RFR: 8313424: JavaFX controls in the title bar [v21]

[Andy Goryachev]

On Tue, 5 Nov 2024 20:41:01 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> modules/javafx.graphics/src/main/java/javafx/scene/layout/HeaderBarBase.java line 51:
>> 
>>> 49:  * can specify draggable content nodes of the {@code HeaderBarBase} with the {@link #setDraggable} method.
>>> 50:  *
>>> 51:  * @apiNote Most application developers should use the {@link HeaderBar} implementation instead of
>> 
>> just curious: what's the reason to split the HB into the two classes?  Can you give an example?
>
> The goal of the JEP is to allow fully customizable header bars (excluding window buttons). `HeaderBarBase` is the basic building block that is required for the headerbar-specific features like dragging, double clicking, and so on. This class is special because its functionality can't be replicated by user code.
> 
> For maximum customizability, `HeaderBarBase` is just a `Region`. Subclasses are free to implement any kind of control on top of that. This is what `HeaderBar` is: an implementation on top of the basic functionality, offering a pretty useful API and layout behavior. It covers many common use cases with the separation between a leading, center, and trailing area.
> 
> But special applications might have special requirements. For example, the Spotify desktop app selectively hides items in its header bar depending on the available space, and sometimes dynamically changes the alignment of items. This would be a case where an application would use a custom implementation of `HeaderBarBase`.

thanks for explanation.  but does it really warrant a base class, couldn't the app either set different components inside the existing HB, or maybe set a different HB?

is there anything that HeaderBar does that may not be needed in a custom title bar?

it just feels that HBBase is not needed.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1605#discussion_r1829997063