CSS font-feature-settings Descriptor

The CSS font-feature-settings descriptor is used with the @font-face at-rule to define the inital settings for the font-feature-settings property when the @font-face at-rule is rendered.

The font-feature-settings descriptor is not to be confused with the font-feature-settings property. The font-feature-settings descriptor does not affect font selection. It is used solely with the @font-face at-rule to define the initial values for the font-feature-settings property, which can then be used elsewhere in the style sheet to change these values.

Official Syntax

The font-feature-settings descriptor has the following syntax (which is the same syntax that the font-feature-settings property uses):

Where

The initial value is normal.

These values are explained below.

normal

Specifies that that no change in glyph selection or positioning occurs due to this property.

string

This value specifies a case-sensitive OpenType feature tag (OpenType feature tags contain four ASCII characters). The value must be a valid string of four ASCII characters and be within the U+20-7E codepoint range.

integer

This is an optional value that can be used for glyph selection. It must be a valid integer of 0 or more.

If the value is 0, the feature is disabled. If used on a boolean feature, a value of 1 enables the feature. When used on non-boolean features, a value of 1 or greater enables the feature and indicates the feature selection index.

If this value is omitted, a value of 1 is assumed.

on

Synonymous with 1.

off

Synonymous with 0.

Official Specifications

The font-feature-settings descriptor is defined in CSS Fonts Module Level 3 (W3C Candidate Recommendation 3 October 2013).