Question

I have encountered a strange behaviour in javaFx2, when moving a pane, that is bigger than the current scene. The pane has set a background-image in a css file, like:

#foo {
    -fx-background-image: url("bar.png");
}

The image is rendered correctly at first, but when I move the pane (to show a different part of it in the scene), the pane is white, where it was not visible before moving and the background-image should be.

Move-code:

private void moveCameraTo(Point p) {
    TranslateTransition translate = TranslateTransitionBuilder.create()
            .node(pane)
`   `       .toX(someX)
            .toY(someY)
            .duration(DEFAULT_TRANSITION_TIME)
            .build();
    translate.play();
}

Here is a image of the fail:

The background is rendered correctly, as soon, as I resize the scene by dragging its borders.

Am I doing something wrong while moving the pane, e.g. missing an update method (although I doubt this exists in javaFx2) or setting a member of the pane?

Answer 1

After a lot of searching and trying, I have come to the conclusion, that this behaviour is a bug.

A workaround for this is, to use a ScrollPane instead of a plain Pane and move the “camera” by setting the vvalue and hvalue in a Timeline, like this:

private void moveCameraTo(Point p) {
        KeyValue yVal = new KeyValue(this.scrollPane.vvalueProperty(),
                p.getY(),
                Interpolator.EASE_BOTH);
        KeyValue xVal = new KeyValue(this.scrollPane.hvalueProperty(),
                p.getX(),
                Interpolator.EASE_BOTH);
        Timeline yTimeline = TimelineBuilder.create().autoReverse(false)
                .keyFrames(new KeyFrame(DEFAULT_TRANSITION_TIME, yVal)).build();
        Timeline xTimeline = TimelineBuilder.create().autoReverse(false)
                .keyFrames(new KeyFrame(DEFAULT_TRANSITION_TIME, xVal)).build();

        yTimeline.play();
        xTimeline.play();
    }

I hope this helps everyone having the same problem.
If anyone got a better solution, please post it!