Struct zng_ext_font::BidiLevel

pub struct BidiLevel(/* private fields */);

Embedding Level

Embedding Levels are numbers between 0 and 126 (inclusive), where even values denote a left-to-right (LTR) direction and odd values a right-to-left (RTL) direction.

This struct maintains a valid status for level numbers, meaning that creating a new level, or mutating an existing level, with the value smaller than 0 (before conversion to u8) or larger than 125 results in an Error.

http://www.unicode.org/reports/tr9/#BD2

Implementations

impl Level

pub fn ltr() -> Level

New LTR level with smallest number value (0).

pub fn rtl() -> Level

New RTL level with smallest number value (1).

pub fn max_implicit_depth() -> u8

Maximum depth of the directional status stack during implicit resolutions.

pub fn max_explicit_depth() -> u8

Maximum depth of the directional status stack during explicit resolutions.

pub fn new(number: u8) -> Result<Level, Error>

Create new level, fail if number is larger than max_depth + 1.

pub fn new_explicit(number: u8) -> Result<Level, Error>

Create new level, fail if number is larger than max_depth.

pub fn number(&self) -> u8

The level number.

pub fn is_ltr(&self) -> bool

If this level is left-to-right.

pub fn is_rtl(&self) -> bool

If this level is right-to-left.

pub fn raise(&mut self, amount: u8) -> Result<(), Error>

Raise level by amount, fail if number is larger than max_depth + 1.

pub fn raise_explicit(&mut self, amount: u8) -> Result<(), Error>

Raise level by amount, fail if number is larger than max_depth.

pub fn lower(&mut self, amount: u8) -> Result<(), Error>

Lower level by amount, fail if number goes below zero.

pub fn new_explicit_next_ltr(&self) -> Result<Level, Error>

The next LTR (even) level greater than this, or fail if number is larger than max_depth.

pub fn new_explicit_next_rtl(&self) -> Result<Level, Error>

The next RTL (odd) level greater than this, or fail if number is larger than max_depth.

pub fn new_lowest_ge_rtl(&self) -> Result<Level, Error>

The lowest RTL (odd) level greater than or equal to this, or fail if number is larger than max_depth + 1.

pub fn bidi_class(&self) -> BidiClass

Generate a character type based on a level (as specified in steps X10 and N2).

pub fn vec(v: &[u8]) -> Vec<Level>

pub fn from_slice_unchecked(v: &[u8]) -> &[Level]

Converts a byte slice to a slice of Levels

Does not check if each level is within bounds (<= [MAX_IMPLICIT_DEPTH]), which is not a requirement for safety but is a requirement for correctness of the algorithm.

Trait Implementations

impl Clone for Level

fn clone(&self) -> Level

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Level

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

Formats the value using the given formatter.

impl From<u8> for Level

fn from(number: u8) -> Level

Create level by number

impl Ord for Level

fn cmp(&self, other: &Level) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl<'a> PartialEq<&'a str> for Level

Used for matching levels in conformance tests

fn eq(&self, s: &&'a str) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq<String> for Level

Used for matching levels in conformance tests

fn eq(&self, s: &String) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for Level

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Level

fn partial_cmp(&self, other: &Level) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Level

impl Eq for Level

impl StructuralPartialEq for Level