datacanvas.java

ALGAE是一个快速创建算法演示的框架。目前支持的算法实现语言包括java和c

package edu.odu.cs.zeil.AlgAE.Client.DataViewer;

import java.awt.*;

import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import java.util.Enumeration;

import edu.odu.cs.zeil.AlgAE.Client.GraphicsInfo;
import edu.odu.cs.zeil.AlgAE.Client.MessageDispatcher;

import edu.odu.cs.zeil.AlgAE.Client.DataViewer.DataGraph.Graph;
import edu.odu.cs.zeil.AlgAE.Client.DataViewer.DataGraph.Node;

import edu.odu.cs.zeil.AlgAE.Debug;


public class DataCanvas extends Canvas
  implements MouseListener, MouseMotionListener
{
  private Container parent;
  private GraphicsInfo graphicsInfo;

  private Node nodeBeingDragged;
  private Dimension dragOffset;
  private MessageDispatcher dispatcher;
  
  public Graph graph;

  
  DataCanvas(Container theParent, MessageDispatcher md)
  {
    parent = theParent;
    dispatcher = md;
    dispatcher.getGraphics().setCanvas (this);
    graph = new Graph(md);
    graphicsInfo = md.getGraphics();
    nodeBeingDragged = null;
    dragOffset = new Dimension();
    setBackground (Color.white);

    addMouseListener(this);
    addMouseMotionListener(this);

  }

  
  void setFontSize (int size)
  {
    dispatcher.getGraphics().setFontSize (size);
  }


  public void mousePressed(MouseEvent event) 
  {
    graph.freeze();
    parent.requestFocus();
    
    int x = event.getX();
    int y = event.getY();
    
    Point dragPos = new Point(x,y);
    Enumeration e = graph.nodes();
    nodeBeingDragged = null;
    while (e.hasMoreElements() && (nodeBeingDragged == null))
      {
	Node n = (Node)e.nextElement();
        if (n.contains(dragPos))
	  {
	    nodeBeingDragged = n;
	    dragOffset.width = n.position().x - x;
	    dragOffset.height = n.position().y - y;
	    repaint();
	  }
      }
  }
  

  public void mouseExited(MouseEvent event) 
  {
    mouseReleased(event);
  }
  
  public void mouseReleased(MouseEvent event) 
  {
    if (nodeBeingDragged != null)
      {
	int x = event.getX();
	int y = event.getY();
    
	nodeBeingDragged.setPosition
	  (new Point(x+dragOffset.width,
		     y+dragOffset.height));
	nodeBeingDragged = null;
        showGraph();
      }
  }

  public void mouseClicked(MouseEvent e) {}
  public void mouseEntered(MouseEvent e) {}


  void setIncrementSteps (int nSteps)
  {
      dispatcher.getGraphics().setInterpolation (0, nSteps);
  }
  
  void showGraph()
  {
    dispatcher.requestDisplay();
  }
  

  public void mouseMoved(MouseEvent event) {}

  public void mouseDragged(MouseEvent event) 
  {
    if (nodeBeingDragged != null)
      {
	int x = event.getX();
	int y = event.getY();
    
	nodeBeingDragged.setPosition
	  (new Point(x+dragOffset.width,
		     y+dragOffset.height));
      }
    repaint();
  }


  

  public void paint (Graphics g) 
  {
    Dimension canvasSize = getSize();
    if (graphicsInfo.doubleBuffering)
      {
	if (graphicsInfo.getRepaintImage() == null)
	  {
	    g.setColor(getBackground());
	    g.fillRect(0, 0, canvasSize.width, canvasSize.height);
	  }
	else
	  {
	    Debug.show (Debug.graphDraw, "dc.paint canvas size", canvasSize);
	    Debug.show (Debug.graphDraw, "dc.paint gi.canvasSize",
			graphicsInfo.getCanvasSize());
	    if ((graphicsInfo.getCanvasSize().width != canvasSize.width)
		|| (graphicsInfo.getCanvasSize().height != canvasSize.height))
	      {
		g.setColor(getBackground());
		g.fillRect(0, 0, canvasSize.width, canvasSize.height);
	      }

	    Debug.show (Debug.events, "drawing image");
	    g.drawImage(graphicsInfo.getRepaintImage(), 0, 0, this);
	    Debug.show (Debug.events, "done drawing image");
	    if (nodeBeingDragged != null)
	      {
		g.setColor(Color.black);
		Point pos = nodeBeingDragged.position();
		Dimension size = nodeBeingDragged.size();
		g.drawRect (pos.x, pos.y, size.width, size.height);
	    }
	  }
      }
    else
      {
	g.setColor(getBackground());
	g.fillRect(0, 0, canvasSize.width, canvasSize.height);
	graph.display (graphicsInfo);
      }
    dispatcher.painted();
  }
  

  public void update (Graphics g) 
  {
    if (graphicsInfo.doubleBuffering)
	paint(g);
    else
      {
	Rectangle clipBox = g.getClipRect(); 
	graphicsInfo.clip (clipBox);
	paint (graphicsInfo.g);
	g.drawImage (graphicsInfo.getRepaintImage(),
		     clipBox.x, clipBox.y, this);
	// buffer.flush();
      }
  }


  public Dimension getPreferredSize() {
    return new Dimension (350,200);
  }

  public  Dimension getMinimumSize() {
    return new Dimension (100,100);
  }

    
  public  Dimension getMaximumSize() {
    return new Dimension (800,600);
  }


}