 Downloadtitle: Getting started
anchor: getting-started
Include Chart.js
First we need to include the Chart.js library on the page. The library occupies a global variable of Chart.
<script src="Chart.js"></script>
Alternatively, if you're using an AMD loader for JavaScript modules, that is also supported in the Chart.js core. Please note: the library will still occupy a global variable of Chart, even if it detects define and define.amd. If this is a problem, you can call noConflict to restore the global Chart variable to it's previous owner.
// Using requirejs
require(['path/to/Chartjs'], function(Chart){
// Use Chart.js as normal here.
// Chart.noConflict restores the Chart global variable to it's previous owner
// The function returns what was previously Chart, allowing you to reassign.
var Chartjs = Chart.noConflict();
});
You can also grab Chart.js using bower:
bower install Chart.js --save
Creating a chart
To create a chart, we need to instantiate the Chart class. To do this, we need to pass in the 2d context of where we want to draw the chart. Here's an example.
<canvas id="myChart" width="400" height="400"></canvas>
// Get the context of the canvas element we want to select
var ctx = document.getElementById("myChart").getContext("2d");
var myNewChart = new Chart(ctx).PolarArea(data);
We can also get the context of our canvas with jQuery. To do this, we need to get the DOM node out of the jQuery collection, and call the getContext("2d") method on that.
// Get context with jQuery - using jQuery's .get() method.
var ctx = $("#myChart").get(0).getContext("2d");
// This will get the first returned node in the jQuery collection.
var myNewChart = new Chart(ctx);
After we've instantiated the Chart class on the canvas we want to draw on, Chart.js will handle the scaling for retina displays.
With the Chart class set up, we can go on to create one of the charts Chart.js has available. In the example below, we would be drawing a Polar area chart.
new Chart(ctx).PolarArea(data, options);
We call a method of the name of the chart we want to create. We pass in the data for that chart type, and the options for that chart as parameters. Chart.js will merge the global defaults with chart type specific defaults, then merge any options passed in as a second argument after data.
Global chart configuration
This concept was introduced in Chart.js 1.0 to keep configuration DRY, and allow for changing options globally across chart types, avoiding the need to specify options for each instance, or the default for a particular chart type.
Chart.defaults.global = {
// Boolean - Whether to animate the chart
animation: true,
// Number - Number of animation steps
animationSteps: 60,
// String - Animation easing effect
animationEasing: "easeOutQuart",
// Boolean - If we should show the scale at all
showScale: true,
// Boolean - If we want to override with a hard coded scale
scaleOverride: false,
// Required if scaleOverride is true
// Number - The number of steps in a hard coded scale
scaleSteps: null,
// Number - The value jump in the hard coded scale
scaleStepWidth: null,
// Number - The scale starting value
scaleStartValue: null,
// String - Colour of the scale line
scaleLineColor: "rgba(0,0,0,.1)",
// Number - Pixel width of the scale line
scaleLineWidth: 1,
// Boolean - Whether to show labels on the scale
scaleShowLabels: true,
// Interpolated JS string - can access value
scaleLabel: "<%=value%>",
// Boolean - Whether the scale should stick to integers, not floats even if drawing space is there
scaleIntegersOnly: true,
// Boolean - Whether the scale should start at zero, or an order of magnitude down from the lowest value
scaleBeginAtZero: false,
// String - Scale label font declaration for the scale label
scaleFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
// Number - Scale label font size in pixels
scaleFontSize: 12,
// String - Scale label font weight style
scaleFontStyle: "normal",
// String - Scale label font colour
scaleFontColor: "#666",
// Boolean - whether or not the chart should be responsive and resize when the browser does.
responsive: false,
// Boolean - whether to maintain the starting aspect ratio or not when responsive, if set to false, will take up entire container
maintainAspectRatio: true,
// Boolean - Determines whether to draw tooltips on the canvas or not
showTooltips: true,
// Function - Determines whether to execute the customTooltips function instead of drawing the built in tooltips (See Advanced - External Tooltips)
customTooltips: false,
// Array - Array of string names to attach tooltip events
tooltipEvents: ["mousemove", "touchstart", "touchmove"],
// String - Tooltip background colour
tooltipFillColor: "rgba(0,0,0,0.8)",
// String - Tooltip label font declaration for the scale label
tooltipFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
// Number - Tooltip label font size in pixels
tooltipFontSize: 14,
// String - Tooltip font weight style
tooltipFontStyle: "normal",
// String - Tooltip label font colour
tooltipFontColor: "#fff",
// String - Tooltip title font declaration for the scale label
tooltipTitleFontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif",
// Number - Tooltip title font size in pixels
tooltipTitleFontSize: 14,
// String - Tooltip title font weight style
tooltipTitleFontStyle: "bold",
// String - Tooltip title font colour
tooltipTitleFontColor: "#fff",
// Number - pixel width of padding around tooltip text
tooltipYPadding: 6,
// Number - pixel width of padding around tooltip text
tooltipXPadding: 6,
// Number - Size of the caret on the tooltip
tooltipCaretSize: 8,
// Number - Pixel radius of the tooltip border
tooltipCornerRadius: 6,
// Number - Pixel offset from point x to tooltip edge
tooltipXOffset: 10,
{% raw %}
// String - Template string for single tooltips
tooltipTemplate: "<%if (label){%><%=label%>: <%}%><%= value %>",
{% endraw %}
// String - Template string for multiple tooltips
multiTooltipTemplate: "<%= value %>",
// Function - Will fire on animation progression.
onAnimationProgress: function(){},
// Function - Will fire on animation completion.
onAnimationComplete: function(){}
}
If for example, you wanted all charts created to be responsive, and resize when the browser window does, the following setting can be changed:
Chart.defaults.global.responsive = true;
Now, every time we create a chart, options.responsive will be true.
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