ArcDrawer.java

 public class ArcDrawer extends AWTDrawVisitor  {
        
        private Graphics2D g2;
        
        public ArcDrawer(Graphics2D g) {
            super(g);
            this.g2 = g;
        }

        @Override
        public void visit(IRenderingElement element) {
           if (element instanceof ArcElement) {
               visit((ArcElement) element);
           } else {
               super.visit(element);
           }
           
        }
        
        public void visit(ArcElement arc) {
            
            // transform the arc endpoints into the diagonal corners of a rect
            double fudge = (arc.orientation == ArcElement.Orientation.N)?
                    0.75 : -0.75;
            int[] p1 = this.transformPoint(arc.x1, arc.y1 + arc.h + fudge);
            int[] p2 = this.transformPoint(arc.x2, arc.y2 - arc.h + fudge);
            Color savedColor = g2.getColor();
            this.g2.setColor(arc.color);
            int x = p1[0];
            int y = p1[1];
            int w = Math.abs(p2[0] - p1[0]);
            int h = Math.abs(p2[1] - p1[1]);
//            System.out.println(
//                    String.format("Arc %d %d %d %d %d %d %d %d %f",
//                            x, y, w, h, p1[0], p1[1], p2[0], p2[1], arc.h));
            if (arc.orientation == ArcElement.Orientation.N) {
                this.g2.drawArc(x, y, w, h, 0, 180);
            } else {
                this.g2.drawArc(x, y, w, h, 0, -180);
            }
            g2.setColor(savedColor);
        }
        
    }