convert COLOR_CHANNEL_MERGE to constexpr function

Change-Id: Ie46e0a47b433517b0bae0deabb447ff5c1000f22
Reviewed-on: https://gerrit.libreoffice.org/47595
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

5 files changed, 16 insertions, 14 deletions

diff --git a/include/tools/color.hxx b/include/tools/color.hxx
index 0173840d80ff..1d0d239d5af5 100644
--- a/include/tools/color.hxx
+++ b/include/tools/color.hxx
@@ -192,9 +192,9 @@ inline sal_uInt8 Color::GetLuminance() const
 
 inline void Color::Merge( const Color& rMergeColor, sal_uInt8 cTransparency )
 {
-    SetRed(COLOR_CHANNEL_MERGE(COLORDATA_RED(mnColor), COLORDATA_RED(rMergeColor.mnColor), cTransparency));
-    SetGreen(COLOR_CHANNEL_MERGE(COLORDATA_GREEN(mnColor), COLORDATA_GREEN(rMergeColor.mnColor), cTransparency));
-    SetBlue(COLOR_CHANNEL_MERGE(COLORDATA_BLUE(mnColor), COLORDATA_BLUE(rMergeColor.mnColor), cTransparency));
+    SetRed(ColorChannelMerge(COLORDATA_RED(mnColor), COLORDATA_RED(rMergeColor.mnColor), cTransparency));
+    SetGreen(ColorChannelMerge(COLORDATA_GREEN(mnColor), COLORDATA_GREEN(rMergeColor.mnColor), cTransparency));
+    SetBlue(ColorChannelMerge(COLORDATA_BLUE(mnColor), COLORDATA_BLUE(rMergeColor.mnColor), cTransparency));
 }
 
 #endif
diff --git a/include/tools/colordata.hxx b/include/tools/colordata.hxx
index ffe5a2d14b44..6008d0c0fc24 100644
--- a/include/tools/colordata.hxx
+++ b/include/tools/colordata.hxx
@@ -92,8 +92,10 @@ constexpr ColorData RGB_COLORDATA(sal_uInt8 r, sal_uInt8 g, sal_uInt8 b) {
 #define COL_AUTHOR9_NORMAL          RGB_COLORDATA(255, 226, 185)
 #define COL_AUTHOR9_LIGHT           RGB_COLORDATA(255, 231, 199)
 
-#define COLOR_CHANNEL_MERGE( _def_cDst, _def_cSrc, _def_cSrcTrans ) \
-    ((sal_uInt8)((((long)(_def_cDst)-(_def_cSrc))*(_def_cSrcTrans)+(((_def_cSrc)<<8)|(_def_cDst)))>>8))
+constexpr sal_uInt8 ColorChannelMerge(sal_uInt8 nDst, sal_uInt8 nSrc, sal_uInt8 nSrcTrans)
+{
+    return (sal_uInt8) ((((sal_Int32)nDst-nSrc)*nSrcTrans+((nSrc<<8)|nDst))>>8);
+};
 
 #endif
 
diff --git a/include/vcl/salbtype.hxx b/include/vcl/salbtype.hxx
index ed38c9a41b8a..e9a3bdf599b7 100644
--- a/include/vcl/salbtype.hxx
+++ b/include/vcl/salbtype.hxx
@@ -480,9 +480,9 @@ inline BitmapColor& BitmapColor::Merge( const BitmapColor& rBitmapColor, sal_uIn
 {
     assert( !mbIndex && "Pixel represents index into colortable" );
     assert( !rBitmapColor.mbIndex && "Pixel represents index into colortable" );
-    mcBlueOrIndex = COLOR_CHANNEL_MERGE( mcBlueOrIndex, rBitmapColor.mcBlueOrIndex, cTransparency );
-    mcGreen = COLOR_CHANNEL_MERGE( mcGreen, rBitmapColor.mcGreen, cTransparency );
-    mcRed = COLOR_CHANNEL_MERGE( mcRed, rBitmapColor.mcRed, cTransparency );
+    mcBlueOrIndex = ColorChannelMerge( mcBlueOrIndex, rBitmapColor.mcBlueOrIndex, cTransparency );
+    mcGreen = ColorChannelMerge( mcGreen, rBitmapColor.mcGreen, cTransparency );
+    mcRed = ColorChannelMerge( mcRed, rBitmapColor.mcRed, cTransparency );
 
     return *this;
 }
diff --git a/vcl/source/outdev/bitmap.cxx b/vcl/source/outdev/bitmap.cxx
index e33cfa60bd70..24b1c5403057 100644
--- a/vcl/source/outdev/bitmap.cxx
+++ b/vcl/source/outdev/bitmap.cxx
@@ -867,11 +867,11 @@ public:
 
                 nAlpha  = (nAlphaLine1  + nMapFY * ((nAlphaLine2  >> 7) - (nAlphaLine1 >> 7))) >> 7;
 
-                *pDestScanline = COLOR_CHANNEL_MERGE(*pDestScanline, nColor1, nAlpha);
+                *pDestScanline = ColorChannelMerge(*pDestScanline, nColor1, nAlpha);
                 pDestScanline++;
-                *pDestScanline = COLOR_CHANNEL_MERGE(*pDestScanline, nColor2, nAlpha);
+                *pDestScanline = ColorChannelMerge(*pDestScanline, nColor2, nAlpha);
                 pDestScanline++;
-                *pDestScanline = COLOR_CHANNEL_MERGE(*pDestScanline, nColor3, nAlpha);
+                *pDestScanline = ColorChannelMerge(*pDestScanline, nColor3, nAlpha);
                 pDestScanline++;
                 pDestScanline++;
             }
diff --git a/vcl/source/outdev/transparent.cxx b/vcl/source/outdev/transparent.cxx
index 31d4c946bb36..764389dcbe78 100644
--- a/vcl/source/outdev/transparent.cxx
+++ b/vcl/source/outdev/transparent.cxx
@@ -558,9 +558,9 @@ void OutputDevice::EmulateDrawTransparent ( const tools::PolyPolygon& rPolyPoly,
                                         }
                                         if( ( *pRScan & cBit ) == cBlack )
                                         {
-                                            pWScan[ 0 ] = COLOR_CHANNEL_MERGE( pWScan[ 0 ], nB, cTrans );
-                                            pWScan[ 1 ] = COLOR_CHANNEL_MERGE( pWScan[ 1 ], nG, cTrans );
-                                            pWScan[ 2 ] = COLOR_CHANNEL_MERGE( pWScan[ 2 ], nR, cTrans );
+                                            pWScan[ 0 ] = ColorChannelMerge( pWScan[ 0 ], nB, cTrans );
+                                            pWScan[ 1 ] = ColorChannelMerge( pWScan[ 1 ], nG, cTrans );
+                                            pWScan[ 2 ] = ColorChannelMerge( pWScan[ 2 ], nR, cTrans );
                                         }
                                     }
                                 }