Police Tape Border for Swing Components
By Aaron Davidson


This custom border will wrap your swing components with police tape. This is useful for getting a user's attention when extra care is required.

You can create a police tape border on any Swing component simply by setting the border like so:

myComponent.setBorder(new PoliceTape (5,10));

The first argument is the tape thickness, and the second argument is the width of the bumblebee stripes.

You can also call the static method

public static Image createPoliceTape(int width, int height, int stripe)

to generate a solid image of the police tape pattern for use as an icon or to fill a background in a custom component.

Here's an example of the police tape in action:


Source Code - PoliceTape.java

package ca.spaz.gui;

import java.awt.*;

import javax.swing.border.*;

/**
 * PoliceTape 1.0
 * 
 * Draws police tape around a component.
 * 
 * Created on March 24, 2007
 * 
 * Source code gifted to public domain. Enjoy.
 * 
 * @author Aaron Davidson <aaron@spaz.ca> 
 */
public class PoliceTape extends AbstractBorder {
   private int thickness = 15;
   private int stripeLength = 50;

   public PoliceTape() { }

   public PoliceTape(int thickness) {
      setThickness(thickness);
   }
   
   public PoliceTape(int thickness, int stripeLength) {
      setThickness(thickness);
      setStripeLength(stripeLength);
   }

   /**
    * Returns the length of each stripe
    */
   public int getStripeLength() {
      return stripeLength;
   }
   
   /**
    * Returns the thickness of the border.
    */
   public int getThickness() {
      return thickness;
   }
    
   /**
    * Paints the border for the specified component with the specified position
    * and size.
    * 
    * @param c
    *           the component for which this border is being painted
    * @param g
    *           the paint graphics
    * @param x
    *           the x position of the painted border
    * @param y
    *           the y position of the painted border
    * @param width
    *           the width of the painted border
    * @param height
    *           the height of the painted border
    */
    public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {        
       Image img = createPoliceTape(width, height, stripeLength);
       // draw top tape
       g.drawImage(img, x, y, x+width, y+thickness, 
                        0, 0,   width,   thickness, null);
       // draw bottom tape
       g.drawImage(img, x, y+height-thickness, x+width, y+height, 
                        0,   height-thickness,   width,   height, null);
       // draw left tape
       g.drawImage(img, x, y+thickness, x+thickness, y+height-thickness, 
                        0,   thickness,   thickness,   height-thickness, null); 
       // draw right tape
       g.drawImage(img, x+width-thickness, y+thickness, x+width, y+height-thickness, 
                          width-thickness,   thickness,   width,   height-thickness, null); 
    } 
  
    /**
     * Return an image filled with police tape.
     * 
     * @param width the width of the image
     * @param height the height of the image
     * @param stripe the width of each bumblebee stripe
     * @return a police tape image
     */
    public static Image createPoliceTape(int width, int height, int stripe) {
      GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
      GraphicsDevice gs = ge.getDefaultScreenDevice();
      GraphicsConfiguration gc = gs.getDefaultConfiguration();

      Image img = gc.createCompatibleImage(width, height, Transparency.OPAQUE);
      Graphics g = img.getGraphics();
      g.setColor(Color.BLACK);
      g.fillRect(0, 0, width, height);
      g.setColor(Color.YELLOW);
      for (int i = 0; i < height; i++) {
         for (int j = -height / stripe; j <= width / stripe; j += 2) {
            g.drawLine(Math.max(0, j * stripe + i), i, Math.min(width, (j + 1)
                  * stripe + i), i);
         }
      } 
      return img;
   }

   /**
    * Sets the length of each stripe
    */
   public void setStripeLength(int stripeLength) {
      this.stripeLength = stripeLength;
   }

   /**
    * Sets the thickness of the border.
    */
   public void setThickness(int thickness) {
      this.thickness = thickness;
   }

   public Insets getBorderInsets(Component c) {
      return new Insets(thickness, thickness, thickness, thickness);
   }

   public Insets getBorderInsets(Component c, Insets insets) {
      insets.left = insets.top = insets.right = insets.bottom = thickness;
      return insets;
   }
    
}