Font problems (affecting Java and others?)
eliasen at mindspring.com
Sun Sep 7 21:17:22 EDT 2008
I'm working on making it possible to get Java to run on the OLPC,
and have a solution to what many of you may have seen: the problem that
any Java program uses a strange italicized serif font, no matter what
font you request. This odd font is used everywhere, and no other fonts
seem to work.
This is focusing on the OpenJDK 126.96.36.199 distribution as found in
yum. (That's "yum install java-1.6.0-openjdk") I've also considered
gcj, but gcj's implementations of things like AWT or Swing is far less
complete than OpenJDK currently. My OLPC is running Joyride 2346. I
was glad to see that despite what our Wiki says about Java, it's
actually relatively easy to make graphical Java programs at least run on
the OLPC, to switch to its window, etc. (I'm not talking about making
it a full-blown activity, which is dependent on a lot of other things
happening, such as not having to set X properties on windows, bug
http://dev.laptop.org/ticket/5271 and having a clean implementation of
the services currently built in Python, and making a C/Java binding to
(By the way, I'm also experimenting with "java-gnome" which creates
GTK bindings for gnome, so Java interfaces can look more like other
Sugar applications, but due to several compounding bugs in our yum
distribution, I can't build that on the OLPC, and can't emulate the OLPC
due to bug http://dev.laptop.org/ticket/7813 . I'll file those later.)
I know that there may be involved workarounds for some of these bugs,
but I think it's important for everyone to know which bugs are seriously
hampering developers who want to contribute, but don't have the time to
research and duplicate lots of workarounds. BTW, is there any progress
The problem is that our font.properties files are not set up
correctly for the fonts distributed on the OLPC. I've verified that
adding one file fixes the problem, but there are several ways of fixing
the problem and I wanted input from others on the proper way to do it.
Here's a page that gives background on how fonts are loaded in Java:
(It's Java 1.5 but it still seems to work the same in OpenJDK 1.6)
When looking at that page, note that Joyride 2346 sets the following:
Thus, it searches for a working font configuration in the following
The one marked with * is the first one that exists. The .bfc files
are a binary format.
In the above directory, there exists a file
By copying this file to the filename "fontconfig.Fedora.properties"
in the same directory, we can create a file that is found before the
.bfc file and test our changes.
Inside the new "fontconfig.Fedora.properties" file, at the end,
there are lines like:
Unfortunately, those font files don't exist, but instead of, say
DejaVuSans.ttf, we have files named DejaVuLGCSans.ttf.
Fixing the "fontconfig.fedora.properties" to change filenames of all
DejaVu... to DejaVuLGC... fixes these problems, and Java implementations
now display correctly.
Now, how is the proper way to fix it? Here are a few alternatives:
1.) Just add the fixed properties file as demonstrated above to the
OLPC's OpenJDK distribution. Doing this is nice because it doesn't
affect any existing files, and it's user-tweakable as opposed to the
compiled .bfc file.
2.) Create symbolic links in the fonts directory, for example,
DejaVuSans.ttf would be a symbolic link to DejaVuLGCSans.ttf. I don't
know if this might help other applications. Note that Fedora 9 usually
contains /usr/share/fonts/dejavu/ *AND* /usr/share/fonts/dejavu-lgc/
directories while the OLPC just contains the former.
3.) Add the missing fonts?
4.) Do some unspecified font fallback trick?
5.) Change "osname" (probably fetched from the Java property
os.name) in the OpenJava JVM from "Fedora" to something more specific to
the OLPC, like "OLPC". This might allow us to push an OLPC
configuration file upstream to the OpenJDK project. I'm not sure where
os.name is set, or how it is detected, though.
Which of these (or some other alternative) is the best way to fix
our Java font problem?
I'll file a bug on this. Is there anyone in charge of packaging the
OpenJDK distribution? I can probably create a patch for it. By the
way, I haven't verified if *all* fonts in our fontconfig file exist,
such as Sazanami, Lohit, Baekmuk, etc., or if we should point it at
other files on the OLPC.
By the way, what's the best way to:
a.) Create a patch for a *new* file
b.) compile a resource file to that .bfc format?
eliasen at mindspring.com
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