public Rectangle GetVisibleRectangleInGraph() { var t = Transform.Inverse; var p0 = new Point(0, 0); var vp = GetCanvasRenderViewport(); var p1 = new Point(vp.Width, vp.Height); var rect=new Rectangle(t*p0, t*p1); if (GeomGraph == null) return rect; return rect.Intersection(GeomGraph.BoundingBox); }