move cairo extract bitmap code from canvas to vcl

part of making GetMask/GetAlpha an internal detail of vcl

Change-Id: I45c2e9fdae08d7f444a64e8e04a6f65bb525cbd1
Reviewed-on: https://gerrit.libreoffice.org/51417
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 291 insertions, 0 deletions

diff --git a/vcl/source/bitmap/BitmapTools.cxx b/vcl/source/bitmap/BitmapTools.cxx
index 3abd1ca537b9..816bad119e13 100644
--- a/vcl/source/bitmap/BitmapTools.cxx
+++ b/vcl/source/bitmap/BitmapTools.cxx
@@ -648,6 +648,297 @@ css::uno::Sequence< sal_Int8 > GetMaskDIB(BitmapEx const & aBmpEx)
     return css::uno::Sequence< sal_Int8 >();
 }
 
+static sal_uInt8 lcl_GetColor(BitmapColor const& rColor)
+{
+    sal_uInt8 nTemp(0);
+    if (rColor.IsIndex())
+    {
+        nTemp = rColor.GetIndex();
+    }
+    else
+    {
+        nTemp = rColor.GetBlue();
+        // greyscale expected here, or what would non-grey colors mean?
+        assert(rColor.GetRed() == nTemp && rColor.GetGreen() == nTemp);
+    }
+    return nTemp;
+}
+
+
+static bool readAlpha( BitmapReadAccess const * pAlphaReadAcc, long nY, const long nWidth, unsigned char* data, long nOff )
+{
+    bool bIsAlpha = false;
+    long nX;
+    int nAlpha;
+    Scanline pReadScan;
+
+    nOff += 3;
+
+    switch( pAlphaReadAcc->GetScanlineFormat() )
+    {
+        case ScanlineFormat::N8BitTcMask:
+            pReadScan = pAlphaReadAcc->GetScanline( nY );
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+                nAlpha = data[ nOff ] = 255 - ( *pReadScan++ );
+                if( nAlpha != 255 )
+                    bIsAlpha = true;
+                nOff += 4;
+            }
+            break;
+        case ScanlineFormat::N8BitPal:
+            pReadScan = pAlphaReadAcc->GetScanline( nY );
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+                BitmapColor const& rColor(
+                    pAlphaReadAcc->GetPaletteColor(*pReadScan));
+                pReadScan++;
+                nAlpha = data[ nOff ] = 255 - lcl_GetColor(rColor);
+                if( nAlpha != 255 )
+                    bIsAlpha = true;
+                nOff += 4;
+            }
+            break;
+        default:
+            SAL_INFO( "canvas.cairo", "fallback to GetColor for alpha - slow, format: " << static_cast<int>(pAlphaReadAcc->GetScanlineFormat()) );
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+                nAlpha = data[ nOff ] = 255 - pAlphaReadAcc->GetColor( nY, nX ).GetIndex();
+                if( nAlpha != 255 )
+                    bIsAlpha = true;
+                nOff += 4;
+            }
+    }
+
+    return bIsAlpha;
+}
+
+
+
+/**
+ * @param data will be filled with alpha data, if xBitmap is alpha/transparent image
+ * @param bHasAlpha will be set to true if resulting surface has alpha
+ **/
+void CanvasCairoExtractBitmapData( BitmapEx & aBmpEx, Bitmap & aBitmap, unsigned char*& data, bool& bHasAlpha )
+{
+    AlphaMask aAlpha = aBmpEx.GetAlpha();
+
+    ::BitmapReadAccess* pBitmapReadAcc = aBitmap.AcquireReadAccess();
+    ::BitmapReadAccess* pAlphaReadAcc = nullptr;
+    const long      nWidth = pBitmapReadAcc->Width();
+    const long      nHeight = pBitmapReadAcc->Height();
+    long nX, nY;
+    bool bIsAlpha = false;
+
+    if( aBmpEx.IsTransparent() || aBmpEx.IsAlpha() )
+        pAlphaReadAcc = aAlpha.AcquireReadAccess();
+
+    data = static_cast<unsigned char*>(malloc( nWidth*nHeight*4 ));
+
+    long nOff = 0;
+    ::Color aColor;
+    unsigned int nAlpha = 255;
+
+    for( nY = 0; nY < nHeight; nY++ )
+    {
+        ::Scanline pReadScan;
+
+        switch( pBitmapReadAcc->GetScanlineFormat() )
+        {
+        case ScanlineFormat::N8BitPal:
+            pReadScan = pBitmapReadAcc->GetScanline( nY );
+            if( pAlphaReadAcc )
+                if( readAlpha( pAlphaReadAcc, nY, nWidth, data, nOff ) )
+                    bIsAlpha = true;
+
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+#ifdef OSL_BIGENDIAN
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff++ ];
+                else
+                    nAlpha = data[ nOff++ ] = 255;
+#else
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff + 3 ];
+                else
+                    nAlpha = data[ nOff + 3 ] = 255;
+#endif
+                aColor = pBitmapReadAcc->GetPaletteColor(*pReadScan++).GetColor();
+
+#ifdef OSL_BIGENDIAN
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( aColor.GetRed() ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( aColor.GetGreen() ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( aColor.GetBlue() ) )/255 );
+#else
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( aColor.GetBlue() ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( aColor.GetGreen() ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( aColor.GetRed() ) )/255 );
+                nOff++;
+#endif
+            }
+            break;
+        case ScanlineFormat::N24BitTcBgr:
+            pReadScan = pBitmapReadAcc->GetScanline( nY );
+            if( pAlphaReadAcc )
+                if( readAlpha( pAlphaReadAcc, nY, nWidth, data, nOff ) )
+                    bIsAlpha = true;
+
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+#ifdef OSL_BIGENDIAN
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff ];
+                else
+                    nAlpha = data[ nOff ] = 255;
+                data[ nOff + 3 ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff + 2 ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff + 1 ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                nOff += 4;
+#else
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff + 3 ];
+                else
+                    nAlpha = data[ nOff + 3 ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                nOff++;
+#endif
+            }
+            break;
+        case ScanlineFormat::N24BitTcRgb:
+            pReadScan = pBitmapReadAcc->GetScanline( nY );
+            if( pAlphaReadAcc )
+                if( readAlpha( pAlphaReadAcc, nY, nWidth, data, nOff ) )
+                    bIsAlpha = true;
+
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+#ifdef OSL_BIGENDIAN
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff++ ];
+                else
+                    nAlpha = data[ nOff++ ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+#else
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff + 3 ];
+                else
+                    nAlpha = data[ nOff + 3 ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 2 ] ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 1 ] ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 0 ] ) )/255 );
+                pReadScan += 3;
+                nOff++;
+#endif
+            }
+            break;
+        case ScanlineFormat::N32BitTcBgra:
+            pReadScan = pBitmapReadAcc->GetScanline( nY );
+            if( pAlphaReadAcc )
+                if( readAlpha( pAlphaReadAcc, nY, nWidth, data, nOff ) )
+                    bIsAlpha = true;
+
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+#ifdef OSL_BIGENDIAN
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff++ ];
+                else
+                    nAlpha = data[ nOff++ ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 2 ] ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 1 ] ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 0 ] ) )/255 );
+                pReadScan += 4;
+#else
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff + 3 ];
+                else
+                    nAlpha = data[ nOff + 3 ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                pReadScan++;
+                nOff++;
+#endif
+            }
+            break;
+        case ScanlineFormat::N32BitTcRgba:
+            pReadScan = pBitmapReadAcc->GetScanline( nY );
+            if( pAlphaReadAcc )
+                if( readAlpha( pAlphaReadAcc, nY, nWidth, data, nOff ) )
+                    bIsAlpha = true;
+
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+#ifdef OSL_BIGENDIAN
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff ++ ];
+                else
+                    nAlpha = data[ nOff ++ ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( *pReadScan++ ) )/255 );
+                pReadScan++;
+#else
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff + 3 ];
+                else
+                    nAlpha = data[ nOff + 3 ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 2 ] ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 1 ] ) )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*( pReadScan[ 0 ] ) )/255 );
+                pReadScan += 4;
+                nOff++;
+#endif
+            }
+            break;
+        default:
+            SAL_INFO( "canvas.cairo", "fallback to GetColor - slow, format: " << static_cast<int>(pBitmapReadAcc->GetScanlineFormat()) );
+
+            if( pAlphaReadAcc )
+                if( readAlpha( pAlphaReadAcc, nY, nWidth, data, nOff ) )
+                    bIsAlpha = true;
+
+            for( nX = 0; nX < nWidth; nX++ )
+            {
+                aColor = pBitmapReadAcc->GetColor( nY, nX ).GetColor();
+
+                // cairo need premultiplied color values
+                // TODO(rodo) handle endianness
+#ifdef OSL_BIGENDIAN
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff++ ];
+                else
+                    nAlpha = data[ nOff++ ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*aColor.GetRed() )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*aColor.GetGreen() )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*aColor.GetBlue() )/255 );
+#else
+                if( pAlphaReadAcc )
+                    nAlpha = data[ nOff + 3 ];
+                else
+                    nAlpha = data[ nOff + 3 ] = 255;
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*aColor.GetBlue() )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*aColor.GetGreen() )/255 );
+                data[ nOff++ ] = sal::static_int_cast<unsigned char>(( nAlpha*aColor.GetRed() )/255 );
+                nOff ++;
+#endif
+            }
+        }
+    }
+
+    ::Bitmap::ReleaseAccess( pBitmapReadAcc );
+    if( pAlphaReadAcc )
+        aAlpha.ReleaseAccess( pAlphaReadAcc );
+
+    bHasAlpha = bIsAlpha;
+
+}
+
 }} // end vcl::bitmap
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */