Name: rm29839 Date: 04/30/98


/*
 * Java2D compositing bug demonstrator applet.
 *
 * This applet demonstrates a bug with compositing in Java2D. It draws
 * 7 images involving transparency. The first three are just sample images
 * involving transparency (call these A, B, and C). The second two are
 * composite drawing of A and B, and then A, B, and C directly onto the
 * applet. These work properly. The final two images are similar
 * composites formed by drawing A and B, and then A, B, and C into a
 * translucent BufferedImage, then drawing the BufferedImage onto the applet
 * surface. These should look the same as the previous 2, but they don't.
 * They produce incorrect colors in various areas.
 *
 * I am running JDK 1.2beta2 on an Pentium+MMX NT 4.0 machine with 16 bit
 * color.
 *
 */
package photoshop_utils;

import java.awt.*;
import java.awt.image.*;
import java.applet.*;

public class draw_bug extends Applet {

  protected static int[] data1;
  protected static Image image1;
  protected static int[] data2;
  protected static Image image2;
  protected static int[] data3;
  protected static Image image3;
  protected static Image comp12;
  protected static Image comp123;

  public void init()
    {
      int x,y;
      int r,g,b,a;
      Graphics2D cdrw;

      /* fill data1 as follows:
           y < 50 : black with alpha = 0
           y >= 50 : red with alpha gradient from 50% to 100%
      */
      data1 = new int[100*100];
      for (y=0; y<100; y++)
        for (x=0; x<100; x++)
          {
            if (y >= 50)
              { r=255; g=0; b=0; a=(255*y)/100;}
            else
              { r=0; g=0; b=0; a=0;}
            data1[y*100+x] = (a<<24) | (r<<16) | (g<<8) | b;
          }

      /* make an image with the data */
      image1 = Toolkit.getDefaultToolkit().createImage(
new MemoryImageSource(100,100,data1,0,100));

      /* fill data2 as follows:
           x < 50 : black with alpha = 0
           x >= 50 : green with alpha gradient from 50% to 100%
      */
      data2 = new int[100*100];
      for (y=0; y<100; y++)
        for (x=0; x<100; x++)
          {
            if (x >= 50)
              { r=0; g=255; b=0; a=(255*x)/100;}
            else
              { r=0; g=0; b=0; a=0;}
            data2[y*100+x] = (a<<24) | (r<<16) | (g<<8) | b;
          }

      /* make an image with the data */
      image2 = Toolkit.getDefaultToolkit().createImage(
new MemoryImageSource(100,100,data2,0,100));

      /* fill data3 as follows:
           x < y : black with alpha = 0
           x >= y : blue with alpha gradient
      */
      data3 = new int[100*100];
      for (y=0; y<100; y++)
        for (x=0; x<100; x++)
          {
            if (x >= y)
              { r=0; g=0; b=255; a=(255*(x+y))/200;}
            else
              { r=0; g=0; b=0; a=0;}
            data3[y*100+x] = (a<<24) | (r<<16) | (g<<8) | b;
          }

      /* make an image with the data */
      image3 = Toolkit.getDefaultToolkit().createImage(
new MemoryImageSource(100,100,data3,0,100));

      /* create a composite of 1 and 2 */
      comp12 = GraphicsEnvironment.getLocalGraphicsEnvironment()
        .getDefaultScreenDevice().getDefaultConfiguration()
        .createCompatibleImage(100,100,Transparency.TRANSLUCENT);
      cdrw = (Graphics2D)comp12.getGraphics();
      cdrw.setComposite(AlphaComposite.getInstance(
                           AlphaComposite.CLEAR));
      cdrw.setColor(Color.white);
      cdrw.clearRect(0,0,100,100);
      cdrw.setComposite(AlphaComposite.getInstance(
                           AlphaComposite.SRC_OVER, 1.0f));
      cdrw.drawImage(image1,0,0,this);
      cdrw.drawImage(image2,0,0,this);

      /* create a composite of 1, 2, and 3 */
      comp123 = GraphicsEnvironment.getLocalGraphicsEnvironment()
        .getDefaultScreenDevice().getDefaultConfiguration()
        .createCompatibleImage(100,100,Transparency.TRANSLUCENT);
      cdrw = (Graphics2D)comp123.getGraphics();
      cdrw.setComposite(AlphaComposite.getInstance(
                           AlphaComposite.CLEAR));
      cdrw.setColor(Color.white);
      cdrw.clearRect(0,0,100,100);
      cdrw.setComposite(AlphaComposite.getInstance(
                           AlphaComposite.SRC_OVER, 1.0f));
      cdrw.drawImage(image1,0,0,this);
      cdrw.drawImage(image2,0,0,this);
      cdrw.drawImage(image3,0,0,this);
    }

  public void paint(Graphics g)
    {
      Graphics2D real_g = (Graphics2D)g;

      /* clear the whole applet */
      Dimension sz = getSize();
      real_g.clearRect(0,0,sz.width,sz.height);


      /* draw image 1 */
      real_g.setComposite(AlphaComposite.getInstance(
                           AlphaComposite.SRC_OVER, 1.0f));
      real_g.drawImage(image1, 0,0, this);
      real_g.drawImage(image1, 300,0, this);
      real_g.drawImage(image1, 400,0, this);

      /* draw image 2 */
      real_g.drawImage(image2, 100,0, this);
      real_g.drawImage(image2, 300,0, this);
      real_g.drawImage(image2, 400,0, this);

      /* draw image 3 */
      real_g.drawImage(image3, 200,0, this);
      real_g.drawImage(image3, 400,0, this);

      /* draw composite of 1 and 2 */
      real_g.drawImage(comp12, 500,0, this);

      /* draw composite of 1, 2, and 3 */
      real_g.drawImage(comp123, 600,0, this);
    }
}

/*
<APPLET CODE="photoshop_utils.draw_bug.class" CODEBASE=".."
                              HEIGHT=150 WIDTH=700>
</APPLET>
*/
(Review ID: 28012)
======================================================================