OpenType feature support in web browsers

[typodermic]

This topic was imported from the Typophile platform

I'd like to direct my customers to current information about which current browsers support OpenType features. I think class based kerning and default ligatures (liga) features are supported by some browsers but I'm not sure which ones. Is someone keeping score?

[PabloImpallari]

Firefox does, others I don't know.

[Ralf H.]

Safari and Chrome support the basic features in recent version.
Firefox as well and any OT features called with a -moz syntax: http://opentype.info/blog/2010/08/14/better-web-typography-with-opentype...
Depending on the browser and the font-size one might need to set:
text-rendering: optimizeLegibility;

[typodermic]

It sounds like Firefox's liga (standard ligatures) feature is on by default? Do Safari & Chrome have liga turned on by default?

Can anyone confirm the class based kerning works in either Chrome, Firefox or Safari?

[Ralf H.]

It sounds like Firefox's liga (standard ligatures) feature is on by default?

It depends on the type size.

Do Safari & Chrome have liga turned on by default?

AFAIK not. But there are extensions for Safari and Chrome to set "rendering:optimizeLegibility" for every page automatically.

Can anyone confirm the class based kerning works in either Chrome, Firefox or Safari?

It is triggered the same way as the ligature support.

[typodermic]

Cheers!

[Tosche]

HI, I'm looking for a list of features supported in web browsers, similar to the link below.
http://www.typotheque.com/fonts/opentype_feature_support

At least I'd like to know if the following features are supported in major browsers or not.
calt rlig isol init medi fina
(Sounds like Arabic, but it's Mongolian)

[PabloImpallari]

Firefox has .liga tured on by default.
Nice :)

Now it seems that it also have .calt turned on by default?
Not nice :(

Anyone can confirm that .calt is ON by default?
Mmm... maybe it's nice :) if I rethink my programming

[DTY]

Here's a link to a discussion about calt in Firefox:
https://bugzilla.mozilla.org/show_bug.cgi?id=463940

As explained there, implementation has been uneven (see also https://typography.guru/forums/topic/48209-forwarding).

[Ralf H.]

The point of the CALT feature is to improve the text display for certain letter combinations. So turning it on by default is the recommended behavior – in contrast to something as DLIG, SSxx and the like.

[Khaled Hosny]

calt should be on by default, if your font is using it for a non-default substitution, then you are using the wrong feature tag (note, the substitution can still be contextual but under a different tag, e.g. dlig, this is very legitimate).

[dlevine]

Is the ccmp feature available on any web browsers?

[PabloImpallari]

By the way:
You can use this: http://www.impallari.com/testing/ to test open type features in web browser, and since the source code is available (here http://www.impallari.com/projects/overview/drag-and-drop-font-testing-page ) you can easily modify it to add more features for more complex testing

[John Hudson]

'ccmp' is a default feature in most OTL shaping engines, so should be applied automatically, i.e. you don't need to specify it in CSS for browser use.