// Copyright 2010 The Go 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 imageimport ()// A Point is an X, Y coordinate pair. The axes increase right and down.typePointstruct { X, Y int}// String returns a string representation of p like "(3,4)".func ( Point) () string {return"(" + strconv.Itoa(.X) + "," + strconv.Itoa(.Y) + ")"}// Add returns the vector p+q.func ( Point) ( Point) Point {returnPoint{.X + .X, .Y + .Y}}// Sub returns the vector p-q.func ( Point) ( Point) Point {returnPoint{.X - .X, .Y - .Y}}// Mul returns the vector p*k.func ( Point) ( int) Point {returnPoint{.X * , .Y * }}// Div returns the vector p/k.func ( Point) ( int) Point {returnPoint{.X / , .Y / }}// In reports whether p is in r.func ( Point) ( Rectangle) bool {return .Min.X <= .X && .X < .Max.X && .Min.Y <= .Y && .Y < .Max.Y}// Mod returns the point q in r such that p.X-q.X is a multiple of r's width// and p.Y-q.Y is a multiple of r's height.func ( Point) ( Rectangle) Point { , := .Dx(), .Dy() = .Sub(.Min) .X = .X % if .X < 0 { .X += } .Y = .Y % if .Y < 0 { .Y += }return .Add(.Min)}// Eq reports whether p and q are equal.func ( Point) ( Point) bool {return == }// ZP is the zero [Point].//// Deprecated: Use a literal [image.Point] instead.varZPPoint// Pt is shorthand for [Point]{X, Y}.func (, int) Point {returnPoint{, }}// A Rectangle contains the points with Min.X <= X < Max.X, Min.Y <= Y < Max.Y.// It is well-formed if Min.X <= Max.X and likewise for Y. Points are always// well-formed. A rectangle's methods always return well-formed outputs for// well-formed inputs.//// A Rectangle is also an [Image] whose bounds are the rectangle itself. At// returns color.Opaque for points in the rectangle and color.Transparent// otherwise.typeRectanglestruct { Min, Max Point}// String returns a string representation of r like "(3,4)-(6,5)".func ( Rectangle) () string {return .Min.String() + "-" + .Max.String()}// Dx returns r's width.func ( Rectangle) () int {return .Max.X - .Min.X}// Dy returns r's height.func ( Rectangle) () int {return .Max.Y - .Min.Y}// Size returns r's width and height.func ( Rectangle) () Point {returnPoint{ .Max.X - .Min.X, .Max.Y - .Min.Y, }}// Add returns the rectangle r translated by p.func ( Rectangle) ( Point) Rectangle {returnRectangle{Point{.Min.X + .X, .Min.Y + .Y},Point{.Max.X + .X, .Max.Y + .Y}, }}// Sub returns the rectangle r translated by -p.func ( Rectangle) ( Point) Rectangle {returnRectangle{Point{.Min.X - .X, .Min.Y - .Y},Point{.Max.X - .X, .Max.Y - .Y}, }}// Inset returns the rectangle r inset by n, which may be negative. If either// of r's dimensions is less than 2*n then an empty rectangle near the center// of r will be returned.func ( Rectangle) ( int) Rectangle {if .Dx() < 2* { .Min.X = (.Min.X + .Max.X) / 2 .Max.X = .Min.X } else { .Min.X += .Max.X -= }if .Dy() < 2* { .Min.Y = (.Min.Y + .Max.Y) / 2 .Max.Y = .Min.Y } else { .Min.Y += .Max.Y -= }return}// Intersect returns the largest rectangle contained by both r and s. If the// two rectangles do not overlap then the zero rectangle will be returned.func ( Rectangle) ( Rectangle) Rectangle {if .Min.X < .Min.X { .Min.X = .Min.X }if .Min.Y < .Min.Y { .Min.Y = .Min.Y }if .Max.X > .Max.X { .Max.X = .Max.X }if .Max.Y > .Max.Y { .Max.Y = .Max.Y }// Letting r0 and s0 be the values of r and s at the time that the method // is called, this next line is equivalent to: // // if max(r0.Min.X, s0.Min.X) >= min(r0.Max.X, s0.Max.X) || likewiseForY { etc }if .Empty() {returnZR }return}// Union returns the smallest rectangle that contains both r and s.func ( Rectangle) ( Rectangle) Rectangle {if .Empty() {return }if .Empty() {return }if .Min.X > .Min.X { .Min.X = .Min.X }if .Min.Y > .Min.Y { .Min.Y = .Min.Y }if .Max.X < .Max.X { .Max.X = .Max.X }if .Max.Y < .Max.Y { .Max.Y = .Max.Y }return}// Empty reports whether the rectangle contains no points.func ( Rectangle) () bool {return .Min.X >= .Max.X || .Min.Y >= .Max.Y}// Eq reports whether r and s contain the same set of points. All empty// rectangles are considered equal.func ( Rectangle) ( Rectangle) bool {return == || .Empty() && .Empty()}// Overlaps reports whether r and s have a non-empty intersection.func ( Rectangle) ( Rectangle) bool {return !.Empty() && !.Empty() && .Min.X < .Max.X && .Min.X < .Max.X && .Min.Y < .Max.Y && .Min.Y < .Max.Y}// In reports whether every point in r is in s.func ( Rectangle) ( Rectangle) bool {if .Empty() {returntrue }// Note that r.Max is an exclusive bound for r, so that r.In(s) // does not require that r.Max.In(s).return .Min.X <= .Min.X && .Max.X <= .Max.X && .Min.Y <= .Min.Y && .Max.Y <= .Max.Y}// Canon returns the canonical version of r. The returned rectangle has minimum// and maximum coordinates swapped if necessary so that it is well-formed.func ( Rectangle) () Rectangle {if .Max.X < .Min.X { .Min.X, .Max.X = .Max.X, .Min.X }if .Max.Y < .Min.Y { .Min.Y, .Max.Y = .Max.Y, .Min.Y }return}// At implements the [Image] interface.func ( Rectangle) (, int) color.Color {if (Point{, }).In() {returncolor.Opaque }returncolor.Transparent}// RGBA64At implements the [RGBA64Image] interface.func ( Rectangle) (, int) color.RGBA64 {if (Point{, }).In() {returncolor.RGBA64{0xffff, 0xffff, 0xffff, 0xffff} }returncolor.RGBA64{}}// Bounds implements the [Image] interface.func ( Rectangle) () Rectangle {return}// ColorModel implements the [Image] interface.func ( Rectangle) () color.Model {returncolor.Alpha16Model}// ZR is the zero [Rectangle].//// Deprecated: Use a literal [image.Rectangle] instead.varZRRectangle// Rect is shorthand for [Rectangle]{Pt(x0, y0), [Pt](x1, y1)}. The returned// rectangle has minimum and maximum coordinates swapped if necessary so that// it is well-formed.func (, , , int) Rectangle {if > { , = , }if > { , = , }returnRectangle{Point{, }, Point{, }}}// mul3NonNeg returns (x * y * z), unless at least one argument is negative or// if the computation overflows the int type, in which case it returns -1.func mul3NonNeg( int, int, int) int {if ( < 0) || ( < 0) || ( < 0) {return -1 } , := bits.Mul64(uint64(), uint64())if != 0 {return -1 } , = bits.Mul64(, uint64())if != 0 {return -1 } := int()if ( < 0) || (uint64() != ) {return -1 }return}// add2NonNeg returns (x + y), unless at least one argument is negative or if// the computation overflows the int type, in which case it returns -1.func add2NonNeg( int, int) int {if ( < 0) || ( < 0) {return -1 } := + if < 0 {return -1 }return}
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