Access and Update a Chart Instance's Axis.

Often times, you will need to update a chart after it has been rendered. This example demonstrates how to access and update an axis. Specifically, we'll update the rotation and color of the axis labels.

A Chart instance's axes can be accessed through the getAxisByKey method. This method takes the axis' key identifier as an argument. If you have explicitly set your axis through the axes attribute, you will know the key identifier. If not, the default key identifier for the value axis is "values" and the default key identifier for the category axis is category. Once you have a reference for the axis, you can update all of its public attributes.

CSS

#mychart {
    margin:10px 10px 10px 10px;
    width:90%;
    max-width: 800px;
    height:400px;
}

HTML

<div id="mychart"></div>

JavaScript

YUI().use('charts', function (Y) 
{ 
    //dataProvider source
    var myDataValues = [ 
        {date:"1/1/2010", miscellaneous:2000, expenses:3700, revenue:2200}, 
        {date:"2/1/2010", miscellaneous:5000, expenses:9100, revenue:100}, 
        {date:"3/1/2010", miscellaneous:4000, expenses:1900, revenue:1500}, 
        {date:"4/1/2010", miscellaneous:3000, expenses:3900, revenue:2800}, 
        {date:"5/1/2010", miscellaneous:500, expenses:7000, revenue:2650},
        {date:"6/1/2010", miscellaneous:3000, expenses:4700, revenue:1200} 
    ];
    
    //Define our axes for the chart.
    var myAxes = {
        financials:{
            keys:["miscellaneous", "revenue", "expenses"],
            position:"right",
            type:"numeric",
            styles:{
                majorTicks:{
                    display: "none"
                }
            }
        },
        dateRange:{
            keys:["date"],
            position:"bottom",
            type:"category",
            styles:{
                majorTicks:{
                    display: "none"
                },
                label: {
                    rotation:-45,
                    margin:{top:5}
                }
            }
        }
    };

    //instantiate the chart
    var myChart = new Y.Chart({
                        type:"column",
                        categoryKey:"date",
                        dataProvider:myDataValues, 
                        axes:myAxes, 
                        horizontalGridlines: true,
                        verticalGridlines: true,
                        render:"#mychart"
                    });

    //Click handler
    Y.on("click", function(e) {
        var axisName = Y.one("#axisSelector").get("value"),
            rotation = parseFloat(Y.one("#rotation").get("value")),
            color = Y.Escape.html(Y.one("#color").get("value")),
            label = null,
            axis;
        if(axisName)
        {
            axis = myChart.getAxisByKey(axisName);
            if(!isNaN(rotation))
            {
                label = {rotation:rotation};
            }
            if(color)
            {
                if(!label)
                {
                    label = {};
                }
                label.color = color;
            }
            if(label)
            {
                axis.set("styles", {label:label});
            }
        }
   }, "#updateAxis");
});