A stacked bar chart is a way of showing data as bars.
<div class="canvas-holder"> <canvas width="250" height="125"></canvas> </div>
var myStackedBarChart = new Chart(ctx).StackedBar(data, options);
var data = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [
{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
data: [65, 59, 80, 81, 56, 55, 40]
},
{
label: "My Second dataset",
fillColor: "rgba(151,187,205,0.5)",
strokeColor: "rgba(151,187,205,0.8)",
highlightFill: "rgba(151,187,205,0.75)",
highlightStroke: "rgba(151,187,205,1)",
data: [28, 48, 40, 19, 86, 27, 90]
}
]
};
These are the customisation options specific to StackedBar charts. These options are merged with the global chart configuration options, and form the options of the chart.
{
//Boolean - Whether the scale should start at zero, or an order of magnitude down from the lowest value
scaleBeginAtZero : true,
//Boolean - Whether grid lines are shown across the chart
scaleShowGridLines : true,
//String - Colour of the grid lines
scaleGridLineColor : "rgba(0,0,0,.05)",
//Number - Width of the grid lines
scaleGridLineWidth : 1,
//Boolean - If there is a stroke on each bar
barShowStroke : true,
//Number - Pixel width of the bar stroke
barStrokeWidth : 2,
//Number - Spacing between each of the X value sets
barValueSpacing : 5,
//Boolean - Whether bars should be rendered on a percentage base
relativeBars : false,
{% raw %}
//String - A legend template
legendTemplate : "<ul class=\"<%=name.toLowerCase()%>-legend\"><% for (var i=0; i<datasets.length; i++){%><li><span style=\"background-color:<%=datasets[i].lineColor%>\"></span><%if(datasets[i].label){%><%=datasets[i].label%><%}%></li><%}%></ul>"
{% endraw %}
}
You can override these for your Chart instance by passing a second argument into the StackedBar method as an object with the keys you want to override.
For example, we could have a stacked bar chart without a stroke on each bar by doing the following:
new Chart(ctx).StackedBar(data, {
barShowStroke: false
});
// This will create a chart with all of the default options, merged from the global config,
// and the StackedBar chart defaults but this particular instance will have `barShowStroke` set to false.
We can also change these defaults values for each StackedBar type that is created, this object is available at Chart.defaults.StackedBar.
Calling getBarsAtEvent(event) on your Chart instance passing an argument of an event, or jQuery event, will return the bar elements that are at that the same position of that event.
canvas.onclick = function(evt){
var activeBars = myStackedBarChart.getBarsAtEvent(evt);
// => activeBars is an array of bars on the canvas that are at the same position as the click event.
};
This functionality may be useful for implementing DOM based tooltips, or triggering custom behaviour in your application.
Calling update() on your Chart instance will re-render the chart with any updated values, allowing you to edit the value of multiple existing points, then render those in one animated render loop.
myStackedBarChart.datasets[0].bars[2].value = 50;
// Would update the first dataset's value of 'March' to be 50
myStackedBarChart.update();
// Calling update now animates the position of March from 90 to 50.
Calling addData(valuesArray, label) on your Chart instance passing an array of values for each dataset, along with a label for those bars.
// The values array passed into addData should be one for each dataset in the chart
myStackedBarChart.addData([40, 60], "August");
// The new data will now animate at the end of the chart.
Calling removeData() on your Chart instance will remove the first value for all datasets on the chart.
myStackedBarChart.removeData();
// The chart will now animate and remove the first bar