rect/rectangle.go
Derek McQuay fc4c1c820b determine size of rectangle
To determine the size of rectangle, it was required to be able to
determine who would be the neighboring points.  A neighbor is a point
that would make the exterior of the rectangle, not the cross-section.
Finding the neighbors allows for a simple l*w to calculate size.
2016-08-26 11:37:55 -07:00

60 lines
1.4 KiB
Go

package rect
import (
"math"
"sort"
)
type Rectangle struct {
P1, P2, P3, P4 Point
}
func (r Rectangle) IsRect() bool {
// make sure they aren't all just the same point
if (r.P1.X == r.P2.X && r.P1.X == r.P3.X && r.P1.X == r.P4.X) &&
(r.P1.Y == r.P2.Y && r.P1.Y == r.P3.Y && r.P1.Y == r.P4.Y) {
return false
}
cx := (r.P1.X + r.P2.X + r.P3.X + r.P4.X) / 4.0
cy := (r.P1.Y + r.P2.Y + r.P3.Y + r.P4.Y) / 4.0
dd1 := math.Sqrt(math.Abs(cx-r.P1.X)) + math.Sqrt(math.Abs(cy-r.P1.Y))
dd2 := math.Sqrt(math.Abs(cx-r.P2.X)) + math.Sqrt(math.Abs(cy-r.P2.Y))
dd3 := math.Sqrt(math.Abs(cx-r.P3.X)) + math.Sqrt(math.Abs(cy-r.P3.Y))
dd4 := math.Sqrt(math.Abs(cx-r.P4.X)) + math.Sqrt(math.Abs(cy-r.P4.Y))
return dd1 == dd2 && dd1 == dd3 && dd1 == dd4
}
func (r Rectangle) Neighbors(p Point) (Point, Point) {
keys := []float64{distance(r.P1, p), distance(r.P2, p), distance(r.P3, p), distance(r.P4, p)}
sort.Float64s(keys)
n := []Point{}
d := distance(r.P1, p)
if keys[1] == d || keys[2] == d {
n = append(n, r.P1)
}
d = distance(r.P2, p)
if keys[1] == d || keys[2] == d {
n = append(n, r.P2)
}
d = distance(r.P3, p)
if keys[1] == d || keys[2] == d {
n = append(n, r.P3)
}
d = distance(r.P4, p)
if keys[1] == d || keys[2] == d {
n = append(n, r.P4)
}
return n[0], n[1]
}
func (r Rectangle) Size() float64 {
n1, n2 := r.Neighbors(r.P1)
return distance(r.P1, n1) * distance(r.P1, n2)
}
//
//func Containment(r1, r2, Rectangle) bool {
//}