The problem seems to be caused by updating the scene graph by a thread
other than the Swing event dispatch thread. This is not allowed, a
solution is explained in the Piccolo2D Patterns.
A consequence of updates by wrong threads is that PRoot discards the
update and repaint process (it checks if the right thread invoked the
update). Subsequent invalidatePaints possibly dont reach the root.
Am Dienstag 03 November 2009 02:36:21 schrieb Nigel:
> The comment in PNode.java reads
>
> // When you do create you own nodes the only method that you
> will // normally need to call is invalidatePaint. This method marks
> the // nodes as having invalid paint, the root node's UI cycle will
> then
> // later discover this damage and report it to the Java repaint
> manager.
>
>
> However, I find that after calling invalidatepaint() the repaint
> manager does not discover the damage unless other events are
> occurring (such as moving the mouse around).
>
> I was expecting that calling invalidatePaint would result in the
> node being repainted some time later - am I doing something wrong
> or is Piccolo?
>
>
> Here is a contrived example (ClockNode.java) - It displays 4 custom
> nodes, each showing a clock's second hand. The top 2 clocks are
> updated from within the event dispatch thread, the lower 2 clocks
> are updated from another thread. The 2 clocks on the left are
> redrawn via a call to repaint and the 2 on the right via a call to
> invalidatePaint.
>
> if you run it you'll see the clock on the right (calling
> invalidatePaint) are only redrawn if you are moving your mouse over
> the window.
>
> ClockNode.java
>
> import java.awt.*;
> import java.awt.geom.*;
> import edu.umd.cs.piccolo.*;
> import edu.umd.cs.piccolo.util.*;
>
> import edu.umd.cs.piccolox.PFrame;
>
> public class ClockNode extends PNode {
>
> private GeneralPath secondHand;
> private int tseconds; // 10ths of seconds
>
> public void tick() {
> tseconds++;
> if ( tseconds >= 600 ) { tseconds = 0; }
> // inform Piccolo that the node needs to be redrawn
> if ( useRepaint ) {
> repaint();
> } else {
> invalidatePaint();
> }
> }
>
> private boolean useRepaint;
> public ClockNode(boolean useRepaint) {
> this.useRepaint = useRepaint;
> // create the needle shape
> secondHand = new GeneralPath(GeneralPath.WIND_EVEN_ODD);
> secondHand.moveTo(-0.1,0);
> secondHand.lineTo(0,1);
> secondHand.lineTo(0.1,0);
> secondHand.closePath();
> }
>
> public void paint(PPaintContext aPaintContext) {
> Graphics2D g2 =
> (Graphics2D)aPaintContext.getGraphics().create();
> // create - as we mess with the transform
> g2.setPaint(Color.BLACK);
> //draw the face
> g2.draw( new Ellipse2D.Double( getX(), getY(), getWidth(),
> getHeight () ));
> //draw the second hand
> g2.translate(getX()+getWidth()/2,getY()+getHeight()/2); //
> translate hand so 0,0 is centre of bounds
> g2.scale(getWidth()/2,getHeight()/2); // scale the needle
> g2.rotate ( Math.toRadians((tseconds*6)/10f+180) );
> g2.fill(secondHand);
> }
>
> public static void main(String args[]) {
> // top left clock - uses repaint
> final ClockNode clockNode1 = new ClockNode(true);
> clockNode1.setBounds(0,0,200,200);
> // top right clock - uses invalidatePaint
> final ClockNode clockNode2 = new ClockNode(false);
> clockNode2.setBounds(210,0,200,200);
> // lower left clock - uses repaint
> final ClockNode clockNode3 = new ClockNode(true);
> clockNode3.setBounds(0,210,200,200);
> // lower right clock - uses invalidatePaint
> final ClockNode clockNode4 = new ClockNode(false);
> clockNode4.setBounds(210,210,200,200);
>
> PFrame pFrame = new PFrame() {
> public void initialize() {
>
> getCanvas().getLayer().addChild(clockNode1);
>
> getCanvas().getLayer().addChild(clockNode2);
>
> getCanvas().getLayer().addChild(clockNode3);
>
> getCanvas().getLayer().addChild(clockNode4);
> setSize(500,500);
> }
> };
>
> // tick clocks 1 and 2 in the event dispatch thread
> new javax.swing.Timer(100, new java.awt.event.ActionListener() {
> public void actionPerformed
> (java.awt.event.ActionEvent evt) {
> clockNode1.tick();
> clockNode2.tick();
> }
> }).start();
>
> // tick clocks 3 and 4 in the timer thread
> java.util.Timer timer = new java.util.Timer(true);
> timer.schedule( new java.util.TimerTask() {
> public void run() {
> clockNode3.tick();
> clockNode4.tick();
> }
> },0,100);
> }
>
> }
>
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