
parent
04d4e6846e
commit
a4efa72179
@ -619,6 +619,22 @@ If the given option is not present, the function returns $0$. Use
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\helpref{wxImage::HasOption}{wximagehasoption} is $0$ is a possibly valid value
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for the option.
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Options for wxPNGHandler
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\twocolwidtha{5cm}%
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\begin{twocollist}
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\twocolitem{wxIMAGE\_OPTION\_PNG\_FORMAT}{Format for saving a PNG file.}
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\twocolitem{wxIMAGE\_OPTION\_PNG\_BITDEPTH}{Bit depth for every channel (R/G/B/A).}
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\end{twocollist}
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Supported values for wxIMAGE\_OPTION\_PNG\_FORMAT:
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\twocolwidtha{5cm}%
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\begin{twocollist}
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\twocolitem{wxPNG\_TYPE\_COLOUR}{Stores RGB image.}
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\twocolitem{wxPNG\_TYPE\_GREY}{Stores grey image, converts from RGB.}
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\twocolitem{wxPNG\_TYPE\_GREY\_RED}{Stores grey image, uses red value as grey.}
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\end{twocollist}
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\wxheading{See also}
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\helpref{wxImage::SetOption}{wximagesetoption},\rtfsp
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@ -21,6 +21,17 @@
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//-----------------------------------------------------------------------------
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#if wxUSE_LIBPNG
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#define wxIMAGE_OPTION_PNG_FORMAT wxT("PngFormat")
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#define wxIMAGE_OPTION_PNG_BITDEPTH wxT("PngBitDepth")
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enum
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{
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wxPNG_TYPE_COLOUR = 0,
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wxPNG_TYPE_GREY = 2,
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wxPNG_TYPE_GREY_RED = 3,
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};
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class WXDLLEXPORT wxPNGHandler: public wxImageHandler
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{
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public:
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@ -664,57 +664,153 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
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// explanation why this line is mandatory
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png_set_write_fn( png_ptr, &wxinfo, wx_PNG_stream_writer, NULL);
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const bool usesAlpha = (image->HasAlpha() || image->HasMask() );
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const int bytesPerPixel = usesAlpha ? 4 : 3;
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png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
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usesAlpha ? PNG_COLOR_TYPE_RGB_ALPHA : PNG_COLOR_TYPE_RGB,
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PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
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const int iColorType = image->HasOption(wxIMAGE_OPTION_PNG_FORMAT)
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? image->GetOptionInt(wxIMAGE_OPTION_PNG_FORMAT)
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: wxPNG_TYPE_COLOUR;
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const int iBitDepth = image->HasOption(wxIMAGE_OPTION_PNG_BITDEPTH)
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? image->GetOptionInt(wxIMAGE_OPTION_PNG_BITDEPTH)
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: 8;
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wxASSERT_MSG( iBitDepth == 8 || iBitDepth == 16,
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_T("PNG bit depth must be 8 or 16") );
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bool bHasAlpha = image->HasAlpha();
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bool bHasMask = image->HasMask();
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bool bUseAlpha = bHasAlpha || bHasMask;
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int iPngColorType;
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if ( iColorType==wxPNG_TYPE_COLOUR )
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{
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iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_RGB_ALPHA
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: PNG_COLOR_TYPE_RGB;
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}
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else
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{
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iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_GRAY_ALPHA
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: PNG_COLOR_TYPE_GRAY;
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}
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png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(),
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iBitDepth, iPngColorType,
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PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
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PNG_FILTER_TYPE_BASE);
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int iElements;
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png_color_8 sig_bit;
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sig_bit.red = 8;
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sig_bit.green = 8;
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sig_bit.blue = 8;
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sig_bit.alpha = 8;
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if ( iPngColorType & PNG_COLOR_MASK_COLOR )
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{
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sig_bit.red =
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sig_bit.green =
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sig_bit.blue = (png_byte)iBitDepth;
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iElements = 3;
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}
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else // grey
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{
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sig_bit.gray = (png_byte)iBitDepth;
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iElements = 1;
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}
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if ( iPngColorType & PNG_COLOR_MASK_ALPHA )
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{
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sig_bit.alpha = (png_byte)iBitDepth;
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iElements++;
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}
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png_set_sBIT( png_ptr, info_ptr, &sig_bit );
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png_write_info( png_ptr, info_ptr );
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png_set_shift( png_ptr, &sig_bit );
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png_set_packing( png_ptr );
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unsigned char *data = (unsigned char *)malloc( image->GetWidth()*bytesPerPixel );
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if (!data)
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unsigned char *
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data = (unsigned char *)malloc( image->GetWidth() * iElements );
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if ( !data )
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{
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png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
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return false;
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}
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for (int y = 0; y < image->GetHeight(); y++)
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{
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unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
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for (int x = 0; x < image->GetWidth(); x++)
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{
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register const int index = x * bytesPerPixel;
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data[index + 0] = *ptr++;
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data[index + 1] = *ptr++;
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data[index + 2] = *ptr++;
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unsigned char *
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pAlpha = (unsigned char *)(bHasAlpha ? image->GetAlpha() : NULL);
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int iHeight = image->GetHeight();
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int iWidth = image->GetWidth();
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if (usesAlpha)
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unsigned char uchMaskRed = bHasMask ? image->GetMaskRed() : 0;
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unsigned char uchMaskGreen = bHasMask ? image->GetMaskGreen() : 0;
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unsigned char uchMaskBlue = bHasMask ? image->GetMaskBlue() : 0;
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unsigned char *pColors = image->GetData();
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for (int y = 0; y != iHeight; ++y)
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{
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unsigned char *pData = data;
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for (int x = 0; x != iWidth; x++)
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{
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unsigned char uchRed = *pColors++;
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unsigned char uchGreen = *pColors++;
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unsigned char uchBlue = *pColors++;
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switch ( iColorType )
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{
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if ( image->HasAlpha() )
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default:
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wxFAIL_MSG( _T("unknown wxPNG_TYPE_XXX") );
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// fall through
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case wxPNG_TYPE_COLOUR:
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*pData++ = uchRed;
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if (iBitDepth > 8)
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*pData++ = 0;
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*pData++ = uchGreen;
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if (iBitDepth > 8)
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*pData++ = 0;
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*pData++ = uchBlue;
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if (iBitDepth > 8)
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*pData++ = 0;
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break;
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case wxPNG_TYPE_GREY:
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{
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unsigned uiColor =
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(unsigned) (76.544*(unsigned)uchRed +
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150.272*(unsigned)uchGreen +
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36.864*(unsigned)uchBlue);
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uiColor >>= (16 - iBitDepth);
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if (iBitDepth > 8)
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{
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*pData++ = (unsigned char)((uiColor >> 8) & 0xFF);
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*pData++ = (unsigned char)(uiColor & 0xFF);
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} else {
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*pData++ = (unsigned char)(uiColor & 0xFF);
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}
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}
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break;
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case wxPNG_TYPE_GREY_RED:
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*pData++ = uchRed;
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if (iBitDepth > 8)
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*pData++ = 0;
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break;
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}
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if ( bUseAlpha )
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{
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unsigned char uchAlpha = 255;
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if ( bHasAlpha )
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uchAlpha = *pAlpha++;
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if ( bHasMask )
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{
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data[index + 3] = image->GetAlpha(x, y);
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}
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else if ( (data[index + 0] != image->GetMaskRed())
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|| (data[index + 1] != image->GetMaskGreen())
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|| (data[index + 2] != image->GetMaskBlue()) )
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{
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data[index + 3] = 255;
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}
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else
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{
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data[index + 3] = 0;
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if ( (uchRed == uchMaskRed)
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&& (uchGreen == uchMaskGreen)
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&& (uchBlue == uchMaskBlue) )
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uchAlpha = 0;
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}
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*pData++ = uchAlpha;
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if (iBitDepth > 8)
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*pData++ = 0;
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}
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}
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png_bytep row_ptr = data;
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png_write_rows( png_ptr, &row_ptr, 1 );
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}
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