bouil/angular-google-chart — pull request #107 by atscott (2014-08-15 17:27:14+00:00)
Title: Ability to Define DataView Columns for Labels

In order to define labels, you have to create a dataView: https://developers.google.com/chart/interactive/docs/gallery/barchart#Labels

The change would allow you to set dataViewColumns on the directive's chart object in the same way:
```javascript
chart.dataViewColumns = [0, 1,
{
calc: "stringify",
sourceColumn: 1,
type: "string",
role: "annotation"
}];
```

I can work on providing the funcitonality in a different way (perhaps another scope variable in the directive) if you think there's a better solution.