--- /dev/null
+/**
+ * @license
+ * Copyright 2015 Petr Shevtsov (petr.shevtsov@gmail.com)
+ * MIT-licensed (http://opensource.org/licenses/MIT)
+ */
+
+/*global Dygraph:false */
+/*jshint globalstrict: true */
+Dygraph.Plugins.Crosshair = (function() {
+ "use strict";
+
+ /**
+ * Creates the crosshair
+ *
+ * @constructor
+ */
+
+ var crosshair = function(opt_options) {
+ this.canvas_ = document.createElement("canvas");
+ opt_options = opt_options || {};
+ this.direction_ = opt_options.direction || null;
+ };
+
+ crosshair.prototype.toString = function() {
+ return "Crosshair Plugin";
+ };
+
+ /**
+ * @param {Dygraph} g Graph instance.
+ * @return {object.<string, function(ev)>} Mapping of event names to callbacks.
+ */
+ crosshair.prototype.activate = function(g) {
+ g.graphDiv.appendChild(this.canvas_);
+
+ return {
+ select: this.select,
+ deselect: this.deselect
+ };
+ };
+
+ crosshair.prototype.select = function(e) {
+ if (this.direction_ === null) {
+ return;
+ }
+
+ var width = e.dygraph.width_;
+ var height = e.dygraph.height_;
+ this.canvas_.width = width;
+ this.canvas_.height = height;
+ this.canvas_.style.width = width + "px"; // for IE
+ this.canvas_.style.height = height + "px"; // for IE
+
+ var ctx = this.canvas_.getContext("2d");
+ ctx.clearRect(0, 0, width, height);
+ ctx.strokeStyle = "rgba(0, 0, 0,0.3)";
+ ctx.beginPath();
+
+ var canvasx = Math.floor(e.dygraph.selPoints_[0].canvasx) + 0.5; // crisper rendering
+
+ if (this.direction_ === "vertical" || this.direction_ === "both") {
+ ctx.moveTo(canvasx, 0);
+ ctx.lineTo(canvasx, height);
+ }
+
+ if (this.direction_ === "horizontal" || this.direction_ === "both") {
+ for (var i = 0; i < e.dygraph.selPoints_.length; i++) {
+ var canvasy = Math.floor(e.dygraph.selPoints_[i].canvasy) + 0.5; // crisper rendering
+ ctx.moveTo(0, canvasy);
+ ctx.lineTo(width, canvasy);
+ }
+ }
+
+ ctx.stroke();
+ ctx.closePath();
+ };
+
+ crosshair.prototype.deselect = function(e) {
+ var ctx = this.canvas_.getContext("2d");
+ ctx.clearRect(0, 0, this.canvas_.width, this.canvas_.height);
+ };
+
+ crosshair.prototype.destroy = function() {
+ this.canvas_ = null;
+ };
+
+ return crosshair;
+})();