Hi all, very interesting topic.
The first one, implementing ClearType support on the TrueType hinting engine level, has been already integrated into FreeType 2.4.10.
I know a large code set from the infinality patch was added to git tree after 2.4.10 was released. Does this code set correspond to the first one?
Normally, CJK characters don't contain TrueType hints at all since this would approximately double the file size.
Since Japanese default fonts, IPA fonts, contain hinting data, I hope this change improves their rendering result. https://bugzilla.novell.com/show_bug.cgi?id=766319 I have not tested yet, I packaged a git head of FreeType2 and pushed it in M17N:Devel. By the way, subpixel rendering have been disabled by our spec file. Is this related to this topic? And can we enable this patch now? https://build.opensuse.org/package/view_file?file=freetype2-subpixel.patch&p... Fuminobu TAKEYAMA (2012/08/30 19:05), Werner LEMBERG wrote:
[wearing my FreeType maintainer hat]
the common sense is infinality comes after 2010. so at least the algorithm it use is not patented. or its author goes into jail before us.
The Infinality patch set consists of basically three parts. The first one, implementing ClearType support on the TrueType hinting engine level, has been already integrated into FreeType 2.4.10. The second one, improvements to the auto-hinter, is not yet added, but we are working on it as soon as FreeType gets a proper framework to control modules (like the auto-hinter). Right now, everything is done via environment variables, and I can't accept this. The third part contains improvements to the ClearType color filter.
Part one and two are not patented. However, to make the third part work, you currently have to activate some FreeType code which is potentially patented. It's rather straightforward to circumvent this by providing sub-pixel handling outside of FreeType (i.e. rasterizing with the horizontal resolution increased by a factor of three, then applying a non-patented color filter), but this isn't implemented in the X server, AFAIK.
Maybe Erik can shed more light onto this issue.
freetype and most of the distros dont include it by default because its fonts list focus on proprietary fonts from MS and Apple which dont be on linux distros thus not the type of freetype and linux distros. [...]
But it will improve a lot for CJK fonts.
Normally, CJK characters don't contain TrueType hints at all since this would approximately double the file size. Instead, bitmap strokes are provided for the most common characters at the most common ppem sizes. In other words, improvements in rasterizing CJK fonts is usually coming from the patches to the auto-hinter.
Werner
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