Struct FontFeatures 

pub struct FontFeatures(pub Arc<Vec<(String, u32)>>);

OpenType feature settings applied while shaping a Font.

Each entry is a four-character feature tag, such as "liga" or "tnum", and a value. A boolean feature is 1 when enabled and 0 when disabled. Some features take other numbers, such as a stylistic set number. The default is empty, which leaves every feature at the font’s own setting.

Set features with Font::features. In JSON configuration, write a map from tag to true, false, or a number. When you deserialize, tags that are not four ASCII alphanumeric characters, and numbers that are not unsigned integers, are logged and skipped.

Examples

let mut code = font("Lilex");
code.features = FontFeatures::disable_ligatures();
assert_eq!(code.features.is_calt_enabled(), Some(false));

let json = r#"{ "tnum": true, "calt": false }"#;
let features: FontFeatures = serde_json::from_str(json).unwrap();
assert_eq!(
    features.tag_value_list(),
    [("tnum".to_string(), 1), ("calt".to_string(), 0)]
);

Tuple Fields

0: Arc<Vec<(String, u32)>>

Implementations

impl FontFeatures

pub fn disable_ligatures() -> Self

Returns features that turn off calt, which many fonts use for programming ligatures.

Other features, such as liga, keep the font’s default.

pub fn tag_value_list(&self) -> &[(String, u32)]

Returns the feature tags and values, in the order they were set.

Only features that were set are listed. A feature that isn’t listed keeps the font’s default.

pub fn is_calt_enabled(&self) -> Option<bool>

Returns whether calt is enabled, or None if this set doesn’t mention calt.

Only the value 1 counts as enabled. Any other value, including 2, returns Some(false).

Trait Implementations

impl Clone for FontFeatures

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FontFeatures

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FontFeatures

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for FontFeatures

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for FontFeatures

impl Hash for FontFeatures

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl JsonSchema for FontFeatures

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn json_schema(_: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

impl PartialEq for FontFeatures

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for FontFeatures

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for FontFeatures