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>

4 files changed, 7 insertions, 7 deletions

diff --git a/filter/qa/cppunit/msfilter-test.cxx b/filter/qa/cppunit/msfilter-test.cxx
index ce7b4b7c4cbd..439aad88b674 100644
--- a/filter/qa/cppunit/msfilter-test.cxx
+++ b/filter/qa/cppunit/msfilter-test.cxx
@@ -56,7 +56,7 @@ void MSFilterTest::testTransColToIco()
     {
         const OString sMessage = "Index of unmatched color: " + OString::number(i);
         CPPUNIT_ASSERT_EQUAL_MESSAGE(sMessage.getStr(), aExpected[i],
-                                     static_cast<sal_uInt16>(msfilter::util::TransColToIco( Color(aStdCol[i]) )));
+                                     static_cast<sal_uInt16>(msfilter::util::TransColToIco( Color(ColorTransparency, aStdCol[i]) )));
     }
 
     // tdf#92471
diff --git a/filter/source/graphicfilter/ieps/ieps.cxx b/filter/source/graphicfilter/ieps/ieps.cxx
index e5753510bbd9..b70407027b7d 100644
--- a/filter/source/graphicfilter/ieps/ieps.cxx
+++ b/filter/source/graphicfilter/ieps/ieps.cxx
@@ -738,7 +738,7 @@ ipsGraphicImport( SvStream & rStream, Graphic & rGraphic, FilterConfigItem* )
                                         if (!bIsValid)
                                             break;
                                         if ( nBitDepth == 1 )
-                                            aBitmap.SetPixel( y, x, Color(static_cast<sal_uInt8>(nDat >> nBitsLeft) & 1) );
+                                            aBitmap.SetPixel( y, x, Color(ColorTransparency, static_cast<sal_uInt8>(nDat >> nBitsLeft) & 1) );
                                         else
                                         {
                                             aBitmap.SetPixel( y, x, nDat ? COL_WHITE : COL_BLACK );  // nBitDepth == 8
diff --git a/filter/source/graphicfilter/itga/itga.cxx b/filter/source/graphicfilter/itga/itga.cxx
index bbaee08117eb..023351c33b4e 100644
--- a/filter/source/graphicfilter/itga/itga.cxx
+++ b/filter/source/graphicfilter/itga/itga.cxx
@@ -638,7 +638,7 @@ bool TGAReader::ImplReadBody()
                                 return false;
                             if ( nDummy >= mpFileHeader->nColorMapLength )
                                 return false;
-                            mpBitmap->SetPixel( nY, nX, Color(nDummy) );
+                            mpBitmap->SetPixel( nY, nX, Color(ColorTransparency, nDummy) );
                         }
                         break;
                     default:
diff --git a/filter/source/msfilter/escherex.cxx b/filter/source/msfilter/escherex.cxx
index 5df267f3f954..31d382796f43 100644
--- a/filter/source/msfilter/escherex.cxx
+++ b/filter/source/msfilter/escherex.cxx
@@ -376,12 +376,12 @@ sal_uInt32 EscherPropertyContainer::GetGradientColor(
         if ( nStartColor & 1 )
         {
             nIntensity = pGradient->StartIntensity;
-            aColor = Color(pGradient->StartColor);
+            aColor = Color(ColorTransparency, pGradient->StartColor);
         }
         else
         {
             nIntensity = pGradient->EndIntensity;
-            aColor = Color(pGradient->EndColor);
+            aColor = Color(ColorTransparency, pGradient->EndColor);
         }
     }
     sal_uInt32  nRed = ( aColor.GetRed() * nIntensity ) / 100;
@@ -1452,7 +1452,7 @@ Graphic lclDrawHatch( const drawing::Hatch& rHatch, const Color& rBackColor, boo
     pVDev->SetLineColor();
     pVDev->SetFillColor(bFillBackground ? rBackColor : COL_TRANSPARENT);
     pVDev->DrawRect(rRect);
-    pVDev->DrawHatch(tools::PolyPolygon(rRect), Hatch(static_cast<HatchStyle>(rHatch.Style), Color(rHatch.Color), rHatch.Distance,
+    pVDev->DrawHatch(tools::PolyPolygon(rRect), Hatch(static_cast<HatchStyle>(rHatch.Style), Color(ColorTransparency, rHatch.Color), rHatch.Distance,
             Degree10(rHatch.Angle)));
     aMtf.Stop();
     aMtf.WindStart();
@@ -1547,7 +1547,7 @@ bool EscherPropertyContainer::CreateGraphicProperties(const uno::Reference<beans
                 Color aBackColor;
                 if ( EscherPropertyValueHelper::GetPropertyValue( aAny, rXPropSet, "FillColor" ) )
                 {
-                    aBackColor = Color(ImplGetColor( *o3tl::doAccess<sal_uInt32>(aAny), false ));
+                    aBackColor = Color(ColorTransparency, ImplGetColor( *o3tl::doAccess<sal_uInt32>(aAny), false ));
                 }
                 bool bFillBackground = false;
                 if ( EscherPropertyValueHelper::GetPropertyValue( aAny, rXPropSet, "FillBackground", true ) )