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use super::*;
/// The directions along which nodes are layouted.
pub type LayoutDirs = Gen<Dir>;
/// The four directions into which content can be laid out.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum Dir {
/// Left to right.
LTR,
/// Right to left.
RTL,
/// Top to bottom.
TTB,
/// Bottom to top.
BTT,
}
impl Dir {
/// The side this direction starts at.
pub fn start(self) -> Side {
match self {
Self::LTR => Side::Left,
Self::RTL => Side::Right,
Self::TTB => Side::Top,
Self::BTT => Side::Bottom,
}
}
/// The side this direction ends at.
pub fn end(self) -> Side {
match self {
Self::LTR => Side::Right,
Self::RTL => Side::Left,
Self::TTB => Side::Bottom,
Self::BTT => Side::Top,
}
}
/// The specific axis this direction belongs to.
pub fn axis(self) -> SpecAxis {
match self {
Self::LTR | Self::RTL => SpecAxis::Horizontal,
Self::TTB | Self::BTT => SpecAxis::Vertical,
}
}
/// Whether this direction points into the positive coordinate direction.
///
/// The positive directions are left-to-right and top-to-bottom.
pub fn is_positive(self) -> bool {
match self {
Self::LTR | Self::TTB => true,
Self::RTL | Self::BTT => false,
}
}
/// The factor for this direction.
///
/// - `1.0` if the direction is positive.
/// - `-1.0` if the direction is negative.
pub fn factor(self) -> f64 {
if self.is_positive() { 1.0 } else { -1.0 }
}
/// The inverse direction.
pub fn inv(self) -> Self {
match self {
Self::LTR => Self::RTL,
Self::RTL => Self::LTR,
Self::TTB => Self::BTT,
Self::BTT => Self::TTB,
}
}
}
impl Display for Dir {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
f.pad(match self {
Self::LTR => "ltr",
Self::RTL => "rtl",
Self::TTB => "ttb",
Self::BTT => "btt",
})
}
}
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