RFR: 8231644: TreeTableView Regression: Indentation wrong using Label as column content type [v3]

[Ajit Ghaisas]

On Tue, 27 Jul 2021 05:45:50 GMT, Marius Hanl <mhanl at openjdk.org> wrote:

>> This PR fixes a long standing issue with the TreeTableView indentation.
>> 
>> ![image](https://user-images.githubusercontent.com/66004280/124681647-473e7380-dec9-11eb-906d-4228fc39cbf9.png)
>> 
>> In short:
>> **TreeTableCellSkin** overrides **leftLabelPadding()** to calculate the indentation (the result of this method is added to **x**).
>> While this is fine, this method is not always called (by **LabeledSkinBase#layoutLabelInArea**), e.g. when no text is set. 
>> So when a TreeTableCell only sets a graphic (e.g. via **setGraphic()** in **updateItem()**), the indentation will be messed up.
>> 
>> Fixed this by adding the calculated indentation to **x** before we call **layoutChildren()**.
>> 
>> We also need/should adjust every other location where `leftLabelPadding()` was used:
>> - **computePrefHeight** -> prefWidth() is always called with -1, so nothing got broken by not overriding this, but we should do it of course to be accurate in case we do one day.
>> - **computePrefWidth** -> this is needed for auto sizing. I saw that it was slightly off without, so this 100% needed.
>> - **computeMinWidth** -> the min width of a cell is not used, so nothing got broken by not overriding this but same as in computePrefHeight(), we should comply with the specs.
>> - **layoutChildren** -> I saw a slight off sizing if the indentation is not subtracted to the width.
>> 
>> As a result of this, all method do effectively the same as they did with an overridden `leftLabelPadding()` (just earlier/later and always now of course).
>> Note: I also added some tests which pass before and pass after.
>
> Marius Hanl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
> 
>  - Merge branch 'master' of https://github.com/openjdk/jfx into 8231644-indentation
>    
>    
 Conflicts:
>    
	modules/javafx.controls/src/main/java/javafx/scene/control/skin/TreeTableCellSkin.java
>  - calculated indentation in every method now which was previously done via leftLabelPadding
>  - 8231644: fixed wrong indentation for tree cells with graphic only

Marked as reviewed by aghaisas (Reviewer).

> > Overall the fix looks ok. The new test fails without the fix and passes with it.
> > Can you please confirm the test programs provided in 2 duplicated bugs of JDK-8231644 also work as expected with this fix?
> 
> Just tried them. They both work fine. :)



> > Overall the fix looks ok. The new test fails without the fix and passes with it.
> > Can you please confirm the test programs provided in 2 duplicated bugs of JDK-8231644 also work as expected with this fix?
> 
> Just tried them. They both work fine. :)
That's great!

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PR: https://git.openjdk.java.net/jfx/pull/568