JavaScript实现计算多边形的质心
计算多边形的质心,可以使用以下公式:
C x = ∑ i = 0 n − 1 ( x i + x i + 1 ) × ( x i × y i + 1 − x i + 1 × y i ) 6 A C_x=\frac{\sum\limits_{i=0}^{n-1}(x_i+x_{i+1})\times(x_i\times y_{i+1}-x_{i+1}\times y_i)}{6A} Cx=6Ai=0∑n−1(xi+xi+1)×(xi×yi+1−xi+1×yi)
C y = ∑ i = 0 n − 1 ( y i + y i + 1 ) × ( x i × y i + 1 − x i + 1 × y i ) 6 A C_y=\frac{\sum\limits_{i=0}^{n-1}(y_i+y_{i+1})\times(x_i\times y_{i+1}-x_{i+1}\times y_i)}{6A} Cy=6Ai=0∑n−1(yi+yi+1)×(xi×yi+1−xi+1×yi)
其中 n n n 为多边形的边数, A A A 为多边形的面积。
下面是 JavaScript 实现代码:
// 计算多边形的面积和质心
function getPolygonCenter(points) {
if (!Array.isArray(points) || points.length < 3) {
return null;
}
// 计算多边形的面积
let area = 0;
for (let i = 0; i < points.length; i++) {
const j = (i + 1) % points.length;
area += points[i].x * points[j].y - points[j].x * points[i].y;
}
area /= 2;
// 计算多边形的质心
let cx = 0, cy = 0;
for (let i = 0; i < points.length; i++) {
const j = (i + 1) % points.length;
const factor = points[i].x * points[j].y - points[j].x * points[i].y;
cx += (points[i].x + points[j].x) * factor;
cy += (points[i].y + points[j].y) * factor;
}
cx /= 6 *