Description
Telesto
2021-02-04 17:56:34 UTC
@Michael My speculation is that you're fix back in the day: https://cgit.freedesktop.org/libreoffice/core/commit/?id=6db39dbd7378351f6476f6db25eb7110c9cfb291 is falling apart.. it maybe never worked perfectly - at least I have seen this also in 4.3 on macOS (and also bug 138919 might fit in) but surely becoming even more prominent. And kind of expecting that the glyph positioning drama of bug 103322 can be directed to this too.. The kerning in example 3 pretty OK after step 3 as far I can tell.. There is also a bounty open for solving this :P. However $250 kind of a joke oh, that's tragic... would be interesting to know if this is a regression and to bibisect it, it used to work reasonably well when i wrote that commit. Pretty straight forward: bug 140101 and bug 140197: https://cgit.freedesktop.org/libreoffice/core/commit/?id=568b820bc2d52c007ee08ad7a3849c94a458115d Bit more dubious, but makes sense bug 139296: https://cgit.freedesktop.org/libreoffice/core/commit/?id=378c74ce290ab772f962db51ff8cba200cb40144 (partly redraw instead of full.. causing misalignment) Bit more dubious, but makes sense bug 138919: https://cgit.freedesktop.org/libreoffice/core/commit/?id=cba7370aab56212ca9e8def72ce821746835b4ff [a change I hijacked the bug, so 2 topics in 1] The deleting of paragraph in case of bug 140101 causes proper font kerning, IMHO. So it's possible to have good kerning. I think I assume there is also a part which never got fixed; bug 103322. I have seen enough shifts in 4.3 on macOS. Pretty sure backend matters. GDI always pretty stable for me. OpenGL/Skia are affected. GEN backend & macOS backend. Not sure about the impact of Harfbuzz, don't think so.. There are two issues: 1. Initial rendering with bad kerning 2. Sub sequential font renderings (repaints) with different kerning. Where the distances between letters suddenly differently distributed (causing certain letters to move left/right; also depending on zoom, backend) 3. There also misalignments top/down, but not totally sure if it's related or not.. 4. There are cases where black line occurs below a paragraph/sentence. Speculating this 2 lines of pixels of the sentence not being repainted (while letters moved horizontally).. I added few screencast here an there. Alternative to RSID explanation: GetTextBreak code (or some combo of both). See bug 138919; involves: https://cgit.freedesktop.org/libreoffice/core/commit/?id=cba7370aab56212ca9e8def72ce821746835b4ff No advantage of having this longer around. Example B/C looking fixed to me. Example A is mentioned somewhere else |