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node_modules/d3-voronoi/src/Diagram.js

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+import {addBeach, removeBeach} from "./Beach";
+import {sortCellHalfedges, cellHalfedgeStart, clipCells} from "./Cell";
+import {firstCircle} from "./Circle";
+import {clipEdges} from "./Edge";
+import RedBlackTree from "./RedBlackTree";
+
+export var epsilon = 1e-6;
+export var epsilon2 = 1e-12;
+export var beaches;
+export var cells;
+export var circles;
+export var edges;
+
+function triangleArea(a, b, c) {
+  return (a[0] - c[0]) * (b[1] - a[1]) - (a[0] - b[0]) * (c[1] - a[1]);
+}
+
+function lexicographic(a, b) {
+  return b[1] - a[1]
+      || b[0] - a[0];
+}
+
+export default function Diagram(sites, extent) {
+  var site = sites.sort(lexicographic).pop(),
+      x,
+      y,
+      circle;
+
+  edges = [];
+  cells = new Array(sites.length);
+  beaches = new RedBlackTree;
+  circles = new RedBlackTree;
+
+  while (true) {
+    circle = firstCircle;
+    if (site && (!circle || site[1] < circle.y || (site[1] === circle.y && site[0] < circle.x))) {
+      if (site[0] !== x || site[1] !== y) {
+        addBeach(site);
+        x = site[0], y = site[1];
+      }
+      site = sites.pop();
+    } else if (circle) {
+      removeBeach(circle.arc);
+    } else {
+      break;
+    }
+  }
+
+  sortCellHalfedges();
+
+  if (extent) {
+    var x0 = +extent[0][0],
+        y0 = +extent[0][1],
+        x1 = +extent[1][0],
+        y1 = +extent[1][1];
+    clipEdges(x0, y0, x1, y1);
+    clipCells(x0, y0, x1, y1);
+  }
+
+  this.edges = edges;
+  this.cells = cells;
+
+  beaches =
+  circles =
+  edges =
+  cells = null;
+}
+
+Diagram.prototype = {
+  constructor: Diagram,
+
+  polygons: function() {
+    var edges = this.edges;
+
+    return this.cells.map(function(cell) {
+      var polygon = cell.halfedges.map(function(i) { return cellHalfedgeStart(cell, edges[i]); });
+      polygon.data = cell.site.data;
+      return polygon;
+    });
+  },
+
+  triangles: function() {
+    var triangles = [],
+        edges = this.edges;
+
+    this.cells.forEach(function(cell, i) {
+      if (!(m = (halfedges = cell.halfedges).length)) return;
+      var site = cell.site,
+          halfedges,
+          j = -1,
+          m,
+          s0,
+          e1 = edges[halfedges[m - 1]],
+          s1 = e1.left === site ? e1.right : e1.left;
+
+      while (++j < m) {
+        s0 = s1;
+        e1 = edges[halfedges[j]];
+        s1 = e1.left === site ? e1.right : e1.left;
+        if (s0 && s1 && i < s0.index && i < s1.index && triangleArea(site, s0, s1) < 0) {
+          triangles.push([site.data, s0.data, s1.data]);
+        }
+      }
+    });
+
+    return triangles;
+  },
+
+  links: function() {
+    return this.edges.filter(function(edge) {
+      return edge.right;
+    }).map(function(edge) {
+      return {
+        source: edge.left.data,
+        target: edge.right.data
+      };
+    });
+  },
+
+  find: function(x, y, radius) {
+    var that = this, i0, i1 = that._found || 0, n = that.cells.length, cell;
+
+    // Use the previously-found cell, or start with an arbitrary one.
+    while (!(cell = that.cells[i1])) if (++i1 >= n) return null;
+    var dx = x - cell.site[0], dy = y - cell.site[1], d2 = dx * dx + dy * dy;
+
+    // Traverse the half-edges to find a closer cell, if any.
+    do {
+      cell = that.cells[i0 = i1], i1 = null;
+      cell.halfedges.forEach(function(e) {
+        var edge = that.edges[e], v = edge.left;
+        if ((v === cell.site || !v) && !(v = edge.right)) return;
+        var vx = x - v[0], vy = y - v[1], v2 = vx * vx + vy * vy;
+        if (v2 < d2) d2 = v2, i1 = v.index;
+      });
+    } while (i1 !== null);
+
+    that._found = i0;
+
+    return radius == null || d2 <= radius * radius ? cell.site : null;
+  }
+}