public PngTextDrawer(IWordsPlacer wordsPlacer, IBrushSelector brushSelector, FontFamily fontFamily, Color backgroundColor, Size imageSize)
{
this.wordsPlacer = wordsPlacer;
this.brushSelector = brushSelector;
this.backgroundColor = backgroundColor;
textFontFamily = fontFamily;
this.imageSize = imageSize;
}
private void DrawPieChart(Canvas canvas, double centerX, double centerY, double innerRadius, double outerRadius, IBrushSelector brushSelector, bool isLegendSymbol)
{
canvas.Children.Clear();
// Add pie chart sectors and add up data values.
double sum = 0;
for (int i = 0; i < Data.Count; ++i)
{
DataPoint data = Data[i];
// Create pie chart sector.
var element = CreateDataPoint(data.DataContext ?? data) as PieChartItem;
if (element == null)
{
// Unsupported DataPointTemplate. Do not draw anything.
return;
}
element.CenterX = centerX;
element.CenterY = centerY;
element.InnerRadius = innerRadius;
element.OuterRadius = outerRadius;
if (brushSelector != null)
{
var brush = brushSelector.SelectBrush(data.DataContext, i);
if (brush != null)
{
element.Background = brush;
}
}
if (isLegendSymbol)
{
// Override dependency properties which might be set using data binding
// or styles.
element.InnerLabel = null;
element.OuterLabel = null;
element.Offset = 0;
element.IsHitTestVisible = false;
}
canvas.Children.Add(element);
sum += data.Y;
}
// Set start and end angles of sectors.
double startAngle = 0;
double valueToAngle = 1 / sum * 2.0 * Math.PI;
for (int i = 0; i < Data.Count; ++i)
{
double angle = Data[i].Y * valueToAngle;
double endAngle = startAngle + angle;
var element = (PieChartItem)canvas.Children[i];
element.StartAngle = startAngle;
element.EndAngle = endAngle;
if (Numeric.IsZero(angle))
{
element.Visibility = Visibility.Collapsed;
}
startAngle = endAngle;
}
}