Arrows to be displayed on the center

JGo
1

Our application requires drawing arrows on the JGoLabeledLink. Other than the from port and the to port i want the arrows to be displayed on the center of all the three segments of the link. how I can get it work?

2

This isn’t perfect, but it was easy to implement:

[code]/*

  • Copyright © Northwoods Software Corporation, 2000-2008. All Rights
  • Reserved.
  • Restricted Rights: Use, duplication, or disclosure by the U.S.
  • Government is subject to restrictions as set forth in subparagraph
  • © (1) (ii) of DFARS 252.227-7013, or in FAR 52.227-19, or in FAR
  • 52.227-14 Alt. III, as applicable.

*/

package com.nwoods.jgo.examples.demo1;

import com.nwoods.jgo.;
import java.awt.;

public class MidArrowLink extends JGoLink {
public MidArrowLink() { }

public MidArrowLink(JGoPort from, JGoPort to) { super(from, to); }

protected void drawArrowHeads(Graphics2D g) {
super.drawArrowHeads(g);
int[] headx = new int[4];
int[] heady = new int[4];

int nPoints = getNumPoints();
if (nPoints < 2) return;
int midEnd = nPoints/2;
int startx, starty, endx, endy;
if (nPoints % 2 == 0) {  // even number of points means odd number of segments
    // get the middle segment (perhaps the only one)
    startx = getPointX(midEnd-1);
    starty = getPointY(midEnd-1);
    endx = getPointX(midEnd);
    endy = getPointY(midEnd);
} else {
    // also find the points on either side of the middle point
    // then figure out if one segment is much longer than the other
    int ax = getPointX(midEnd-1);
    int ay = getPointY(midEnd-1);
    int bx = getPointX(midEnd);
    int by = getPointY(midEnd);
    int cx = getPointX(midEnd+1);
    int cy = getPointY(midEnd+1);
    float d1x = bx-ax;
    float d1y = by-ay;
    float d2x = cx-bx;
    float d2y = cy-by;
    if (d1x*d1x+d1y*d1y >= d2x*d2x+d2y*d2y) {
      startx = ax;
      starty = ay;
      endx = bx;
      endy = by;
    } else {
      startx = bx;
      starty = by;
      endx = cx;
      endy = cy;
    }
}
int mx = (startx+endx)/2;
int my = (starty+endy)/2;
// this has the end point being the middle of the middle segment of the stroke
calculateFilledArrowhead(startx,starty,mx,my, 1, headx,heady);
drawArrowhead(g, true, headx, heady);

}
}[/code]