Handle distortions near poles.

d3 · Dec 14, 2012 · c7d4fab · c7d4fab
1 parent cf2e854
commit c7d4fab
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Showing 3 changed files with 9 additions and 14 deletions.
diff --git a/d3.js b/d3.js
@@ -5757,11 +5757,9 @@
     function resampleLineTo(x0, y0, λ0, a0, b0, c0, x1, y1, λ1, a1, b1, c1, depth, listener) {
       var dx = x1 - x0, dy = y1 - y0, distance2 = dx * dx + dy * dy;
       if (distance2 > 4 * δ2 && depth--) {
-        var a = a0 + a1, b = b0 + b1, c = c0 + c1, m = Math.sqrt(a * a + b * b + c * c), φ2 = Math.asin(c /= m), λ2 = Math.abs(Math.abs(c) - 1) < ε ? (λ0 + λ1) / 2 : Math.atan2(b, a), p = projectPoint(λ2, φ2), x2 = p[0], y2 = p[1], dx2 = x0 - x2, dy2 = y0 - y2, dz = dx * dy2 - dy * dx2;
-        if (dz * dz / distance2 > δ2) {
-          a /= m;
-          b /= m;
-          resampleLineTo(x0, y0, λ0, a0, b0, c0, x2, y2, λ2, a, b, c, depth, listener);
+        var a = a0 + a1, b = b0 + b1, c = c0 + c1, m = Math.sqrt(a * a + b * b + c * c), φ2 = Math.asin(c /= m), λ2 = Math.abs(Math.abs(c) - 1) < ε ? (λ0 + λ1) / 2 : Math.atan2(b, a), p = projectPoint(λ2, φ2), x2 = p[0], y2 = p[1], dx2 = x2 - x0, dy2 = y2 - y0, dz = dy * dx2 - dx * dy2;
+        if (dz * dz / distance2 > δ2 || Math.abs((dx * dx2 + dy * dy2) / distance2 - .5) > .4) {
+          resampleLineTo(x0, y0, λ0, a0, b0, c0, x2, y2, λ2, a /= m, b /= m, c, depth, listener);
           listener.point(x2, y2);
           resampleLineTo(x2, y2, λ2, a, b, c, x1, y1, λ1, a1, b1, c1, depth, listener);
         }