bundles/org.simantics.debug.graphical/src/org/simantics/debug/graphical/layout/LayoutAlgorithm.java

   1 package org.simantics.debug.graphical.layout;
   2
   3 public class LayoutAlgorithm {
   4
   5     final double OPTIMAL_DISTANCE = 150.0;
   6     final double C = 0.1;
   7     final double K = C / OPTIMAL_DISTANCE;
   8     final double G = K;
   9     final double Q = C * OPTIMAL_DISTANCE * OPTIMAL_DISTANCE;
  10     final double TOLERANCE = 1e-3;
  11     final int MAX_ITERATIONS = 10000;
  12     final double MAX_MOVE2 = 40000.0;
  13
  14     int size;
  15     double[] posX;
  16     double[] posY;
  17     double[] forceX;
  18     double[] forceY;
  19
  20     int[][] neighbors;
  21
  22     public LayoutAlgorithm(int[][] neighbors) {
  23         this.size = neighbors.length;
  24         this.neighbors = neighbors;
  25         this.posX = new double[size];
  26         this.posY = new double[size];
  27         this.forceX = new double[size];
  28         this.forceY = new double[size];
  29     }
  30
  31     public double[] getPosX() {
  32         return posX;
  33     }
  34
  35     public double[] getPosY() {
  36         return posY;
  37     }
  38
  39     private void computeForces() {
  40         for(int i=0;i<size;++i) {
  41             double x = posX[i];
  42             double y = posY[i];
  43             double fx = -G * x;
  44             double fy = -G * y;
  45
  46             for(int j=0;j<size;++j)
  47                 if(j != i) {
  48                     double dx = posX[j] - x;
  49                     double dy = posY[j] - y;
  50                     double l2 = dx*dx + dy*dy;
  51                     /*double l = Math.sqrt(l2);
  52                     double l3 = l*l2;*/
  53                     fx -= Q * dx / l2;
  54                     fy -= Q * dy / l2;
  55                 }
  56
  57             for(int j : neighbors[i]) {
  58                 double dx = posX[j] - x;
  59                 double dy = posY[j] - y;
  60                 double l2 = dx*dx + dy*dy;
  61                 double l = Math.sqrt(l2);
  62                 fx += K * l * dx;
  63                 fy += K * l * dy;
  64             }
  65
  66             forceX[i] = fx;
  67             forceY[i] = fy;
  68         }
  69     }
  70
  71     private boolean converged() {
  72         for(int i=0;i<size;++i) {
  73             double fx = forceX[i];
  74             double fy = forceY[i];
  75             double f2 = fx*fx + fy*fy;
  76             if(f2 > TOLERANCE)
  77                 return false;
  78         }
  79         return true;
  80     }
  81
  82     private void moveAll() {
  83         for(int i=0;i<size;++i) {
  84             double fx = forceX[i];
  85             double fy = forceY[i];
  86             double f2 = fx*fx + fy*fy;
  87             if(f2 > MAX_MOVE2) {
  88                 double s = Math.sqrt(MAX_MOVE2 / f2);
  89                 fx *= s;
  90                 fy *= s;
  91             }
  92             posX[i] += fx;
  93             posY[i] += fy;
  94         }
  95         computeForces();
  96     }
  97
  98     public void optimize() {
  99         computeForces();
 100
 101         for(int iter=0;iter<MAX_ITERATIONS;++iter) {
 102             if(converged())
 103                 break;
 104             moveAll();
 105         }
 106     }
 107 }