egui/emath/src/align.rs
2021-01-17 12:24:13 +01:00

117 lines
3.6 KiB
Rust

//! One- and two-dimensional alignment ([`Align::Center`], [`Align2::LEFT_TOP`] etc).
use crate::*;
/// left/center/right or top/center/bottom alignment for e.g. anchors and layouts.
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
pub enum Align {
/// Left or top.
Min,
/// Horizontal or vertical center.
Center,
/// Right or bottom.
Max,
}
impl Align {
/// Convenience for [`Self::Min`]
pub fn left() -> Self {
Self::Min
}
/// Convenience for [`Self::Max`]
pub fn right() -> Self {
Self::Max
}
/// Convenience for [`Self::Min`]
pub fn top() -> Self {
Self::Min
}
/// Convenience for [`Self::Max`]
pub fn bottom() -> Self {
Self::Max
}
/// Convert `Min => 0.0`, `Center => 0.5` or `Max => 1.0`.
pub fn to_factor(&self) -> f32 {
match self {
Self::Min => 0.0,
Self::Center => 0.5,
Self::Max => 1.0,
}
}
}
impl Default for Align {
fn default() -> Align {
Align::Min
}
}
// ----------------------------------------------------------------------------
/// Two-dimension alignment, e.g. [`Align2::LEFT_TOP`].
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
pub struct Align2(pub [Align; 2]);
impl Align2 {
pub const LEFT_BOTTOM: Align2 = Align2([Align::Min, Align::Max]);
pub const LEFT_CENTER: Align2 = Align2([Align::Min, Align::Center]);
pub const LEFT_TOP: Align2 = Align2([Align::Min, Align::Min]);
pub const CENTER_BOTTOM: Align2 = Align2([Align::Center, Align::Max]);
pub const CENTER_CENTER: Align2 = Align2([Align::Center, Align::Center]);
pub const CENTER_TOP: Align2 = Align2([Align::Center, Align::Min]);
pub const RIGHT_BOTTOM: Align2 = Align2([Align::Max, Align::Max]);
pub const RIGHT_CENTER: Align2 = Align2([Align::Max, Align::Center]);
pub const RIGHT_TOP: Align2 = Align2([Align::Max, Align::Min]);
}
impl Align2 {
pub fn x(self) -> Align {
self.0[0]
}
pub fn y(self) -> Align {
self.0[1]
}
/// Used e.g. to anchor a piece of text to a part of the rectangle.
/// Give a position within the rect, specified by the aligns
pub fn anchor_rect(self, rect: Rect) -> Rect {
let x = match self.x() {
Align::Min => rect.left(),
Align::Center => rect.left() - 0.5 * rect.width(),
Align::Max => rect.left() - rect.width(),
};
let y = match self.y() {
Align::Min => rect.top(),
Align::Center => rect.top() - 0.5 * rect.height(),
Align::Max => rect.top() - rect.height(),
};
Rect::from_min_size(pos2(x, y), rect.size())
}
/// e.g. center a size within a given frame
pub fn align_size_within_rect(self, size: Vec2, frame: Rect) -> Rect {
let x = match self.x() {
Align::Min => frame.left(),
Align::Center => frame.center().x - size.x / 2.0,
Align::Max => frame.right() - size.x,
};
let y = match self.y() {
Align::Min => frame.top(),
Align::Center => frame.center().y - size.y / 2.0,
Align::Max => frame.bottom() - size.y,
};
Rect::from_min_size(Pos2::new(x, y), size)
}
}
pub fn center_size_in_rect(size: Vec2, frame: Rect) -> Rect {
Align2::CENTER_CENTER.align_size_within_rect(size, frame)
}