dygraphs lets you add annotations (markers) to individual points on your + chart. These markers have a short bit of text or an icon that's displayed + over the chart, plus a longer description that appears when you hover over + them.
+ +There are two methods which are used to add, remove and modify annotations:
+ +setAnnotations(array) |
+ Set the list of annotations currently displayed. This overwrites + existing annotations and redraws the dygraph. | +
annotations |
+ Returns an array of the currently-displayed annotations. | +
Calling dygraph.setAnnotations(dygraph.annotations()) is a
+ no-op: it simply causes the chart to refresh.
Let's say we have a simple chart and wish to add an annotation. Here's how:
+ +
+<script type="text/javascript">
+ g = new Dygraph(
+ document.getElementById("graphdiv"),
+ "Date,Temperature\n" +
+ "2008-05-07,75\n" +
+ "2008-05-08,70\n" +
+ "2008-05-09,80\n"
+ );
+
+ g.setAnnotations([
+ {
+ series: "Temperature",
+ x: "2008-05-08",
+ shortText: "L",
+ text: "Coldest Day"
+ }
+ ]);
+</script>
+
+ Annotations are JavaScript dictionaries. The series and x fields are required: they indicate which point the annotation should be attached to. If specified, shortText will appear on the annotation "flag". If you don't specify shortText, you can specify icon instead to display a small picture. The text parameter specifies hovertext. If you highlight the annotation and leave the mouse still, it will appear.
To remove or modify existing annotations, call the
+ annotations method to get an array of annotations. Modify that
+ array, then pass it back in to setAnnotations. For example, this
+ code deletes the second annotation and changes the series to which the first
+ is attached:
+ var annotations = g.annotations(); + annotations.splice(1,1); // remove the second annotation + annotations[0].series = "Series 2"; + g.setAnnotations(annotations); // causes a redraw ++ +
For a more real-life example, see the annotations demo
+ +These properties can all be set in the dictionary for an annotation. The use of each one is demonstrated on the annotations demo page.
+ +| Property | Description |
series | Required The name of the series to which the annotated point belongs. |
x | Required 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". |
shortText | Text that will appear on the annotation's flag. |
text | A longer description of the annotation which will appear when the user hovers over it. |
icon | Specify in place of shortText to mark the annotation with an image rather than text. If you specify this, you must specify width and height. |
width | Width (in pixels) of the annotation flag or icon. |
height | Height (in pixels) of the annotation flag or icon. |
cssClass | CSS class to use for styling the annotation. |
tickHeight | Height of the tick mark (in pixels) connecting the point to its flag or icon. |
attachAtBottom | If true, attach annotations to the x-axis, rather than to actual points. |
clickHandler | See Handlers, below |
mouseOverHandler | See Handlers, below |
mouseOutHandler | See Handlers, below |
dblClickHandler | See Handlers, below |
dygraphs lets you attach event handlers to your annotations. These can be + specified globally (for all annotations) or on a per-annotation basis:
+ +| Per-point field | Global option |
clickHandler | annotationClickHandler |
mouseOverHandler | annotationMouseOverHandler |
mouseOutHandler | annotationMouseOutHandler |
dblClickHandler | annotationDblClickHandler |
These event handlers all take the same parameters:
+ +
+ g.updateOptions( {
+ annotationClickHandler: function(annotation, point, dygraph, event) {
+ // ... access/modify annotation.series, annotation.x, ...
+ }
+ });
+
+
+ Again, check out the annotations demo + for concrete examples of usage of all these handlers.
+ + +