/*
    * Copyright (c) 2003, 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.
    * 
    */
   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;
  
  /**
   * Scales to the absolute value passed as an argument.
   * It first resets the scaling Functions, then uses
   * the relative CrossoverScalingControl to achieve the
   * absolute value.
   * 
   * @author Tom Nelson 
   *
   */
  public class AbsoluteCrossoverScalingControl extends CrossoverScalingControl
          implements ScalingControl {
  
  	/**
       * Scale to the absolute value passed as 'amount'.
  	 * 
  	 * @param vv the VisualizationServer used for rendering; provides the layout and view transformers.
  	 * @param amount the amount by which to scale
  	 * @param at the point of reference for scaling
  	 */
  	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;
          
          Point2D transformedAt
          	= vv.getRenderContext().getMultiLayerTransformer().inverseTransform(Layer.VIEW, at);
          
          // return the Functions to 1.0
          layoutTransformer.scale(inverseModelScale, inverseModelScale, transformedAt);
          viewTransformer.scale(inverseViewScale, inverseViewScale, at);
  
          super.scale(vv, amount, at);
      }
  }