/*
    * 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.transform;
  
  import java.awt.Component;
  import java.awt.Dimension;
  import java.awt.Shape;
  import java.awt.event.ComponentAdapter;
  import java.awt.event.ComponentEvent;
  import java.awt.geom.AffineTransform;
  import java.awt.geom.Ellipse2D;
  import java.awt.geom.Point2D;
  import java.awt.geom.Rectangle2D;
  import java.awt.geom.RectangularShape;
  
  /**
   * LensTransformer wraps a MutableAffineTransformer and modifies
   * the transform and inverseTransform methods so that they create a
   * projection of the graph points within an elliptical lens.
   * 
   * LensTransformer uses an
   * affine transform to cause translation, scaling, rotation, and shearing
   * while applying a possibly non-affine filter in its transform and
   * inverseTransform methods.
   * 
   * @author Tom Nelson
   */
  public abstract class LensTransformer extends MutableTransformerDecorator implements MutableTransformer {
  
      /**
       * the area affected by the transform
       */
      protected RectangularShape lensShape = new Ellipse2D.Float();
      
      protected float magnification = 0.7f;
      
      /**
       * Create an instance with a possibly shared transform.
       * 
       * @param component the component used for rendering
       * @param delegate the transformer to use
       */
      public LensTransformer(Component component, MutableTransformer delegate) {
      		super(delegate);
          setComponent(component);
          component.addComponentListener(new ComponentListenerImpl());
     }
      
      /**
       * Set values from the passed component.
       * @param component the component used for rendering
       */
      private void setComponent(Component component) {
          Dimension d = component.getSize();
          if(d.width <= 0 || d.height <= 0) {
              d = component.getPreferredSize();
          }
          float ewidth = d.width/1.5f;
          float eheight = d.height/1.5f;
          lensShape.setFrame(d.width/2-ewidth/2, d.height/2-eheight/2, ewidth, eheight);
      }
      
      public float getMagnification() {
          return magnification;
      }
  
      public void setMagnification(float magnification) {
          this.magnification = magnification;
      }
      
      public Point2D getViewCenter() {
          return new Point2D.Double(lensShape.getCenterX(), lensShape.getCenterY());
      }
  
      public void setViewCenter(Point2D viewCenter) {
          double width = lensShape.getWidth();
          double height = lensShape.getHeight();
          lensShape.setFrame(viewCenter.getX()-width/2,
                  viewCenter.getY()-height/2,
                  width, height);
      }
  
      public double getViewRadius() {
          return lensShape.getHeight()/2;
      }
  
      public void setViewRadius(double viewRadius) {
          double x = lensShape.getCenterX();
          double y = lensShape.getCenterY();
          double viewRatio = getRatio();
          lensShape.setFrame(x-viewRadius/viewRatio,
                  y-viewRadius,
                  2*viewRadius/viewRatio,
                 2*viewRadius);
     }
     
     /**
      * @return the ratio between the lens height and lens width
      */
     public double getRatio() {
         return lensShape.getHeight()/lensShape.getWidth();
     }
     
     public void setLensShape(RectangularShape ellipse) {
         this.lensShape = ellipse;
     }
     public RectangularShape getLensShape() {
         return lensShape;
     }
     public void setToIdentity() {
         this.delegate.setToIdentity();
     }
 
     /**
      * react to size changes on a component
      */
     protected class ComponentListenerImpl extends ComponentAdapter {
         public void componentResized(ComponentEvent e) {
             setComponent(e.getComponent());
          }
     }
     
     /**
      * override base class transform to project the fisheye effect
      */
     public abstract Point2D transform(Point2D graphPoint);
     
     /**
      * override base class to un-project the fisheye effect
      */
     public abstract Point2D inverseTransform(Point2D viewPoint);
     
     public double getDistanceFromCenter(Point2D p) {
     	
         double dx = lensShape.getCenterX()-p.getX();
         double dy = lensShape.getCenterY()-p.getY();
         dx *= getRatio();
         return Math.sqrt(dx*dx + dy*dy);
     }
     
     /**
      * return the supplied shape, translated to the coordinates
      * that result from calling transform on its center
      */
     public Shape transform(Shape shape) {
     	Rectangle2D bounds = shape.getBounds2D();
     	Point2D center = new Point2D.Double(bounds.getCenterX(),bounds.getCenterY());
     	Point2D newCenter = transform(center);
     	double dx = newCenter.getX()-center.getX();
     	double dy = newCenter.getY()-center.getY();
     	AffineTransform at = AffineTransform.getTranslateInstance(dx,dy);
     	return at.createTransformedShape(shape);
     }
     
     /**
      * Returns the supplied shape, translated to the coordinates
      * that result from calling inverseTransform on its center.
      */
     public Shape inverseTransform(Shape shape) {
     	Rectangle2D bounds = shape.getBounds2D();
     	Point2D center = new Point2D.Double(bounds.getCenterX(),bounds.getCenterY());
     	Point2D newCenter = inverseTransform(center);
     	double dx = newCenter.getX()-center.getX();
     	double dy = newCenter.getY()-center.getY();
     	AffineTransform at = AffineTransform.getTranslateInstance(dx,dy);
     	return at.createTransformedShape(shape);
     }
 
 }