Blinking Circle

Question

Hi,
I have a background with a drawn polygons. I am trying to make a circle of a particular size blink on a particular location on top of the background. Can someone please let me know how to achieve this effect ?
Thanks

Answer 1

Option 1:
Draw your polygons, etc to an off screen image.
When you paint, copy the contents of off-screen image, then optionally paint the circle.
That way the background (buffer) is never actually modified by the circle.
Option 2: before you paint the Circle, copy and save the area you're painting to. Paint it back when you're done.
You'll eventually have something that looks like this:
//somewhere
Image offScreenImage = createImage(getWidth(), getHeight());
paint(Graphics g)
  //maybe you need to update the offscreen image, maybe not
  if (something is different)
     Graphics2D offscreenGraphics = (Graphics2D)offScreenImage.getGraphics();
     //... paint
  //copy offscreen onto g
  g.drawImage(offScreenImage, 0, 0, null);
  //optionally paint circle onto g
}