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import {cartesian} from "../cartesian.js";
import {abs, asin, atan2, cos, epsilon, radians, sqrt} from "../math.js";
import {transformer} from "../transform.js";
var maxDepth = 16, // maximum depth of subdivision
cosMinDistance = cos(30 * radians); // cos(minimum angular distance)
export default function(project, delta2) {
return +delta2 ? resample(project, delta2) : resampleNone(project);
}
function resampleNone(project) {
return transformer({
point: function(x, y) {
x = project(x, y);
this.stream.point(x[0], x[1]);
}
});
}
function resample(project, delta2) {
function resampleLineTo(x0, y0, lambda0, a0, b0, c0, x1, y1, lambda1, a1, b1, c1, depth, stream) {
var dx = x1 - x0,
dy = y1 - y0,
d2 = dx * dx + dy * dy;
if (d2 > 4 * delta2 && depth--) {
var a = a0 + a1,
b = b0 + b1,
c = c0 + c1,
m = sqrt(a * a + b * b + c * c),
phi2 = asin(c /= m),
lambda2 = abs(abs(c) - 1) < epsilon || abs(lambda0 - lambda1) < epsilon ? (lambda0 + lambda1) / 2 : atan2(b, a),
p = project(lambda2, phi2),
x2 = p[0],
y2 = p[1],
dx2 = x2 - x0,
dy2 = y2 - y0,
dz = dy * dx2 - dx * dy2;
if (dz * dz / d2 > delta2 // perpendicular projected distance
|| abs((dx * dx2 + dy * dy2) / d2 - 0.5) > 0.3 // midpoint close to an end
|| a0 * a1 + b0 * b1 + c0 * c1 < cosMinDistance) { // angular distance
resampleLineTo(x0, y0, lambda0, a0, b0, c0, x2, y2, lambda2, a /= m, b /= m, c, depth, stream);
stream.point(x2, y2);
resampleLineTo(x2, y2, lambda2, a, b, c, x1, y1, lambda1, a1, b1, c1, depth, stream);
}
}
}
return function(stream) {
var lambda00, x00, y00, a00, b00, c00, // first point
lambda0, x0, y0, a0, b0, c0; // previous point
var resampleStream = {
point: point,
lineStart: lineStart,
lineEnd: lineEnd,
polygonStart: function() { stream.polygonStart(); resampleStream.lineStart = ringStart; },
polygonEnd: function() { stream.polygonEnd(); resampleStream.lineStart = lineStart; }
};
function point(x, y) {
x = project(x, y);
stream.point(x[0], x[1]);
}
function lineStart() {
x0 = NaN;
resampleStream.point = linePoint;
stream.lineStart();
}
function linePoint(lambda, phi) {
var c = cartesian([lambda, phi]), p = project(lambda, phi);
resampleLineTo(x0, y0, lambda0, a0, b0, c0, x0 = p[0], y0 = p[1], lambda0 = lambda, a0 = c[0], b0 = c[1], c0 = c[2], maxDepth, stream);
stream.point(x0, y0);
}
function lineEnd() {
resampleStream.point = point;
stream.lineEnd();
}
function ringStart() {
lineStart();
resampleStream.point = ringPoint;
resampleStream.lineEnd = ringEnd;
}
function ringPoint(lambda, phi) {
linePoint(lambda00 = lambda, phi), x00 = x0, y00 = y0, a00 = a0, b00 = b0, c00 = c0;
resampleStream.point = linePoint;
}
function ringEnd() {
resampleLineTo(x0, y0, lambda0, a0, b0, c0, x00, y00, lambda00, a00, b00, c00, maxDepth, stream);
resampleStream.lineEnd = lineEnd;
lineEnd();
}
return resampleStream;
};
}