restore SvtGraphicStroke::set[Start|End]Arrow

partial revert of 743e627b
because we want to use that then unused code now

Change-Id: I94fe173dda053ce1b72b3b776a9855ce9ecc249b

include/vcl/graphictools.hxx

@@ -142,6 +142,34 @@ public:
     // mutators
     /// Set path to stroke
     void    setPath             ( const Polygon& );
+    /** Set the polygon that is put at the start of the line
+
+        The polygon has to be in a special normalized position, and
+        already scaled to the desired size: the center of the stroked
+        path will meet the given polygon at (0,0) from negative y
+        values. Thus, an arrow would have its baseline on the x axis,
+        going upwards to positive y values. Furthermore, the polygon
+        also has to be scaled appropriately: the width of the joining
+        stroke is defined to be SvtGraphicStroke::normalizedArrowWidth
+        (0x10000), i.e. ranging from x=-0x8000 to x=0x8000. If your
+        arrow does have this width, it will fit every stroke with
+        every stroke width exactly.
+     */
+    void    setStartArrow       ( const PolyPolygon& );
+    /** Set the polygon that is put at the end of the line
+
+        The polygon has to be in a special normalized position, and
+        already scaled to the desired size: the center of the stroked
+        path will meet the given polygon at (0,0) from negative y
+        values. Thus, an arrow would have its baseline on the x axis,
+        going upwards to positive y values. Furthermore, the polygon
+        also has to be scaled appropriately: the width of the joining
+        stroke is defined to be SvtGraphicStroke::normalizedArrowWidth
+        (0x10000), i.e. ranging from x=-0x8000 to x=0x8000. If your
+        arrow does have this width, it will fit every stroke with
+        every stroke width exactly.
+     */
+    void    setEndArrow         ( const PolyPolygon& );
     /// Affine scaling in both X and Y dimensions
     void    scale               ( double fScaleX, double fScaleY );
 

vcl/source/gdi/graphictools.cxx

@@ -111,6 +111,17 @@ void SvtGraphicStroke::setPath( const Polygon& rPoly )
     maPath = rPoly;
 }
 
+void SvtGraphicStroke::setStartArrow( const PolyPolygon& rPoly )
+{
+    maStartArrow = rPoly;
+}
+
+void SvtGraphicStroke::setEndArrow( const PolyPolygon& rPoly )
+{
+    maEndArrow = rPoly;
+}
+
+
 void SvtGraphicStroke::scale( double fXScale, double fYScale )
 {
     // Clearly scaling stroke-width for fat lines is rather a problem