Re: RFR: 8389653: Enhance JavaFX with virtual layout containers, and allow ordinary Nodes to participate

[John Hendrikx]

On Mon, 3 Aug 2026 21:12:40 GMT, Andy Goryachev <ango...@openjdk.org> wrote:

> Not a review (yet), but a question: would it be better to include two panes 
> instead of one, to gauge the amount of common code?
> 
> The `BorderPane` perhaps?

I checked out `BorderPane` -- it is a bit more complicated than `StackPane` and 
would also require moving more code from `Region` to `LayoutSupport` making the 
review a bit harder. Perhaps exclude it for now? I don't mind making another PR 
later with support for it.

The API for `BorderPaneLayout` would look similar to `StackPaneLayout` except 
that instead of a `setChildren` you would have a method like this:


    void setPositions(Layoutable center, Layoutable top, Layoutable right, 
Layoutable bottom, Layoutable left) {
        this.center = center;
        this.top = top;
        this.right = right;
        this.bottom = bottom;
        this.left = left;

        invalidate();
    }


Any positions that are not occupied (or are not for managed children as layouts 
don't deal with those) should be set to `null`. So `BorderPane` would do 
something like:


    private void syncLayout() {
        if (layoutSynced) {
            return;
        }

        borderPaneLayout.setPositions(
            managedOrNull(getCenter()),
            managedOrNull(getTop()),
            managedOrNull(getRight()),
            managedOrNull(getBottom()),
            managedOrNull(getLeft())
        );
        borderPaneLayout.setInsets(getInsets());
        borderPaneLayout.setSnapToPixel(isSnapToPixel());
        borderPaneLayout.setRenderScaleContext(renderScaleContext());

        layoutSynced = true;
    }

-------------

PR Comment: https://git.openjdk.org/jfx/pull/2241#issuecomment-5194234348