Priority: P2: Important
Affects Version/s: 4.7.4
Fix Version/s: None
Fedora 15 - Linux 126.96.36.199-2.rc1.fc15.x86_64 #1 SMP x86_64
Red Hat Enterprise Linux 5 - Linux 2.6.18-194.17.1.el5 #1 SMP x86_64
Arch Linux - Linux Kernel 3.0, x86_64, unknown full kernel string at this time.
**Preface: This is essentially a bug for QtWebKit, however I believe it may have something to do with Qt's internal rendering of Freetype/Truetype fonts which is causing the issue.
You are able to download the TTF of the font to test it within a Qt application and see if it exhibits the same issue. This would confirm if it is a specific issue with QtWebKit or Qt itself (I believe it is the latter)**
We have a large canvas that is intended to draw text and images, and scale between different sizes. This works fine for most rendering engines (including GTK+ WebKit, Chromium/Chrome port of WebKit and Safari itself), however QTWebKit has an issue when the font-sizes we render get too large.
On the same machine, when rendering TheanoModern between QtWebKit and Chrome, QtWebKit exhibits the attached issue where certain characters (containing curves) are rendered incorrectly. As shown in the attachment 'qtwebkitbug.png' you can see the text when rendered at 69px (Scaled up from 30 at a factor of 2.3) which is correct, however bumping up the scale to 2.5 (81px) and above always exhibits this issue.
As mentioned before, QtWebKit is the only WebKit port that displays this issue, and it is only on RH/Arch based linuxes which makes me believe it may be a Free/TrueType library that is not installed, thus forcing Qt to use it's own renderer rather than an external library. I have ensured that the FreeType libraries are up to date on all machines to no avail, perhaps there is another library that may need installing.
The font TheanoModern is available here for testing - http://www.fontsquirrel.com/fonts/Theano-Modern