Question

Using ExtJS4, I need to draw a straight line across a column chart indicating the average of the series. Does anyone have know of an example of this or have a suggestion on how to do it?

Answer 1

I usually have the average value calculated on server side and held in the store. For exmaple, My store will be:

Ext.data.Store({
    fields: ['name','active','avg'],
    autoLoad: true,
    proxy: {
    type: 'ajax',
    url : '/location/to/data'
    }
}) 

The ‘avg’ holds the average value. The average line is drawn using the following series configuration:

{
    type: 'line',
    xField: 'name',
    yField: 'avg',
    showMarkers: false    // Ensures that markers don't show up on the line...              
}