javascript - How to align Chart.JS line chart labels to the center -

i'm using chart.js 1.0.2 create line chart:

what i'm trying move labels on bottom of chart center of each rectangle (instead of being aligned vertical grid lines):

there no documentation on chartjs.org believe smart trick problem can solved. ideas on how can accomplished?

offsetgridlines (boolean) if true, labels shifted between grid lines.

type: 'line', data: data, options: {     ...     scales: {         xaxes: [{             gridlines: {                 offsetgridlines: true             }         ]}     } }