Start Pie chart at an angle

Question

I am trying to start a Pie Chart at an angle PI. I saw some documentation on it but it always start at PI/2. What am I doing wrong?

"var grafica = new RGraph.SVG.Pie({ id: 'cc', data: data, start: RGraph.PI, options: { linewidth: 0, donut:true, donutWidth:40;})

Answer 1

If by "Pi/2" you mean that you want it to start at the east axis, then there's no option for the SVG Pie chart to alter the start point so you'll need to update the source code. Fortunately it's quite easy.

In the RGraph.svg.pie.js file you can find this:

this.drawSegments = function (opt)
{
    var start   = 0,
        end     = 0,
        angle   = 0,
        sum     = RGraph.SVG.arraySum(this.data),
        segment = 0;

You just need to update the angle so that it looks like this:

this.drawSegments = function (opt)
{
    var start   = 0,
        end     = 0,
        angle   = 1.57,
        sum     = RGraph.SVG.arraySum(this.data),
        segment = 0;

(angles are measured in radians - not degrees).