geom/rectangle.go

package geom

// Rectangle represents a 2-dimensional surface with as boundaries Min (inclusive) and Max (exclusive).
type Rectangle struct {
	Min, Max Point
}

// Rect is a shorthand function to create a rectangle.
func Rect(x0, y0, x1, y1 int) Rectangle {
	if x0 > x1 {
		x0, x1 = x1, x0
	}
	if y0 > y1 {
		y0, y1 = y1, y0
	}
	return Rectangle{Point{x0, y0}, Point{x1, y1}}
}

// RectRel is a shorthand function to create a rectangle specifying its width and height instead of a second coordinate.
func RectRel(x, y, w, h int) Rectangle {
	return Rectangle{Point{x, y}, Point{x + w, y + h}}
}

// Add translates rectangle r by point p.
func (r Rectangle) Add(p Point) Rectangle {
	return Rectangle{
		Point{r.Min.X + p.X, r.Min.Y + p.Y},
		Point{r.Max.X + p.X, r.Max.Y + p.Y},
	}
}

// Dx returns the width of r.
func (r Rectangle) Dx() int {
	return r.Max.X - r.Min.X
}

// Dy returns the height of r.
func (r Rectangle) Dy() int {
	return r.Max.Y - r.Min.Y
}

// Size returns the size of the rectangle.
func (r Rectangle) Size() Point {
	return Point{r.Max.X - r.Min.X, r.Max.Y - r.Min.Y}
}

// Sub translates rectangle r in the opposite direction of point p.
func (r Rectangle) Sub(p Point) Rectangle {
	return Rectangle{
		Point{r.Min.X - p.X, r.Min.Y - p.Y},
		Point{r.Max.X - p.X, r.Max.Y - p.Y},
	}
}