geom/point.go

package geom

import (
	"fmt"

	"opslag.de/schobers/geom/ints"
)

// ZeroPt represents the coordinate (0, 0)
var ZeroPt = Point{0, 0}

// OnePt represents the coordinate (1, 1)
var OnePt = Point{1, 1}

// North represents the coordinate next to the ZeroPt (Y == -1)
var North = Point{0, -1}

// East represents the coordinate next to the ZeroPt (X == 1)
var East = Point{1, 0}

// South represents the coordinate next to the ZeroPt (Y == 1)
var South = Point{0, 1}

// West represents the coordinate next to the ZeroPt (X == -1)
var West = Point{-1, 0}

// Point represents a 2-dimensional point.
type Point struct {
	X, Y int
}

// Pt is a shorthand function to create a point.
func Pt(x, y int) Point {
	return Point{x, y}
}

// NewPt is a short function to create a point and return a pointer to it.
func NewPt(x, y int) *Point {
	return &Point{x, y}
}

// Abs returns a point the absolute values of X and Y.
func (p Point) Abs() Point {
	return Pt(ints.Abs(p.X), ints.Abs(p.Y))
}

// Add returns the sum of p and q.
func (p Point) Add(q Point) Point {
	return p.Add2D(q.X, q.Y)
}

// Add2D adds x and y to X and Y of point p and returns the sum.
func (p Point) Add2D(x, y int) Point {
	return Pt(p.X+x, p.Y+y)
}

// Less returns true if q is above (Y is smaller) or left (X is smaller) than p. Otherwise returns false.
func (p Point) Less(q Point) bool {
	if p.Y == q.Y {
		return p.X < q.X
	}
	return p.Y < q.Y
}

// DistInt returns the integer distance between the points p and q.
func (p Point) DistInt(q Point) int {
	return ints.SubAbs(p.X, q.X) + ints.SubAbs(p.Y, q.Y)
}

// Mul multiplier the X and Y values of point p with t and returns the result.
func (p Point) Mul(t int) Point {
	return Pt(p.X*t, p.Y*t)
}

// Norm returns the point with both X and Y normalized.
func (p Point) Norm() Point {
	return Pt(ints.Norm(p.X), ints.Norm(p.Y))
}

// String returns a string representation of point p "X, Y".
func (p Point) String() string {
	return fmt.Sprintf("%d, %d", p.X, p.Y)
}

// StringBrackets formats the point p as a string  "(X, Y)".
func (p Point) StringBrackets() string {
	return fmt.Sprintf("(%d, %d)", p.X, p.Y)
}

// StringCompact returns a compact string representation of point p "X,Y".
func (p Point) StringCompact() string {
	return fmt.Sprintf("%d,%d", p.X, p.Y)
}

// Sub returns the difference of p and q.
func (p Point) Sub(p2 Point) Point {
	return Pt(p.X-p2.X, p.Y-p2.Y)
}

// MinMaxPoints returns the extremes of all the given points.
func MinMaxPoints(p ...Point) (min Point, max Point) {
	if 0 == len(p) {
		return Point{}, Point{}
	}
	min, max = p[0], p[0]
	for i := 1; i < len(p); i++ {
		var pt = p[i]
		if pt.X < min.X {
			min.X = pt.X
		} else if pt.X > max.X {
			max.X = pt.X
		}
		if pt.Y < min.Y {
			min.Y = pt.Y
		} else if pt.Y > max.Y {
			max.Y = pt.Y
		}
	}
	return min, max
}