110 lines
3.7 KiB
Markdown
110 lines
3.7 KiB
Markdown
# Flot [](https://travis-ci.org/flot/flot)
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## About ##
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Flot is a Javascript plotting library for jQuery.
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Read more at the website: <http://www.flotcharts.org/>
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Take a look at the the examples in examples/index.html; they should give a good
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impression of what Flot can do, and the source code of the examples is probably
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the fastest way to learn how to use Flot.
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## Installation ##
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Just include the Javascript file after you've included jQuery.
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Generally, all browsers that support the HTML5 canvas tag are
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supported.
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For support for Internet Explorer < 9, you can use [Excanvas]
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[excanvas], a canvas emulator; this is used in the examples bundled
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with Flot. You just include the excanvas script like this:
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```html
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<!--[if lte IE 8]><script language="javascript" type="text/javascript" src="excanvas.min.js"></script><![endif]-->
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```
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If it's not working on your development IE 6.0, check that it has
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support for VML which Excanvas is relying on. It appears that some
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stripped down versions used for test environments on virtual machines
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lack the VML support.
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You can also try using [Flashcanvas][flashcanvas], which uses Flash to
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do the emulation. Although Flash can be a bit slower to load than VML,
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if you've got a lot of points, the Flash version can be much faster
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overall. Flot contains some wrapper code for activating Excanvas which
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Flashcanvas is compatible with.
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You need at least jQuery 1.2.6, but try at least 1.3.2 for interactive
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charts because of performance improvements in event handling.
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## Basic usage ##
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Create a placeholder div to put the graph in:
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```html
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<div id="placeholder"></div>
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```
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You need to set the width and height of this div, otherwise the plot
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library doesn't know how to scale the graph. You can do it inline like
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this:
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```html
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<div id="placeholder" style="width:600px;height:300px"></div>
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```
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You can also do it with an external stylesheet. Make sure that the
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placeholder isn't within something with a display:none CSS property -
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in that case, Flot has trouble measuring label dimensions which
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results in garbled looks and might have trouble measuring the
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placeholder dimensions which is fatal (it'll throw an exception).
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Then when the div is ready in the DOM, which is usually on document
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ready, run the plot function:
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```js
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$.plot($("#placeholder"), data, options);
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```
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Here, data is an array of data series and options is an object with
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settings if you want to customize the plot. Take a look at the
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examples for some ideas of what to put in or look at the
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[API reference](API.md). Here's a quick example that'll draw a line
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from (0, 0) to (1, 1):
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```js
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$.plot($("#placeholder"), [ [[0, 0], [1, 1]] ], { yaxis: { max: 1 } });
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```
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The plot function immediately draws the chart and then returns a plot
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object with a couple of methods.
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## What's with the name? ##
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First: it's pronounced with a short o, like "plot". Not like "flawed".
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So "Flot" rhymes with "plot".
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And if you look up "flot" in a Danish-to-English dictionary, some of
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the words that come up are "good-looking", "attractive", "stylish",
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"smart", "impressive", "extravagant". One of the main goals with Flot
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is pretty looks.
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## Notes about the examples ##
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In order to have a useful, functional example of time-series plots using time
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zones, date.js from [timezone-js][timezone-js] (released under the Apache 2.0
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license) and the [Olson][olson] time zone database (released to the public
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domain) have been included in the examples directory. They are used in
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examples/axes-time-zones/index.html.
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[excanvas]: http://code.google.com/p/explorercanvas/
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[flashcanvas]: http://code.google.com/p/flashcanvas/
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[timezone-js]: https://github.com/mde/timezone-js
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[olson]: http://ftp.iana.org/time-zones
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