Improved subpixel font rendering packages for Edgy

[hugmenot]

Earlier this year FreeType developer David Turner posted some patches for Cairo and Xft that improved the rendering of fonts on LCD screens (but also CRTs with Trinitron layout). These were put up with the proviso that he was unsure whether they would infringe patented algorithms around Microsoft’s ClearType technology.

The most recent patches by David have been incorporated into a series of packages that replace the libraries libreetype6, libcairo2 and libxft2 on Edgy. The patches move the filtering from Xft and Cairo to Freetype with the effect that letters have less color fringing and more faithful letter outlines. This is achieved by more advanced subpixel filtering methods and getting rid of stem quantization. Some people dislike this kind of “hack” visually, but for many it is a good trade-off of letter contrast and font aesthetics. These patches have meanwhile been released with FreeType 2.3.0.

User mlind is hosting readymade packages for Edgy in his own repo. These are the sources (enter in /etc/apt/sources.list)

deb http://www.telemail.fi/mlind/ubuntu edgy fonts
deb-src http://www.telemail.fi/mlind/ubuntu edgy fonts

The signing keys for mlind’s repo can be obtained with these commands

gpg --recv-keys 937215FF
gpg --export --armor 937215FF | sudo apt-key add -

Then update your package cache (apt-get update) and start an upgrade (apt-get dist-upgrade or equivalent). The patched packages will be installed over the official unpatched versions since they have a slightly higher version number. To get back to the standard packages use the “Package → Force version...” function in Synaptic on all packages listed under “Origin → elisanet.fi” or an equivalent function with other tools.

It’s up to taste (or debate) whether the font internal shape instructions (hints) lead to better results or the automatic hinter that uses generic heuristics. The two systems – i.e., either the byte-code interpreter or the auto-hinter – can be toggled with

sudo dpkg-reconfigure fontconfig-config

Be sure to set subpixel rendering to “always” on the second screen (and bitmap fonts to “No”). The amount of hinting applied can be adjusted in the Gnome Font Settings dialog.

To reduce the superbold appearance it might help to switch the autohinter off for bold faces.
This can be done by adding some lines in the .fonts.conf file in the user home directory or in the system-wide /etc/fonts/fonts.conf. A complete user file is attached to this post.

<match target="font">
 <test name="weight" compare="more"><const>medium</const></test>
 <edit mode="assign" name="autohint"><bool>false</bool></edit>
</match>

The patches alone can be found on David’s Freetype page
and in a FreeType release > 2.3.0 where the code has to be enabled with the macro FT_CONFIG_OPTION_SUBPIXEL_RENDERING before compiling.

[mlind]

I'll subscribe to this thread. Although I'm not Edgy user yet, I'm going to install these packages once Knot 2 is out.

[desperado666]

And i need the original turner patches to build new ones.

Does somebody have them?

[mlind]

Originally Posted by desperado666 And i need the original turner patches to build new ones. Does somebody have them?

Those aren't the two patches mentioned on first post? You can download source package(s) from repository mentioned on first post too, and get patches from debian/patches folder.

I can rebuild and upload the packages if required.

[no1wantdthisname]

I prefer the default font rendering. These packages make fonts really blurry.

[MetalMusicAddict]

Originally Posted by hugmenot These were put up with the proviso that he was unsure whether they would infringe patented algorithms around Microsoft’s ClearType technology.

So why would he think they would. Wouldnt you know one way or another? Honest question.

[Amaranth]

It's best not to check. You get in more trouble for knowingly infringing on a patent.

[hugmenot]

Originally Posted by no1wantdthisname I prefer the default font rendering. These packages make fonts really blurry.

After using the udated patches for a couple of days I really wonder whether you’re right. I can’t help the impression that contrast was better with Davids Turner’s original patches.
Jinghua told me that they were a direct port however. Could be the newer Freetype, though.

[Amaranth]

I turned off all hinting, it looks a lot like OS X or WinXP fonts now.

[saracen]

Originally Posted by hugmenot After using the udated patches for a couple of days I really wonder whether you’re right. I can’t help the impression that contrast was better with Davids Turner’s original patches. Jinghua told me that they were a direct port however. Could be the newer Freetype, though.

Ya I agree. They definitely feel more blurry. What font are you using there in your screenie? And what gtk and compiz themes?