Images

[colin shuker]

Hi, I was wondering if it was possible to get an Image/BufferedImage, on to a JPanel, similar to when you do...

class Drawer extends JPanel
{
    public Drawer()
    {
       this.setBackground(Color.yellow);
    }
    ...
}

I know I can simply do a drawImage(...) inside the paintComponent(...) method, but I am having to repaint the screen many times with several small images, and I wanted to do it so the background does not have to be continuously repainted.

Is this possible? Thanks

[Nathan Pruett]

No matter what you do - the background is going to be continuously repainted... all that setBackground(Color background) does is set some variable in the JComponent superclass that gets used in JComponent.paintComponent() as:

g.setColor(background);
g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);

If you're worried about re-doing stuff in the paint method that you don't need to re-do every time (like scaling, rotating, modifying an image, string, geometric shape, etc.) then you can create a BufferedImage, paint to the BufferedImage's Graphics, and then inside your paintComponent() method, just paint the BufferedImage only.

(somewhere outside of paintComponent...)
...
    bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    Graphics g = bi.createGraphics();
        // paint to the BufferedImage's Graphics context.
    g.dispose();
...
public void paintComponent(Graphics g)
{
    super.paintComponent(g);
    g.drawImage(bufferedImage, x, y, this);
}

[colin shuker]

Thanks, thats kind of the same thing I was trying today, double buffering I think its called.

I still have a problem though with my applet.
Rubiks Cube

I'm using double buffering (painting to an Image, then displaying image),
but I'm still getting a little bit of black flickering that can be seen when the cube is twisted(by pulling on a non-center face), the black flickering can usually be seen where two small faces join, whilst being twisted.

I have found, that on a Mac computer this flickering is really bad, but hardly noticeable when using windows.
I assumed double buffering would fix this, but it hasn't, any ideas?

Thanks
[ April 03, 2007: Message edited by: colin shuker ]

[dave taubler]

By the way, nice applet!