GNOME Bugzilla – Bug 607159
Pango doesn't render the o correctly, when a j is near
Last modified: 2010-05-13 17:09:13 UTC
Created attachment 151549 [details] mis-rendered o on the Geany menu bar This issue actually sounds a bit weird, but I will attach two pictures which show the problem: Everytime somewhere a word shows up with a j following to an o, the o isn't rendered correctly. This for example occurs in Geany, where a menu point is called "Projekte" in German or "Projects" in English. It also occurs in Thunar, which lists my home directory including a folder named "projects". This just occurs when you set the font-size to 8pt, while the font resolution is 96pt. Changing the font-size as workaround to 9pt or 7pt fixes this, the o is rendered correctly then. I'm using Fedora 12 with pango-1.26.2-1.fc12.x86_64 gtk2-2.18.6-1.fc12.x86_64
Created attachment 151550 [details] mis-rendered o in Thunar
Additionally figured out, why the "Projekte" in the Thunar-screenshot doesn't have the problem. It's written with a big P. When writing it with a small p, the same problem occurs as for "projects". I also noticed this behaviour in a pidgin-window a few minutes ago.
Oh, sorry I've missed to mention the font: DejaVu Sans. I also noticed this with some other sans-serif fonts.
Weird. Haven't seen anything like this before. Do you have freetype-freeworld installed by any chance?
Yes, I have installed freetype-freeworld-2.3.11-1.fc12.i686. The system is basically a x86_64 system, and most packages are. There are some i686 because I need them to run Skype. Seems Qt or anything else had this one (freetype-freeworld-2.3.11-1.fc12.i686) as dependency.
Sounds like a FreeType bug. Can you confirm that it doesn't happen without freetype-freeworld? At any rate, you need to report to FreeType.
Unfortunately, uninstalling the freetype-freeworld package didn't solve the problem. Do you think this still a freetype bug then? (Since there still is freetype.x86_64 which seems to be needed by any package on the system.)
Still unlikely to be pango. Pango doesn't do the actual rendering. cairo does. And cairo gets the bitmaps from FreeType. Can you reproduce in gedit, or using the pango-view cmdline tool?
I can reproduce it with gedit, yes. I'll attach two screenshots which show this. Unfortunately I don't know how to use pango-view from command-line, in special what files to open, would it be possible to provide a short description for that?
Created attachment 152263 [details] mis-rendered o in gedit
Created attachment 152265 [details] mis-rendered o in gedit second shot This one also shows the directory listing with "projects" in the left.
Something like: $ pango-vew --text 'oj' --font 'dejavu sans 10' --dpi 72
Created attachment 152268 [details] $ pango-view --text 'oj' --font 'dejavu sans 8' --dpi 96 $ pango-view --text 'oj' --font 'dejavu sans 8' --dpi 96 results in the attached screenshot $ pango-view --text 'oj' --font 'dejavu sans 10' --dpi 72 works very fine (tell me if you like this one to be shot too)
Renders just fine here. Are you sure this happens without freetype-freeworld? The rendering suggests otherwise. Can you report it to freetype mailing list please?
Yes, it's sure this happens without freetype-freeworld. The package is still uninstalled. I've reported the issue to the mailing list of freetype as you suggested, I'll let you know as soon as there is any reply.
Thanks.
Already got answer from Werner Lemberg a few days ago. Sorry for my delayed reaction. He set you in CC as he wrote that mail, I wrote him today and added your @gnome.org-address to CC too. Did you receive those mails?
The keyword for this issue seems to be "subpixel hinting". Switching it from RGB (vertical) to RGB - with most intense subpixel hinting - actually solves the issue, the o is displayed correctly again, even if it seems there is a bit more "letter-spacing" in general now. This is a really weird behaviour. Especially because I had the setting on RGB vertical for a very very long time (I have this TFT display since four or five years now) and didn't face the problem before. Maybe this is a hint to the root cause of the issue. Or is this a Layer 8 problem? :)
I strongly suggest that you try ftview; there you can cycle through the various horizontal and vertical RGB/BGR modes. If you can reproduce the issue this would be very helpful to identify the exact problem.
I unfortunately can not reproduce the issue with any LCD setting in ftview. The o always is displayed correctly. :( I can't seem to figure out, whats the best setting anyway. As I said, my usual setting was RGB vertical, but horizontal RGB also seems appropriate as long as the displayed font is non-bold. With bold fonts there are some chars or letters which are displayed a bit "washy", e.g. the "e". It seems more clear with the vertical RGB setting. Well, I guess this is most likely a layer 8 problem, because the horizontal RGB setting is very unusual to me. I'll try to work with the horizontal RGB setting a few days more and see if I can get used to it. :) Anyway the mis-rendered o still exists in some cases (as mentioned in comments above, the screenshots still represent the behaviour), but I unfortunately have no more idea how to reproduce it at present. It seems very sporadically. I will let you know as soon as I discover something new which may helps to figure out the problem.