Hi Andy,
I'm confused, nowhere do I propose to remove or otherwise make the CSS
reference system implemented by FX unusable.
I'm first trying to ascertain if this would be expected behavior (it is
indeed unspecified, and the default currently seems to have been chosen
for implementation ease, not for user friendliness).
**IF** we're considering this worth changing, the change would simply be
that when you override a variable (like -fx-base) that this is done
WITHOUT elevating all styles that use it to the level of an AUTHOR
stylesheet (ie. they remain at USER_AGENT level as they're specified by
Modena). This is not a bad view, because in a sense, we're not really
specifying a style, we're only overriding a variable. The actual style
is still specified in Modena, which is a USER_AGENT level stylesheet.
As for the bug fix, please read up a bit more on what was fixed, and
what this is now exposing. The fix is almost completely unrelated (it
fixed accidental changes to unrelated controls at the same level (ie.
siblings) due to cache sharing where one has had a programmatic change,
and the other didn't). This was caused by a CSS calculation bug
(calculation was skipped for all styleable properties that already had a
setter change, if they were encountered first by the CSS system). Now
that this isn't the case anymore, set values are overwritten with CSS
styles more aggressively. Normally those however are only styles that
originate from an AUTHOR stylesheet, so this can be seen as expected by
the user (after all, they WROTE that stylesheet). But because all
styles that use a variable are being promoted to AUTHOR level, this also
includes all unseen styles in Modena if you specify the variable in your
AUTHOR stylesheet.
> Nowhere did we **actualy** override -fx-text-fill " is not
technically correct since this color depends on -fx-base.
That really depends on your view point. Is overriding a variable the
same as defining all styles (in your AUTHOR stylesheet) that use that
variable? If it was a pre-processor, that created a fully resolved
Modena.css, then this would not be the case. But it is not implemented
as such.
> And I would not want to change how it works currently because this is
the only way (short of overwriting the whole modena.css styleshseet) for
an application to effect a system-wide change like reacting to changes
in the user preferences or the platform theme.
To be clear, I'm not proposing to change that at all.
--John
On 09/07/2024 20:00, Andy Goryachev wrote:
1) a buggy implementation coupled with lack of specification creates a
certain expectation
2) bug gets fixed
3) people complain because the feature now works as it should?
I think (and this is my personal opinion, in the absence of a formal
specification) that this works as expected now. The statement "
Nowhere did we **actualy** override -fx-text-fill" is not technically
correct since this color depends on -fx-base.
And I would not want to change how it works currently because this is
the only way (short of overwriting the whole modena.css styleshseet)
for an application to effect a system-wide change like reacting to
changes in the user preferences or the platform theme.
-andy
*From: *John Hendrikx <john.hendr...@gmail.com>
*Date: *Tuesday, July 9, 2024 at 10:45
*To: *Andy Goryachev <andy.goryac...@oracle.com>, openjfx-dev
<openjfx-dev@openjdk.org>
*Subject: *Re: [External] : Re: CSS Lookups and their origins
(possible regression)
Well, it is coming as a surprise to many. With the fix for the CSS
caching bug since JavaFX 21, this "normal" behavior is becoming much
more obvious.
Let me repeat one more time:
If I have a Label, and I manually set its text fill with a setter to
YELLOW. In JavaFX 17, when I now add a stylesheet that is empty aside
from `-fx-base: WHITE`, the label's text fill stays YELLOW.
Now do this in JavaFX 21. As soon as you add the stylesheet with
`-fx-base: WHITE` in it, the set value to YELLOW is overridden, even
though technically this value for -fx-text-fill is defined by Modena
(which should not be overriding set values). Nowhere did we
**actualy** override -fx-text-fill, yet the CSS subsystem now sees
**all** values defined by Modena that are somehow linked to -fx-base
as defined directly by the developer...
The reason this didn't happen in JavaFX prior to 21 is because there
was a bug where a CSS value was not fully calculated if the property
it encountered was overridden via a set value. That was a bug however
as cache entries are shared amongst similar styled nodes, and so not
calculating it fully could have effects on other nodes that shared
that cache entry but did NOT have a property set directly. Now that
this bug is fixed, this problem is odd behavior is popping up where
simply specifying -fx-base in an empty stylesheet is somehow
overriding a programmatically set text fill. Users are confused by
this, as nowhere in their stylesheet do they themselves override text
fill.
This entire mechanism is not specified by CSS, but is unique to FX.
The most similar mechanism in CSS (see Michael's answer) says the
priority of a style should not be changed when it is using a reference.
--John
On 09/07/2024 17:43, Andy Goryachev wrote:
> all styles used in Modena that rely on -fx-base directly or
indirectly suddenly have a higher priority
I think it works as designed (and as expected).
-andy
*From: *John Hendrikx <john.hendr...@gmail.com>
<mailto:john.hendr...@gmail.com>
*Date: *Tuesday, July 9, 2024 at 08:25
*To: *Andy Goryachev <andy.goryac...@oracle.com>
<mailto:andy.goryac...@oracle.com>, openjfx-dev
<openjfx-dev@openjdk.org> <mailto:openjfx-dev@openjdk.org>
*Subject: *[External] : Re: CSS Lookups and their origins
(possible regression)
It's not that you can't use -fx-base, but that as it is currently
that all styles used in Modena that rely on -fx-base directly or
indirectly suddenly have a higher priority (above setters) even
though you didn't specifically specify them in your own
stylesheet. All such styles are being elevated from USER_AGENT to
AUTHOR level (which is above USER level which is used for setters).
--John
On 09/07/2024 17:03, Andy Goryachev wrote:
I've used this feature in the past to change the colors in all
the controls, so to me this is the expected behavior.
So in your case (if I got it right), you need to set the
direct style on the label (.setStyle("-fx-text-fill:yellow"))
instead of setting the text fill programmatically. Right?
-andy
*From: *openjfx-dev <openjfx-dev-r...@openjdk.org>
<mailto:openjfx-dev-r...@openjdk.org> on behalf of John
Hendrikx <john.hendr...@gmail.com>
<mailto:john.hendr...@gmail.com>
*Date: *Monday, July 8, 2024 at 17:11
*To: *openjfx-dev <openjfx-dev@openjdk.org>
<mailto:openjfx-dev@openjdk.org>
*Subject: *Re: CSS Lookups and their origins (possible regression)
I realized I worded the TLDR poorly.
Let me try again:
TLDR; should styles which use references (like -fx-base used
in Modena) become AUTHOR level styles if -fx-base is specified
in an AUTHOR stylesheet? The act of simply specifying
-fx-base in your own AUTHOR stylesheet elevates hundreds of
styles from Modena to AUTHOR level, as if you specified them
directly...
--John
On 09/07/2024 02:07, John Hendrikx wrote:
Hi List,
TLDR; should a CSS reference like -fx-base convert all
styles that use this value (or derive from it) become
AUTHOR level styles (higher priority than setters) ?
Long version:
In JavaFX 21, I did a fix (see #1072) to solve a problem
where a CSS value could be reset on an unrelated control.
This happened when the CSS engine encountered a stylable
that is overridden by the user (with a setter), and
decided NOT to proceed with the full CSS value calculation
(as it could not override the user setting if that CSS
value had lower priority). However, not proceeding with
the calculation meant that a "SKIP" was stored in a shared
cache which was incorrect. This is because when this
"SKIP" is later encountered for an unrelated control (the
cache entries are shared for controls with the same styles
at the same level), they could get their values reset
because they were assumed to be unstyled.
However, this fix has exposed what seems to be a deeper
bug or perhaps an unfortunate default:
JavaFX has a special feature where you can refer to
certain other styles by using a reference (which is
resolved, recursively, to a final value). This does not
seem to be a CSS standard, but is a feature only FX has.
It works by saying something like:
-fx-base: RED;
And then using it like this:
-fx-text-fill: -fx-base;
This feature works accross stylesheets of different
origins, so an AUTHOR stylesheet can specify -fx-base, and
when a USER_AGENT refers to -fx-base, the value comes from
the AUTHOR stylesheet.
JavaFX then changes the origin of the style to the highest
priority encountered while resolving the reference. This
means that Modena can specify "-fx-text-fill: -fx-base",
and when "-fx-base" is then part of the AUTHOR style
sheet, that ALL Modena styles that use -fx-base will be
considered AUTHOR level styles, as per this comment:
// The origin of this parsed value is the greatest of
// any of the resolved reference. If a resolved reference
// comes from an inline style, for example, then the value
// calculated from the resolved lookup should have inline
// as its origin. Otherwise, an inline style could be
// stored in shared cache.
I feel that this is a really unfortunate choice. The
style after all was specified by Modena, only its value
came from another (higher priority) style sheet. I think
a more logical choice would have been to not change the
priority at all, unless a "-fx-text-fill" is explicitly
made part of the AUTHOR stylesheet.
A consequence of this (and which is much more visible
after the fix) is that creating a Label with a
setTextFill(Color.YELLOW) in its constructor will only
result in a yellow text fill if the AUTHOR stylesheet did
not override any of the Modena colors involved in
calculating the Modena -fx-text-fill default. Overriding
-fx-base in any way will result in the text fill of the
label to be overridden (as the reference came from an
AUTHOR stylesheet, which trumps a setter which is of a
lower style origin).
The comment also alludes to a potential problem. If an
inline style would specify "-fx-base", but would be
treated as if it came from Modena (USER_AGENT level), then
this value could get stored in the cache as everything
except INLINE styles can be cached. However, I feel that
the changing of style origin level was then probably done
to solve a CACHING problem, instead of what made logical
sense for users. If we agree that a resolved reference
should not change the style origin level, then this would
need to be addressed, by perhaps marking such a calculated
value as uncacheable, instead of overloading the meaning
of style origin.
I'd like to hear your thoughts, and also how to proceed.
JavaFX versions before 21 seemingly allowed overriding
reference without much consequence because if the user
overrode the value manually, the cache entry would be set
to "SKIP". Now that this is no longer the case, JavaFX
more aggressively overrides user set values if they happen
to use a referenced value. See code below.
--John
.root {
-fx-base: #ff0000;
}
*package*app;
*import*javafx.application.Application;
*import*javafx.scene.Scene;
*import*javafx.scene.control.Label;
*import*javafx.scene.paint.Color;
*import*javafx.stage.Stage;
*public**class*TestApp *extends*Application {
*public**static**void*main(String[] args) {
/launch/(args);
}
@Override
*public**void*start(Stage primaryStage) {
Scene scene = *new*Scene(*new*MyLabel());
// See the difference with/without -fx-base in the
_stylesheet_
scene.getStylesheets().add(TestApp.*class*.getResource("/style.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
}
}
*class*MyLabel *extends*Label {
*public*MyLabel() {
setTextFill(Color.YELLOW);
setText("Hello world");
}
}
