Tom,
You can do one better than dream - you can file a JBS issue where we can
continue to discuss it :-)
-- Jonathan
On 24/01/17 10:21 PM, Tom Schindl wrote:
Hi Jonathan & Kevin,
Let's take CSS-Performance on the side for a moment.
I think the request I have is in itself already legal because there
might be situations where I as a component developer want to rule out
CSS-Processing for a complete SG-Area.
It might be performance (as it is in the case I initially mentioned) but
I think there are other use cases as well. Let's assume I write a
JavaFX-PDF-Viewer (something I really start doing just today) and I want
to avoid someone changing any of the SG-Objects I create (even by accident).
A similar problem we see today with the code-editor control we
developed, unbound CSS-Rules have a good chance to effect the Text-Nodes
who make up our editor and cause performance problems because we have so
many Text-Nodes making up the editor!
Today I have no other option than to programmatically setting all sorts
of properties because then the CSS-Engine then skips them but this
eagerly creates Property-Instances which once more effects memory usage.
I think that I as a control/component developer HAVE TO HAVE the chance
to define that the complete SG below me is managed by me and CSS does
NOT have to be applied to it.
I would propose the following simple "API":
private boolean cssSensitive = true;
public boolean isCssSensitive() {
return cssSensitive;
}
public void setCssSensitive(boolean cssSensitive) {
if( this.cssSensitive != cssSensitive ) {
this.cssSensitive = cssSensitive;
if( cssSensitive ) {
reapplyCSS(); // or is applyCSS() not sure
}
}
}
private void doProcessCSS() {
if( ! cssSensitive ) {
return;
}
}
I do understand that I'm too late in JDK9 cycle to add such an API but
one could at least dream about such a thing.
Tom
On 24.01.17 00:15, Jonathan Giles wrote:
There are two different topics here, both of which are near and dear to
my heart (and also make me feel like I've been doing JavaFX for way too
long!).
The specific case of TabPane doing CSS / layout on the content of all
tabs is something captured here:
https://bugs.openjdk.java.net/browse/JDK-8092206
It dates back to 2012 and I remember spending considerable amount of
effort with my team working through this. As can be seen in some of the
comments, there were attempts to improve performance (and they were
really nice), but the outcome was to back it out as we could not change
the default semantics of loading and doing all work on all tabs. The
second-to-last comment was a proposal for some API that would specify
the policy. I really would like to pick this back up for JDK 10, as JDK
9 is locked and loaded in this regard. I have retargeted this for JDK 10
just now.
As Kevin notes, improving performance is a big push I want to get
underway for JDK 10. The more general comment made in your email is -
how can we get better performance out of our critical paths (CSS,
layout, TableView, etc). That's something we will be actively exploring.
There are a lot of ideas, some will yield results and some won't. I've
been running into a few of those dead-ends myself recently as I do
preliminary investigations.
If anyone is interested in exploring performance-related topics in
JavaFX, I've got plenty of areas to explore :-) Ping me off-list and we
can discuss.
Unfortunately, again, unless there is some critical oversight these
discussions and investigations into performance and additional API are
by default targeted to JDK 10 rather than JDK 9.
-- Jonathan
On 20/01/17 11:43 PM, Tom Schindl wrote:
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
