double buffering and paint

Question

I'm using both double buffering and Swing Events which seem to conflict. I'm using a JSlider and trying to double buffer. It actually does the double buffering draw, but the double buffering gets painted again and I lose my image. I'm using a JSlider to do the double buffering draw, and the event system seems to re-draw the frame (with 2 components, an image and the slider). How do I do this the right way? I've tried setting a repaint variable to signal not to repaint in the component but this does not work. Is there some sort of event switch to stop repainting of certain components? Should I not use double buffering? Here's a code snippet.

private void drawOneByOne(ImageComponent imgComponent, JFrame f,
        MapObjects mapObjects, int number) {
    f.createBufferStrategy(2); 

    BufferStrategy bufferStrategy = f.getBufferStrategy();
    Graphics2D g = (Graphics2D)bufferStrategy.getDrawGraphics();            
    bufferStrategy = f.getBufferStrategy();
    g = (Graphics2D)bufferStrategy.getDrawGraphics();
    // draw the map and then the points
    imgComponent.paint(g);
    for (int i = 0; i < number; i++) {
        imgComponent.drawPoint(mapObjects.get(i),g);
    }
    imgComponent.repaint = false;
    bufferStrategy.show();
    g.dispose();
    imgComponent.repaint = true;
}
public void stateChanged(ChangeEvent e) {
    JSlider source = (JSlider)e.getSource();
    if (!source.getValueIsAdjusting()) {
        int voterNumber = source.getValue();
        System.out.println("Drawing One By One, " + voterNumber);
        drawOneByOne(this.imgComponent, this.f, this.mapObjects, voterNumber);
    }
}

. . .

For better help sooner, post an [SSCCE](http://sscce.org/). – Andrew Thompson Jun 09 '13 at 17:01 — Andrew Thompson, Jun 09 '13 at 17:01

score 0 · Answer 1 · answered Jun 09 '13 at 16:47

0

Swing is easily doublebuffered via setDoubleBuffered(true) if that is all you wanted to achieve. There is nothing wrong with double-buffering, it just uses more memory, call it on the parentcontainer of your swingcomponents. You have no control over the repaint, the OS calls it whenever it deems necessary unless you call setIgnoreRepaint on the JFrame.

answered Jun 09 '13 at 16:47

arynaq

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I thought that it was set by default to be true for all JComponent children. – Hovercraft Full Of Eels Jun 09 '13 at 16:53
2

Swing components inherit double buffering from the parent container. Since by default the root pane is double buffered all components are double buffered. – camickr Jun 09 '13 at 17:06
My info is outdated then, should have known though, never noticed any flickering on swing components. – arynaq Jun 10 '13 at 00:12

double buffering and paint

1 Answers1