Connected.Components/Components/Chart/Charts/Pie.razor.cs

using Microsoft.AspNetCore.Components;

namespace Connected.Components;

partial class Pie : Chart
{
	[CascadingParameter] public Chart ChartParent { get; set; }

	private List<SvgPath> _paths = new();
	private List<SvgLegend> _legends = new();

	protected override void OnParametersSet()
	{
		_paths.Clear();
		_legends.Clear();
		double startx, starty, endx, endy;
		var ndata = GetNormalizedData();
		double cumulativeRadians = 0;
		for (var i = 0; i < ndata.Length; i++)
		{
			var data = ndata[i];
			startx = Math.Cos(cumulativeRadians);
			starty = Math.Sin(cumulativeRadians);
			cumulativeRadians += 2 * Math.PI * data;
			endx = Math.Cos(cumulativeRadians);
			endy = Math.Sin(cumulativeRadians);
			var largeArcFlag = data > 0.5 ? 1 : 0;
			var path = new SvgPath()
			{
				Index = i,
				Data = $"M {ToS(startx)} {ToS(starty)} A 1 1 0 {ToS(largeArcFlag)} 1 {ToS(endx)} {ToS(endy)} L 0 0"
			};
			_paths.Add(path);
		}

		var counter = 0;
		foreach (var data in ndata)
		{
			var percent = data * 100;
			var labels = "";
			if (counter < InputLabels.Length)
			{
				labels = InputLabels[counter];
			}
			var legend = new SvgLegend()
			{
				Index = counter,
				Labels = labels,
				Data = ToS(Math.Round(percent, 1))
			};
			_legends.Add(legend);
			counter += 1;
		}
	}
}