crabshell-ui 0.1.0

//! Points, sizes and rectangles. Every unit is a logical pixel; the renderer
//! multiplies by the output's scale.

/// A point in logical pixels, measured from the window's top-left corner.
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Point {
  /// Distance from the left edge.
  pub x: f32,
  /// Distance from the top edge.
  pub y: f32,
}

impl Point {
  /// A point at `x`, `y`.
  pub const fn new(x: f32, y: f32) -> Point {
    Point { x, y }
  }
}

/// A width and height in logical pixels.
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Size {
  /// The width.
  pub width: f32,
  /// The height.
  pub height: f32,
}

impl Size {
  /// A size of `width` by `height`.
  pub const fn new(width: f32, height: f32) -> Size {
    Size { width, height }
  }
}

/// A rectangle in logical pixels: its top-left corner and its size.
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Rect {
  /// The left edge.
  pub x: f32,
  /// The top edge.
  pub y: f32,
  /// The width.
  pub width: f32,
  /// The height.
  pub height: f32,
}

impl Rect {
  /// A rectangle with its top-left corner at `x`, `y`.
  pub const fn new(x: f32, y: f32, width: f32, height: f32) -> Rect {
    Rect {
      x,
      y,
      width,
      height,
    }
  }

  /// The right edge.
  pub fn right(&self) -> f32 {
    self.x + self.width
  }

  /// The bottom edge.
  pub fn bottom(&self) -> f32 {
    self.y + self.height
  }

  /// Whether the rectangle covers no area.
  pub fn is_empty(&self) -> bool {
    self.width <= 0.0 || self.height <= 0.0
  }

  /// Whether `point` lies inside. The left and top edges count as inside,
  /// the right and bottom edges don't, so two rectangles that touch never
  /// both contain a point.
  pub fn contains(&self, point: Point) -> bool {
    point.x >= self.x && point.x < self.right() && point.y >= self.y && point.y < self.bottom()
  }

  /// The smallest rectangle that covers both. An empty rectangle adds
  /// nothing.
  pub fn union(&self, other: Rect) -> Rect {
    if other.is_empty() {
      return *self;
    }
    if self.is_empty() {
      return other;
    }
    let x = self.x.min(other.x);
    let y = self.y.min(other.y);
    Rect::new(
      x,
      y,
      self.right().max(other.right()) - x,
      self.bottom().max(other.bottom()) - y,
    )
  }
}