| import {cartesian} from "../cartesian.js"; |
| import {abs, asin, atan2, cos, epsilon, radians, sqrt} from "../math.js"; |
| import {transformer} from "../transform.js"; |
|
|
| var maxDepth = 16, |
| cosMinDistance = cos(30 * radians); |
|
|
| 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 |
| || abs((dx * dx2 + dy * dy2) / d2 - 0.5) > 0.3 |
| || a0 * a1 + b0 * b1 + c0 * c1 < cosMinDistance) { |
| 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, |
| lambda0, x0, y0, a0, b0, c0; |
|
|
| 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; |
| }; |
| } |
|
|
