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use crate::Vec2;
use crate::XY;
use std::cmp::min;
pub type Position = XY<Offset>;
impl Position {
pub fn center() -> Self {
Position::new(Offset::Center, Offset::Center)
}
pub fn absolute<T: Into<Vec2>>(offset: T) -> Self {
let offset = offset.into();
Position::new(Offset::Absolute(offset.x), Offset::Absolute(offset.y))
}
pub fn parent<T: Into<XY<isize>>>(offset: T) -> Self {
let offset = offset.into();
Position::new(Offset::Parent(offset.x), Offset::Parent(offset.y))
}
pub fn compute_offset<S, A, P>(
&self,
size: S,
available: A,
parent: P,
) -> Vec2
where
S: Into<Vec2>,
A: Into<Vec2>,
P: Into<Vec2>,
{
let available = available.into();
let size = size.into();
let parent = parent.into();
Vec2::new(
self.x.compute_offset(size.x, available.x, parent.x),
self.y.compute_offset(size.y, available.y, parent.y),
)
}
}
#[derive(PartialEq, Eq, Debug, Clone, Copy, Hash)]
pub enum Offset {
Center,
Absolute(usize),
Parent(isize),
}
impl Offset {
pub fn compute_offset(
&self,
size: usize,
available: usize,
parent: usize,
) -> usize {
if size > available {
0
} else {
match *self {
Offset::Center => (available - size) / 2,
Offset::Absolute(offset) => min(offset, available - size),
Offset::Parent(offset) => {
min((parent as isize + offset) as usize, available - size)
}
}
}
}
}
#[cfg(test)]
mod tests {
use super::Position;
use crate::Vec2;
#[test]
fn test_center() {
let c = Position::center();
assert_eq!(Vec2::new(2, 1), c.compute_offset((1, 1), (5, 3), (0, 0)));
assert_eq!(Vec2::new(2, 0), c.compute_offset((1, 3), (5, 3), (0, 0)));
assert_eq!(Vec2::new(1, 1), c.compute_offset((3, 1), (5, 3), (0, 0)));
assert_eq!(Vec2::new(0, 1), c.compute_offset((5, 1), (5, 3), (0, 0)));
assert_eq!(Vec2::new(0, 0), c.compute_offset((5, 3), (5, 3), (0, 0)));
assert_eq!(Vec2::new(0, 0), c.compute_offset((5, 3), (3, 1), (0, 0)));
}
}