1465 lines
51 KiB
Markdown
1465 lines
51 KiB
Markdown
# Flot Reference #
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Consider a call to the plot function:
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```js
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var plot = $.plot(placeholder, data, options)
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```
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The placeholder is a jQuery object or DOM element or jQuery expression
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that the plot will be put into. This placeholder needs to have its
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width and height set as explained in the [README](README.md) (go read that now if
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you haven't, it's short). The plot will modify some properties of the
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placeholder so it's recommended you simply pass in a div that you
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don't use for anything else. Make sure you check any fancy styling
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you apply to the div, e.g. background images have been reported to be a
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problem on IE 7.
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The plot function can also be used as a jQuery chainable property. This form
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naturally can't return the plot object directly, but you can still access it
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via the 'plot' data key, like this:
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```js
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var plot = $("#placeholder").plot(data, options).data("plot");
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```
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The format of the data is documented below, as is the available
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options. The plot object returned from the call has some methods you
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can call. These are documented separately below.
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Note that in general Flot gives no guarantees if you change any of the
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objects you pass in to the plot function or get out of it since
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they're not necessarily deep-copied.
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## Data Format ##
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The data is an array of data series:
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```js
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[ series1, series2, ... ]
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```
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A series can either be raw data or an object with properties. The raw
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data format is an array of points:
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```js
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[ [x1, y1], [x2, y2], ... ]
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```
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E.g.
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```js
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[ [1, 3], [2, 14.01], [3.5, 3.14] ]
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```
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Note that to simplify the internal logic in Flot both the x and y
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values must be numbers (even if specifying time series, see below for
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how to do this). This is a common problem because you might retrieve
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data from the database and serialize them directly to JSON without
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noticing the wrong type. If you're getting mysterious errors, double
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check that you're inputting numbers and not strings.
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If a null is specified as a point or if one of the coordinates is null
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or couldn't be converted to a number, the point is ignored when
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drawing. As a special case, a null value for lines is interpreted as a
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line segment end, i.e. the points before and after the null value are
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not connected.
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Lines and points take two coordinates. For filled lines and bars, you
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can specify a third coordinate which is the bottom of the filled
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area/bar (defaults to 0).
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The format of a single series object is as follows:
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```js
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{
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color: color or number
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data: rawdata
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label: string
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lines: specific lines options
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bars: specific bars options
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points: specific points options
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xaxis: number
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yaxis: number
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clickable: boolean
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hoverable: boolean
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shadowSize: number
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highlightColor: color or number
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}
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```
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You don't have to specify any of them except the data, the rest are
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options that will get default values. Typically you'd only specify
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label and data, like this:
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```js
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{
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label: "y = 3",
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data: [[0, 3], [10, 3]]
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}
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```
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The label is used for the legend, if you don't specify one, the series
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will not show up in the legend.
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If you don't specify color, the series will get a color from the
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auto-generated colors. The color is either a CSS color specification
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(like "rgb(255, 100, 123)") or an integer that specifies which of
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auto-generated colors to select, e.g. 0 will get color no. 0, etc.
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The latter is mostly useful if you let the user add and remove series,
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in which case you can hard-code the color index to prevent the colors
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from jumping around between the series.
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The "xaxis" and "yaxis" options specify which axis to use. The axes
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are numbered from 1 (default), so { yaxis: 2} means that the series
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should be plotted against the second y axis.
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"clickable" and "hoverable" can be set to false to disable
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interactivity for specific series if interactivity is turned on in
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the plot, see below.
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The rest of the options are all documented below as they are the same
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as the default options passed in via the options parameter in the plot
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commmand. When you specify them for a specific data series, they will
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override the default options for the plot for that data series.
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Here's a complete example of a simple data specification:
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```js
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[ { label: "Foo", data: [ [10, 1], [17, -14], [30, 5] ] },
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{ label: "Bar", data: [ [11, 13], [19, 11], [30, -7] ] }
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]
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```
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## Plot Options ##
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All options are completely optional. They are documented individually
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below, to change them you just specify them in an object, e.g.
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```js
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var options = {
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series: {
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lines: { show: true },
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points: { show: true }
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}
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};
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$.plot(placeholder, data, options);
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```
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## Customizing the legend ##
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```js
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legend: {
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show: boolean
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labelFormatter: null or (fn: string, series object -> string)
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labelBoxBorderColor: color
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noColumns: number
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position: "ne" or "nw" or "se" or "sw"
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margin: number of pixels or [x margin, y margin]
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backgroundColor: null or color
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backgroundOpacity: number between 0 and 1
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container: null or jQuery object/DOM element/jQuery expression
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sorted: null/false, true, "ascending", "descending", "reverse", or a comparator
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}
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```
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The legend is generated as a table with the data series labels and
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small label boxes with the color of the series. If you want to format
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the labels in some way, e.g. make them to links, you can pass in a
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function for "labelFormatter". Here's an example that makes them
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clickable:
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```js
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labelFormatter: function(label, series) {
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// series is the series object for the label
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return '<a href="#' + label + '">' + label + '</a>';
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}
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```
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To prevent a series from showing up in the legend, simply have the function
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return null.
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"noColumns" is the number of columns to divide the legend table into.
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"position" specifies the overall placement of the legend within the
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plot (top-right, top-left, etc.) and margin the distance to the plot
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edge (this can be either a number or an array of two numbers like [x,
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y]). "backgroundColor" and "backgroundOpacity" specifies the
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background. The default is a partly transparent auto-detected
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background.
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If you want the legend to appear somewhere else in the DOM, you can
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specify "container" as a jQuery object/expression to put the legend
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table into. The "position" and "margin" etc. options will then be
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ignored. Note that Flot will overwrite the contents of the container.
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Legend entries appear in the same order as their series by default. If "sorted"
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is "reverse" then they appear in the opposite order from their series. To sort
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them alphabetically, you can specify true, "ascending" or "descending", where
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true and "ascending" are equivalent.
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You can also provide your own comparator function that accepts two
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objects with "label" and "color" properties, and returns zero if they
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are equal, a positive value if the first is greater than the second,
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and a negative value if the first is less than the second.
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```js
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sorted: function(a, b) {
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// sort alphabetically in ascending order
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return a.label == b.label ? 0 : (
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a.label > b.label ? 1 : -1
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)
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}
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```
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## Customizing the axes ##
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```js
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xaxis, yaxis: {
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show: null or true/false
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position: "bottom" or "top" or "left" or "right"
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mode: null or "time" ("time" requires jquery.flot.time.js plugin)
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timezone: null, "browser" or timezone (only makes sense for mode: "time")
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color: null or color spec
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tickColor: null or color spec
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font: null or font spec object
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min: null or number
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max: null or number
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autoscaleMargin: null or number
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transform: null or fn: number -> number
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inverseTransform: null or fn: number -> number
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ticks: null or number or ticks array or (fn: axis -> ticks array)
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tickSize: number or array
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minTickSize: number or array
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tickFormatter: (fn: number, object -> string) or string
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tickDecimals: null or number
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labelWidth: null or number
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labelHeight: null or number
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reserveSpace: null or true
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tickLength: null or number
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alignTicksWithAxis: null or number
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}
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```
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All axes have the same kind of options. The following describes how to
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configure one axis, see below for what to do if you've got more than
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one x axis or y axis.
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If you don't set the "show" option (i.e. it is null), visibility is
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auto-detected, i.e. the axis will show up if there's data associated
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with it. You can override this by setting the "show" option to true or
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false.
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The "position" option specifies where the axis is placed, bottom or
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top for x axes, left or right for y axes. The "mode" option determines
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how the data is interpreted, the default of null means as decimal
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numbers. Use "time" for time series data; see the time series data
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section. The time plugin (jquery.flot.time.js) is required for time
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series support.
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The "color" option determines the color of the line and ticks for the axis, and
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defaults to the grid color with transparency. For more fine-grained control you
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can also set the color of the ticks separately with "tickColor".
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You can customize the font and color used to draw the axis tick labels with CSS
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or directly via the "font" option. When "font" is null - the default - each
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tick label is given the 'flot-tick-label' class. For compatibility with Flot
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0.7 and earlier the labels are also given the 'tickLabel' class, but this is
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deprecated and scheduled to be removed with the release of version 1.0.0.
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To enable more granular control over styles, labels are divided between a set
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of text containers, with each holding the labels for one axis. These containers
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are given the classes 'flot-[x|y]-axis', and 'flot-[x|y]#-axis', where '#' is
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the number of the axis when there are multiple axes. For example, the x-axis
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labels for a simple plot with only a single x-axis might look like this:
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```html
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<div class='flot-x-axis flot-x1-axis'>
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<div class='flot-tick-label'>January 2013</div>
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...
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</div>
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```
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For direct control over label styles you can also provide "font" as an object
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with this format:
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```js
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{
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size: 11,
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lineHeight: 13,
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style: "italic",
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weight: "bold",
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family: "sans-serif",
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variant: "small-caps",
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color: "#545454"
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}
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```
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The size and lineHeight must be expressed in pixels; CSS units such as 'em'
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or 'smaller' are not allowed.
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The options "min"/"max" are the precise minimum/maximum value on the
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scale. If you don't specify either of them, a value will automatically
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be chosen based on the minimum/maximum data values. Note that Flot
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always examines all the data values you feed to it, even if a
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restriction on another axis may make some of them invisible (this
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makes interactive use more stable).
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The "autoscaleMargin" is a bit esoteric: it's the fraction of margin
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that the scaling algorithm will add to avoid that the outermost points
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ends up on the grid border. Note that this margin is only applied when
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a min or max value is not explicitly set. If a margin is specified,
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the plot will furthermore extend the axis end-point to the nearest
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whole tick. The default value is "null" for the x axes and 0.02 for y
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axes which seems appropriate for most cases.
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"transform" and "inverseTransform" are callbacks you can put in to
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change the way the data is drawn. You can design a function to
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compress or expand certain parts of the axis non-linearly, e.g.
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suppress weekends or compress far away points with a logarithm or some
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other means. When Flot draws the plot, each value is first put through
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the transform function. Here's an example, the x axis can be turned
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into a natural logarithm axis with the following code:
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```js
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xaxis: {
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transform: function (v) { return Math.log(v); },
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inverseTransform: function (v) { return Math.exp(v); }
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}
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```
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Similarly, for reversing the y axis so the values appear in inverse
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order:
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```js
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yaxis: {
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transform: function (v) { return -v; },
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inverseTransform: function (v) { return -v; }
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}
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```
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Note that for finding extrema, Flot assumes that the transform
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function does not reorder values (it should be monotone).
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The inverseTransform is simply the inverse of the transform function
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(so v == inverseTransform(transform(v)) for all relevant v). It is
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required for converting from canvas coordinates to data coordinates,
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e.g. for a mouse interaction where a certain pixel is clicked. If you
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don't use any interactive features of Flot, you may not need it.
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The rest of the options deal with the ticks.
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If you don't specify any ticks, a tick generator algorithm will make
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some for you. The algorithm has two passes. It first estimates how
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many ticks would be reasonable and uses this number to compute a nice
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round tick interval size. Then it generates the ticks.
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You can specify how many ticks the algorithm aims for by setting
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"ticks" to a number. The algorithm always tries to generate reasonably
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round tick values so even if you ask for three ticks, you might get
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five if that fits better with the rounding. If you don't want any
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ticks at all, set "ticks" to 0 or an empty array.
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Another option is to skip the rounding part and directly set the tick
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interval size with "tickSize". If you set it to 2, you'll get ticks at
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2, 4, 6, etc. Alternatively, you can specify that you just don't want
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ticks at a size less than a specific tick size with "minTickSize".
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Note that for time series, the format is an array like [2, "month"],
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see the next section.
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If you want to completely override the tick algorithm, you can specify
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an array for "ticks", either like this:
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```js
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ticks: [0, 1.2, 2.4]
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```
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Or like this where the labels are also customized:
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```js
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ticks: [[0, "zero"], [1.2, "one mark"], [2.4, "two marks"]]
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```
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You can mix the two if you like.
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For extra flexibility you can specify a function as the "ticks"
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parameter. The function will be called with an object with the axis
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min and max and should return a ticks array. Here's a simplistic tick
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generator that spits out intervals of pi, suitable for use on the x
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axis for trigonometric functions:
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```js
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function piTickGenerator(axis) {
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var res = [], i = Math.floor(axis.min / Math.PI);
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do {
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var v = i * Math.PI;
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res.push([v, i + "\u03c0"]);
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++i;
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} while (v < axis.max);
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return res;
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}
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```
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You can control how the ticks look like with "tickDecimals", the
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number of decimals to display (default is auto-detected).
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Alternatively, for ultimate control over how ticks are formatted you can
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provide a function to "tickFormatter". The function is passed two
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parameters, the tick value and an axis object with information, and
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should return a string. The default formatter looks like this:
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```js
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function formatter(val, axis) {
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return val.toFixed(axis.tickDecimals);
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}
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```
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The axis object has "min" and "max" with the range of the axis,
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"tickDecimals" with the number of decimals to round the value to and
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"tickSize" with the size of the interval between ticks as calculated
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by the automatic axis scaling algorithm (or specified by you). Here's
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an example of a custom formatter:
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```js
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function suffixFormatter(val, axis) {
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if (val > 1000000)
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return (val / 1000000).toFixed(axis.tickDecimals) + " MB";
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else if (val > 1000)
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return (val / 1000).toFixed(axis.tickDecimals) + " kB";
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else
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return val.toFixed(axis.tickDecimals) + " B";
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}
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```
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"labelWidth" and "labelHeight" specifies a fixed size of the tick
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labels in pixels. They're useful in case you need to align several
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plots. "reserveSpace" means that even if an axis isn't shown, Flot
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should reserve space for it - it is useful in combination with
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labelWidth and labelHeight for aligning multi-axis charts.
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"tickLength" is the length of the tick lines in pixels. By default, the
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innermost axes will have ticks that extend all across the plot, while
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any extra axes use small ticks. A value of null means use the default,
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while a number means small ticks of that length - set it to 0 to hide
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the lines completely.
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If you set "alignTicksWithAxis" to the number of another axis, e.g.
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alignTicksWithAxis: 1, Flot will ensure that the autogenerated ticks
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of this axis are aligned with the ticks of the other axis. This may
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improve the looks, e.g. if you have one y axis to the left and one to
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the right, because the grid lines will then match the ticks in both
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ends. The trade-off is that the forced ticks won't necessarily be at
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natural places.
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## Multiple axes ##
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If you need more than one x axis or y axis, you need to specify for
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each data series which axis they are to use, as described under the
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format of the data series, e.g. { data: [...], yaxis: 2 } specifies
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that a series should be plotted against the second y axis.
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To actually configure that axis, you can't use the xaxis/yaxis options
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directly - instead there are two arrays in the options:
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```js
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xaxes: []
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yaxes: []
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```
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Here's an example of configuring a single x axis and two y axes (we
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can leave options of the first y axis empty as the defaults are fine):
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```js
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{
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xaxes: [ { position: "top" } ],
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yaxes: [ { }, { position: "right", min: 20 } ]
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}
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```
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The arrays get their default values from the xaxis/yaxis settings, so
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say you want to have all y axes start at zero, you can simply specify
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yaxis: { min: 0 } instead of adding a min parameter to all the axes.
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Generally, the various interfaces in Flot dealing with data points
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either accept an xaxis/yaxis parameter to specify which axis number to
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use (starting from 1), or lets you specify the coordinate directly as
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x2/x3/... or x2axis/x3axis/... instead of "x" or "xaxis".
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## Time series data ##
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Please note that it is now required to include the time plugin,
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jquery.flot.time.js, for time series support.
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Time series are a bit more difficult than scalar data because
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calendars don't follow a simple base 10 system. For many cases, Flot
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abstracts most of this away, but it can still be a bit difficult to
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get the data into Flot. So we'll first discuss the data format.
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The time series support in Flot is based on Javascript timestamps,
|
|
i.e. everywhere a time value is expected or handed over, a Javascript
|
|
timestamp number is used. This is a number, not a Date object. A
|
|
Javascript timestamp is the number of milliseconds since January 1,
|
|
1970 00:00:00 UTC. This is almost the same as Unix timestamps, except it's
|
|
in milliseconds, so remember to multiply by 1000!
|
|
|
|
You can see a timestamp like this
|
|
|
|
```js
|
|
alert((new Date()).getTime())
|
|
```
|
|
|
|
There are different schools of thought when it comes to diplay of
|
|
timestamps. Many will want the timestamps to be displayed according to
|
|
a certain time zone, usually the time zone in which the data has been
|
|
produced. Some want the localized experience, where the timestamps are
|
|
displayed according to the local time of the visitor. Flot supports
|
|
both. Optionally you can include a third-party library to get
|
|
additional timezone support.
|
|
|
|
Default behavior is that Flot always displays timestamps according to
|
|
UTC. The reason being that the core Javascript Date object does not
|
|
support other fixed time zones. Often your data is at another time
|
|
zone, so it may take a little bit of tweaking to work around this
|
|
limitation.
|
|
|
|
The easiest way to think about it is to pretend that the data
|
|
production time zone is UTC, even if it isn't. So if you have a
|
|
datapoint at 2002-02-20 08:00, you can generate a timestamp for eight
|
|
o'clock UTC even if it really happened eight o'clock UTC+0200.
|
|
|
|
In PHP you can get an appropriate timestamp with:
|
|
|
|
```php
|
|
strtotime("2002-02-20 UTC") * 1000
|
|
```
|
|
|
|
In Python you can get it with something like:
|
|
|
|
```python
|
|
calendar.timegm(datetime_object.timetuple()) * 1000
|
|
```
|
|
|
|
In .NET you can get it with something like:
|
|
|
|
```aspx
|
|
public static int GetJavascriptTimestamp(System.DateTime input)
|
|
{
|
|
System.TimeSpan span = new System.TimeSpan(System.DateTime.Parse("1/1/1970").Ticks);
|
|
System.DateTime time = input.Subtract(span);
|
|
return (long)(time.Ticks / 10000);
|
|
}
|
|
```
|
|
|
|
Javascript also has some support for parsing date strings, so it is
|
|
possible to generate the timestamps manually client-side.
|
|
|
|
If you've already got the real UTC timestamp, it's too late to use the
|
|
pretend trick described above. But you can fix up the timestamps by
|
|
adding the time zone offset, e.g. for UTC+0200 you would add 2 hours
|
|
to the UTC timestamp you got. Then it'll look right on the plot. Most
|
|
programming environments have some means of getting the timezone
|
|
offset for a specific date (note that you need to get the offset for
|
|
each individual timestamp to account for daylight savings).
|
|
|
|
The alternative with core Javascript is to interpret the timestamps
|
|
according to the time zone that the visitor is in, which means that
|
|
the ticks will shift with the time zone and daylight savings of each
|
|
visitor. This behavior is enabled by setting the axis option
|
|
"timezone" to the value "browser".
|
|
|
|
If you need more time zone functionality than this, there is still
|
|
another option. If you include the "timezone-js" library
|
|
<https://github.com/mde/timezone-js> in the page and set axis.timezone
|
|
to a value recognized by said library, Flot will use timezone-js to
|
|
interpret the timestamps according to that time zone.
|
|
|
|
Once you've gotten the timestamps into the data and specified "time"
|
|
as the axis mode, Flot will automatically generate relevant ticks and
|
|
format them. As always, you can tweak the ticks via the "ticks" option
|
|
- just remember that the values should be timestamps (numbers), not
|
|
Date objects.
|
|
|
|
Tick generation and formatting can also be controlled separately
|
|
through the following axis options:
|
|
|
|
```js
|
|
minTickSize: array
|
|
timeformat: null or format string
|
|
monthNames: null or array of size 12 of strings
|
|
dayNames: null or array of size 7 of strings
|
|
twelveHourClock: boolean
|
|
```
|
|
|
|
Here "timeformat" is a format string to use. You might use it like
|
|
this:
|
|
|
|
```js
|
|
xaxis: {
|
|
mode: "time",
|
|
timeformat: "%Y/%m/%d"
|
|
}
|
|
```
|
|
|
|
This will result in tick labels like "2000/12/24". A subset of the
|
|
standard strftime specifiers are supported (plus the nonstandard %q):
|
|
|
|
```js
|
|
%a: weekday name (customizable)
|
|
%b: month name (customizable)
|
|
%d: day of month, zero-padded (01-31)
|
|
%e: day of month, space-padded ( 1-31)
|
|
%H: hours, 24-hour time, zero-padded (00-23)
|
|
%I: hours, 12-hour time, zero-padded (01-12)
|
|
%m: month, zero-padded (01-12)
|
|
%M: minutes, zero-padded (00-59)
|
|
%q: quarter (1-4)
|
|
%S: seconds, zero-padded (00-59)
|
|
%y: year (two digits)
|
|
%Y: year (four digits)
|
|
%p: am/pm
|
|
%P: AM/PM (uppercase version of %p)
|
|
%w: weekday as number (0-6, 0 being Sunday)
|
|
```
|
|
|
|
Flot 0.8 switched from %h to the standard %H hours specifier. The %h specifier
|
|
is still available, for backwards-compatibility, but is deprecated and
|
|
scheduled to be removed permanently with the release of version 1.0.
|
|
|
|
You can customize the month names with the "monthNames" option. For
|
|
instance, for Danish you might specify:
|
|
|
|
```js
|
|
monthNames: ["jan", "feb", "mar", "apr", "maj", "jun", "jul", "aug", "sep", "okt", "nov", "dec"]
|
|
```
|
|
|
|
Similarly you can customize the weekday names with the "dayNames"
|
|
option. An example in French:
|
|
|
|
```js
|
|
dayNames: ["dim", "lun", "mar", "mer", "jeu", "ven", "sam"]
|
|
```
|
|
|
|
If you set "twelveHourClock" to true, the autogenerated timestamps
|
|
will use 12 hour AM/PM timestamps instead of 24 hour. This only
|
|
applies if you have not set "timeformat". Use the "%I" and "%p" or
|
|
"%P" options if you want to build your own format string with 12-hour
|
|
times.
|
|
|
|
If the Date object has a strftime property (and it is a function), it
|
|
will be used instead of the built-in formatter. Thus you can include
|
|
a strftime library such as http://hacks.bluesmoon.info/strftime/ for
|
|
more powerful date/time formatting.
|
|
|
|
If everything else fails, you can control the formatting by specifying
|
|
a custom tick formatter function as usual. Here's a simple example
|
|
which will format December 24 as 24/12:
|
|
|
|
```js
|
|
tickFormatter: function (val, axis) {
|
|
var d = new Date(val);
|
|
return d.getUTCDate() + "/" + (d.getUTCMonth() + 1);
|
|
}
|
|
```
|
|
|
|
Note that for the time mode "tickSize" and "minTickSize" are a bit
|
|
special in that they are arrays on the form "[value, unit]" where unit
|
|
is one of "second", "minute", "hour", "day", "month" and "year". So
|
|
you can specify
|
|
|
|
```js
|
|
minTickSize: [1, "month"]
|
|
```
|
|
|
|
to get a tick interval size of at least 1 month and correspondingly,
|
|
if axis.tickSize is [2, "day"] in the tick formatter, the ticks have
|
|
been produced with two days in-between.
|
|
|
|
|
|
## Customizing the data series ##
|
|
|
|
```js
|
|
series: {
|
|
lines, points, bars: {
|
|
show: boolean
|
|
lineWidth: number
|
|
fill: boolean or number
|
|
fillColor: null or color/gradient
|
|
}
|
|
|
|
lines, bars: {
|
|
zero: boolean
|
|
}
|
|
|
|
points: {
|
|
radius: number
|
|
symbol: "circle" or function
|
|
}
|
|
|
|
bars: {
|
|
barWidth: number
|
|
align: "left", "right" or "center"
|
|
horizontal: boolean
|
|
}
|
|
|
|
lines: {
|
|
steps: boolean
|
|
}
|
|
|
|
shadowSize: number
|
|
highlightColor: color or number
|
|
}
|
|
|
|
colors: [ color1, color2, ... ]
|
|
```
|
|
|
|
The options inside "series: {}" are copied to each of the series. So
|
|
you can specify that all series should have bars by putting it in the
|
|
global options, or override it for individual series by specifying
|
|
bars in a particular the series object in the array of data.
|
|
|
|
The most important options are "lines", "points" and "bars" that
|
|
specify whether and how lines, points and bars should be shown for
|
|
each data series. In case you don't specify anything at all, Flot will
|
|
default to showing lines (you can turn this off with
|
|
lines: { show: false }). You can specify the various types
|
|
independently of each other, and Flot will happily draw each of them
|
|
in turn (this is probably only useful for lines and points), e.g.
|
|
|
|
```js
|
|
var options = {
|
|
series: {
|
|
lines: { show: true, fill: true, fillColor: "rgba(255, 255, 255, 0.8)" },
|
|
points: { show: true, fill: false }
|
|
}
|
|
};
|
|
```
|
|
|
|
"lineWidth" is the thickness of the line or outline in pixels. You can
|
|
set it to 0 to prevent a line or outline from being drawn; this will
|
|
also hide the shadow.
|
|
|
|
"fill" is whether the shape should be filled. For lines, this produces
|
|
area graphs. You can use "fillColor" to specify the color of the fill.
|
|
If "fillColor" evaluates to false (default for everything except
|
|
points which are filled with white), the fill color is auto-set to the
|
|
color of the data series. You can adjust the opacity of the fill by
|
|
setting fill to a number between 0 (fully transparent) and 1 (fully
|
|
opaque).
|
|
|
|
For bars, fillColor can be a gradient, see the gradient documentation
|
|
below. "barWidth" is the width of the bars in units of the x axis (or
|
|
the y axis if "horizontal" is true), contrary to most other measures
|
|
that are specified in pixels. For instance, for time series the unit
|
|
is milliseconds so 24 * 60 * 60 * 1000 produces bars with the width of
|
|
a day. "align" specifies whether a bar should be left-aligned
|
|
(default), right-aligned or centered on top of the value it represents.
|
|
When "horizontal" is on, the bars are drawn horizontally, i.e. from the
|
|
y axis instead of the x axis; note that the bar end points are still
|
|
defined in the same way so you'll probably want to swap the
|
|
coordinates if you've been plotting vertical bars first.
|
|
|
|
Area and bar charts normally start from zero, regardless of the data's range.
|
|
This is because they convey information through size, and starting from a
|
|
different value would distort their meaning. In cases where the fill is purely
|
|
for decorative purposes, however, "zero" allows you to override this behavior.
|
|
It defaults to true for filled lines and bars; setting it to false tells the
|
|
series to use the same automatic scaling as an un-filled line.
|
|
|
|
For lines, "steps" specifies whether two adjacent data points are
|
|
connected with a straight (possibly diagonal) line or with first a
|
|
horizontal and then a vertical line. Note that this transforms the
|
|
data by adding extra points.
|
|
|
|
For points, you can specify the radius and the symbol. The only
|
|
built-in symbol type is circles, for other types you can use a plugin
|
|
or define them yourself by specifying a callback:
|
|
|
|
```js
|
|
function cross(ctx, x, y, radius, shadow) {
|
|
var size = radius * Math.sqrt(Math.PI) / 2;
|
|
ctx.moveTo(x - size, y - size);
|
|
ctx.lineTo(x + size, y + size);
|
|
ctx.moveTo(x - size, y + size);
|
|
ctx.lineTo(x + size, y - size);
|
|
}
|
|
```
|
|
|
|
The parameters are the drawing context, x and y coordinates of the
|
|
center of the point, a radius which corresponds to what the circle
|
|
would have used and whether the call is to draw a shadow (due to
|
|
limited canvas support, shadows are currently faked through extra
|
|
draws). It's good practice to ensure that the area covered by the
|
|
symbol is the same as for the circle with the given radius, this
|
|
ensures that all symbols have approximately the same visual weight.
|
|
|
|
"shadowSize" is the default size of shadows in pixels. Set it to 0 to
|
|
remove shadows.
|
|
|
|
"highlightColor" is the default color of the translucent overlay used
|
|
to highlight the series when the mouse hovers over it.
|
|
|
|
The "colors" array specifies a default color theme to get colors for
|
|
the data series from. You can specify as many colors as you like, like
|
|
this:
|
|
|
|
```js
|
|
colors: ["#d18b2c", "#dba255", "#919733"]
|
|
```
|
|
|
|
If there are more data series than colors, Flot will try to generate
|
|
extra colors by lightening and darkening colors in the theme.
|
|
|
|
|
|
## Customizing the grid ##
|
|
|
|
```js
|
|
grid: {
|
|
show: boolean
|
|
aboveData: boolean
|
|
color: color
|
|
backgroundColor: color/gradient or null
|
|
margin: number or margin object
|
|
labelMargin: number
|
|
axisMargin: number
|
|
markings: array of markings or (fn: axes -> array of markings)
|
|
borderWidth: number or object with "top", "right", "bottom" and "left" properties with different widths
|
|
borderColor: color or null or object with "top", "right", "bottom" and "left" properties with different colors
|
|
minBorderMargin: number or null
|
|
clickable: boolean
|
|
hoverable: boolean
|
|
autoHighlight: boolean
|
|
mouseActiveRadius: number
|
|
}
|
|
|
|
interaction: {
|
|
redrawOverlayInterval: number or -1
|
|
}
|
|
```
|
|
|
|
The grid is the thing with the axes and a number of ticks. Many of the
|
|
things in the grid are configured under the individual axes, but not
|
|
all. "color" is the color of the grid itself whereas "backgroundColor"
|
|
specifies the background color inside the grid area, here null means
|
|
that the background is transparent. You can also set a gradient, see
|
|
the gradient documentation below.
|
|
|
|
You can turn off the whole grid including tick labels by setting
|
|
"show" to false. "aboveData" determines whether the grid is drawn
|
|
above the data or below (below is default).
|
|
|
|
"margin" is the space in pixels between the canvas edge and the grid,
|
|
which can be either a number or an object with individual margins for
|
|
each side, in the form:
|
|
|
|
```js
|
|
margin: {
|
|
top: top margin in pixels
|
|
left: left margin in pixels
|
|
bottom: bottom margin in pixels
|
|
right: right margin in pixels
|
|
}
|
|
```
|
|
|
|
"labelMargin" is the space in pixels between tick labels and axis
|
|
line, and "axisMargin" is the space in pixels between axes when there
|
|
are two next to each other.
|
|
|
|
"borderWidth" is the width of the border around the plot. Set it to 0
|
|
to disable the border. Set it to an object with "top", "right",
|
|
"bottom" and "left" properties to use different widths. You can
|
|
also set "borderColor" if you want the border to have a different color
|
|
than the grid lines. Set it to an object with "top", "right", "bottom"
|
|
and "left" properties to use different colors. "minBorderMargin" controls
|
|
the default minimum margin around the border - it's used to make sure
|
|
that points aren't accidentally clipped by the canvas edge so by default
|
|
the value is computed from the point radius.
|
|
|
|
"markings" is used to draw simple lines and rectangular areas in the
|
|
background of the plot. You can either specify an array of ranges on
|
|
the form { xaxis: { from, to }, yaxis: { from, to } } (with multiple
|
|
axes, you can specify coordinates for other axes instead, e.g. as
|
|
x2axis/x3axis/...) or with a function that returns such an array given
|
|
the axes for the plot in an object as the first parameter.
|
|
|
|
You can set the color of markings by specifying "color" in the ranges
|
|
object. Here's an example array:
|
|
|
|
```js
|
|
markings: [ { xaxis: { from: 0, to: 2 }, yaxis: { from: 10, to: 10 }, color: "#bb0000" }, ... ]
|
|
```
|
|
|
|
If you leave out one of the values, that value is assumed to go to the
|
|
border of the plot. So for example if you only specify { xaxis: {
|
|
from: 0, to: 2 } } it means an area that extends from the top to the
|
|
bottom of the plot in the x range 0-2.
|
|
|
|
A line is drawn if from and to are the same, e.g.
|
|
|
|
```js
|
|
markings: [ { yaxis: { from: 1, to: 1 } }, ... ]
|
|
```
|
|
|
|
would draw a line parallel to the x axis at y = 1. You can control the
|
|
line width with "lineWidth" in the range object.
|
|
|
|
An example function that makes vertical stripes might look like this:
|
|
|
|
```js
|
|
markings: function (axes) {
|
|
var markings = [];
|
|
for (var x = Math.floor(axes.xaxis.min); x < axes.xaxis.max; x += 2)
|
|
markings.push({ xaxis: { from: x, to: x + 1 } });
|
|
return markings;
|
|
}
|
|
```
|
|
|
|
If you set "clickable" to true, the plot will listen for click events
|
|
on the plot area and fire a "plotclick" event on the placeholder with
|
|
a position and a nearby data item object as parameters. The coordinates
|
|
are available both in the unit of the axes (not in pixels) and in
|
|
global screen coordinates.
|
|
|
|
Likewise, if you set "hoverable" to true, the plot will listen for
|
|
mouse move events on the plot area and fire a "plothover" event with
|
|
the same parameters as the "plotclick" event. If "autoHighlight" is
|
|
true (the default), nearby data items are highlighted automatically.
|
|
If needed, you can disable highlighting and control it yourself with
|
|
the highlight/unhighlight plot methods described elsewhere.
|
|
|
|
You can use "plotclick" and "plothover" events like this:
|
|
|
|
```js
|
|
$.plot($("#placeholder"), [ d ], { grid: { clickable: true } });
|
|
|
|
$("#placeholder").bind("plotclick", function (event, pos, item) {
|
|
alert("You clicked at " + pos.x + ", " + pos.y);
|
|
// axis coordinates for other axes, if present, are in pos.x2, pos.x3, ...
|
|
// if you need global screen coordinates, they are pos.pageX, pos.pageY
|
|
|
|
if (item) {
|
|
highlight(item.series, item.datapoint);
|
|
alert("You clicked a point!");
|
|
}
|
|
});
|
|
```
|
|
|
|
The item object in this example is either null or a nearby object on the form:
|
|
|
|
```js
|
|
item: {
|
|
datapoint: the point, e.g. [0, 2]
|
|
dataIndex: the index of the point in the data array
|
|
series: the series object
|
|
seriesIndex: the index of the series
|
|
pageX, pageY: the global screen coordinates of the point
|
|
}
|
|
```
|
|
|
|
For instance, if you have specified the data like this
|
|
|
|
```js
|
|
$.plot($("#placeholder"), [ { label: "Foo", data: [[0, 10], [7, 3]] } ], ...);
|
|
```
|
|
|
|
and the mouse is near the point (7, 3), "datapoint" is [7, 3],
|
|
"dataIndex" will be 1, "series" is a normalized series object with
|
|
among other things the "Foo" label in series.label and the color in
|
|
series.color, and "seriesIndex" is 0. Note that plugins and options
|
|
that transform the data can shift the indexes from what you specified
|
|
in the original data array.
|
|
|
|
If you use the above events to update some other information and want
|
|
to clear out that info in case the mouse goes away, you'll probably
|
|
also need to listen to "mouseout" events on the placeholder div.
|
|
|
|
"mouseActiveRadius" specifies how far the mouse can be from an item
|
|
and still activate it. If there are two or more points within this
|
|
radius, Flot chooses the closest item. For bars, the top-most bar
|
|
(from the latest specified data series) is chosen.
|
|
|
|
If you want to disable interactivity for a specific data series, you
|
|
can set "hoverable" and "clickable" to false in the options for that
|
|
series, like this:
|
|
|
|
```js
|
|
{ data: [...], label: "Foo", clickable: false }
|
|
```
|
|
|
|
"redrawOverlayInterval" specifies the maximum time to delay a redraw
|
|
of interactive things (this works as a rate limiting device). The
|
|
default is capped to 60 frames per second. You can set it to -1 to
|
|
disable the rate limiting.
|
|
|
|
|
|
## Specifying gradients ##
|
|
|
|
A gradient is specified like this:
|
|
|
|
```js
|
|
{ colors: [ color1, color2, ... ] }
|
|
```
|
|
|
|
For instance, you might specify a background on the grid going from
|
|
black to gray like this:
|
|
|
|
```js
|
|
grid: {
|
|
backgroundColor: { colors: ["#000", "#999"] }
|
|
}
|
|
```
|
|
|
|
For the series you can specify the gradient as an object that
|
|
specifies the scaling of the brightness and the opacity of the series
|
|
color, e.g.
|
|
|
|
```js
|
|
{ colors: [{ opacity: 0.8 }, { brightness: 0.6, opacity: 0.8 } ] }
|
|
```
|
|
|
|
where the first color simply has its alpha scaled, whereas the second
|
|
is also darkened. For instance, for bars the following makes the bars
|
|
gradually disappear, without outline:
|
|
|
|
```js
|
|
bars: {
|
|
show: true,
|
|
lineWidth: 0,
|
|
fill: true,
|
|
fillColor: { colors: [ { opacity: 0.8 }, { opacity: 0.1 } ] }
|
|
}
|
|
```
|
|
|
|
Flot currently only supports vertical gradients drawn from top to
|
|
bottom because that's what works with IE.
|
|
|
|
|
|
## Plot Methods ##
|
|
|
|
The Plot object returned from the plot function has some methods you
|
|
can call:
|
|
|
|
- highlight(series, datapoint)
|
|
|
|
Highlight a specific datapoint in the data series. You can either
|
|
specify the actual objects, e.g. if you got them from a
|
|
"plotclick" event, or you can specify the indices, e.g.
|
|
highlight(1, 3) to highlight the fourth point in the second series
|
|
(remember, zero-based indexing).
|
|
|
|
- unhighlight(series, datapoint) or unhighlight()
|
|
|
|
Remove the highlighting of the point, same parameters as
|
|
highlight.
|
|
|
|
If you call unhighlight with no parameters, e.g. as
|
|
plot.unhighlight(), all current highlights are removed.
|
|
|
|
- setData(data)
|
|
|
|
You can use this to reset the data used. Note that axis scaling,
|
|
ticks, legend etc. will not be recomputed (use setupGrid() to do
|
|
that). You'll probably want to call draw() afterwards.
|
|
|
|
You can use this function to speed up redrawing a small plot if
|
|
you know that the axes won't change. Put in the new data with
|
|
setData(newdata), call draw(), and you're good to go. Note that
|
|
for large datasets, almost all the time is consumed in draw()
|
|
plotting the data so in this case don't bother.
|
|
|
|
- setupGrid()
|
|
|
|
Recalculate and set axis scaling, ticks, legend etc.
|
|
|
|
Note that because of the drawing model of the canvas, this
|
|
function will immediately redraw (actually reinsert in the DOM)
|
|
the labels and the legend, but not the actual tick lines because
|
|
they're drawn on the canvas. You need to call draw() to get the
|
|
canvas redrawn.
|
|
|
|
- draw()
|
|
|
|
Redraws the plot canvas.
|
|
|
|
- triggerRedrawOverlay()
|
|
|
|
Schedules an update of an overlay canvas used for drawing
|
|
interactive things like a selection and point highlights. This
|
|
is mostly useful for writing plugins. The redraw doesn't happen
|
|
immediately, instead a timer is set to catch multiple successive
|
|
redraws (e.g. from a mousemove). You can get to the overlay by
|
|
setting up a drawOverlay hook.
|
|
|
|
- width()/height()
|
|
|
|
Gets the width and height of the plotting area inside the grid.
|
|
This is smaller than the canvas or placeholder dimensions as some
|
|
extra space is needed (e.g. for labels).
|
|
|
|
- offset()
|
|
|
|
Returns the offset of the plotting area inside the grid relative
|
|
to the document, useful for instance for calculating mouse
|
|
positions (event.pageX/Y minus this offset is the pixel position
|
|
inside the plot).
|
|
|
|
- pointOffset({ x: xpos, y: ypos })
|
|
|
|
Returns the calculated offset of the data point at (x, y) in data
|
|
space within the placeholder div. If you are working with multiple
|
|
axes, you can specify the x and y axis references, e.g.
|
|
|
|
```js
|
|
o = pointOffset({ x: xpos, y: ypos, xaxis: 2, yaxis: 3 })
|
|
// o.left and o.top now contains the offset within the div
|
|
````
|
|
|
|
- resize()
|
|
|
|
Tells Flot to resize the drawing canvas to the size of the
|
|
placeholder. You need to run setupGrid() and draw() afterwards as
|
|
canvas resizing is a destructive operation. This is used
|
|
internally by the resize plugin.
|
|
|
|
- shutdown()
|
|
|
|
Cleans up any event handlers Flot has currently registered. This
|
|
is used internally.
|
|
|
|
There are also some members that let you peek inside the internal
|
|
workings of Flot which is useful in some cases. Note that if you change
|
|
something in the objects returned, you're changing the objects used by
|
|
Flot to keep track of its state, so be careful.
|
|
|
|
- getData()
|
|
|
|
Returns an array of the data series currently used in normalized
|
|
form with missing settings filled in according to the global
|
|
options. So for instance to find out what color Flot has assigned
|
|
to the data series, you could do this:
|
|
|
|
```js
|
|
var series = plot.getData();
|
|
for (var i = 0; i < series.length; ++i)
|
|
alert(series[i].color);
|
|
```
|
|
|
|
A notable other interesting field besides color is datapoints
|
|
which has a field "points" with the normalized data points in a
|
|
flat array (the field "pointsize" is the increment in the flat
|
|
array to get to the next point so for a dataset consisting only of
|
|
(x,y) pairs it would be 2).
|
|
|
|
- getAxes()
|
|
|
|
Gets an object with the axes. The axes are returned as the
|
|
attributes of the object, so for instance getAxes().xaxis is the
|
|
x axis.
|
|
|
|
Various things are stuffed inside an axis object, e.g. you could
|
|
use getAxes().xaxis.ticks to find out what the ticks are for the
|
|
xaxis. Two other useful attributes are p2c and c2p, functions for
|
|
transforming from data point space to the canvas plot space and
|
|
back. Both returns values that are offset with the plot offset.
|
|
Check the Flot source code for the complete set of attributes (or
|
|
output an axis with console.log() and inspect it).
|
|
|
|
With multiple axes, the extra axes are returned as x2axis, x3axis,
|
|
etc., e.g. getAxes().y2axis is the second y axis. You can check
|
|
y2axis.used to see whether the axis is associated with any data
|
|
points and y2axis.show to see if it is currently shown.
|
|
|
|
- getPlaceholder()
|
|
|
|
Returns placeholder that the plot was put into. This can be useful
|
|
for plugins for adding DOM elements or firing events.
|
|
|
|
- getCanvas()
|
|
|
|
Returns the canvas used for drawing in case you need to hack on it
|
|
yourself. You'll probably need to get the plot offset too.
|
|
|
|
- getPlotOffset()
|
|
|
|
Gets the offset that the grid has within the canvas as an object
|
|
with distances from the canvas edges as "left", "right", "top",
|
|
"bottom". I.e., if you draw a circle on the canvas with the center
|
|
placed at (left, top), its center will be at the top-most, left
|
|
corner of the grid.
|
|
|
|
- getOptions()
|
|
|
|
Gets the options for the plot, normalized, with default values
|
|
filled in. You get a reference to actual values used by Flot, so
|
|
if you modify the values in here, Flot will use the new values.
|
|
If you change something, you probably have to call draw() or
|
|
setupGrid() or triggerRedrawOverlay() to see the change.
|
|
|
|
|
|
## Hooks ##
|
|
|
|
In addition to the public methods, the Plot object also has some hooks
|
|
that can be used to modify the plotting process. You can install a
|
|
callback function at various points in the process, the function then
|
|
gets access to the internal data structures in Flot.
|
|
|
|
Here's an overview of the phases Flot goes through:
|
|
|
|
1. Plugin initialization, parsing options
|
|
|
|
2. Constructing the canvases used for drawing
|
|
|
|
3. Set data: parsing data specification, calculating colors,
|
|
copying raw data points into internal format,
|
|
normalizing them, finding max/min for axis auto-scaling
|
|
|
|
4. Grid setup: calculating axis spacing, ticks, inserting tick
|
|
labels, the legend
|
|
|
|
5. Draw: drawing the grid, drawing each of the series in turn
|
|
|
|
6. Setting up event handling for interactive features
|
|
|
|
7. Responding to events, if any
|
|
|
|
8. Shutdown: this mostly happens in case a plot is overwritten
|
|
|
|
Each hook is simply a function which is put in the appropriate array.
|
|
You can add them through the "hooks" option, and they are also available
|
|
after the plot is constructed as the "hooks" attribute on the returned
|
|
plot object, e.g.
|
|
|
|
```js
|
|
// define a simple draw hook
|
|
function hellohook(plot, canvascontext) { alert("hello!"); };
|
|
|
|
// pass it in, in an array since we might want to specify several
|
|
var plot = $.plot(placeholder, data, { hooks: { draw: [hellohook] } });
|
|
|
|
// we can now find it again in plot.hooks.draw[0] unless a plugin
|
|
// has added other hooks
|
|
```
|
|
|
|
The available hooks are described below. All hook callbacks get the
|
|
plot object as first parameter. You can find some examples of defined
|
|
hooks in the plugins bundled with Flot.
|
|
|
|
- processOptions [phase 1]
|
|
|
|
```function(plot, options)```
|
|
|
|
Called after Flot has parsed and merged options. Useful in the
|
|
instance where customizations beyond simple merging of default
|
|
values is needed. A plugin might use it to detect that it has been
|
|
enabled and then turn on or off other options.
|
|
|
|
|
|
- processRawData [phase 3]
|
|
|
|
```function(plot, series, data, datapoints)```
|
|
|
|
Called before Flot copies and normalizes the raw data for the given
|
|
series. If the function fills in datapoints.points with normalized
|
|
points and sets datapoints.pointsize to the size of the points,
|
|
Flot will skip the copying/normalization step for this series.
|
|
|
|
In any case, you might be interested in setting datapoints.format,
|
|
an array of objects for specifying how a point is normalized and
|
|
how it interferes with axis scaling. It accepts the following options:
|
|
|
|
```js
|
|
{
|
|
x, y: boolean,
|
|
number: boolean,
|
|
required: boolean,
|
|
defaultValue: value,
|
|
autoscale: boolean
|
|
}
|
|
```
|
|
|
|
"x" and "y" specify whether the value is plotted against the x or y axis,
|
|
and is currently used only to calculate axis min-max ranges. The default
|
|
format array, for example, looks like this:
|
|
|
|
```js
|
|
[
|
|
{ x: true, number: true, required: true },
|
|
{ y: true, number: true, required: true }
|
|
]
|
|
```
|
|
|
|
This indicates that a point, i.e. [0, 25], consists of two values, with the
|
|
first being plotted on the x axis and the second on the y axis.
|
|
|
|
If "number" is true, then the value must be numeric, and is set to null if
|
|
it cannot be converted to a number.
|
|
|
|
"defaultValue" provides a fallback in case the original value is null. This
|
|
is for instance handy for bars, where one can omit the third coordinate
|
|
(the bottom of the bar), which then defaults to zero.
|
|
|
|
If "required" is true, then the value must exist (be non-null) for the
|
|
point as a whole to be valid. If no value is provided, then the entire
|
|
point is cleared out with nulls, turning it into a gap in the series.
|
|
|
|
"autoscale" determines whether the value is considered when calculating an
|
|
automatic min-max range for the axes that the value is plotted against.
|
|
|
|
- processDatapoints [phase 3]
|
|
|
|
```function(plot, series, datapoints)```
|
|
|
|
Called after normalization of the given series but before finding
|
|
min/max of the data points. This hook is useful for implementing data
|
|
transformations. "datapoints" contains the normalized data points in
|
|
a flat array as datapoints.points with the size of a single point
|
|
given in datapoints.pointsize. Here's a simple transform that
|
|
multiplies all y coordinates by 2:
|
|
|
|
```js
|
|
function multiply(plot, series, datapoints) {
|
|
var points = datapoints.points, ps = datapoints.pointsize;
|
|
for (var i = 0; i < points.length; i += ps)
|
|
points[i + 1] *= 2;
|
|
}
|
|
```
|
|
|
|
Note that you must leave datapoints in a good condition as Flot
|
|
doesn't check it or do any normalization on it afterwards.
|
|
|
|
- processOffset [phase 4]
|
|
|
|
```function(plot, offset)```
|
|
|
|
Called after Flot has initialized the plot's offset, but before it
|
|
draws any axes or plot elements. This hook is useful for customizing
|
|
the margins between the grid and the edge of the canvas. "offset" is
|
|
an object with attributes "top", "bottom", "left" and "right",
|
|
corresponding to the margins on the four sides of the plot.
|
|
|
|
- drawBackground [phase 5]
|
|
|
|
```function(plot, canvascontext)```
|
|
|
|
Called before all other drawing operations. Used to draw backgrounds
|
|
or other custom elements before the plot or axes have been drawn.
|
|
|
|
- drawSeries [phase 5]
|
|
|
|
```function(plot, canvascontext, series)```
|
|
|
|
Hook for custom drawing of a single series. Called just before the
|
|
standard drawing routine has been called in the loop that draws
|
|
each series.
|
|
|
|
- draw [phase 5]
|
|
|
|
```function(plot, canvascontext)```
|
|
|
|
Hook for drawing on the canvas. Called after the grid is drawn
|
|
(unless it's disabled or grid.aboveData is set) and the series have
|
|
been plotted (in case any points, lines or bars have been turned
|
|
on). For examples of how to draw things, look at the source code.
|
|
|
|
- bindEvents [phase 6]
|
|
|
|
```function(plot, eventHolder)```
|
|
|
|
Called after Flot has setup its event handlers. Should set any
|
|
necessary event handlers on eventHolder, a jQuery object with the
|
|
canvas, e.g.
|
|
|
|
```js
|
|
function (plot, eventHolder) {
|
|
eventHolder.mousedown(function (e) {
|
|
alert("You pressed the mouse at " + e.pageX + " " + e.pageY);
|
|
});
|
|
}
|
|
```
|
|
|
|
Interesting events include click, mousemove, mouseup/down. You can
|
|
use all jQuery events. Usually, the event handlers will update the
|
|
state by drawing something (add a drawOverlay hook and call
|
|
triggerRedrawOverlay) or firing an externally visible event for
|
|
user code. See the crosshair plugin for an example.
|
|
|
|
Currently, eventHolder actually contains both the static canvas
|
|
used for the plot itself and the overlay canvas used for
|
|
interactive features because some versions of IE get the stacking
|
|
order wrong. The hook only gets one event, though (either for the
|
|
overlay or for the static canvas).
|
|
|
|
Note that custom plot events generated by Flot are not generated on
|
|
eventHolder, but on the div placeholder supplied as the first
|
|
argument to the plot call. You can get that with
|
|
plot.getPlaceholder() - that's probably also the one you should use
|
|
if you need to fire a custom event.
|
|
|
|
- drawOverlay [phase 7]
|
|
|
|
```function (plot, canvascontext)```
|
|
|
|
The drawOverlay hook is used for interactive things that need a
|
|
canvas to draw on. The model currently used by Flot works the way
|
|
that an extra overlay canvas is positioned on top of the static
|
|
canvas. This overlay is cleared and then completely redrawn
|
|
whenever something interesting happens. This hook is called when
|
|
the overlay canvas is to be redrawn.
|
|
|
|
"canvascontext" is the 2D context of the overlay canvas. You can
|
|
use this to draw things. You'll most likely need some of the
|
|
metrics computed by Flot, e.g. plot.width()/plot.height(). See the
|
|
crosshair plugin for an example.
|
|
|
|
- shutdown [phase 8]
|
|
|
|
```function (plot, eventHolder)```
|
|
|
|
Run when plot.shutdown() is called, which usually only happens in
|
|
case a plot is overwritten by a new plot. If you're writing a
|
|
plugin that adds extra DOM elements or event handlers, you should
|
|
add a callback to clean up after you. Take a look at the section in
|
|
PLUGINS.txt for more info.
|
|
|
|
|
|
## Plugins ##
|
|
|
|
Plugins extend the functionality of Flot. To use a plugin, simply
|
|
include its Javascript file after Flot in the HTML page.
|
|
|
|
If you're worried about download size/latency, you can concatenate all
|
|
the plugins you use, and Flot itself for that matter, into one big file
|
|
(make sure you get the order right), then optionally run it through a
|
|
Javascript minifier such as YUI Compressor.
|
|
|
|
Here's a brief explanation of how the plugin plumbings work:
|
|
|
|
Each plugin registers itself in the global array $.plot.plugins. When
|
|
you make a new plot object with $.plot, Flot goes through this array
|
|
calling the "init" function of each plugin and merging default options
|
|
from the "option" attribute of the plugin. The init function gets a
|
|
reference to the plot object created and uses this to register hooks
|
|
and add new public methods if needed.
|
|
|
|
See the PLUGINS.txt file for details on how to write a plugin. As the
|
|
above description hints, it's actually pretty easy.
|
|
|
|
|
|
## Version number ##
|
|
|
|
The version number of Flot is available in ```$.plot.version```.
|