On Wed, 7 Feb 2024 15:06:18 GMT, John Hendrikx <jhendr...@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 with a new target base due to a > merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains 16 additional > commits since the last revision: > > - Merge branch 'openjdk:master' into feature/wrapped-aligned-text-rendering > - Fix test comment > - More test cases (for hard wrapping) and another small fix > - Improve tests, fix a bug > - Fix bug which confused char index with glyph index > - Move test that needs QuantumToolkit to system tests > - Clean-up, re-enable and extend ancient TextLayout test > - TextRun getAdvance should return 0 when positions array is null > - Fix justify alignment to take all trailing spaces into account > - Fix trailing space calculation to access positions array directly > - ... and 6 more: https://git.openjdk.org/jfx/compare/c1e97be2...388696a6 I fixed the slight inaccuracies surrounding the float/double conversion but it didn't fix the flickering scrollbar. My theory is now that how the wrap width of the `Text` node is updated is not entirely legal (I posted on the mailinglist to see if anyone can remember how this is supposed to work when you update a value (that may cause layout changes) based on a property that is already changed by layout code). What I'm thinking is that `ScrollPane.viewportBoundsProperty`, which is only set in `layoutChildren` of its skin, should not be bound to the `Text` wrapping width -- a layout is already running, and updating another property that will affect layout will result in undefined behavior. I see the same issue when I bind that value to a simple `Label`'s text -- the text width is often incorrect resulting in an ellipsis being displayed. So I'm thinking the reason the horizontal scroll bar appears on the `ScrollPane` is because the bounds it calculated were based on the previous `Text`'s wrapping width, and is not recalculated again when we update the `Text` wrapping width **during** layout. ------------- PR Comment: https://git.openjdk.org/jfx/pull/1236#issuecomment-1935203621
