Initial commit

node_modules/d3-force/src/simulation.js

@@ -0,0 +1,143 @@
+import {dispatch} from "d3-dispatch";
+import {map} from "d3-collection";
+import {timer} from "d3-timer";
+
+export function x(d) {
+  return d.x;
+}
+
+export function y(d) {
+  return d.y;
+}
+
+var initialRadius = 10,
+    initialAngle = Math.PI * (3 - Math.sqrt(5));
+
+export default function(nodes) {
+  var simulation,
+      alpha = 1,
+      alphaMin = 0.001,
+      alphaDecay = 1 - Math.pow(alphaMin, 1 / 300),
+      alphaTarget = 0,
+      velocityDecay = 0.6,
+      forces = map(),
+      stepper = timer(step),
+      event = dispatch("tick", "end");
+
+  if (nodes == null) nodes = [];
+
+  function step() {
+    tick();
+    event.call("tick", simulation);
+    if (alpha < alphaMin) {
+      stepper.stop();
+      event.call("end", simulation);
+    }
+  }
+
+  function tick() {
+    var i, n = nodes.length, node;
+
+    alpha += (alphaTarget - alpha) * alphaDecay;
+
+    forces.each(function(force) {
+      force(alpha);
+    });
+
+    for (i = 0; i < n; ++i) {
+      node = nodes[i];
+      if (node.fx == null) node.x += node.vx *= velocityDecay;
+      else node.x = node.fx, node.vx = 0;
+      if (node.fy == null) node.y += node.vy *= velocityDecay;
+      else node.y = node.fy, node.vy = 0;
+    }
+  }
+
+  function initializeNodes() {
+    for (var i = 0, n = nodes.length, node; i < n; ++i) {
+      node = nodes[i], node.index = i;
+      if (isNaN(node.x) || isNaN(node.y)) {
+        var radius = initialRadius * Math.sqrt(i), angle = i * initialAngle;
+        node.x = radius * Math.cos(angle);
+        node.y = radius * Math.sin(angle);
+      }
+      if (isNaN(node.vx) || isNaN(node.vy)) {
+        node.vx = node.vy = 0;
+      }
+    }
+  }
+
+  function initializeForce(force) {
+    if (force.initialize) force.initialize(nodes);
+    return force;
+  }
+
+  initializeNodes();
+
+  return simulation = {
+    tick: tick,
+
+    restart: function() {
+      return stepper.restart(step), simulation;
+    },
+
+    stop: function() {
+      return stepper.stop(), simulation;
+    },
+
+    nodes: function(_) {
+      return arguments.length ? (nodes = _, initializeNodes(), forces.each(initializeForce), simulation) : nodes;
+    },
+
+    alpha: function(_) {
+      return arguments.length ? (alpha = +_, simulation) : alpha;
+    },
+
+    alphaMin: function(_) {
+      return arguments.length ? (alphaMin = +_, simulation) : alphaMin;
+    },
+
+    alphaDecay: function(_) {
+      return arguments.length ? (alphaDecay = +_, simulation) : +alphaDecay;
+    },
+
+    alphaTarget: function(_) {
+      return arguments.length ? (alphaTarget = +_, simulation) : alphaTarget;
+    },
+
+    velocityDecay: function(_) {
+      return arguments.length ? (velocityDecay = 1 - _, simulation) : 1 - velocityDecay;
+    },
+
+    force: function(name, _) {
+      return arguments.length > 1 ? ((_ == null ? forces.remove(name) : forces.set(name, initializeForce(_))), simulation) : forces.get(name);
+    },
+
+    find: function(x, y, radius) {
+      var i = 0,
+          n = nodes.length,
+          dx,
+          dy,
+          d2,
+          node,
+          closest;
+
+      if (radius == null) radius = Infinity;
+      else radius *= radius;
+
+      for (i = 0; i < n; ++i) {
+        node = nodes[i];
+        dx = x - node.x;
+        dy = y - node.y;
+        d2 = dx * dx + dy * dy;
+        if (d2 < radius) closest = node, radius = d2;
+      }
+
+      return closest;
+    },
+
+    on: function(name, _) {
+      return arguments.length > 1 ? (event.on(name, _), simulation) : event.on(name);
+    }
+  };
+}