protected override void GenerateChart()
{
RootElement.Children.Clear();
var data = ItemsSource;
var validData = data == null ? null : data.Where(d => d.Value > 0);
if (validData != null && validData.Any())
{
if (validData.Count() == 1)
{
// Only one valid dat ==> draw a circle
int colorIndex = validData.Select((k, ind) => ind).FirstOrDefault();
var kvp = data.Where(d => d.Value > 0).First();
EllipseGeometry ellipseGeometry = new EllipseGeometry()
{
RadiusX = 1,
RadiusY = 1
};
Path path = new Path()
{
Stretch = Stretch.Uniform,
Fill = GetColorByIndex(colorIndex),
Data = ellipseGeometry
};
SetTooltip(path, kvp.Key, string.Format("{0} (100%)", FormattedValue(kvp.Value)));
RootElement.Children.Add(path);
}
else
{
//We have more than one value to display. Generate pie shapes:
var total = validData.Sum(d => d.Value);
double current = 0;
int colorIndex = 0;
const double offset = 0; //Rotational offset (set it to Math.PI * .5 to start first segment upwards, set it to 0 to look like arcgis.com)
foreach (var kvp in data)
{
var val = kvp.Value;
if (val <= 0.0) // not valid
{
colorIndex++;
continue;
}
var fraction = val / total;
double angle0 = 2 * Math.PI * current - offset;
double angle1 = 2 * Math.PI * (current + fraction) - offset;
PathFigure pathFigure = new PathFigure {IsClosed = true, StartPoint = new Point(1, 1)};
pathFigure.Segments.Add(new LineSegment { Point = new Point(Math.Cos(angle0) + 1, Math.Sin(angle0) + 1) });
bool isLargeArc = fraction > .5;
pathFigure.Segments.Add(
new ArcSegment
{
Point = new Point(Math.Cos(angle1) + 1, Math.Sin(angle1) + 1),
IsLargeArc = isLargeArc,
Size = new Size(1, 1),
SweepDirection = SweepDirection.Clockwise
});
pathFigure.Segments.Add(new LineSegment() { Point = new Point(1, 1) });
//Add these two empty line segments to force the drawing to stretch properly
//with 1,1 at the center ( 0,0->2,2 is the bounding box for the figure)
PathFigure pathFigure2 = new PathFigure() { StartPoint = new Point(0, 0) };
pathFigure2.Segments.Add(new LineSegment() { Point = new Point(0, 0) });
PathFigure pathFigure3 = new PathFigure() { StartPoint = new Point(2, 2) };
pathFigure3.Segments.Add(new LineSegment() { Point = new Point(2, 2) });
PathGeometry pathGeometry = new PathGeometry();
pathGeometry.Figures.Add(pathFigure2);
pathGeometry.Figures.Add(pathFigure3);
pathGeometry.Figures.Add(pathFigure);
Path path = new Path()
{
Stretch = Stretch.Uniform,
Fill = GetColorByIndex(colorIndex),
Data = pathGeometry
};
// Add outline separating pie slices
PathFigure outLineFigure = new PathFigure { IsClosed = false, StartPoint = new Point(1, 1) };
outLineFigure.Segments.Add(new LineSegment() { Point = new Point(Math.Cos(angle0) + 1, Math.Sin(angle0) + 1) });
//Add these two empty line segments to force the drawing to stretch properly
//with 1,1 at the center ( 0,0->2,2 is the bounding box for the figure)
PathFigure outLineFigure2 = new PathFigure() { StartPoint = new Point(0, 0) };
outLineFigure2.Segments.Add(new LineSegment() { Point = new Point(0, 0) });
PathFigure outLineFigure3 = new PathFigure() { StartPoint = new Point(2, 2) };
outLineFigure3.Segments.Add(new LineSegment() { Point = new Point(2, 2) });
PathGeometry outLineGeometry = new PathGeometry();
outLineGeometry.Figures.Add(outLineFigure2);
outLineGeometry.Figures.Add(outLineFigure3);
outLineGeometry.Figures.Add(outLineFigure);
Path outLine = new Path()
{
Fill = null,
Stretch = Stretch.Uniform,
Stroke = new SolidColorBrush(Colors.White),
StrokeThickness = 1.0,
Data = outLineGeometry
};
SetTooltip(path, kvp.Key, string.Format("{0} ({1:0.##%})", FormattedValue(val), fraction));
RootElement.Children.Add(path);
RootElement.Children.Add(outLine);
current += fraction;
colorIndex++;
}
}
}
}
