Need an official way to exclude parts of the SceneGraph from CSS-Processing

[Michael Paus]

Hi Tom,

I am wondering whether it is really necessary to provide special API
for this case or whether this is not just an implementation issue of
controls like the TabPane.

For performance reasons (not only CSS-processing) I normally track
selection changes in TabPanes and similar controls and then explicitly
remove all invisible branches from the scene graph and keep them
elsewhere so that I can re-attach them if needed.

But I also do this tracking for a second reason because I also want
to tell my model which tab is visible so that I can shut down all
processing in my model which only updates properties which are
only used in the currently invisible branches of the scene graph.

I think if currently invisible branches of the scene graph are explicitly
detached from it, this does also solve your original problem of
reparenting, doesn't it? It would however be nice if the TabPane would
do the detaching/attaching itself.

Michael


Am 20.01.17 um 11:43 schrieb Tom Schindl:
> Hi,
>
> One of the biggest problems when working with JavaFX is that if you
> reparent a big portion of the SceneGraph is that a full CSS-Pass is
> applied on all reparented SG-Nodes even if those nodes are currently not
> visible (eg. because they are part of a TabPane).
>
> I general I think it is ok to also applyCSS changes on currently not
> visible nodes (eg they still have an influence on layout-bounds) but
> there are situations like the above mentioned example of TabPane that it
> is unnecessary overhead to apply applyCSS changes on those parts of the
> SG until they get visible.
>
> I would not mind if the CSS-Pass on JavaFX would be as performant as the
> one from current browsers but unfortunately it isn't so I'd like to
> discuss the possibility of a API to *temporarily* exclude portions of
> the SG from CSS-Passes.
>
> In JavaFX8 i was able to hack that in by overwriting impl_processCSS in
> a subclass who changed to doProcessCSS who now is private so my hack
> does not work anymore.
>
> To give you an impression on what performance gains we are talking about
> just look at the video I recorded -
> https://tomsondev.bestsolution.at/2016/11/25/improving-minmax-performance-in-e4-on-javafx-applications/
>
> Tom
>