Struct harfbuzz_rs::Tag

#[repr(transparent)]
pub struct Tag(pub hb_tag_t);

A type to represent 4-byte SFNT tags.

Tables, features, etc. in OpenType and many other font formats use SFNT tags as identifiers. These are 4-bytes long and usually each byte represents an ASCII value. Tag provides methods to create such identifiers from individual chars or a str slice and to get the string representation of a Tag.

Methods

impl Tag

pub const fn new(a: char, b: char, c: char, d: char) -> Self

Create a Tag from its four-char textual representation.

All the arguments must be ASCII values.

Examples

use harfbuzz_rs::Tag;
let cmap_tag = Tag::new('c', 'm', 'a', 'p');
assert_eq!(cmap_tag.to_string(), "cmap")

pub const fn to_bytes(self) -> [u8; 4]

Returns tag as 4-element byte array.

Examples

let tag = Tag::new('a', 'b', 'c', 'd');
assert_eq!(&tag.to_bytes(), b"abcd");

Trait Implementations

impl Eq for Tag

impl Clone for Tag

fn clone(&self) -> Tag

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Copy for Tag

impl PartialEq<Tag> for Tag

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Hash for Tag

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, 

Feeds a slice of this type into the given [Hasher].

impl Debug for Tag

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

Formats the value using the given formatter.

impl Display for Tag

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

Formats the value using the given formatter.

impl FromStr for Tag

type Err = TagFromStrErr

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Tag, TagFromStrErr>

Parses a Tag from a &str that contains four or less ASCII characters. When the string's length is smaller than 4 it is extended with ' ' (Space) characters. The remaining bytes of strings longer than 4 bytes are ignored.

Examples

use harfbuzz_rs::Tag;
use std::str::FromStr;
let tag1 = Tag::from_str("ABCD").unwrap();
let tag2 = Tag::new('A', 'B', 'C', 'D');
assert_eq!(tag1, tag2);