08-27-周三_17-09-29

node_modules/dagre-d3-renderer/lib/intersect/intersect-polygon.js

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+import intersectLine from './intersect-line'
+
+/*
+ * Returns the point ({x, y}) at which the point argument intersects with the
+ * node argument assuming that it has the shape specified by polygon.
+ */
+function intersectPolygon (node, polyPoints, point) {
+  const x1 = node.x
+  const y1 = node.y
+
+  const intersections = []
+
+  let minX = Number.POSITIVE_INFINITY
+  let minY = Number.POSITIVE_INFINITY
+  polyPoints.forEach(function (entry) {
+    minX = Math.min(minX, entry.x)
+    minY = Math.min(minY, entry.y)
+  })
+
+  const left = x1 - node.width / 2 - minX
+  const top = y1 - node.height / 2 - minY
+
+  for (let i = 0; i < polyPoints.length; i += 1) {
+    const p1 = polyPoints[i]
+    const p2 = polyPoints[i < polyPoints.length - 1 ? i + 1 : 0]
+    const intersect = intersectLine(node, point,
+      {x: left + p1.x, y: top + p1.y}, {x: left + p2.x, y: top + p2.y})
+    if (intersect) {
+      intersections.push(intersect)
+    }
+  }
+
+  if (!intersections.length) {
+    console.log('NO INTERSECTION FOUND, RETURN NODE CENTER', node)
+    return node
+  }
+
+  if (intersections.length > 1) {
+    // More intersections, find the one nearest to edge end point
+    intersections.sort(function (p, q) {
+      const pdx = p.x - point.x
+      const pdy = p.y - point.y
+      const distp = Math.sqrt(pdx * pdx + pdy * pdy)
+
+      const qdx = q.x - point.x
+      const qdy = q.y - point.y
+      const distq = Math.sqrt(qdx * qdx + qdy * qdy)
+
+      return (distp < distq) ? -1 : (distp === distq ? 0 : 1)
+    })
+  }
+  return intersections[0]
+}
+
+export default intersectPolygon