vcl: Add support for backend-dependent blending of bitmaps (mask and alpha)

Change-Id: Iba64eb42965c86ca5655b9a105ef3f397e033ecf

2 files changed, 54 insertions, 3 deletions

diff --git a/vcl/source/gdi/salgdilayout.cxx b/vcl/source/gdi/salgdilayout.cxx
index 59b39ced9cee..dc419a0b7ef4 100644
--- a/vcl/source/gdi/salgdilayout.cxx
+++ b/vcl/source/gdi/salgdilayout.cxx
@@ -738,6 +738,36 @@ bool SalGraphics::GetNativeControlRegion( ControlType nType, ControlPart nPart,
                                                 rNativeBoundingRegion, rNativeContentRegion );
 }
 
+bool SalGraphics::BlendBitmap( const SalTwoRect& rPosAry,
+                               const SalBitmap& rBitmap,
+                               const OutputDevice *pOutDev )
+{
+    if( (m_nLayout & SAL_LAYOUT_BIDI_RTL) || (pOutDev && pOutDev->IsRTLEnabled()) )
+    {
+        SalTwoRect aPosAry2 = rPosAry;
+        mirror( aPosAry2.mnDestX, aPosAry2.mnDestWidth, pOutDev );
+        return blendBitmap( aPosAry2, rBitmap );
+    }
+    else
+        return blendBitmap( rPosAry, rBitmap );
+}
+
+bool SalGraphics::BlendAlphaBitmap( const SalTwoRect& rPosAry,
+                                    const SalBitmap& rSrcBitmap,
+                                    const SalBitmap& rMaskBitmap,
+                                    const SalBitmap& rAlphaBitmap,
+                                    const OutputDevice *pOutDev )
+{
+    if( (m_nLayout & SAL_LAYOUT_BIDI_RTL) || (pOutDev && pOutDev->IsRTLEnabled()) )
+    {
+        SalTwoRect aPosAry2 = rPosAry;
+        mirror( aPosAry2.mnDestX, aPosAry2.mnDestWidth, pOutDev );
+        return blendAlphaBitmap( aPosAry2, rSrcBitmap, rMaskBitmap, rAlphaBitmap );
+    }
+    else
+        return blendAlphaBitmap( rPosAry, rSrcBitmap, rMaskBitmap, rAlphaBitmap );
+}
+
 bool SalGraphics::DrawAlphaBitmap( const SalTwoRect& rPosAry,
                                    const SalBitmap& rSourceBitmap,
                                    const SalBitmap& rAlphaBitmap,
diff --git a/vcl/source/outdev/bitmap.cxx b/vcl/source/outdev/bitmap.cxx
index 93a04b850372..cb7d594aea89 100644
--- a/vcl/source/outdev/bitmap.cxx
+++ b/vcl/source/outdev/bitmap.cxx
@@ -648,7 +648,7 @@ void OutputDevice::DrawDeviceAlphaBitmap( const Bitmap& rBmp, const AlphaMask& r
         static const char* pDisableNative = getenv( "SAL_DISABLE_NATIVE_ALPHA");
         // #i83087# Naturally, system alpha blending cannot work with
         // separate alpha VDev
-        bool bTryDirectPaint(!mpAlphaVDev && !pDisableNative && !bHMirr && !bVMirr);
+        bool bTryDirectPaint(!pDisableNative && !bHMirr && !bVMirr);
 
         if(bTryDirectPaint)
         {
@@ -662,8 +662,22 @@ void OutputDevice::DrawDeviceAlphaBitmap( const Bitmap& rBmp, const AlphaMask& r
             SalBitmap* pSalSrcBmp = rBmp.ImplGetImpBitmap()->ImplGetSalBitmap();
             SalBitmap* pSalAlphaBmp = rAlpha.ImplGetImpBitmap()->ImplGetSalBitmap();
 
-            if (mpGraphics->DrawAlphaBitmap( aTR, *pSalSrcBmp, *pSalAlphaBmp, this ))
-                return;
+            // try the blen the alpha bitmap with the alpha virtual device
+            if( mpAlphaVDev )
+            {
+                Bitmap aAlphaBitmap( mpAlphaVDev->GetBitmap( aRelPt, aOutSz ) );
+                SalBitmap* pSalAlphaBmp2 = aAlphaBitmap.ImplGetImpBitmap()->ImplGetSalBitmap();
+                if( mpGraphics->BlendAlphaBitmap( aTR, *pSalSrcBmp, *pSalAlphaBmp, *pSalAlphaBmp2, this ) )
+                {
+                    mpAlphaVDev->BlendBitmap( aTR, rAlpha );
+                    return;
+                }
+            }
+            else
+            {
+                if (mpGraphics->DrawAlphaBitmap( aTR, *pSalSrcBmp, *pSalAlphaBmp, this ))
+                    return;
+            }
         }
 
         // we need to make sure OpenGL never reaches this slow code path
@@ -1194,6 +1208,13 @@ namespace
     }
 }
 
+bool OutputDevice::BlendBitmap(
+            const SalTwoRect&   rPosAry,
+            const Bitmap&       rBmp )
+{
+    return mpGraphics->BlendBitmap( rPosAry, *rBmp.ImplGetImpBitmap()->ImplGetSalBitmap(), this );
+}
+
 Bitmap OutputDevice::BlendBitmapWithAlpha(
             Bitmap&             aBmp,
             BitmapReadAccess*   pP,