RFR: JDK-8314215 Trailing Spaces before Line Breaks Affect the Center Alignment of Text [v13]

[John Hendrikx]

On Fri, 9 Feb 2024 23:37:16 GMT, John Hendrikx <jhendrikx at openjdk.org> wrote:

>> There are a number of tickets open related to text rendering:
>> 
>> https://bugs.openjdk.org/browse/JDK-8314215
>> 
>> https://bugs.openjdk.org/browse/JDK-8145496
>> 
>> https://bugs.openjdk.org/browse/JDK-8129014
>> 
>> They have in common that wrapped text is taking the trailing spaces on each wrapped line into account when calculating where to wrap.  This looks okay for text that is left aligned (as the spaces will be trailing the lines and generally aren't a problem, but looks weird with CENTER and RIGHT alignments.  Even with LEFT alignment there are artifacts of this behavior, where a line like `AAA  BBB  CCC` (note the **double** spaces) gets split up into `AAA  `, `BBB  ` and `CCC`, but if space reduces further, it will wrap **too** early because the space is taken into account (ie. `AAA` may still have fit just fine, but `AAA  ` doesn't, so the engine wraps it to `AA` + `A  ` or something).
>> 
>> The fix for this is two fold; first the individual lines of text should not include any trailing spaces into their widths; second, the code that is taking the trailing space into account when wrapping should ignore all trailing spaces (currently it is ignoring all but one trailing space).  With these two fixes, the layout in LEFT/CENTER/RIGHT alignments all look great, and there is no more early wrapping due to a space being taking into account while the actual text still would have fit (this is annoying in tight layouts, where a line can be wrapped early even though it looks like it would have fit).
>> 
>> If it were that simple, we'd be done, but there may be another issue here that needs solving: wrapped aligned TextArea's.
>> 
>> TextArea don't directly support text alignment (via a setTextAlignment method like Label) but you can change it via CSS.
>> 
>> For Left alignment + wrapping, TextArea will ignore any spaces typed before a line that was wrapped.  In other words, you can type spaces as much as you want, and they won't show up and the cursor won't move.  The spaces are all getting appended to the previous line.  When you cursor through these spaces, the cursor can be rendered out of the control's bounds.  To illustrate, if you have the text `AAA                 BBB CCC`, and the text gets wrapped to `AAA`, `BBB`, `CCC`, typing spaces before `BBB` will not show up.  If you cursor back, the cursor may be outside the control bounds because so many spaces are trailing `AAA`.
>> 
>> The above behavior has NOT changed, is pretty standard for wrapped text controls,...
>
> John Hendrikx has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - Fix test description
>  - Improve test
>    
>    - Test TextSpans (rich text) and String text (plain text)
>    - Add test cases for leading spaces, tabs
>    - Fix justified test to take hard wrapped lines into account correctly
>  - Convert class to record

> I see, so the test in graphics was @ignore("JDK-8087615")
> 
> I'd suggest to move the failing cases into a separate method and @ignore that. We still have JDK-8087615 to deal with the failure, but at least we'll have a good working test with the rest of the scenarios.
> 
> What do you think?

I think other tests may fail on other people's local environments, what you discovered may just be the tip of the iceberg, so we'd effectively be disabling many of these tests -- they really require a predictable environment (I would include fonts in the `src/test/resources` folder and load those if that was allowed)

I think I would favor running these only on the build environment.

Could you check if your Monaco font has those complex glyphs that it mentions in the failure message?  `brown लोमड़ी jumps`?

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PR Comment: https://git.openjdk.org/jfx/pull/1236#issuecomment-1936742756