I've let the gnome maintainer know, thanks! On 13 Jan 2014 17:13, "Dave Arnold" <[email protected]> wrote:
> Hi Mike, > > I have reproduced your results with version 0.0.15 of Cantarell-Regular > (CFF). I do not see any FreeType bugs, but have found some system > integration and font issues. Here is what I have found. > > 1) The new CFF rasterizer automatically increases the weight of fonts at > small sizes, in order to maintain contrast and improve readability. To do > this, it assumes the system is adjusting gamma for text (as Werner > mentioned earlier). In most displays, I find a compromise of gamma 1.8 is > best, but anything down to 1.4 should look ok. Your screen shot shows that > that linearized blending is not being used on the text. That is, gamma > adjustment is not being done, and your gamma is 1.0. Using gamma 1.0 has > several negative effects on anti-aliasing; one is to make black-on-white > text look heavier. So, we are effectively darkening the text twice. I don't > know if this is a Fedora issue or a LibreOffice issue. FreeType does have a > control to disable darkening, and that might help work around the issue if > you can't get the system to do gamma adjustment. > > 2) The hints in Cantarell-Regular are wrong for many glyphs. In CFF fonts, > the hints describe where the important stems of the glyph are located. The > rasterizer then works to align those hints to the pixel grid. Normally, > this would align the stems as well. In Cantarell, the hints don't always > match the stems. For example, the top of the 'c' has a hint at (408,481) > while the stem is actually at (423,491). On the other hand, for the 'o', > which has a very similar shape, both hint and stem are (426,490). As a > result, the 'c' shows overshoot while the 'o' does not. This overshoot > contributes to a general fuzziness apparent on most lowercase letters. > > I have attached a screen shot comparing the rendering you are seeing with > our expected rendering. This was prepared using FreeType's ftview program, > 15 ppem Cantarell v0.0.15 and gamma 1.8. It addresses issue 1). Issue 2) is > improved because the overshoot is lighter. > > Please let me know if you have any questions. Thanks. > > -Dave > > > On 1/13/2014 11:52 AM, Michael Cronenworth wrote: > >> Dave Arnold wrote: >> >>> Thanks for sending the screen shots. It gives me a better idea of what >>> you are >>> seeing. >>> >>> Are you finding any problems with Nimbus Sans or Sans, or just with >>> Cantarell? >>> >> Cantarell is the only font that I have seen have negative effects. As >> shown in >> the screenshots, other fonts appear normal, as do Monospace type fonts in >> terminals. >> >> As Werner says, we expect rendering differences in CFF fonts for 2.5.0, >>> so I >>> assume you are using a CFF version of Cantarell. I agree it is >>> surprising how >>> much darker the 2.5.0 rendering of Cantarell is in your screen shot. >>> Also, it is >>> showing overshoot at baseline and x-height. That would contribute to >>> fuzziness. >>> >>> I'd like to understand this better, but I have not been able to locate an >>> OpenType/CFF version of Cantarell; I can find only OpenType/TrueType >>> versions. >>> Could you send me a copy of the font you are using for your test? >>> >> Fedora uses the font directly from upstream with no patches/features >> applied. >> >> http://ftp.gnome.org/pub/GNOME/sources/cantarell-fonts/ >> 0.0/cantarell-fonts-0.0.15.tar.xz >> >> Running "fc-query" on the file reports "fontformat: "CFF"(s)" so I assume >> the >> latest upstream font generates an OpenType/CFF version, but I am not a >> font expert. >> >> You can find the Fedora package on the Fedora build system. If you do not >> have a >> system to extract the otf files I could place them somewhere. >> >> http://koji.fedoraproject.org/koji/buildinfo?buildID=467138 >> >> Thanks. >>> >> Thank you for looking into this. There are many user reports of this >> issue so >> my, subjective, opinion that the Cantarell font looks "worse" is not >> unique. >> >> https://bugzilla.redhat.com/show_bug.cgi?id=995643 >> https://bugzilla.redhat.com/show_bug.cgi?id=1035486 >> https://bugzilla.redhat.com/show_bug.cgi?id=1051689 >> >> > > _______________________________________________ > Freetype mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/freetype > >
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