make the Color constructors explicitly specify transparency

to reduce the churn, we leave the existing constructor in place,
and add a clang plugin to detect when the value passed to the
existing constructor may contain transparency/alpha data.

i.e. we leave expressions like Color(0xffffff) alone, but
warn about any non-constant expression, and any expression
like Color(0xff000000)

Change-Id: Id2ce58e08882d9b7bd0b9f88eca97359dcdbcc8c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/109362
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 1 insertions, 1 deletions

diff --git a/vcl/source/graphic/GraphicObject2.cxx b/vcl/source/graphic/GraphicObject2.cxx
index 82ce4dd07fcf..f2a67a6f8203 100644
--- a/vcl/source/graphic/GraphicObject2.cxx
+++ b/vcl/source/graphic/GraphicObject2.cxx
@@ -476,7 +476,7 @@ void GraphicObject::ImplTransformBitmap( BitmapEx&          rBmpEx,
             }
 
             aBmpEx2.Scale(Size(nPadTotalWidth, nPadTotalHeight));
-            aBmpEx2.Erase( Color(0xFF,0,0,0) );
+            aBmpEx2.Erase( Color(ColorAlpha,0,0,0,0) );
             aBmpEx2.CopyPixel( tools::Rectangle( Point(nPadLeft, nPadTop), aBmpSize ), tools::Rectangle( Point(0, 0), aBmpSize ), &rBmpEx );
             rBmpEx = aBmpEx2;
         }