alpha.cxx

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 * This file incorporates work covered by the following license notice:
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#include <vcl/bitmapaccess.hxx>
#include <tools/color.hxx>
#include <vcl/alpha.hxx>
#include <bitmapwriteaccess.hxx>
#include <sal/log.hxx>

AlphaMask::AlphaMask() = default;

AlphaMask::AlphaMask( const Bitmap& rBitmap ) :
    Bitmap( rBitmap )
{
    if( !!rBitmap )
        Convert( BmpConversion::N8BitNoConversion );
}

AlphaMask::AlphaMask( const AlphaMask& ) = default;

AlphaMask::AlphaMask( AlphaMask&& ) = default;

AlphaMask::AlphaMask( const Size& rSizePixel, const sal_uInt8* pEraseTransparency ) :
    Bitmap( rSizePixel, 8, &Bitmap::GetGreyPalette( 256 ) )
{
    if( pEraseTransparency )
        Bitmap::Erase( Color( *pEraseTransparency, *pEraseTransparency, *pEraseTransparency ) );
}

AlphaMask::~AlphaMask() = default;

AlphaMask& AlphaMask::operator=( const Bitmap& rBitmap )
{
    *static_cast<Bitmap*>(this) = rBitmap;

    if( !!rBitmap )
        Convert( BmpConversion::N8BitNoConversion );

    return *this;
}

const Bitmap& AlphaMask::ImplGetBitmap() const
{
    return *this;
}

void AlphaMask::ImplSetBitmap( const Bitmap& rBitmap )
{
    SAL_WARN_IF( 8 != rBitmap.GetBitCount(), "vcl.gdi", "Bitmap should be 8bpp, not " << rBitmap.GetBitCount() << "bpp" );
    SAL_WARN_IF( !rBitmap.HasGreyPalette(), "vcl.gdi", "Bitmap isn't greyscale" );
    *static_cast<Bitmap*>(this) = rBitmap;
}

Bitmap const & AlphaMask::GetBitmap() const
{
    return ImplGetBitmap();
}

void AlphaMask::Erase( sal_uInt8 cTransparency )
{
    Bitmap::Erase( Color( cTransparency, cTransparency, cTransparency ) );
}

void AlphaMask::Replace( const Bitmap& rMask, sal_uInt8 cReplaceTransparency )
{
    Bitmap::ScopedReadAccess pMaskAcc( const_cast<Bitmap&>(rMask) );
    AlphaScopedWriteAccess pAcc(*this);

    if( pMaskAcc && pAcc )
    {
        const BitmapColor   aReplace( cReplaceTransparency );
        const long          nWidth = std::min( pMaskAcc->Width(), pAcc->Width() );
        const long          nHeight = std::min( pMaskAcc->Height(), pAcc->Height() );
        const BitmapColor   aMaskWhite( pMaskAcc->GetBestMatchingColor( COL_WHITE ) );

        for( long nY = 0; nY < nHeight; nY++ )
        {
            Scanline pScanline = pAcc->GetScanline(nY);
            Scanline pScanlineMask = pMaskAcc->GetScanline(nY);
            for( long nX = 0; nX < nWidth; nX++ )
                if( pMaskAcc->GetPixelFromData( pScanlineMask, nX ) == aMaskWhite )
                    pAcc->SetPixelOnData( pScanline, nX, aReplace );
        }
    }
}

void AlphaMask::Replace( sal_uInt8 cSearchTransparency, sal_uInt8 cReplaceTransparency )
{
    AlphaScopedWriteAccess pAcc(*this);

    if( pAcc && pAcc->GetBitCount() == 8 )
    {
        const long nWidth = pAcc->Width(), nHeight = pAcc->Height();

        if( pAcc->GetScanlineFormat() == ScanlineFormat::N8BitPal )
        {
            for( long nY = 0; nY < nHeight; nY++ )
            {
                Scanline pScan = pAcc->GetScanline( nY );

                for( long nX = 0; nX < nWidth; nX++, pScan++ )
                {
                    if( *pScan == cSearchTransparency )
                        *pScan = cReplaceTransparency;
                }
            }
        }
        else
        {
            BitmapColor aReplace( cReplaceTransparency );

            for( long nY = 0; nY < nHeight; nY++ )
            {
                Scanline pScanline = pAcc->GetScanline(nY);
                for( long nX = 0; nX < nWidth; nX++ )
                {
                    if( pAcc->GetIndexFromData( pScanline, nX ) == cSearchTransparency )
                        pAcc->SetPixelOnData( pScanline, nX, aReplace );
                }
            }
        }
    }
}

void AlphaMask::ReleaseAccess( BitmapReadAccess* pAccess )
{
    if( pAccess )
    {
        Bitmap::ReleaseAccess( pAccess );
        Convert( BmpConversion::N8BitNoConversion );
    }
}

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