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// Copyright ©2016 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vg
// A Point is a location in 2d space.
//
// Points are used for drawing, not for data. For
// data, see the XYer interface.
type Point struct {
X, Y Length
}
// Dot returns the dot product of two points.
func (p Point) Dot(q Point) Length {
return p.X*q.X + p.Y*q.Y
}
// Add returns the component-wise sum of two points.
func (p Point) Add(q Point) Point {
return Point{p.X + q.X, p.Y + q.Y}
}
// Sub returns the component-wise difference of two points.
func (p Point) Sub(q Point) Point {
return Point{p.X - q.X, p.Y - q.Y}
}
// Scale returns the component-wise product of a point and a scalar.
func (p Point) Scale(s Length) Point {
return Point{p.X * s, p.Y * s}
}
// A Rectangle represents a rectangular region of 2d space.
type Rectangle struct {
Min Point
Max Point
}
// Size returns the width and height of a Rectangle.
func (r Rectangle) Size() Point {
return Point{
X: r.Max.X - r.Min.X,
Y: r.Max.Y - r.Min.Y,
}
}
// Path returns the path of a Rect specified by its
// upper left corner, width and height.
func (r Rectangle) Path() (p Path) {
p.Move(r.Min)
p.Line(Point{X: r.Max.X, Y: r.Min.Y})
p.Line(r.Max)
p.Line(Point{X: r.Min.X, Y: r.Max.Y})
p.Close()
return
}
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