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
0or more.If the value is
0, the feature is disabled. If used on a boolean feature, a value of1enables the feature. When used on non-boolean features, a value of1or greater enables the feature and indicates the feature selection index.If this value is omitted, a value of
1is 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).