Added series index params in pie labelFormatter

[lukeupup]

Hi,

First of all I'd like to thank you for creating such a wonderful lib. I am using flotr2 to develop a website that contains many kinds of chart.

However, I found that there's one thing that can't satisfy my requirement - that is, I want to show some extra info in pie chart's label. Currently labelFormatter can only show the total value and current value. I added some data in the series I passed to flotr, but the pie chart just cannot access them.

I think I can show more info if I know the index of the pie slice. So I just add a count attribute, so that it can tell me what the index of the current part.

[NisSAM]

+1 I also think that adding series number or series object as a second parameter to labelFormat will be great. Not only for pie diagrams but for any diagram type.

[lukeupup]

Added more options for pie chart:

• Now you can see hover effect when your mouse is over the pie chart. You can customize fillColor and fillOpacity.
• Added labelDistance in pie option. It can determine how far it is from the pie' edge to the label text.

  Flotr.draw(context, data, {
    pie: {
      labelDistance: 10,
      // ...
    },
    //...
  });

• Added radiateLabel option. It can make the label shown radiately.

  Flotr.draw(context, data, {
    pie: {
      htmlText: false, // must be false for rotating the label
      radiateLabel: true,
      // ...
    },
    //...
  });