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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [image/] [geom.go] - Blame information for rev 843

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Line No. Rev Author Line
1 747 jeremybenn 
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package image
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import (
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        "strconv"
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)
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// A Point is an X, Y coordinate pair. The axes increase right and down.
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type Point struct {
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        X, Y int
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}
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// String returns a string representation of p like "(3,4)".
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func (p Point) String() string {
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        return "(" + strconv.Itoa(p.X) + "," + strconv.Itoa(p.Y) + ")"
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}
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// Add returns the vector p+q.
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func (p Point) Add(q Point) Point {
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        return Point{p.X + q.X, p.Y + q.Y}
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}
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// Sub returns the vector p-q.
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func (p Point) Sub(q Point) Point {
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        return Point{p.X - q.X, p.Y - q.Y}
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}
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// Mul returns the vector p*k.
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func (p Point) Mul(k int) Point {
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        return Point{p.X * k, p.Y * k}
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}
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// Div returns the vector p/k.
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func (p Point) Div(k int) Point {
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        return Point{p.X / k, p.Y / k}
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}
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// In returns whether p is in r.
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func (p Point) In(r Rectangle) bool {
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        return r.Min.X <= p.X && p.X < r.Max.X &&
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                r.Min.Y <= p.Y && p.Y < r.Max.Y
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}
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// Mod returns the point q in r such that p.X-q.X is a multiple of r's width
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// and p.Y-q.Y is a multiple of r's height.
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func (p Point) Mod(r Rectangle) Point {
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        w, h := r.Dx(), r.Dy()
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        p = p.Sub(r.Min)
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        p.X = p.X % w
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        if p.X < 0 {
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                p.X += w
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        }
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        p.Y = p.Y % h
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        if p.Y < 0 {
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                p.Y += h
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        }
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        return p.Add(r.Min)
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}
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// Eq returns whether p and q are equal.
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func (p Point) Eq(q Point) bool {
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        return p.X == q.X && p.Y == q.Y
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}
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// ZP is the zero Point.
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var ZP Point
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// Pt is shorthand for Point{X, Y}.
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func Pt(X, Y int) Point {
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        return Point{X, Y}
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}
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// A Rectangle contains the points with Min.X <= X < Max.X, Min.Y <= Y < Max.Y.
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// It is well-formed if Min.X <= Max.X and likewise for Y. Points are always
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// well-formed. A rectangle's methods always return well-formed outputs for
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// well-formed inputs.
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type Rectangle struct {
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        Min, Max Point
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}
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// String returns a string representation of r like "(3,4)-(6,5)".
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func (r Rectangle) String() string {
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        return r.Min.String() + "-" + r.Max.String()
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}
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// Dx returns r's width.
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func (r Rectangle) Dx() int {
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        return r.Max.X - r.Min.X
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}
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// Dy returns r's height.
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func (r Rectangle) Dy() int {
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        return r.Max.Y - r.Min.Y
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}
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// Size returns r's width and height.
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func (r Rectangle) Size() Point {
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        return Point{
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                r.Max.X - r.Min.X,
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                r.Max.Y - r.Min.Y,
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        }
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}
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// Add returns the rectangle r translated by p.
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func (r Rectangle) Add(p Point) Rectangle {
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        return Rectangle{
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                Point{r.Min.X + p.X, r.Min.Y + p.Y},
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                Point{r.Max.X + p.X, r.Max.Y + p.Y},
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        }
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}
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// Sub returns the rectangle r translated by -p.
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func (r Rectangle) Sub(p Point) Rectangle {
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        return Rectangle{
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                Point{r.Min.X - p.X, r.Min.Y - p.Y},
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                Point{r.Max.X - p.X, r.Max.Y - p.Y},
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        }
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}
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// Inset returns the rectangle r inset by n, which may be negative. If either
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// of r's dimensions is less than 2*n then an empty rectangle near the center
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// of r will be returned.
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func (r Rectangle) Inset(n int) Rectangle {
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        if r.Dx() < 2*n {
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                r.Min.X = (r.Min.X + r.Max.X) / 2
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                r.Max.X = r.Min.X
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        } else {
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                r.Min.X += n
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                r.Max.X -= n
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        }
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        if r.Dy() < 2*n {
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                r.Min.Y = (r.Min.Y + r.Max.Y) / 2
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                r.Max.Y = r.Min.Y
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        } else {
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                r.Min.Y += n
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                r.Max.Y -= n
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        }
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        return r
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}
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// Intersect returns the largest rectangle contained by both r and s. If the
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// two rectangles do not overlap then the zero rectangle will be returned.
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func (r Rectangle) Intersect(s Rectangle) Rectangle {
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        if r.Min.X < s.Min.X {
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                r.Min.X = s.Min.X
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        }
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        if r.Min.Y < s.Min.Y {
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                r.Min.Y = s.Min.Y
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        }
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        if r.Max.X > s.Max.X {
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                r.Max.X = s.Max.X
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        }
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        if r.Max.Y > s.Max.Y {
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                r.Max.Y = s.Max.Y
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        }
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        if r.Min.X > r.Max.X || r.Min.Y > r.Max.Y {
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                return ZR
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        }
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        return r
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}
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// Union returns the smallest rectangle that contains both r and s.
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func (r Rectangle) Union(s Rectangle) Rectangle {
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        if r.Min.X > s.Min.X {
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                r.Min.X = s.Min.X
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        }
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        if r.Min.Y > s.Min.Y {
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                r.Min.Y = s.Min.Y
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        }
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        if r.Max.X < s.Max.X {
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                r.Max.X = s.Max.X
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        }
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        if r.Max.Y < s.Max.Y {
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                r.Max.Y = s.Max.Y
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        }
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        return r
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}
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// Empty returns whether the rectangle contains no points.
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func (r Rectangle) Empty() bool {
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        return r.Min.X >= r.Max.X || r.Min.Y >= r.Max.Y
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}
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// Eq returns whether r and s are equal.
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func (r Rectangle) Eq(s Rectangle) bool {
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        return r.Min.X == s.Min.X && r.Min.Y == s.Min.Y &&
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                r.Max.X == s.Max.X && r.Max.Y == s.Max.Y
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}
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// Overlaps returns whether r and s have a non-empty intersection.
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func (r Rectangle) Overlaps(s Rectangle) bool {
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        return r.Min.X < s.Max.X && s.Min.X < r.Max.X &&
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                r.Min.Y < s.Max.Y && s.Min.Y < r.Max.Y
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}
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// In returns whether every point in r is in s.
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func (r Rectangle) In(s Rectangle) bool {
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        if r.Empty() {
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                return true
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        }
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        // Note that r.Max is an exclusive bound for r, so that r.In(s)
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        // does not require that r.Max.In(s).
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        return s.Min.X <= r.Min.X && r.Max.X <= s.Max.X &&
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                s.Min.Y <= r.Min.Y && r.Max.Y <= s.Max.Y
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}
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// Canon returns the canonical version of r. The returned rectangle has minimum
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// and maximum coordinates swapped if necessary so that it is well-formed.
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func (r Rectangle) Canon() Rectangle {
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        if r.Max.X < r.Min.X {
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                r.Min.X, r.Max.X = r.Max.X, r.Min.X
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        }
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        if r.Max.Y < r.Min.Y {
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                r.Min.Y, r.Max.Y = r.Max.Y, r.Min.Y
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        }
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        return r
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}
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// ZR is the zero Rectangle.
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var ZR Rectangle
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// Rect is shorthand for Rectangle{Pt(x0, y0), Pt(x1, y1)}.
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func Rect(x0, y0, x1, y1 int) Rectangle {
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        if x0 > x1 {
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                x0, x1 = x1, x0
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        }
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        if y0 > y1 {
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                y0, y1 = y1, y0
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        }
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        return Rectangle{Point{x0, y0}, Point{x1, y1}}
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}

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