RFR: 8371067: RichTextArea: requestLayout by inline node doesn't reach VFlow [v2]

[Andy Goryachev]

On Fri, 21 Nov 2025 08:40:18 GMT, Marius Hanl <mhanl at openjdk.org> wrote:

>>> is to take another look at the problem and how to solve it.
>> 
>> The RTA design is that VFlow deals with the layout.  It views the thing not as a collection of independent cells, but as a virtual flow - a change in one cell might require the reflow of many other parts, toggling scroll bars visibility, reshaping the selection shapes, etc.
>> 
>> In an ideal world, the layout of text and embedded nodes would be a responsibility of the (prism) text layout, making it easier to have for example a Label with rich text.  But we don't have that option, so this design uses a collection of text cells to present the visible area, managed by the VFlow.
>
> Let me repeat what I mean:
> - If you call: `setManaged(false)`, you will effectively tell JavaFX: I'm the layout root, I can handle ALL layout changes from my children without my parents.
> - This is not the case here, so making the `TextCell` unmanaged while still retrieving a parent (`VFlow`) fights this design.
> - Which leads me to the conclusion: Maybe this should not be unmanaged, since it does not fulfill the required preconditions
> - Checking the `VirtualFlow` as an example, it will not set anything to unmanaged
> 
> Lets check some existing examples of unmanaged nodes:
> 
> `XYChart`. See how this was done by design, the consequences were known:
> https://github.com/openjdk/jfx/blob/33abf5d4b3d2b90f66581c4e25c542adf285fadd/modules/javafx.controls/src/main/java/javafx/scene/chart/XYChart.java#L523-L525
> 
> ---
> 
> `ScrollPaneSkin` has actually the same case as you. This is how they dealt with it:
> https://github.com/openjdk/jfx/blob/33abf5d4b3d2b90f66581c4e25c542adf285fadd/modules/javafx.controls/src/main/java/javafx/scene/control/skin/ScrollPaneSkin.java#L652-L653
> https://github.com/openjdk/jfx/blob/33abf5d4b3d2b90f66581c4e25c542adf285fadd/modules/javafx.controls/src/main/java/javafx/scene/control/skin/ScrollPaneSkin.java#L679-L689
> 
> This could be a solution for your problem. Since they also set the parent `viewRect` as unmanaged, the layout request will never hit the `ScrollPane`. But with that solution the child of the `viewRect`, called `viewContent` does request the `ScrollPane` layout. A clever solution without anything like ancestor searching. What do you think?

The documentation on `Node.managed` property states 

Defines whether or not this node's layout will be managed by its parent. 


The layout of TextCell is not managed by its parent (`VFlow.content`), **by design**.

The `VFlow` is the entity that does the layout, for a reason.  It's a complicated thing, and multiple moving parts are connected (one example: it performs multiple layout cycles in the same layout pass when scrollbars appear/disappear during the layout pass, to avoid jumping and flicker - something we occasionally see with `ScrollPane` and `ListView`, see Note 1).

Notes

1. I occasionally see the continuous flicker/layout when resizing the list of pages in the latest Monkey Tester, but so far I was unable to capture the exact conditions to create a reproducible test case (this is unrelated to this PR)

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PR Review Comment: https://git.openjdk.org/jfx/pull/1975#discussion_r2550174581