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// Copyright 2018 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use crate::sys;
/// Direction of text flow during layout.
///
/// This maps to the [`hb_direction_t`](crate::sys::hb_direction_t) from
/// [`harfbuzz-sys`](crate::sys). It can be converted to
/// or from `hb_direction_t` using the [`From`]
/// and [`Into`] traits:
///
/// ```
/// # use harfbuzz::{Direction, sys};
/// assert_eq!(Direction::from(sys::HB_DIRECTION_LTR), Direction::LTR);
/// assert_eq!(sys::hb_direction_t::from(Direction::BTT), sys::HB_DIRECTION_BTT);
///
/// let hb_dir: sys::hb_direction_t = Direction::LTR.into();
/// assert_eq!(hb_dir, sys::HB_DIRECTION_LTR);
///
/// let dir: Direction = sys::HB_DIRECTION_TTB.into();
/// assert_eq!(dir, Direction::TTB);
/// ```
#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
pub enum Direction {
/// Initial, unset direction.
///
/// This corresponds to [`HB_DIRECTION_INVALID`](crate::sys::HB_DIRECTION_INVALID).
Invalid,
/// Text is set horizontally from left to right.
///
/// This corresponds to [`HB_DIRECTION_LTR`](crate::sys::HB_DIRECTION_LTR).
LTR,
/// Text is set horizontally from right to left.
///
/// This corresponds to [`HB_DIRECTION_RTL`](crate::sys::HB_DIRECTION_RTL).
RTL,
/// Text is set vertically from top to bottom.
///
/// This corresponds to [`HB_DIRECTION_TTB`](crate::sys::HB_DIRECTION_TTB).
TTB,
/// Text is set vertically from bottom to top.
///
/// This corresponds to [`HB_DIRECTION_BTT`](crate::sys::HB_DIRECTION_BTT).
BTT,
}
impl From<sys::hb_direction_t> for Direction {
fn from(s: sys::hb_direction_t) -> Self {
match s {
sys::HB_DIRECTION_INVALID => Direction::Invalid,
sys::HB_DIRECTION_LTR => Direction::LTR,
sys::HB_DIRECTION_RTL => Direction::RTL,
sys::HB_DIRECTION_TTB => Direction::TTB,
sys::HB_DIRECTION_BTT => Direction::BTT,
_ => Direction::Invalid,
}
}
}
impl From<Direction> for sys::hb_direction_t {
fn from(s: Direction) -> Self {
match s {
Direction::Invalid => sys::HB_DIRECTION_INVALID,
Direction::LTR => sys::HB_DIRECTION_LTR,
Direction::RTL => sys::HB_DIRECTION_RTL,
Direction::TTB => sys::HB_DIRECTION_TTB,
Direction::BTT => sys::HB_DIRECTION_BTT,
}
}
}