Created attachment 121043 [details]
open file from bug 95060, attachment 119611 [details] in linux
Arial - Combining Diacritics will not stack
Combining Diacritics will stack
works OK in Windows Version: 184.108.40.206.alpha0+ (x64)
Build ID: e7c78e67292ad93c6a4a0772d8b06a0e6e7d26c8
Threads 1; Ver: Windows 6.1; Render: default;
TinderBox: Win-x86_64@62-TDF, Branch:MASTER, Time: 2015-11-30_22:37:14
Created attachment 121044 [details]
Created attachment 121045 [details]
Created attachment 121046 [details]
LO 3.5, linux
Believe this mishandling of the Arial TTF is an OpenGL composition issue.
Disable OpenGL and the Arial combined diacritics will stack.
But, the Graphite based glyphs composed with Uniscribe on Windows are corrupt even with OpenGL disabled. Unreadable when it is enabled.
On Windows 10 Pro, with nVidia GTX-750ti
Build ID: f34b4844473d08c0c264ba4453a875e32f5c326b
Threads 8; Ver: Windows 6.19; Render: default;
TinderBox: Win-x86@39, Branch:master, Time: 2015-12-01_06:36:58
Locale: en-US (en_US)
Graphite fonts don't go through the Uniscribe code path at all.
So is this a Linux or Windows bug? Metadata says Linux, but comments talk about Windows.
I guess here it is best to disregard any talk about Windows and really treat this as a Linux specific bug, as that is what the initial bug submission says. It even says the corresponding thing works fine on Windows.
Created attachment 121346 [details]
combining diacritics on Windows Arial not correct with OpenGL
@Tor, no stacking/combining diacritics not work for Arial on Windows if OpenGL is enabled.
See the two attachments I'm adding. Arial is incorrect on Windows when OpenGL enabled and one where Arial is correct on Windows when OpenGL is disabled.
Created attachment 121347 [details]
combining diacticits is correct on Windows Arial without OpenGL
There are two bugs here.
1. OpenGL causing diacritics to shift even for non-Graphite fonts.
2. Graphite on Windows having diacritics shift at zooms below something silly due to a bug in GDI.
I suggest we make this bug be about the OpenGL problem. We're working on that one and just need to get D2D to play ball.
The OpenGL issue with "stacking" of glyphs does affect all OS.
On Windows with
Build ID: fe37d93a110cb9941c61fed0c71369a21a7d2765
CPU Threads: 8; OS Version: Windows 6.2; UI Render: GL;
TinderBox: Win-x86@62-merge-TDF, Branch:MASTER, Time: 2015-12-30_23:13:15
Locale: en-US (en_US)
OpenGL issue remains.
With OpenGL enabled, the non-Graphite fonts (so the Uniscribe composition on Windows) remains garbled when glyphs are combined. (Checked Arial and Liberation Sans). Disabling OpenGL permits the glyps to stack correctly.
Things have improved for the Graphite fonts, where stacking glyphs as combined diacritics appear the same with or without OpenGL active--the stacking remains incorrect in either mode, but they are now consistent and at the same scale. (Checked Linux Biolinum G and Linux Libertine G).
So again, is this a Windows or Linux bug or both? I can’t reproduce this on Linux with or without OpenGL.
Created attachment 128083 [details]
combining diacritics on Windows -- with OpenGL
Created attachment 128084 [details]
combining diacritics on Windows -- with default Graphics
Going to call this Windows only. Handling the combined diacritics are really ugly with OpenGL rendereing enabled in a recent build of 5.3.0 master. But also with default graphics the combined diacritics do not stack--so some font layout issues in both WinLayout and SimpleWinLayout.
See new clips of the sample test file--attachment 121043 [details] with current 5.3.0 master.
No handling mark stacking correctly on Windows is expected since we do not currently do any OpenType layout for Latin script, and should be fixed with bug 89870.
The OpenGL bug seems to be completely unrelated and should be reported seperately if not already.