stroketest.java

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/**
   @version 1.02 2004-08-24
   @author Cay Horstmann
*/

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;

/**
   This program demonstrates different stroke types.
*/
public class StrokeTest
{  
   public static void main(String[] args)
   {  
      JFrame frame = new StrokeTestFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setVisible(true);
   }
}

/**
   This frame lets the user choose the cap, join, and
   line style, and shows the resulting stroke.
*/
class StrokeTestFrame extends JFrame
{  
   public StrokeTestFrame()
   {  
      setTitle("StrokeTest");
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      canvas = new StrokePanel();
      add(canvas, BorderLayout.CENTER);

      buttonPanel = new JPanel();
      buttonPanel.setLayout(new GridLayout(3, 3));
      add(buttonPanel, BorderLayout.NORTH);

      ButtonGroup group1 = new ButtonGroup();      
      makeCapButton("Butt Cap", BasicStroke.CAP_BUTT, group1);
      makeCapButton("Round Cap", BasicStroke.CAP_ROUND, group1);
      makeCapButton("Square Cap", BasicStroke.CAP_SQUARE, group1);

      ButtonGroup group2 = new ButtonGroup();      
      makeJoinButton("Miter Join", BasicStroke.JOIN_MITER, group2);
      makeJoinButton("Bevel Join", BasicStroke.JOIN_BEVEL, group2);
      makeJoinButton("Round Join", BasicStroke.JOIN_ROUND, group2);

      ButtonGroup group3 = new ButtonGroup();      
      makeDashButton("Solid Line", false, group3);
      makeDashButton("Dashed Line", true, group3);
   }

   /**
      Makes a radio button to change the cap style.
      @param label the button label
      @param style the cap style
      @param group the radio button group
   */
   private void makeCapButton(String label, final int style, ButtonGroup group)
   {
      // select first button in group
      boolean selected = group.getButtonCount() == 0;
      JRadioButton button = new JRadioButton(label, selected);
      buttonPanel.add(button);
      group.add(button);
      button.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               canvas.setCap(style);
            }
         });
   }

   /**
      Makes a radio button to change the join style.
      @param label the button label
      @param style the join style
      @param group the radio button group
   */
   private void makeJoinButton(String label, final int style,
      ButtonGroup group)
   {
      // select first button in group
      boolean selected = group.getButtonCount() == 0;
      JRadioButton button = new JRadioButton(label, selected);
      buttonPanel.add(button);
      group.add(button);
      button.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               canvas.setJoin(style);
            }
         });
   }

   /**
      Makes a radio button to set solid or dashed lines
      @param label the button label
      @param style false for solid, true for dashed lines
      @param group the radio button group
   */
   private void makeDashButton(String label, final boolean style,
      ButtonGroup group)
   {
      // select first button in group
      boolean selected = group.getButtonCount() == 0;
      JRadioButton button = new JRadioButton(label, selected);
      buttonPanel.add(button);
      group.add(button);
      button.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               canvas.setDash(style);
            }
         });
   }

   private StrokePanel canvas;
   private JPanel buttonPanel;

   private static final int DEFAULT_WIDTH = 400;
   private static final int DEFAULT_HEIGHT = 400;
}

/**
   This panel draws two joined lines, using different
   stroke objects, and allows the user to drag the three 
   points defining the lines. 
*/
class StrokePanel extends JPanel
{  
   public StrokePanel()
   {  
      addMouseListener(new
         MouseAdapter()
         {
            public void mousePressed(MouseEvent event)
            {  
               Point p = event.getPoint();
               for (int i = 0; i < points.length; i++)
               {  
                  double x = points[i].getX() - SIZE / 2;
                  double y = points[i].getY() - SIZE / 2;
                  Rectangle2D r = new Rectangle2D.Double(x, y, SIZE, SIZE);
                  if (r.contains(p))
                  {  
                     current = i;
                     return;
                  }
               }
            }
        
            public void mouseReleased(MouseEvent event)
            {  
               current = -1;
            }
         });

      addMouseMotionListener(new
         MouseMotionAdapter()
         {
            public void mouseDragged(MouseEvent event)
            {  
               if (current == -1) return;
               points[current] = event.getPoint();
               repaint();
            }
         });

      points = new Point2D[3];
      points[0] = new Point2D.Double(200, 100);
      points[1] = new Point2D.Double(100, 200);
      points[2] = new Point2D.Double(200, 200);
      current = -1;
      width = 8.0F;
   }

   public void paintComponent(Graphics g)
   {  
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g;
      GeneralPath path = new GeneralPath();
      path.moveTo((float) points[0].getX(), (float) points[0].getY());
      for (int i = 1; i < points.length; i++)
         path.lineTo((float) points[i].getX(), (float) points[i].getY());
      BasicStroke stroke;
      if (dash)
      {  
         float miterLimit = 10.0F;
         float[] dashPattern = { 10F, 10F, 10F, 10F, 10F, 10F,
            30F, 10F, 30F, 10F, 30F, 10F, 10F, 10F, 10F, 10F, 10F, 30F };
         float dashPhase = 0;
         stroke = new BasicStroke(width, cap, join, miterLimit, dashPattern, dashPhase);
      }
      else
         stroke = new BasicStroke(width, cap, join);
      g2.setStroke(stroke);
      g2.draw(path);
   }

   /**
      Sets the join style.
      @param j the join style
   */
   public void setJoin(int j) 
   { 
      join = j; 
      repaint(); 
   }

   /**
      Sets the cap style.
      @param c the cap style
   */
   public void setCap(int c) 
   { 
      cap = c; 
      repaint(); 
   }

   /**
      Sets solid or dashed lines
      @param d false for solid, true for dashed lines
   */
   public void setDash(boolean d) 
   { 
      dash = d; 
      repaint(); 
   }

   private Point2D[] points;
   private static int SIZE = 10;
   private int current;
   private float width;
   private int cap;
   private int join;
   private boolean dash;
}