Remove flicker from SWT Canvas in Paint Listner

Question

I have a thread which animates a gif image inside a Canvas control by calling it's redraw method. But there is flickering of images which is observed. I tried using the SWT.NO_REDRAW_RESIZE style bit but it didn't help.

Below is the Thread's run code

while (!UIManager.stop){
                long currentTime = System.currentTimeMillis();
                int delayTime = UIManager.loader.data[UIManager.imageNumber].delayTime;
                while(currentTime + delayTime * 10 > System.currentTimeMillis()){
                  // Wait till the delay time has passed

                }

                UIManager.imageNumber = UIManager.imageNumber == UIManager.loader.data.length-1 ? 0 : UIManager.imageNumber+1;



                display.asyncExec(new Runnable() {                                      
                    @Override
                    public void run() {
                        // TODO Auto-generated method stub

                        if(!UIManager.stop){
                        UIManager.image = new Image(display, UIManager.loader.data[UIManager.imageNumber] );

                        if(!UIManager.gifCanvas.isDisposed())
                            UIManager.gifCanvas.redraw();

                        }
                    }
                });

and the Canvas paint listener is as follows

gifCanvas = new Canvas(gifComposite,SWT.NO_REDRAW_RESIZE);
        gifCanvas.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
        gifCanvas.setLayoutData(introGifData);
        gifCanvas.addPaintListener(new PaintListener() {
            public void paintControl(PaintEvent e) {                
                e.gc.drawImage(image,0,0);
                }
        });     

I don't know where I am going wrong. Your help will be appreciated.

Answer 1

Canvas supports SWT.DOUBLE_BUFFERED, try adding that as a style in the Canvas creation:

gifCanvas = new Canvas (gifComposite, SWT.NO_REDRAW_RESIZE | SWT.DOUBLE_BUFFERED);