commit e61590d3445172da25bdec04ce6b7158af565eb6
author Mike Kaganski <mike.kaganski@collabora.com> Mon Aug 24 00:13:19 2020 +0300
committer Caolán McNamara <caolanm@redhat.com> Mon Aug 24 10:07:08 2020 +0200
tree b9d472adbf938b52132f110e73ce2179dd4e6b3f
parent 3515423cab85a2ac3e748f252049c3eb59fd6d1a

tdf#136047: fix OutputDevice::DrawTransformBitmapExDirect for ...

transparent bitmap case
This has been broken in commit 9c621ee8ea41a1c53bfeca49827290826785973e,
where transparent bitmap started to override any transparency of vdev
with transparency of its pixels, and not use alpha when drawing RGB when
mpAlphaVDev was present.

Instead, this restores using alpha in RGB output, and blends alpha to
what is already in mpAlphaVDev.

Change-Id: Id82717def4535336450a7118f8bd29a1660c9520
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/101254
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
(cherry picked from commit 9ff0cd1f6b2200940ac51e580809e2a17c4b9550)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/101158
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

vcl/source/outdev/bitmap.cxx

diff --git a/vcl/source/outdev/bitmap.cxx b/vcl/source/outdev/bitmap.cxx
index 83c1843..dcb9a6b 100644
--- a/vcl/source/outdev/bitmap.cxx
+++ b/vcl/source/outdev/bitmap.cxx
@@ -1050,7 +1050,6 @@ bool OutputDevice::DrawTransformBitmapExDirect(
    const basegfx::B2DPoint aTopX(aFullTransform * basegfx::B2DPoint(1.0, 0.0));
    const basegfx::B2DPoint aTopY(aFullTransform * basegfx::B2DPoint(0.0, 1.0));
    SalBitmap* pSalSrcBmp = rBitmapEx.GetBitmap().ImplGetSalBitmap().get();
    SalBitmap* pSalAlphaBmp = nullptr;
    Bitmap aAlphaBitmap;

    if(rBitmapEx.IsTransparent())
@@ -1063,8 +1062,6 @@ bool OutputDevice::DrawTransformBitmapExDirect(
        {
            aAlphaBitmap = rBitmapEx.GetMask();
        }
        if (!mpAlphaVDev)
            pSalAlphaBmp = aAlphaBitmap.ImplGetSalBitmap().get();
    }
    else if (mpAlphaVDev)
    {
@@ -1072,6 +1069,8 @@ bool OutputDevice::DrawTransformBitmapExDirect(
        aAlphaBitmap.Erase(COL_BLACK);
    }

    SalBitmap* pSalAlphaBmp = aAlphaBitmap.ImplGetSalBitmap().get();

    bDone = mpGraphics->DrawTransformedBitmap(
        aNull,
        aTopX,
@@ -1081,7 +1080,12 @@ bool OutputDevice::DrawTransformBitmapExDirect(
        this);

    if (mpAlphaVDev)
        mpAlphaVDev->DrawTransformBitmapExDirect(aFullTransform, BitmapEx(aAlphaBitmap));
    {
        // Merge bitmap alpha to alpha device
        Bitmap aBlack(rBitmapEx.GetSizePixel(), 1);
        aBlack.Erase(COL_BLACK);
        mpAlphaVDev->DrawTransformBitmapExDirect(aFullTransform, BitmapEx(aBlack, aAlphaBitmap));
    }

    return bDone;
};