First commit.

Signed-off-by: Chen Xiao <abigwc@gmail.com>
2026-05-08 14:43:16 +08:00
commit 0b64e2de94
10989 changed files with 2253791 additions and 0 deletions
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+import clipBuffer from "./buffer.js";
+import clipRejoin from "./rejoin.js";
+import {epsilon, halfPi} from "../math.js";
+import polygonContains from "../polygonContains.js";
+import {merge} from "d3-array";
+
+export default function(pointVisible, clipLine, interpolate, start) {
+  return function(sink) {
+    var line = clipLine(sink),
+        ringBuffer = clipBuffer(),
+        ringSink = clipLine(ringBuffer),
+        polygonStarted = false,
+        polygon,
+        segments,
+        ring;
+
+    var clip = {
+      point: point,
+      lineStart: lineStart,
+      lineEnd: lineEnd,
+      polygonStart: function() {
+        clip.point = pointRing;
+        clip.lineStart = ringStart;
+        clip.lineEnd = ringEnd;
+        segments = [];
+        polygon = [];
+      },
+      polygonEnd: function() {
+        clip.point = point;
+        clip.lineStart = lineStart;
+        clip.lineEnd = lineEnd;
+        segments = merge(segments);
+        var startInside = polygonContains(polygon, start);
+        if (segments.length) {
+          if (!polygonStarted) sink.polygonStart(), polygonStarted = true;
+          clipRejoin(segments, compareIntersection, startInside, interpolate, sink);
+        } else if (startInside) {
+          if (!polygonStarted) sink.polygonStart(), polygonStarted = true;
+          sink.lineStart();
+          interpolate(null, null, 1, sink);
+          sink.lineEnd();
+        }
+        if (polygonStarted) sink.polygonEnd(), polygonStarted = false;
+        segments = polygon = null;
+      },
+      sphere: function() {
+        sink.polygonStart();
+        sink.lineStart();
+        interpolate(null, null, 1, sink);
+        sink.lineEnd();
+        sink.polygonEnd();
+      }
+    };
+
+    function point(lambda, phi) {
+      if (pointVisible(lambda, phi)) sink.point(lambda, phi);
+    }
+
+    function pointLine(lambda, phi) {
+      line.point(lambda, phi);
+    }
+
+    function lineStart() {
+      clip.point = pointLine;
+      line.lineStart();
+    }
+
+    function lineEnd() {
+      clip.point = point;
+      line.lineEnd();
+    }
+
+    function pointRing(lambda, phi) {
+      ring.push([lambda, phi]);
+      ringSink.point(lambda, phi);
+    }
+
+    function ringStart() {
+      ringSink.lineStart();
+      ring = [];
+    }
+
+    function ringEnd() {
+      pointRing(ring[0][0], ring[0][1]);
+      ringSink.lineEnd();
+
+      var clean = ringSink.clean(),
+          ringSegments = ringBuffer.result(),
+          i, n = ringSegments.length, m,
+          segment,
+          point;
+
+      ring.pop();
+      polygon.push(ring);
+      ring = null;
+
+      if (!n) return;
+
+      // No intersections.
+      if (clean & 1) {
+        segment = ringSegments[0];
+        if ((m = segment.length - 1) > 0) {
+          if (!polygonStarted) sink.polygonStart(), polygonStarted = true;
+          sink.lineStart();
+          for (i = 0; i < m; ++i) sink.point((point = segment[i])[0], point[1]);
+          sink.lineEnd();
+        }
+        return;
+      }
+
+      // Rejoin connected segments.
+      // TODO reuse ringBuffer.rejoin()?
+      if (n > 1 && clean & 2) ringSegments.push(ringSegments.pop().concat(ringSegments.shift()));
+
+      segments.push(ringSegments.filter(validSegment));
+    }
+
+    return clip;
+  };
+}
+
+function validSegment(segment) {
+  return segment.length > 1;
+}
+
+// Intersections are sorted along the clip edge. For both antimeridian cutting
+// and circle clipping, the same comparison is used.
+function compareIntersection(a, b) {
+  return ((a = a.x)[0] < 0 ? a[1] - halfPi - epsilon : halfPi - a[1])
+       - ((b = b.x)[0] < 0 ? b[1] - halfPi - epsilon : halfPi - b[1]);
+}