Twenty Fifteen: font kerning everywhere

[afercia]

Twenty Fifteen comes with a beautiful typography and Noto Serif does contain information on kerning pairs.
Let's consider to enable font kerning wherever possible in a safe, standardized way (no text-rendering: optimizeLegibility;).

Chrome on Windows:

For reference:

Advanced web typography: Kerning
Posted on 08 April 2014
​http://www.elliotjaystocks.com/blog/kerning/

Browser support:
​https://developer.mozilla.org/en-US/docs/Web/CSS/font-feature-settings#Browser_compatibility

[iamtakashi]

Nice! It does make it a lot better. I'd like try this out and see if any issue comes up in the beta phase.

[afercia]

Replying to iamtakashi:

Nice! I does make it a lot better. I'd like try this out and see if any issue comes up in the beta phase.

Yup, I'm curious especially about mobile devices, If there are any performance issues, the kerning could be limited to just headings. Seen on ​Typekit blog where they apply kernel just to paragraphs and lists.

[iandstewart]

Cool. @josephscott is doing some performance testing. It'll be a neat test.

[josephscott]

Replying to afercia:

Yup, I'm curious especially about mobile devices, If there are any performance issues, the kerning could be limited to just headings. Seen on ​Typekit blog where they apply kernel just to paragraphs and lists.

Unless implementing the kerning is particularly CPU intensive ( my guess is it isn't, but I don't have data to back that up ) I don't think this will have much impact on mobile performance. I expect for devices using a mobile connection downloading ~45KB of font files from Google is going to be a bigger impact that a CSS kerning option.

[iandstewart]

In 30217:

Twenty Fifteen: kern everything -- it reads better.

Props afercia, fixes #30195.

[ocean90]

[30217] is producing a BSOD in Chrome 38.0.2125.111 on OS X 10.10. Also confirmed by tywayne, see ​https://wordpress.slack.com/archives/core-themes/p1415054055000717. But only when the admin bar is visible.

Re-opening for some investigations.

[iamtakashi]

A few people reported this crushes their Chrome 38.0.2125.111 in OS X 10.10. It didn't occur to me and I was curious why my Chrome was fine.

After a bit of testing, it appears to me that it was fine for me because I had installed Noto Sans in my system. As soon as I disable the font from the system, Chrome starts to crush. Obviously, only few people have installed the font in their system and this is a default theme which people make child themes with all sorts of other fonts. Although this is a cool idea and I really liked it but it seems to be too early to use in a default theme.

Thoughts?

[iamtakashi]

Remove font kerning because it crushes Chrome.

[iandstewart]

Thoughts?

Yes, let's not crash people's browsers. :)

[afercia]

it seems to be too early to use in a default theme

Totally agree. Bit sad though :)
For the ones interested, thanks to @ocean90 live debugging on Slack :) we can summarize:

@ocean90, @tywayne, @mattwiebe, @obenland
they all experienced a tab crash in Chrome 38.0.2125.111 on OS X 10.10 but only when logged in and the admin bar is visible.

@iandstewart couldn't reproduce

@mattwiebe reports:
I also got tab crashing... I then moved to Canary and it was fine.

@iamtakashi pointed out the crash doesn't happen on Mac when "Noto Sans" is installed in your system fonts. @iamtakashi what about "Noto Serif"? was Serif installed too?

Crash not happening on Canary intrigued me and maybe I've found something, not sure but maybe the reason why Canary doesn't crash is this:
​https://code.google.com/p/chromium/issues/detail?id=334269#c49
Sep 30, 2014
Switch to HarfBuzz on Mac and remove CoreText shaper

see also: Consider using harfbuzz on Mac and Windows
​https://code.google.com/p/chromium/issues/detail?id=286450

​HarfBuzz is an OpenType text shaping engine.
"This is what is used in latest versions of Firefox, GNOME, ChromeOS, Chrome Linux, LibreOffice, XeTeX, and Android among other places."

As far as I understand, Chrome on Mac is currently using Core Text and from version 40 will use HarfBuzz.

I can't test on a Mac, my guess is it has to do also with Core Text fonts fallback and the order Google fonts are downloaded. Seems when the admin bar is visible, 'Open Sans' is downloaded before "Noto" and this could be relevant.
Btw, just for testing purposes I'm attaching a patch for the ones willing to debug :)

[afercia]

do not commit, just for testing purposes

[iamtakashi]

Replying to afercia:

@iamtakashi what about "Noto Serif"? was Serif installed too?

Both Serif and Sand are installed but disabling/enabling Not Serif didn't make any difference.

Btw, just for testing purposes I'm attaching a patch for the ones willing to debug :)

I've tried the patch but Chrome still crushes without installing Noto Sans in the system.

Totally agree. Bit sad though :)

Indeed but let's leave this out from the theme at this point.

[iandstewart]

In 30229:

Twenty Fifteen: Crashing chrome if you don't have Noto installed probably isn't the best experience -- removing font kerning.

Props iamtakashi, fixes #30195