font-feature-settings testcase

OTL feature calt

According to Microsoft’s OpenType Layout tag registry, “[t]his feature should be active by default.”

	default	explicit ON	explicit OFF	unrelated setting
CSS		font-feature-settings: "calt" 1;	font-feature-settings: "calt" 0;	font-feature-settings: "dumb" 1;
Expected state of feature	ON	ON	OFF	ON
Characters	qit	qit	qit	qit
Display in your browser	qit	qit	qit	qit
Picture with correct display
Firefox 50.0.2	ON	ON	OFF	ON
Safari 10.0.1	ON	ON	OFF	ON
Google Chrome 55.0.2883.87	ON	ON	OFF	ON
Microsoft Edge 38.14393.0.0	OFF	ON	OFF	OFF
Internet Explorer 11.447.14393.0	OFF	ON	OFF	OFF

OTL feature ccmp

According to Microsoft’s OpenType Layout tag registry, “[t]his feature should be on by default.”

	default	explicit ON	explicit OFF	unrelated setting
CSS		font-feature-settings: "ccmp" 1;	font-feature-settings: "ccmp" 0;	font-feature-settings: "dumb" 1;
Expected state of feature	ON	ON	OFF	ON
Characters	qit	qit	qit	qit
Display in your browser	qit	qit	qit	qit
Picture with correct display
Firefox 50.0.2	ON	ON	OFF	ON
Safari 10.0.1	ON	ON	ON	ON
Google Chrome 55.0.2883.87	ON	ON	OFF	ON
Microsoft Edge 38.14393.0.0	OFF	ON	ON	ON¹
Internet Explorer 11.447.14393.0	OFF	ON	ON	ON¹

1. In Microsoft Edge and Internet Explorer, the feature ccmp fails to be turned on by default. However, any arbitrary setting of font-feature-settings will turn the feature on, including "ccmp" 0 (which is supposed to turn off the feature) and "dumb" 1 (which does not have any meaning and should fall back to the default).

Information

The OTL testcase fonts have been built using the following feature file: tengtelcOTL.fea.

It uses the calt feature for two different Contextual Chaining Substitution lookups (for the ccmp testcase font, calt has been replaced by ccmp, but the Contextual Chaining Substitution lookups are the same):

• A first lookup that replaces the character i by a dot above if it follows the character q.
• A second lookup that replaces either character of the sequence qt by an interlocking alternative glyph, disregarding any intervening mark glyphs (like the dot above from the first lookup).