Name: gm110360			Date: 12/18/2001


java version "1.4.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta3-b84)
Java HotSpot(TM) Client VM (build 1.4.0-beta3-b84, mixed mode)

java version "1.4.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta3-b84)
Java HotSpot(TM) Client VM (build 1.4.0-beta3-b84, mixed mode)

I want to develop smooth (and fast) scrolling for my game, which uses a
VolatileImage as backbuffer for double buffering.
  To do this i wanted to use copyArea(x,y,width,height,dx,dy) on this
VolatileImage,but the problem is that copyArea
works very!!!! slow with 0<dx<10 & dy=0 and slow with 0<dy<10. In all other
cases it works great .
(This Bug is very  similar to id 4392912)

I have wrote a small testprogramm  (which copies an 800*600 Image 100 times)
with these results ( AMD Duron 800 mHz ,Geforce2 mx):
  
dx=1 , dy=0:
VolatileImage: 6369 ms

dx=-1 , dy=0:
VolatileImage: 0 ms

dx=0 , dy=1:
VolatileImage: 431 ms

dx=0 , dy=-1:
VolatileImage: 0 ms

dx=1 , dy=1:
VolatileImage: 431 ms

dx=-1 , dy=-1:
VolatileImage: 0 ms

dx=1 , dy=-1:
VolatileImage: 10 ms

dx=-1 , dy=1:
VolatileImage: 431 ms

-----------------------------------

dx=5 , dy=0:
VolatileImage: 1272 ms

dx=-5 , dy=0:
VolatileImage: 0 ms

dx=0 , dy=5:
VolatileImage: 240 ms

dx=0 , dy=-5:
VolatileImage: 0 ms

dx=5 , dy=5:
VolatileImage: 280 ms

dx=-5 , dy=-5:
VolatileImage: 0 ms

dx=5 , dy=-5:
VolatileImage: 0 ms

dx=-5 , dy=5:
VolatileImage: 280 ms


The TestProgramm:

import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.geom.*;

public class CopyAreaTest extends JFrame
{
  BufferedImage offScr1;
  Graphics2D offScrG_1;
  VolatileImage offScr2;
  Graphics2D offScrG_2;
  int width=800;
  int height=600;

  public CopyAreaTest()
  {
    this.setSize(width,height);
    this.setVisible(true);

    offScr1=new BufferedImage(this.getWidth(),this.getHeight
(),BufferedImage.TYPE_INT_RGB);
    offScrG_1=offScr1.createGraphics();

    offScr2=createVolatileImage(getWidth(),getHeight());
    offScrG_2=offScr2.createGraphics();
  }


  public void performeTest(int dx,int dy)
  {
    System.out.println("dx="+dx+ " , dy="+dy+":");

    long t=System.currentTimeMillis();
    for (int i=0;i<100;i++)
    {
      offScrG_1.copyArea(0,0,width,height,dx,dy);
    }
    System.out.println("BufferedImage: "+(System.currentTimeMillis()-t )+ "
ms");
    t=System.currentTimeMillis();

    for (int i=0;i<100;i++)
    {
      offScrG_2.copyArea(0,0,width,height,dx,dy);
    }
    System.out.println("VolatileImage: "+(System.currentTimeMillis()-t )+ "
ms");

    System.out.println();

  }

  public static void main(String args[])
  {
    CopyAreaTest test=new CopyAreaTest();

    test.performeTest(1,0);
    test.performeTest(-1,0);
    test.performeTest(0,1);
    test.performeTest(0,-1);
    test.performeTest(1,1);
    test.performeTest(-1,-1);
    test.performeTest(1,-1);
    test.performeTest(-1,1);

    System.out.println("-----------------------------------");
    System.out.println();

    test.performeTest(5,0);
    test.performeTest(-5,0);
    test.performeTest(0,5);
    test.performeTest(0,-5);
    test.performeTest(5,5);
    test.performeTest(-5,-5);
    test.performeTest(5,-5);
    test.performeTest(-5,5);

    test.dispose();
  }
}
(Review ID: 136927) 
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