Resolves: tdf#96224 don't fiddle around with a separate alpha buffer

use a format that supports alpha directly

now we can unify the android and linux cases as well and drop the
BGRX support

Change-Id: I3c845913691d8194822423005d308cfa7ef13ec3
Reviewed-on: https://gerrit.libreoffice.org/20440
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit bc45215ec6e5d508415465ad3f619c3dbe23f7c8)

2 files changed, 4 insertions, 35 deletions

diff --git a/desktop/qa/desktop_lib/test_desktop_lib.cxx b/desktop/qa/desktop_lib/test_desktop_lib.cxx
index 07607dd6b365..987ac1be9618 100644
--- a/desktop/qa/desktop_lib/test_desktop_lib.cxx
+++ b/desktop/qa/desktop_lib/test_desktop_lib.cxx
@@ -316,7 +316,7 @@ void DesktopLOKTest::testPaintTile()
     LibLODocument_Impl* pDocument = loadDoc("blank_text.odt");
     int nCanvasWidth = 100;
     int nCanvasHeight = 300;
-    sal_Int32 nStride = basebmp::getBitmapDeviceStrideForWidth(basebmp::Format::ThirtyTwoBitTcMaskBGRX,
+    sal_Int32 nStride = basebmp::getBitmapDeviceStrideForWidth(basebmp::Format::ThirtyTwoBitTcMaskBGRA,
                                                                nCanvasWidth);
     std::vector<unsigned char> aBuffer(nStride * nCanvasHeight);
     int nTilePosX = 0;
diff --git a/desktop/source/lib/init.cxx b/desktop/source/lib/init.cxx
index 2bdea806e3cf..963bb1bcf072 100644
--- a/desktop/source/lib/init.cxx
+++ b/desktop/source/lib/init.cxx
@@ -886,33 +886,17 @@ void doc_paintTile (LibreOfficeKitDocument* pThis,
 
     pDoc->paintTile(*pDevice.get(), nCanvasWidth, nCanvasHeight,
                     nTilePosX, nTilePosY, nTileWidth, nTileHeight);
-#elif defined(ANDROID)
-    ScopedVclPtrInstance< VirtualDevice > pDevice(nullptr, Size(1, 1), DeviceFormat::DEFAULT) ;
-
-    boost::shared_array<sal_uInt8> aBuffer(pBuffer, NoDelete< sal_uInt8 >());
-
-    boost::shared_array<sal_uInt8> aAlphaBuffer;
-
-    pDevice->SetOutputSizePixelScaleOffsetAndBuffer(
-                Size(nCanvasWidth, nCanvasHeight), Fraction(1.0), Point(),
-                aBuffer, aAlphaBuffer);
-
-    pDoc->paintTile(*pDevice.get(), nCanvasWidth, nCanvasHeight,
-                    nTilePosX, nTilePosY, nTileWidth, nTileHeight);
 #else
     ScopedVclPtrInstance< VirtualDevice > pDevice(nullptr, Size(1, 1), DeviceFormat::DEFAULT) ;
 
+#if !defined(ANDROID)
     // Set background to transparent by default.
     pDevice->SetBackground(Wallpaper(Color(COL_TRANSPARENT)));
+#endif
 
     boost::shared_array< sal_uInt8 > aBuffer( pBuffer, NoDelete< sal_uInt8 >() );
 
-    // Allocate a separate buffer for the alpha device.
-    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>());
+    boost::shared_array<sal_uInt8> aAlphaBuffer;
 
     pDevice->SetOutputSizePixelScaleOffsetAndBuffer(
                 Size(nCanvasWidth, nCanvasHeight), Fraction(1.0), Point(),
@@ -933,21 +917,6 @@ void doc_paintTile (LibreOfficeKitDocument* pThis,
         pDevice->DrawRect(aRect);
         pDevice->Pop();
     }
-
-    // Overwrite pBuffer's alpha channel with the separate alpha buffer.
-    for (int nRow = 0; nRow < nCanvasHeight; ++nRow)
-    {
-        for (int nCol = 0; nCol < nCanvasWidth; ++nCol)
-        {
-            const int nOffset = (nRow * nStride) + nCol * 4;
-            // VCL's transparent is 0, RGBA's transparent is 0xff.
-            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
 
 #else