VirtualDevices either match another device depth, or are 1 bit

cairo can therefore always render to a svp virtual device with
need for a fallback

Change-Id: I5d03ae541820389e26f7448444444be009fb28a4

1 files changed, 14 insertions, 11 deletions

diff --git a/desktop/source/lib/init.cxx b/desktop/source/lib/init.cxx
index 68eb01dd67ba..69ff1c3b1aaf 100644
--- a/desktop/source/lib/init.cxx
+++ b/desktop/source/lib/init.cxx
@@ -882,12 +882,12 @@ void doc_paintTile (LibreOfficeKitDocument* pThis,
     SystemGraphicsData aData;
     aData.rCGContext = reinterpret_cast<CGContextRef>(pBuffer);
     // the Size argument is irrelevant, I hope
-    ScopedVclPtrInstance<VirtualDevice> pDevice(&aData, Size(1, 1), DeviceFormat::FULLCOLOR);
+    ScopedVclPtrInstance<VirtualDevice> pDevice(&aData, Size(1, 1), DeviceFormat::DEFAULT);
 
     pDoc->paintTile(*pDevice.get(), nCanvasWidth, nCanvasHeight,
                     nTilePosX, nTilePosY, nTileWidth, nTileHeight);
 #elif defined(ANDROID)
-    ScopedVclPtrInstance< VirtualDevice > pDevice(nullptr, Size(1, 1), DeviceFormat::FULLCOLOR) ;
+    ScopedVclPtrInstance< VirtualDevice > pDevice(nullptr, Size(1, 1), DeviceFormat::DEFAULT) ;
 
     boost::shared_array<sal_uInt8> aBuffer(pBuffer, NoDelete< sal_uInt8 >());
 
@@ -900,20 +900,19 @@ void doc_paintTile (LibreOfficeKitDocument* pThis,
     pDoc->paintTile(*pDevice.get(), nCanvasWidth, nCanvasHeight,
                     nTilePosX, nTilePosY, nTileWidth, nTileHeight);
 #else
-    ScopedVclPtrInstance< VirtualDevice > pDevice(nullptr, Size(1, 1), DeviceFormat::FULLCOLOR) ;
+    ScopedVclPtrInstance< VirtualDevice > pDevice(nullptr, Size(1, 1), DeviceFormat::DEFAULT) ;
 
     // Set background to transparent by default.
-    memset(pBuffer, 0, nCanvasWidth * nCanvasHeight * 4);
     pDevice->SetBackground(Wallpaper(Color(COL_TRANSPARENT)));
 
     boost::shared_array< sal_uInt8 > aBuffer( pBuffer, NoDelete< sal_uInt8 >() );
 
     // Allocate a separate buffer for the alpha device.
-    std::vector<sal_uInt8> aAlpha(nCanvasWidth * nCanvasHeight);
-    memset(aAlpha.data(), 0, nCanvasWidth * nCanvasHeight);
-// TO_DO: enable alpha
-//    boost::shared_array<sal_uInt8> aAlphaBuffer(aAlpha.data(), NoDelete<sal_uInt8>());
-    boost::shared_array<sal_uInt8> aAlphaBuffer;
+    sal_Int32 nStride = basebmp::getBitmapDeviceStrideForWidth(basebmp::Format::ThirtyTwoBitTcMaskBGRX,
+                                                               nCanvasWidth);
+    std::vector<sal_uInt8> aAlpha(nCanvasHeight * nStride);
+
+    boost::shared_array<sal_uInt8> aAlphaBuffer(aAlpha.data(), NoDelete<sal_uInt8>());
 
     pDevice->SetOutputSizePixelScaleOffsetAndBuffer(
                 Size(nCanvasWidth, nCanvasHeight), Fraction(1.0), Point(),
@@ -927,11 +926,15 @@ void doc_paintTile (LibreOfficeKitDocument* pThis,
     {
         for (int nCol = 0; nCol < nCanvasWidth; ++nCol)
         {
-            const int nOffset = (nCanvasWidth * nRow) + nCol;
+            const int nOffset = (nRow * nStride) + nCol * 4;
             // VCL's transparent is 0, RGBA's transparent is 0xff.
-            pBuffer[nOffset * 4 +3] = 0xff - aAlpha[nOffset];
+            pBuffer[nOffset + 3] = 0xff - aAlpha[nOffset];
+            double fAlpha = pBuffer[nOffset + 3]/255.0;
+            for (int i = 0; i < 3; ++i)
+                pBuffer[nOffset + i] *= fAlpha;
         }
     }
+
 #endif
 
     static bool bDebug = getenv("LOK_DEBUG") != nullptr;