[OpenJDK 2D-Dev] Font rendering quality in Linux

Artur Rataj arturrataj at gmail.com
Fri Dec 16 00:32:47 UTC 2016

On Fri, Dec 16, 2016 at 12:54 AM, Phil Race <philip.race at oracle.com> wrote:

> As I started to say on that list, it seems to me that this may be a
> font-specific problem.
Fonts have hints. I've seen similar issues when the hints are poor.

Unfortunately there is no easy way to know if they are poor.
Some clients/apps/rendering systems by policy ignore hints so they may look
> OK,
> but then they may not look as good on a case where the hints were good and
> important.
> If I knew exactly what font you were using I could look at it.

The problem is more or less visible in a number of fonts, including the
standard ones used by Java in dialogs, and several very high quality fonts
supplied with Ubuntu. Of course, the actual differences vary with fonts.

Also, the poor quality of font rendering of Java/Linux is known. This why
there are the patches, the alternative "fixed" versions of OpenJDK etc.

> Oracle's builds use a one that ships with the JDK binaries (not source)
> All openjdk builds use freetype. On Linux this means Ubuntu's openjdk will
> use the exact same copy of freetype as used for rendering the rest of your
> desktop!

Thanks, so I was wrong. Then, it might be a misconfigured freetype, a buggy
interface to freetype or whatever.

> So if it looks bad with that, it will look bad on your desktop unless the
> font is interpreted differently.

Not true. The particular font, like a lot of the other (if you wish, I may
send you example images), is badly rendered only in Java. Other Freetype
apps render these fonts very well, thanks to the exceptional quality of
that library.

If I run Netbeans with its standard fonts and --jdk-home of the Android
Studio jdk, the GUI quality is immediately improved, thanks to the fonts
rendered as expected from a properly supported Freetype.
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