/// <summary>
/// Fills a SKPoint array of data points absolute pixel positions.
/// </summary>
/// <param name="graph">Graphics object.</param>
/// <param name="area">Chart area.</param>
/// <param name="series">Point series.</param>
/// <returns>Array of data points position.</returns>
override protected SKPoint[] GetPointsPosition(ChartGraphics graph, ChartArea area, Series series)
{
SKPoint[] pointPos = new SKPoint[series.Points.Count + 1];
int index = 0;
foreach (DataPoint point in series.Points)
{
// Change Y value if line is out of plot area
double yValue = GetYValue(Common, area, series, point, index, 0);
// Recalculates y position
double yPosition = area.AxisY.GetPosition(yValue);
// Recalculates x position
double xPosition = area.circularCenter.X;
// Add point position into array
pointPos[index] = graph.GetAbsolutePoint(new SKPoint((float)xPosition, (float)yPosition));
// Rotate position
float sectorAngle = area.CircularPositionToAngle(point.XValue);
SKMatrix matrix = SkiaSharpExtensions.CreateRotationDegrees(sectorAngle, graph.GetAbsolutePoint(area.circularCenter));
SKPoint[] rotatedPoint = new SKPoint[] { pointPos[index] };
matrix.TransformPoints(rotatedPoint);
pointPos[index] = rotatedPoint[0];
index++;
}
// Add last center point
pointPos[index] = graph.GetAbsolutePoint(area.circularCenter);
return(pointPos);
}
/// <summary>
/// Draws a cardinal spline through a specified array of SKPoint structures
/// using a specified tension. The drawing begins offset from
/// the beginning of the array.
/// </summary>
/// <param name="pen">Pen object that determines the color, width, and height of the curve.</param>
/// <param name="points">Array of SKPoint structures that define the spline.</param>
/// <param name="offset">Offset from the first element in the array of the points parameter to the starting point in the curve.</param>
/// <param name="numberOfSegments">Number of segments after the starting point to include in the curve.</param>
/// <param name="tension">Value greater than or equal to 0.0F that specifies the tension of the curve.</param>
public void DrawCurve(
SKPaint pen,
SKPoint[] points,
int offset,
int numberOfSegments,
float tension
)
{
pen.IsAntialias = true;
Graphics.DrawPath(SkiaSharpExtensions.CreateSpline(points), pen);
}