src/extras/unzoom.js

   1 // Copyright (c) 2013 Google, Inc.
   2 //
   3 // Permission is hereby granted, free of charge, to any person obtaining a copy
   4 // of this software and associated documentation files (the "Software"), to deal
   5 // in the Software without restriction, including without limitation the rights
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   7 // copies of the Software, and to permit persons to whom the Software is
   8 // furnished to do so, subject to the following conditions:
   9 //
  10 // The above copyright notice and this permission notice shall be included in
  11 // all copies or substantial portions of the Software.
  12 //
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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  18 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  19 // THE SOFTWARE.
  20
  21 /*global Dygraph:false */
  22
  23 /**
  24  * @fileoverview Plug-in for providing unzoom-on-hover.
  25  *
  26  * @author konigsberg@google.com (Robert Konigsberg)
  27  */
  28 Dygraph.Plugins.Unzoom = (function() {
  29
  30   "use strict";
  31
  32   /**
  33    * Create a new instance.
  34    *
  35    * @constructor
  36    */
  37   var unzoom = function() {
  38     this.button_ = null;
  39
  40     // True when the mouse is over the canvas. Must be tracked
  41     // because the unzoom button state can change even when the
  42     // mouse-over state hasn't.
  43     this.over_ = false;
  44   };
  45
  46   unzoom.prototype.toString = function() {
  47     return 'Unzoom Plugin';
  48   };
  49
  50   unzoom.prototype.activate = function(g) {
  51     return {
  52       willDrawChart: this.willDrawChart
  53     };
  54   };
  55
  56   unzoom.prototype.willDrawChart = function(e) {
  57     var g = e.dygraph;
  58
  59     if (this.button_ !== null) {
  60       // short-circuit: show the button only when we're moused over, and zoomed in.
  61       var showButton = g.isZoomed() && this.over_;
  62       this.show(showButton);
  63       return;
  64     }
  65
  66     this.button_ = document.createElement('button');
  67     this.button_.innerHTML = 'Reset Zoom';
  68     this.button_.style.display = 'none';
  69     this.button_.style.position = 'absolute';
  70     var area = g.plotter_.area;
  71     this.button_.style.top = (area.y + 4) + 'px';
  72     this.button_.style.left = (area.x + 4) + 'px';
  73     this.button_.style.zIndex = 11;
  74     var parent = g.graphDiv;
  75     parent.insertBefore(this.button_, parent.firstChild);
  76
  77     var self = this;
  78     this.button_.onclick = function() {
  79       g.resetZoom();
  80     };
  81
  82     g.addAndTrackEvent(parent, 'mouseover', function() {
  83       if (g.isZoomed()) {
  84         self.show(true);
  85       }
  86       self.over_ = true;
  87     });
  88
  89     g.addAndTrackEvent(parent, 'mouseout', function() {
  90       self.show(false);
  91       self.over_ = false;
  92     });
  93   };
  94
  95   unzoom.prototype.show = function(enabled) {
  96     this.button_.style.display = enabled ? '' : 'none';
  97   };
  98
  99   unzoom.prototype.destroy = function() {
 100     this.button_.parentElement.removeChild(this.button_);
 101   };
 102
 103   return unzoom;
 104
 105 })();