File name
Commit message
Commit date
File name
Commit message
Commit date
File name
Commit message
Commit date
File name
Commit message
Commit date
File name
Commit message
Commit date
import {sqrt} from "../math.js";
// TODO Enforce positive area for exterior, negative area for interior?
var X0 = 0,
Y0 = 0,
Z0 = 0,
X1 = 0,
Y1 = 0,
Z1 = 0,
X2 = 0,
Y2 = 0,
Z2 = 0,
x00,
y00,
x0,
y0;
var centroidStream = {
point: centroidPoint,
lineStart: centroidLineStart,
lineEnd: centroidLineEnd,
polygonStart: function() {
centroidStream.lineStart = centroidRingStart;
centroidStream.lineEnd = centroidRingEnd;
},
polygonEnd: function() {
centroidStream.point = centroidPoint;
centroidStream.lineStart = centroidLineStart;
centroidStream.lineEnd = centroidLineEnd;
},
result: function() {
var centroid = Z2 ? [X2 / Z2, Y2 / Z2]
: Z1 ? [X1 / Z1, Y1 / Z1]
: Z0 ? [X0 / Z0, Y0 / Z0]
: [NaN, NaN];
X0 = Y0 = Z0 =
X1 = Y1 = Z1 =
X2 = Y2 = Z2 = 0;
return centroid;
}
};
function centroidPoint(x, y) {
X0 += x;
Y0 += y;
++Z0;
}
function centroidLineStart() {
centroidStream.point = centroidPointFirstLine;
}
function centroidPointFirstLine(x, y) {
centroidStream.point = centroidPointLine;
centroidPoint(x0 = x, y0 = y);
}
function centroidPointLine(x, y) {
var dx = x - x0, dy = y - y0, z = sqrt(dx * dx + dy * dy);
X1 += z * (x0 + x) / 2;
Y1 += z * (y0 + y) / 2;
Z1 += z;
centroidPoint(x0 = x, y0 = y);
}
function centroidLineEnd() {
centroidStream.point = centroidPoint;
}
function centroidRingStart() {
centroidStream.point = centroidPointFirstRing;
}
function centroidRingEnd() {
centroidPointRing(x00, y00);
}
function centroidPointFirstRing(x, y) {
centroidStream.point = centroidPointRing;
centroidPoint(x00 = x0 = x, y00 = y0 = y);
}
function centroidPointRing(x, y) {
var dx = x - x0,
dy = y - y0,
z = sqrt(dx * dx + dy * dy);
X1 += z * (x0 + x) / 2;
Y1 += z * (y0 + y) / 2;
Z1 += z;
z = y0 * x - x0 * y;
X2 += z * (x0 + x);
Y2 += z * (y0 + y);
Z2 += z * 3;
centroidPoint(x0 = x, y0 = y);
}
export default centroidStream;