Re: Speedup some java code

[Jerzy Puchala <jerzypuc@scdi.com>]

Hi!

There are three links which can be useful:

http://java.sun.com/docs/books/tutorial/extra/fullscreen/doublebuf.html
http://java.sun.com/docs/books/tutorial/2d/images/doublebuffering.html

And maybe the code example from here will help:

http://www.yourek.org/grafika/doubleBuffering.html

Best of luck

Jerzy Puchala

On 5 Nov 2002, cfowler wrote:

> Hello.  I have some awt 2D code that is blinking in the JPanel.  I need
> to speed it up if possible.
> 
> Can someone who knows see an ability in this code to speed up the
> repaint?  This is coming from a class that extends JPanel and at one
> time extended Canvas from awt.
> 
> 
> 
>   public void update(Graphics g) {
>     int j,beg; boolean ok;
>     g.setFont(PTFont);
>     //draw lines
>     for (int i=0;i<lines;i++) { 
>      if (lineRedraw[i] == true) {
>       lineRedraw[i] = false;
>       j=0;
>       Color fg,bg;
>       while (j < columns-1) {
>        fg=screenfg[i][j];
>        bg=screenbg[i][j];
>        beg=j;ok=true;
>        while (++j < columns && ok)
>         if (fg!=screenfg[i][j] || bg!=screenbg[i][j]) ok = false;
>        if (ok==false) j--;
>        g.setColor(bg);
>        g.fillRect(3+beg*charOffset, 2+i*lineOffset, charOffset*(j-beg),
> lineOffset);
>        g.setColor(fg);
>        g.drawChars(screen[i], beg, j-beg, 3+beg*charOffset,
> topOffset+i*lineOffset);
>       }
>      }
>     }
>     //draw cursor
>     g.setColor(new Color(screenbg[yloc][xloc].getRGB() ^ 0xFFFFFF));
>     g.fillRect(3+xloc*charOffset, 2+yloc*lineOffset, charOffset,
> lineOffset);
>     g.setColor(new Color(screenfg[yloc][xloc].getRGB() ^ 0xFFFFFF));
>     g.drawChars(screen[yloc], xloc, 1, 3+xloc*charOffset,
> topOffset+yloc*lineOffset);
>     lineRedraw[yloc]=true;
>   }
>   
>   public void paint(Graphics g) {
>     for (int i=0;i<lines;i++) lineRedraw[i] = true;
>     g.setColor(d_bgcolor);
>     g.fillRect(1,1,PTWidth-1,PTHeight-1);
>     g.setColor(d_fgcolor);
>     g.drawRect(0,0,PTWidth,PTHeight);
>     update (g);
>   }
> 
> 

-- 
+--------------------------------+
|         Jerzy Puchala          |
+--------------------------------+
|       jerzypuc@scdi.com        |
+--------------------------------+