DrawPolygonGradient
virtual void DrawPolygonGradient(size_t numPoints, const BPoint points[], bool isClosed,
virtual void DrawPolygonGradient(size_t numPoints, const BPoint points[], bool isClosed,
callbacks.DrawPolygonGradient(*numPoints, points, isClosed, *gradient,
virtual void DrawPolygonGradient(size_t numPoints, const BPoint points[], bool isClosed,
virtual void DrawPolygonGradient(size_t numPoints, const BPoint points[], bool isClosed,