mathtools/internal/lib/shoelace.go

/*
Copyright © 2025 filifa

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package lib

type Point struct {
	X float64
	Y float64
}

/*
Area computes the area of a polygon given its vertices using the shoelace formula.
*/
func Area(points []Point) float64 {
	total := float64(0)
	n := len(points)
	for i, p := range points {
		q := points[(i+1)%n]
		total += (p.Y + q.Y) * (p.X - q.X)
	}

	return total / 2
}