<Swing Dev> JDK-8178091 : Bug I will workin on

[Walter Laan]

Note that the example code in JDK-8178091 sleeps on the EDT, so you’re lucky it paints at all instead of hanging the UI.

It looks like you adapted the code from http://codereview.stackexchange.com/questions/29630/simple-java-animation-with-swing where no-one experienced with Swing pointed out this error ☹.

Using a javax.swing.Timer (not the java.util.Timer!) and it runs okay (using Win10, Java 8u101):

    private void go() {

        new Timer(10, new ActionListener() {
            // Les coordonnées de départ de notre rond
            private int x = pan.getPosX(), y = pan.getPosY();
            // Le booléen pour savoir si l'on recule ou non sur l'axe x
            private boolean backX = false;
            // Le booléen pour savoir si l'on recule ou non sur l'axe y
            private boolean backY = false;

            @Override
            public void actionPerformed(ActionEvent e) {
                // Si la coordonnée x est inférieure à 1, on avance
                if(x < 1) {
                    backX = false;
                }
                // Si la coordonnée x est supérieure à la taille du Panneau moins la taille du rond, on recule
                if(x > pan.getWidth() - 50) {
                    backX = true;
                }
                // Idem pour l'axe y
                if(y < 1) {
                    backY = false;
                }
                if(y > pan.getHeight() - 50) {
                    backY = true;
                }

                // Si on avance, on incrémente la coordonnée
                // backX est un booléen, donc !backX revient à écrire
                // if (backX == false)
                if(!backX) {
                    pan.setPosX(++x);
                // Sinon, on décrémente
                }
                else {
                    pan.setPosX(--x);
                }
                // Idem pour l'axe Y
                if(!backY) {
                    pan.setPosY(++y);
                }
                else {
                    pan.setPosY(--y);
                }

                // On redessine notre Panneau
                pan.repaint();
            }
        }).start();
    }

Hope that helps,
Walter.

From: swing-dev [mailto:swing-dev-bounces at openjdk.java.net] On Behalf Of Patrick Chen
Sent: maandag 10 april 2017 12:23
To: swing-dev at openjdk.java.net
Subject: Re: <Swing Dev> JDK-8178091 : Bug I will workin on

(edit : for example this game coded in java : https://github.com/cloudStrif/GoldenSunD will work with java 7
but clearly not with java8 (linux 64 bits) because of lags)

2017-04-10 12:19 GMT+02:00 Patrick Chen <chen.j.patrick at gmail.com<mailto:chen.j.patrick at gmail.com>>:
Hi every one ,
just wanted to inform that I am working to fix this bug.

it is when we devellop animations thanks to repaint() method ,
for java 7 it works well
but with java8 not ,
(linux 64 bits it doesn't really work )

so after watching the source code it seem that it is not a swing problem
but AWT : Component.java .

thank you



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