/*
    * Copyright (c) 2005, The JUNG Authors 
    *
    * All rights reserved.
    *
    * This software is open-source under the BSD license; see either
    * "license.txt" or
    * https://github.com/jrtom/jung/blob/master/LICENSE for a description.
    * Created on Mar 8, 2005
   *
   */
  package edu.uci.ics.jung.visualization.control;
  
  import java.awt.geom.Point2D;
  
  import edu.uci.ics.jung.visualization.Layer;
  import edu.uci.ics.jung.visualization.VisualizationServer;
  import edu.uci.ics.jung.visualization.transform.MutableTransformer;
  
  /** 
   * A scaling control that has a crossover point.
   * When the overall scale of the view and
   * model is less than the crossover point, the scaling is applied
   * to the view's transform and the graph nodes, labels, etc grow
   * smaller. This preserves the overall shape of the graph.
   * When the scale is larger than the crossover, the scaling is
   * applied to the graph layout. The graph spreads out, but the
   * vertices and labels grow no larger than their original size. 
   * 
   * @author Tom Nelson
   */
  public class CrossoverScalingControl implements ScalingControl {
  
      /**
       * Point where scale crosses over from view to layout.
       */
      protected double crossover = 1.0;
      
      /**
       * Sets the crossover point to the specified value.
       * @param crossover the crossover point to use (defaults to 1.0)
       */
  	public void setCrossover(double crossover) {
  	    this.crossover = crossover;
  	}
  
      /**
       * @return the current crossover value
       */
      public double getCrossover() {
          return crossover;
      }
      
  	public void scale(VisualizationServer<?,?> vv, float amount, Point2D at) {
  	        
  	    MutableTransformer layoutTransformer = vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.LAYOUT);
  	    MutableTransformer viewTransformer = vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.VIEW);
  	    double modelScale = layoutTransformer.getScale();
  	    double viewScale = viewTransformer.getScale();
  	    double inverseModelScale = Math.sqrt(crossover)/modelScale;
  	    double inverseViewScale = Math.sqrt(crossover)/viewScale;
  	    double scale = modelScale * viewScale;
  	    
  	    Point2D transformedAt = vv.getRenderContext().getMultiLayerTransformer().inverseTransform(Layer.VIEW, at);
  	    
          if((scale*amount - crossover)*(scale*amount - crossover) < 0.001) {
              // close to the control point, return both Functions to a scale of sqrt crossover value
              layoutTransformer.scale(inverseModelScale, inverseModelScale, transformedAt);
              viewTransformer.scale(inverseViewScale, inverseViewScale, at);
          } else if(scale*amount < crossover) {
              // scale the viewTransformer, return the layoutTransformer to sqrt crossover value
  	        viewTransformer.scale(amount, amount, at);
  	        layoutTransformer.scale(inverseModelScale, inverseModelScale, transformedAt);
  	    } else {
              // scale the layoutTransformer, return the viewTransformer to crossover value
  	        layoutTransformer.scale(amount, amount, transformedAt);
  	        viewTransformer.scale(inverseViewScale, inverseViewScale, at);
  	    }
  	    vv.repaint();
  	}
  }