rename ImpBitmap::ImplConvert to ConvertToGreyscale

in preparation for removing ImpBitmap

Change-Id: I1d56f2a4698559e3ff3b321577c29272ab050482
Reviewed-on: https://gerrit.libreoffice.org/52940Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

vcl/inc/impbmp.hxx

@@ -70,7 +70,7 @@ public:
     bool                ImplScalingSupported() const;
     bool                ImplScale( const double& rScaleX, const double& rScaleY, BmpScaleFlag nScaleFlag );
     bool                ImplReplace( const Color& rSearchColor, const Color& rReplaceColor, sal_uInt8 nTol );
-    bool                ImplConvert( BmpConversion eConversion );
+    bool                ConvertToGreyscale();
 };
 
 #endif // INCLUDED_VCL_INC_IMPBMP_HXX

vcl/source/gdi/bitmap3.cxx

@@ -224,12 +224,17 @@ bool Bitmap::Convert( BmpConversion eConversion )
     // try to convert in backend
     if (mxImpBmp)
     {
-        std::shared_ptr<ImpBitmap> xImpBmp(new ImpBitmap);
-        if (xImpBmp->ImplCreate(*mxImpBmp) && xImpBmp->ImplConvert(eConversion))
+        // avoid large chunk of obsolete and hopefully rarely used conversions.
+        if (eConversion == BmpConversion::N8BitGreys)
         {
-            ImplSetImpBitmap(xImpBmp);
-            SAL_INFO( "vcl.opengl", "Ref count: " << mxImpBmp.use_count() );
-            return true;
+            std::shared_ptr<ImpBitmap> xImpBmp(new ImpBitmap);
+            // frequently used conversion for creating alpha masks
+            if (xImpBmp->ImplCreate(*mxImpBmp) && xImpBmp->ConvertToGreyscale())
+            {
+                ImplSetImpBitmap(xImpBmp);
+                SAL_INFO( "vcl.opengl", "Ref count: " << mxImpBmp.use_count() );
+                return true;
+            }
         }
     }
 

vcl/source/gdi/impbmp.cxx

@@ -114,13 +114,8 @@ bool ImpBitmap::ImplReplace( const Color& rSearchColor, const Color& rReplaceCol
     return mpSalBitmap->Replace( rSearchColor, rReplaceColor, nTol );
 }
 
-bool ImpBitmap::ImplConvert( BmpConversion eConversion )
+bool ImpBitmap::ConvertToGreyscale()
 {
-    // avoid large chunk of obsolete and hopefully rarely used conversions.
-    if (eConversion != BmpConversion::N8BitGreys)
-        return false;
-
-    // frequently used conversion for creating alpha masks
     return mpSalBitmap->ConvertToGreyscale();
 }