Created attachment 752904 [details] annotated screenshot 2013-05-22-03-10-27-mozilla-central-firefox-24.0a1.en-US.linux-x86_64 22.0 Beta With system font hinting enabled, at the default zoom, at http://www.mozilla.org/en-US/firefox/new/#download-fx , * the green text has "d"s missing a stroke, making them look like "a"s, * the black text in the three steps has too little space between "c" and "l", making "click" look like "dick" (although that text is so small it is hard to read anyway). Debian GNU/Linux 7.0, the "open-source" "radeon" driver, no graphics acceleration. In Xfce4's Appearance window, on the "Fonts" tab: * [x] Enable anti-aliasing; * set "Hinting" to "Medium" or "Full". Xfce's default font size and pixel Sub-pixel order are not relevant. DPI is 96, that of the monitor.
FWIW, I've been unable to reproduce on a notebook Debian 7 XFCE using the same settings. The only difference being that I have an Intel GPU. Though I'm not sure if this is GPU related.
Aleksej could you please test some previous Firefox versions to see if this is a regression?
I can reproduce this in a VM so this rules out GPU as the cause. It's trivial for me to reproduce in Debian 7 with XFCE4 installed. 1. Load http://www.mozilla.org/en-US/firefox/new/#download-fx > Notice the 'd' looks like a 'd' 2. XFCE menu > Settings > Appearance > Fonts 3. Set Hinting to 'full' or 'medium' (does not reproduce on 'slight' or 'none') 4. Reload http://www.mozilla.org/en-US/firefox/new/#download-fx > Notice the 'd' looks broken Note that changing the XFCE subpixel setting to RGB or anything else doesn't seem to matter either. These seems to be directly related to Hinting in XFCE. Note this also does not reproduce with Chromium under the same conditions so I think this is a combination of an XFCE and Firefox bug.
I checked Debian's default browser, Iceweasel 10.0.12 (based on Firefox 10.0.12esr) and it reproduces so this is not a recent Firefox regression if a regression at all. Aleksej, that means you can ignore my request in comment 2.
Summary: Issues with text in "Open Sans" fonts at default zoom level with medium or full hinting: "d"→"a", "click"→"dick". Debian, Xfce, open source radeon driver. → Debian XFCE with Font Hinting enabled misrenders Open Sans fonts
WFM: 2008-12-05-14-mozilla-central-firefox-3.2a1pre.en-US.linux-x86_64 no glyphs: 2008-12-06-02-mozilla-central-firefox-3.2a1pre.en-US.linux-x86_64 … no glyphs: 2009-04-23-04-mozilla-central-firefox-3.6a1pre.en-US.linux-x86_64 bug: 2009-04-24-03-mozilla-central-firefox-3.6a1pre.en-US.linux-x86_64
It seems that the problem exists only with Cairo, but if there is a regression range in the first few months of Cairo support, it probably cannot be found with the modern Pango: The all-glyphs-missing starts with https://hg.mozilla.org/mozilla-central/pushloghtml?startdate=2008-12-05+10%3A00&enddate=2008-12-06+02%3A00, with checkins for cairo-related bugs: bug 462798, bug 458169, bug 467874; and ends with https://hg.mozilla.org/mozilla-central/pushloghtml?startdate=2009-04-23+00%3A00&enddate=2009-04-24+04%3A00, with bug 489445 caused by a change in Pango being fixed.
While this may technically be a "regression" I don't think we'd treat it as one given that information. If a workaround fix can be found for this particular use case then we'd likely take it but I find it extremely doubtful that we'd revert any of the changes in comment 6. On top of that this seems to be a very isolated use case which few users will actually hit. I'm not sure we'd be able to assign developer resources to resolve this anytime soon. There's just far too much more higher priority work going on right now. Of course, all of this assumes that this bug is 100% Firefox's fault and not a regression introduced by XFCE being exposed by Firefox or a bug in the Open Sans font itself. FWIW, this bug would be moot for mozilla.org if and when we choose to adopt a new font.
Summary: Debian XFCE with Font Hinting enabled misrenders Open Sans fonts → Debian Xfce with Font Hinting enabled misrenders Open Sans fonts
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