java - Why does my applet flash for every repaint? -

i found java game code online , trying modify it. converted jframe applet, game started blink every time repaint screen. tried double buffering no difference.

source:

    private void paintdisks(graphics g) {         try {             (disk d : disk)                 paintdisk(g, d);         } catch (exception ex) {             //system.out.println(ex.getmessage());             paintdisks(g); // retry disks never not painted         }     }     private void paintdisk(graphics g, disk d) {         if (d == null)             return;         if (diskimg[d.player] == null) {             g.setcolor(colour[d.player]);             g.filloval((int)d.x - 1, (int)d.y - 1, 32, 32);         } else {             g.drawimage(diskimg[d.player],                        (int)d.x - 1, (int)d.y - 1,                         32, 32, this);         }     }      @override     public void paint(graphics g) {         // paint real panel stuff         super.paint(g);          graphics gr;          if (offscreenbuffer==null ||               (! (offscreenbuffer.getwidth(this) == this.size().width               && offscreenbuffer.getheight(this) == this.size().height)))         {             offscreenbuffer = this.createimage(size().width, size().height);         }          gr = offscreenbuffer.getgraphics();          gr.clearrect(0,0,offscreenbuffer.getwidth(this),offscreenbuffer.getheight(this));          // paint disks         paintdisks(gr);          // paint curser ontop of disks         paintcurser(gr);          g.drawimage(offscreenbuffer, 0, 0, this);        }      @override     public void run() {          while (true) {             repaint();              try {                 thread.sleep(9, 1);             } catch (interruptedexception ex) {                 system.out.println(ex.getmessage());             }         }     }  } 

short answer: not call super.paint() in board.paint() method.

long answer: applet container own display properties including background color set via setbackground(color.white); part of constructor. invoking super.paint(g) causing applet paint white background display graphics, invoke contained component painting. cause of flicker - each paint cycle, painting on-screen display white copying offscreenbuffer image on-screen display.

probably best explicit, forget applet background, remove super.paint(g), , paint steps yourself. you'll need replace clearrect() setcolor() , fillrect().

also should implement update() well.

@override public void update(graphics g) { paint(g); }  @override public void paint(graphics g) {     // no super.paint(g)      if (offscreenbuffer==null ||           (! (offscreenbuffer.getwidth(this) == this.size().width           && offscreenbuffer.getheight(this) == this.size().height)))     {         offscreenbuffer = this.createimage(size().width, size().height);     }      graphics gr = offscreenbuffer.getgraphics();      // blank canvas     gr.setcolor(color.white);     gr.fillrect(0,0,offscreenbuffer.getwidth(this),offscreenbuffer.getheight(this));      // paint disks     paintdisks(gr);      // paint curser ontop of disks     paintcurser(gr);      g.drawimage(offscreenbuffer, 0, 0, this);    }