Revert "Remove unused basegfx::tools::containsOnlyHorizontalAndVerticalEdges"

Is used in vcl/win/source/gdi/salgdi.cxx.

This reverts commit 34fa29ed.

Conflicts:
	unusedcode.easy

Change-Id: I0ee3c2bc0ec5649045ae415b44482f63da360634

basegfx/source/polygon/b2dpolypolygontools.cxx

@@ -497,6 +497,24 @@ namespace basegfx
             return aRetval;
         }
 
+        bool containsOnlyHorizontalAndVerticalEdges(const B2DPolyPolygon& rCandidate)
+        {
+            if(rCandidate.areControlPointsUsed())
+            {
+                return false;
+            }
+
+            for(sal_uInt32 a(0); a < rCandidate.count(); a++)
+            {
+                if(!containsOnlyHorizontalAndVerticalEdges(rCandidate.getB2DPolygon(a)))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
         B2DPolyPolygon createSevenSegmentPolyPolygon(sal_Char nNumber, bool bLitSegments)
         {
             // config here

include/basegfx/polygon/b2dpolypolygontools.hxx

@@ -287,6 +287,11 @@ namespace basegfx
         */
         BASEGFX_DLLPUBLIC B2DPolyPolygon snapPointsOfHorizontalOrVerticalEdges(const B2DPolyPolygon& rCandidate);
 
+        /** returns true if the Polygon only contains horizontal or vertical edges
+            so that it could be represented by RegionBands
+        */
+        BASEGFX_DLLPUBLIC bool containsOnlyHorizontalAndVerticalEdges(const B2DPolyPolygon& rCandidate);
+
         /// converters for com::sun::star::drawing::PointSequence
         BASEGFX_DLLPUBLIC B2DPolyPolygon UnoPointSequenceSequenceToB2DPolyPolygon(
             const com::sun::star::drawing::PointSequenceSequence& rPointSequenceSequenceSource,