[Bug 48146] Re: Poor font rendering in kpdf

Sergei Ivanov svivanov at pdmi.ras.ru
Thu Dec 18 20:51:33 UTC 2008

I fond the origin of the problem and a solution. The rendering propblem
occurs when you have all of the following:

1. TrueType bytecode interpreter enabled in the freetype library. (This
is a compile-time option which is off by default due to patent issues,
Ubuntu turns it on while Fedora does not.)

2. Kpdf using anti-aliasing. (No idea where this is configured, maybe
from the global KDE setting).

3. A pdf file with embedded bitmapped (or maybe any non-TrueType) fonts.
This is typical for pdfs generated by TeX.

When all of this happens, kpdf uses its own (or KDE's) anti-aliasing
*and* freetype's autohinting. Each of the features is supposed to
improve the view but their combination works poorly.

A solution is to turn off the check for bytecode interpreter in kpdf. On
Ubuntu, this piece of code actually lives in libpoppler which is a
separate package. The attached patch to poppler fixes the problem for
me. I don't know if it breaks something else. I checked evince and it
does not seem to be affected.

The same file is present in kpdf source. It should be patched there if
kpdf is compiled without poppler.

** Attachment added: "disable freetype's autohinting when anti-aliasing"

Poor font rendering in kpdf
You received this bug notification because you are a member of Kubuntu
Bugs, which is a direct subscriber.

More information about the kubuntu-bugs mailing list