docs/annotations.html

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   3     <title>dygraphs annotations</title>
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  16     <h2>dygraphs Annotations</h2>
  17
  18     <p>dygraphs lets you add annotations (markers) to individual points on your
  19     chart. These markers have a short bit of text or an icon that's displayed
  20     over the chart, plus a longer description that appears when you hover over
  21     them.</p>
  22
  23     <h3>Demo: Dow Jones Industrial Average</h3>
  24     <div id="dow_chart" style="width: 800px; height: 250px;"></div>
  25     <script type="text/javascript">
  26       // From http://www.econstats.com/eqty/eq_d_mi_3.csv
  27       stockchart = new Dygraph(
  28         document.getElementById('dow_chart'),
  29         "dow.txt",
  30         {
  31           showRoller: true,
  32           customBars: true,
  33           labelsKMB: true,
  34           labelsDivWidth: 300,
  35           drawCallback: function(g, is_initial) {
  36             if (!is_initial) return;
  37
  38             g.setAnnotations( [
  39             {
  40               series: "Real",
  41               x: "1929-08-15",
  42               shortText: "A",
  43               text: "1929 Stock Market Peak"
  44             },
  45             {
  46               series: "Nominal",
  47               x: "1987-08-15",
  48               shortText: "B",
  49               text: "1987 Crash"
  50             },
  51             {
  52               series: "Nominal",
  53               x: "1999-12-15",
  54               shortText: "C",
  55               text: "1999 (.com) Peak"
  56             },
  57             {
  58               series: "Nominal",
  59               x: "2007-10-15",
  60               shortText: "D",
  61               text: "All-Time Market Peak"
  62             }
  63             ] );
  64           }
  65         }
  66       );
  67     </script>
  68
  69     <h3>Adding Annotations</h3>
  70
  71     <p>There are two methods which are used to add, remove and modify annotations:</p>
  72
  73     <table class="thinborder">
  74     <tr>
  75       <td><code>setAnnotations(array)</code></td>
  76       <td>Set the list of annotations currently displayed. This overwrites
  77       existing annotations and redraws the dygraph.</td>
  78     </tr>
  79     <tr>
  80       <td><code>annotations</code></td>
  81       <td>Returns an array of the currently-displayed annotations.</td>
  82     </tr>
  83     </table>
  84
  85     <p>Calling <code>dygraph.setAnnotations(dygraph.annotations())</code> is a
  86     no-op: it simply causes the chart to refresh.</p>
  87
  88     <p>Let's say we have a simple chart and wish to add an annotation. Here's how:</p>
  89
  90       <div class="example" style="clear:both;">
  91         <div class="codeblock" style="float:left;width:400px;">
  92           <h3 style="text-align:center">HTML</h3>
  93   <pre>
  94 &lt;script type=&quot;text/javascript&quot;&gt;
  95   g = new Dygraph(
  96     document.getElementById(&quot;graphdiv&quot;),
  97     &quot;Date,Temperature\n&quot; +
  98     &quot;2008-05-07,75\n&quot; +
  99     &quot;2008-05-08,70\n&quot; +
 100     &quot;2008-05-09,80\n&quot;
 101   );
 102
 103   g.setAnnotations([
 104   {
 105     series: &quot;Temperature&quot;,
 106     x: &quot;2008-05-08&quot;,
 107     shortText: &quot;L&quot;,
 108     text: &quot;Coldest Day&quot;
 109   }
 110   ]);
 111 &lt;/script&gt;
 112 </pre>
 113         </div>
 114         <div class="codeoutput" style="float:left;">
 115           <h3 style="text-align:center">OUTPUT</h3>
 116           <div id="graphdiv" style="width: 350px; height: 250px;"></div>
 117           <script type="text/javascript">
 118             g = new Dygraph(
 119
 120               // containing div
 121               document.getElementById("graphdiv"),
 122
 123               // CSV or path to a CSV file.
 124               "Date,Temperature\n" +
 125               "2008-05-07,75\n" +
 126               "2008-05-08,70\n" +
 127               "2008-05-09,80\n"
 128             );
 129             g.setAnnotations([
 130             {
 131               series: "Temperature",
 132               x: "2008-05-08",
 133               shortText: "L",
 134               text: "Coldest Day"
 135             }
 136             ]);
 137           </script>
 138         </div>
 139       </div>
 140
 141   <p style="clear:both">Annotations are JavaScript dictionaries. The <code>series</code> and <code>x</code> fields are required: they indicate which point the annotation should be attached to. If specified, <code>shortText</code> will appear on the annotation "flag". If you don't specify <code>shortText</code>, you can specify <code>icon</code> instead to display a small picture. The <code>text</code> parameter specifies hovertext. If you highlight the annotation and leave the mouse still, it will appear.</p>
 142
 143   <h3>Modifying Annotations</h3>
 144   <p>To remove or modify existing annotations, call the
 145   <code>annotations</code> method to get an array of annotations. Modify that
 146   array, then pass it back in to <code>setAnnotations</code>. For example, this
 147   code deletes the second annotation and changes the series to which the first
 148   is attached:</p>
 149
 150   <pre>
 151   var annotations = g.annotations();
 152   annotations.splice(1,1);  // remove the second annotation
 153   annotations[0].series = "Series 2";
 154   g.setAnnotations(annotations);  // causes a redraw
 155   </pre>
 156
 157   <p>For a more real-life example, see the <a
 158   href="tests/annotation.html">annotations demo</a></p>
 159
 160   <h3>Annotations property reference</h3>
 161   <p>These properties can all be set in the dictionary for an annotation. The use of each one is demonstrated on the <a href="tests/annotation.html">annotations demo</a> page.</p>
 162
 163   <table class="thinborder">
 164   <tr> <td><b>Property</b></td><td><b>Description</b></td> </tr>
 165   <tr><td><code>series</code></td> <td><i>Required</i> The name of the series to which the annotated point belongs.</td></tr>
 166   <tr><td><code>x</code></td><td><i>Required</i> The x value of the point. This should be the same as the value you specified in your CSV file, e.g. "2010-09-13".</td></tr>
 167   <tr><td><code>shortText</code></td><td>Text that will appear on the annotation's flag.</td></tr>
 168   <tr><td><code>text</code></td><td>A longer description of the annotation which will appear when the user hovers over it.</td></tr>
 169   <tr><td><code>icon</code></td><td>Specify in place of <code>shortText</code> to mark the annotation with an image rather than text. If you specify this, you must specify <code>width</code> and <code>height</code>.</td></tr>
 170   <tr><td><code>width</code></td><td>Width (in pixels) of the annotation flag or icon.</td></tr>
 171   <tr><td><code>height</code></td><td>Height (in pixels) of the annotation flag or icon.</td></tr>
 172   <tr><td><code>cssClass</code></td><td>CSS class to use for styling the annotation.</td></tr>
 173   <tr><td><code>tickHeight</code></td><td>Height of the tick mark (in pixels) connecting the point to its flag or icon.</td></tr>
 174   <tr><td><code>attachAtBottom</code></td><td>If true, attach annotations to the x-axis, rather than to actual points.</td></tr>
 175   <tr><td><code>clickHandler</code></td>    <td>See Handlers, below</td></tr>
 176   <tr><td><code>mouseOverHandler</code></td><td>See Handlers, below</td></tr>
 177   <tr><td><code>mouseOutHandler</code></td> <td>See Handlers, below</td></tr>
 178   <tr><td><code>dblClickHandler</code></td> <td>See Handlers, below</td></tr>
 179   </table>
 180
 181   <h3>Annotation event handlers</h3>
 182
 183   <p>dygraphs lets you attach event handlers to your annotations. These can be
 184   specified globally (for all annotations) or on a per-annotation basis:</p>
 185
 186   <table class="thinborder">
 187   <tr><td><b>Per-point field</b></td><td><b>Global option</b></td></tr>
 188   <tr><td><code>clickHandler</code></td>    <td><code>annotationClickHandler</code></td></tr>
 189   <tr><td><code>mouseOverHandler</code></td><td><code>annotationMouseOverHandler</code></td></tr>
 190   <tr><td><code>mouseOutHandler</code></td> <td><code>annotationMouseOutHandler</code></td></tr>
 191   <tr><td><code>dblClickHandler</code></td> <td><code>annotationDblClickHandler</code></td></tr>
 192   </table>
 193
 194   <p>These event handlers all take the same parameters:</p>
 195
 196   <pre>
 197   g.updateOptions( {
 198     annotationClickHandler: function(annotation, point, dygraph, event) {
 199       // ... access/modify annotation.series, annotation.x, ...
 200     }
 201   });
 202   </pre>
 203
 204   <p>Again, check out the <a href="tests/annotation.html">annotations demo</a>
 205   for concrete examples of usage of all these handlers.</p>
 206
 207   </body>
 208 </html>