RFR: 8185887: TableRowSkinBase fails to correctly virtualize cells in horizontal direction [v4]

[Andy Goryachev]

On Fri, 10 Jan 2025 15:19:48 GMT, henrykdz <duke at openjdk.org> wrote:

>> Marius Hanl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:
>> 
>>  - Merge branch 'master' of https://github.com/openjdk/jfx into 8185887-virtualization
>>    
>>    # Conflicts:
>>    #	modules/javafx.controls/src/test/java/test/javafx/scene/control/skin/VirtualFlowTest.java
>>  - Merge branch 'master' of https://github.com/openjdk/jfx into 8185887-virtualization
>>    
>>    # Conflicts:
>>    #	modules/javafx.controls/src/main/java/javafx/scene/control/skin/TableRowSkinBase.java
>>    #	modules/javafx.controls/src/main/java/javafx/scene/control/skin/TreeTableRowSkin.java
>>    #	modules/javafx.controls/src/main/java/javafx/scene/control/skin/VirtualFlow.java
>>  - 8185887: Reset disclosureNodeDirty in updateDisclosureNodeAndGraphic()
>>  - 8185887: TableRowSkinBase fails to correctly virtualize cells in horizontal direction
>
> Hey Guys, i am just new here, pls anyone help with my observation: 
> Bug Report: JavaFX TreeView - Incorrect Cell Index Update on Expand/Collapse
> Issue:
> When expanding or collapsing a TreeItem in a TreeView, an incorrect cell index is updated. Specifically, a cell index mirrored vertically around the center of the visible area is updated instead of the correct cell. This indicates a flaw in the cell index update logic or the visible cell list update mechanism.
> 
> This issue is particularly noticeable when cells are styled using CSS, as the incorrect update results in a visual glitch or flicker. Even without CSS, the problem manifests as a subtle graphical irregularity due to the rapid update process.
> 
> Steps to Reproduce:
> 
> Create a TreeView with enough items to enable scrolling.
> Scroll to make a specific range of indices visible (e.g., indices 4 to 13).
> Apply distinct CSS styles to cells to make updates visually apparent.
> Expand or collapse a TreeItem within the visible range (e.g., index 5).
> Observe that the mirrored index (e.g., index 12) is updated instead of the correct index.
> Observed Behavior:
> When a TreeItem at index i is expanded/collapsed, the index updated is:
> 
> Mirrored Index = 2 ⋅ Center − 𝑖
> 
> Examples:
> Expanding/collapsing index 5 incorrectly updates index 12.
> Expanding/collapsing index 10 incorrectly updates index 3.
> Expected Behavior:
> Only the cell corresponding to the expanded/collapsed TreeItem should be updated.
> 
> Impact:
> Visual inconsistencies and graphical glitches in the TreeView.
> Subtle flickering or graphical irregularities during expand/collapse actions, especially noticeable with styled cells.
> Suggested Cause:
> A miscalculation or incorrect implementation in the logic for updating cell indices or the visible cell list during expand/collapse operations.
> 
> Environment:
> Observed in JavaFX versions 16 through 23.
> Present across different platforms and configurations.

@henrykdz : 
thank you for the bug report!  I can help you to file a bug.  Two questions:
1. is the issue you describe still present when tested with the changes in this PR?  Or is it a separate issue?
2. can you create a simple SCCE (self-contained short example), see for instance https://github.com/andy-goryachev-oracle/Test/blob/main/src/goryachev/bugs/TreeView_RenderingFailure_8346824_8347357.java

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PR Comment: https://git.openjdk.org/jfx/pull/1644#issuecomment-2582991131