RFR: 8313424: JavaFX controls in the title bar [v19]

[Andy Goryachev]

On Tue, 5 Nov 2024 06:00:55 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> modules/javafx.graphics/src/main/java/javafx/application/ConditionalFeature.java line 156:
>> 
>>> 154:      * Indicates that a system supports {@link javafx.stage.StageStyle#EXTENDED}.
>>> 155:      * <p>
>>> 156:      * This feature is currently supported on Windows, Linux, and macOS.
>> 
>> would it make sense to add more information similarly to UNIFIED_WINDOW on L151?
>> maybe pointing to different levels of support?
>> 
>> I don't know whether it makes sense to bring the whole table from the JEP here, but maybe somewhere (HeaderBar)?
>
> It links directly to `StageStyle.EXTENDED`, which contains lots of information. I don't think we need it here.
> 
> By the way, there are no support levels. The feature is supported in its entirety, as specified, on all desktop platforms. The table in the JEP is just informational to help OpenJFX developers understand what we're talking about. It's not a specification, and it can't be a specification because we either don't control things (for example, we have no influence on rounded corners, this could be changed with any future OS version) or because we'd be specifying us into a corner. There's no point prescribing every minute detail, and then being responsible to keep it working _exactly_ as described, even though the semantics are unchanged.
> 
> The relevant parts are specified in `StageStyle.EXTENDED` and `HeaderBar`, and I wouldn't go further than this. We don't specify the details of `StageStyle.DECORATED` for each OS; why should we do it for `StageStyle.EXTENDED`?

I guess you are right here: from the app dev perspective, there is no difference between the supported platforms.  All good.

I do suggest to bring a condensed version of the table in the JEP (or a simple <ul> here to show what's being painted by the platform and what is not.  In other words, instead of reading 1k of text, I want to see a short list indicating that, for example, close button is painted by the platform, and the title bar is not painted.

Can you do something like this?  (Alternatively, there might be a better place to do that, but where?)

>> modules/javafx.graphics/src/main/java/javafx/scene/layout/HeaderBar.java line 53:
>> 
>>> 51:  * account for the default window buttons (minimize, maximize, close). If a child is configured to be
>>> 52:  * centered in the {@code center} area, it is laid out with respect to the stage, and not with respect
>>> 53:  * to the {@code center} area. This ensures that the child will appear centered in the stage regardless
>> 
>> should there be more fine tuned control for growing/shrinking?
>> 
>> can the application just add a single container like GridPane that handles the resizing?
>
> What do you mean with growing and shrinking?
> 
> An application can add a single `GridPane` to `HeaderBar.center`, and set its prefWidth to `POSITIVE_INFINITY`. This will extend the `GridPane` across the entire width of the header bar (excluding the window button area).

maybe what's needed is to borrow some text from the `BorderPane`, along the lines of 

> "The top and bottom children will be resized to their preferred heights and extend the width of the border pane. The left and right children will be resized to their preferred widths and extend the length between the top and bottom nodes. And the center node will be resized to fill the available space in the middle. Any of the positions may be null. "

the important parts are
- how children are resized
- any can be null

(the layout in the HB is like the one in the `BorderPane`, right?)

>> modules/javafx.graphics/src/main/java/javafx/scene/layout/HeaderBar.java line 59:
>> 
>>> 57:  * {@code HeaderBar} honors the minimum, preferred, and maximum sizes of its children. If the child's
>>> 58:  * resizable range prevents it from be resized to fit within its position, it will be vertically centered
>>> 59:  * relative to the available space; this alignment can be customized with a layout constraint.
>> 
>> what if the components are too large to fit, will clipping occur?  should this behavior be mentioned?
>
> The components can't be too large to fit:
> `{@code HeaderBar} honors the minimum, preferred, and maximum sizes of its children.`

I want to know what happens when the layout is over-constrained.  For example, consider the layout to have the leading, the center, and the trailing nodes set, and the leading one has minWidth set to 10_000.  What happens?

Will the center and the trailing nodes be shown or clipped?  will the layout attempt to squeeze all three to fit the available space?

Can I get this answer from the javadoc?

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PR Review Comment: https://git.openjdk.org/jfx/pull/1605#discussion_r1829645476
PR Review Comment: https://git.openjdk.org/jfx/pull/1605#discussion_r1829654387
PR Review Comment: https://git.openjdk.org/jfx/pull/1605#discussion_r1829666593