textpane.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.gui;

import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Panel;
import java.awt.Scrollbar;

import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;


import java.awt.*;
import edu.odu.cs.zeil.AlgAE.Debug;

import edu.odu.cs.zeil.AlgAE.gui.ScrollableTextCanvas;


/**
 * TextPane.java
 *
 * A GUI element that displays a sequence of text lines, with scroll bars.
 * The program can request that a specific line of text be highlighted
 * and centered within the visible area.
 *
 * This is very similar in appearance and functionality to the
 * java.awt.TextArea, except that there is no way to tell a TextArea
 * to scroll itself to a desired line.
 *
 * Created: Wed July 30, 1998
 *
 * @author Steven Zeil
 * @version
 */

public class TextPane extends Panel
{
  private ScrollableTextCanvas canvas;
  private Scrollbar horizontal;
  private Scrollbar vertical;
  

  public TextPane() {
    canvas = new ScrollableTextCanvas (this);
    setLayout (new BorderLayout());
    add ("Center", canvas);
    horizontal = new Scrollbar (Scrollbar.HORIZONTAL);
    vertical = new Scrollbar (Scrollbar.VERTICAL);
    add ("East", vertical);
    add ("South", horizontal);
    
    horizontal.addAdjustmentListener (new AdjustmentListener()
      {
	public void adjustmentValueChanged (AdjustmentEvent e)
	  {
	    canvas.setStartingColumn (e.getValue());
	  }
      });

    vertical.addAdjustmentListener (new AdjustmentListener()
      {
	public void adjustmentValueChanged (AdjustmentEvent e)
	  {
	    canvas.setStartingLine (e.getValue());
	  }
      });

    addComponentListener (new ComponentAdapter()
      {
	public void componentResized (ComponentEvent c)
	  {
	      Debug.show (Debug.splitters, "TextPane.resized " + c);
	      setScrolls();
	  }
      });
  }


  private void setScrolls()
  {
    horizontal.setMinimum (0);
    horizontal.setMaximum (canvas.getMaxWidth());
    horizontal.setVisibleAmount (canvas.getWidth());

    vertical.setMinimum (0);
    vertical.setMaximum (canvas.getMaxHeight()+1);
    vertical.setVisibleAmount (canvas.getHeight());
  }
  
  public synchronized void addLine (String line)
  {
    canvas.addLine (line);
    setScrolls();
  }

  public synchronized void doneAdding()
  {
    canvas.doneAdding();
    setScrolls();
    validate();
  }

  public synchronized void focusOnLine (int lineNumber)
  {
    canvas.focusOnLine (lineNumber);
    setScrolls();
    vertical.setValue (canvas.getStartingLine());
    repaint();
  }

  public void setFont (Font f)
  {
    canvas.setFont (f);
    repaint();
  }
  

  public void paint (Graphics g)
  {
    setScrolls();
    super.paint(g);
  }
  

} // TextPane