ref: e2ab54a896f822fa85f785f5426dd69186185f55 gio/ui/f32/f32.go -rw-r--r-- 2.4 KiB View raw
                                                                                
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// SPDX-License-Identifier: Unlicense OR MIT
/*
Package f32 is a float32 implementation of package image's
Point and Rectangle

The coordinate space has the origin in the top left
corner with the axes extending right and down.
*/
package f32

// A Point is a two dimensional point.
type Point struct {
	X, Y float32
}

// A Rectangle contains the points (X, Y) where Min.X <= X < Max.X,
// Min.Y <= Y < Max.Y.
type Rectangle struct {
	Min, Max Point
}

// Add return the point p+p2.
func (p Point) Add(p2 Point) Point {
	return Point{X: p.X + p2.X, Y: p.Y + p2.Y}
}

// Sub returns the vector p-p2.
func (p Point) Sub(p2 Point) Point {
	return Point{X: p.X - p2.X, Y: p.Y - p2.Y}
}

// Mul returns p scaled by s.
func (p Point) Mul(s float32) Point {
	return Point{X: p.X * s, Y: p.Y * s}
}

// Size returns r's width and height.
func (r Rectangle) Size() Point {
	return Point{X: r.Dx(), Y: r.Dy()}
}

// Dx returns r's width.
func (r Rectangle) Dx() float32 {
	return r.Max.X - r.Min.X
}

// Dy returns r's Height.
func (r Rectangle) Dy() float32 {
	return r.Max.Y - r.Min.Y
}

// Intersect returns the intersection of r and s.
func (r Rectangle) Intersect(s Rectangle) Rectangle {
	if r.Min.X < s.Min.X {
		r.Min.X = s.Min.X
	}
	if r.Min.Y < s.Min.Y {
		r.Min.Y = s.Min.Y
	}
	if r.Max.X > s.Max.X {
		r.Max.X = s.Max.X
	}
	if r.Max.Y > s.Max.Y {
		r.Max.Y = s.Max.Y
	}
	return r
}

// Union returns the union of r and s.
func (r Rectangle) Union(s Rectangle) Rectangle {
	if r.Min.X > s.Min.X {
		r.Min.X = s.Min.X
	}
	if r.Min.Y > s.Min.Y {
		r.Min.Y = s.Min.Y
	}
	if r.Max.X < s.Max.X {
		r.Max.X = s.Max.X
	}
	if r.Max.Y < s.Max.Y {
		r.Max.Y = s.Max.Y
	}
	return r
}

// Canon returns the canonical version of r, where Min is to
// the upper left of Max.
func (r Rectangle) Canon() Rectangle {
	if r.Max.X < r.Min.X {
		r.Min.X, r.Max.X = r.Max.X, r.Min.X
	}
	if r.Max.Y < r.Min.Y {
		r.Min.Y, r.Max.Y = r.Max.Y, r.Min.Y
	}
	return r
}

// Empty reports whether r represents the empty area.
func (r Rectangle) Empty() bool {
	return r.Min.X >= r.Max.X || r.Min.Y >= r.Max.Y
}

// Add offsets r with the vector 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},
	}
}

// Sub offsets r with the vector -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},
	}
}