iOS & macOS Charting Documentation - SciChart iOS & macOS Charts SDK v4.x

The Donut Chart Type

In SciChart, the Donut Chart type is represented by the SCIPieChartSurface class.

The SCIDonutRenderableSeries is very similar to the Pie Chart, except it has a round hole in its center. A SCIPieSegment represents a percentage that corresponds to a particular value. This value appears drawn on every segment and can be set in code.

Donut Chart Type

NOTE: Examples for the Donut Chart can be found in the SciChart iOS Examples Suite as well as on GitHub:

The SCIPieSegment allows you to specify different styles to control rendering of the segments, e.g.:

NOTE: To learn more about Pens and Brushes and how to utilize them, please refer to the SCIPenStyle, SCIBrushStyle and SCIFontStyle article.

Also, you can control whether to draw labels on segments or not via the ISCIPieRenderableSeries.drawLabels property.

Create a Donut Chart

To create a Donut Chart, you have to provide a SCIPieRenderableSeriesCollection and assign it to SCIPieChartSurface.renderableSeries property. The data source is a collection of objects that conforms to the ISCIPieRenderableSeries protocol, which contains a list of SCIPieSegment instances to draw.

// Assume a surface has been created and configured somewhere SCIPieChartSurface pieChartSurface; pieChartSurface.holeRadius = 100; pieChartSurface.holeRadiusSizingMode = SCISizingMode_Absolute; // Create Donut Series and fill it with Segments SCIDonutRenderableSeries *donutSeries = [SCIDonutRenderableSeries new]; [donutSeries.segmentsCollection add:[self segmentWithValue:40 title:@“Green” centerColor:0xff84BC3D edgeColor:0xff5B8829]]; [donutSeries.segmentsCollection add:[self segmentWithValue:10 title:@“Red” centerColor:0xffe04a2f edgeColor:0xffB7161B]]; [donutSeries.segmentsCollection add:[self segmentWithValue:20 title:@“Blue” centerColor:0xff4AB6C1 edgeColor:0xff2182AD]]; [donutSeries.segmentsCollection add:[self segmentWithValue:15 title:@“Yellow” centerColor:0xffFFFF00 edgeColor:0xfffed325]]; [pieChartSurface.renderableSeries add:donutSeries]; - (SCIPieSegment *)segmentWithValue:(double)segmentValue title:(NSString *)title centerColor:(unsigned int)centerColor edgeColor:(unsigned int)edgeColor { SCIPieSegment *segment = [SCIPieSegment new]; segment.value = segmentValue; segment.title = title; segment.fillStyle = [[SCIRadialGradientBrushStyle alloc] initWithCenterColorCode:centerColor edgeColorCode:edgeColor]; return segment; }
// Assume a surface has been created and configured somewhere let pieChartSurface: SCIPieChartSurface pieChartSurface.holeRadius = 100 // Create Donut Series and fill it with Segments let donutSeries = SCIDonutRenderableSeries() donutSeries.segmentsCollection.add(segmentWithValue(segmentValue: 40, title: “Green”, centerColor: 0xff84BC3D, edgeColor: 0xff5B8829)) donutSeries.segmentsCollection.add(segmentWithValue(segmentValue: 10, title: “Red”, centerColor: 0xffe04a2f, edgeColor: 0xffB7161B)) donutSeries.segmentsCollection.add(segmentWithValue(segmentValue: 20, title: “Blue”, centerColor: 0xff4AB6C1, edgeColor: 0xff2182AD)) donutSeries.segmentsCollection.add(segmentWithValue(segmentValue: 15, title: “Yellow”, centerColor: 0xffFFFF00, edgeColor: 0xfffed325)) pieChartSurface.renderableSeries.add(donutSeries) func segmentWithValue(segmentValue: Double, title: String, centerColor: UInt32, edgeColor: UInt32) -> SCIPieSegment { let segment = SCIPieSegment() segment.value = segmentValue segment.title = title segment.fillStyle = SCIRadialGradientBrushStyle(centerColorCode: centerColor, edgeColorCode: edgeColor) return segment }
// Assume a surface has been created and configured somewhere SCIPieChartSurface pieChartSurface; pieChartSurface.HoleRadius = 100; pieChartSurface.HoleRadiusSizingMode = SCISizingMode.Absolute; // Create Donut Series and fill it with Segments var donutSeries = new SCIDonutRenderableSeries { SegmentsCollection = new SCIPieSegmentCollection { new SCIPieSegment { Value = 40, Title = “Green”, FillStyle = new SCIRadialGradientBrushStyle(0xff84BC3D, 0xff5B8829) }, new SCIPieSegment { Value = 10, Title = “Red”, FillStyle = new SCIRadialGradientBrushStyle(0xffe04a2f, 0xffB7161B) }, new SCIPieSegment { Value = 20, Title = “Blue”, FillStyle = new SCIRadialGradientBrushStyle(0xff4AB6C1, 0xff2182AD) }, new SCIPieSegment { Value = 15, Title = “Yellow”, FillStyle = new SCIRadialGradientBrushStyle(0xffFFFF00, 0xfffed325) }, }, }; pieChartSurface.RenderableSeries.Add(donutSeries);

Changing the size of the Donut Chart

If you want to change the size of the Donut Chart you can use a combination of the following properties:

The above allows you to specify how much space the Donut Chart should use for its rendering. If you use Absolute mode then ISCIPieRenderableSeries.height accepts size in pixels, and if you use Relative mode, it expects value from 0 to 1, which tells how much of the available space it should use for rendering (e.g. 0.5 will tell Donut series to use 50% of available space).

Also, you can control the center hole size via the ISCIPieChartSurface.holeRadius property.

SCIPieChartSurface Modifiers

The SCIPieChartSurface supports modifiers like Legend, Selection, and Tooltip.

Donut Chart Modifiers

Legend and Selection modifiers are synced if both are added. A SCIPieSegment can be selected by clicking on either of them (via the Selection Modifier) or the corresponding item in the Legend. This action provides visual feedback on the chart and the Legend.

Donut Chart Legend

To add the SCIPieChartLegendModifier, use the following code:

SCIPieChartLegendModifier *legendModifier = [SCIPieChartLegendModifier new]; legendModifier.sourceSeries = donutSeries; legendModifier.margins = UIEdgeInsetsMake(17, 17, 17, 17); legendModifier.position = SCIAlignment_Bottom | SCIAlignment_CenterHorizontal; [pieChartSurface.chartModifiers add:legendModifier];
let legendModifier = SCIPieChartLegendModifier() legendModifier.sourceSeries = donutSeries; legendModifier.margins = UIEdgeInsets(top: 17, left: 17, bottom: 17, right: 17) legendModifier.position = [.bottom, .centerHorizontal] pieChartSurface.chartModifiers.add(legendModifier)`
pieChartSurface.ChartModifiers.Add(new SCIPieChartLegendModifier { SourceSeries = donutSeries, Position = SCIAlignment.Bottom | SCIAlignment.CenterHorizontal, Margins = new UIEdgeInsets(17, 17, 17, 17), });

NOTE: SCIPieChartLegendModifier works similar to SCILegendModifier and has a similar API. To learn more, please visit the SCILegendModifier usage article.

Donut Chart Selection

To add the SCIPieSegmentSelectionModifier, please use the following code:

SCIPieSegmentSelectionModifier *selectionModifier = [SCIPieSegmentSelectionModifier new]; [pieChartSurface.chartModifiers add:selectionModifier];
let selectionModifier = SCIPieSelectionModifier() pieChartSurface.chartModifiers.add(selectionModifier)
pieChartSurface.ChartModifiers.Add(new SCIPieSegmentSelectionModifier());

NOTE: SCIPieSegmentSelectionModifier works similar to SCISeriesSelectionModifier and has a similar API. To learn more, please visit the SCISeriesSelectionModifier usage article.

Donut Chart Tooltip

The SCIPieChartTooltipModifier allows inspecting SCIPieDonutRenderableSeriesBase.segmentsCollection at a touch point. To add the SCIPieChartTooltipModifier, use the following code:

[pieChartSurface.chartModifiers add:[SCIPieChartTooltipModifier new]];
pieChartSurface.ChartModifiers.Add(new SCIPieChartTooltipModifier());

NOTE: SCIPieChartTooltipModifier works similar to SCITooltipModifier and has a similar API. To learn more, please visit SCITooltipModifier Usage article.

Pie Segment Label Formatter

By default, the Pie Segment Label displays a relative percentage calculated on values of all segments in SCIPieDonutRenderableSeriesBase.segmentsCollection. This behavior can be controlled and to do so you’ll need to subclass SCIPieSegmentLabelFormatterBase and provide your custom data in -[ISCIPieSegmentLabelFormatter formatLabelForPieSegment:] method. As an example, let’s create a label that displays a segment absolute value. Assume, we create a donutSeries and add four segments with values 40, 10, 20, and 15. Here is the code sample, how to do this:

// CustomPieSegmentLabelFormatter.h @interface CustomPieSegmentLabelFormatter : SCIPieSegmentLabelFormatterBase @end // CustomPieSegmentLabelFormatter.m @implementation CustomPieSegmentLabelFormatter - (NSString *)formatLabelForPieSegment:(id)pieSegment { return [NSString stringWithFormat:@“%f”, pieSegment.value]; } @end // Assume a donutSeries has been created somewhere SCIDonutRenderableSeries *donutSeries = [SCIDonutRenderableSeries new]; donutSeries.pieSegmentLabelFormatter = [CustomPieSegmentLabelFormatter new];
class CustomPieSegmentLabelFormatter: SCIPieSegmentLabelFormatterBase { override func formatLabel(for pieSegment: ISCIPieSegment!) -> String! { return “\(pieSegment.value)” } } // Assume a donutSeries has been created somewhere let donutSeries = SCIDonutRenderableSeries() donutSeries.pieSegmentLabelFormatter = CustomPieSegmentLabelFormatter()
class CustomPieSegmentLabelFormatter : SCIPieSegmentLabelFormatterBase { public override string FormatLabel(IISCIPieSegment pieSegment) { return pieSegment.Value.ToString(); } } // Assume a donutSeries has been created somewhere var donutSeries = new SCIDonutRenderableSeries; donutSeries.PieSegmentLabelFormatter = new CustomPieSegmentLabelFormatter();

This produces the following output:

Donut Series with custom label formatter

Multi Pie Donut Chart

In SciChart you can have both Pie Chart and Donut Chart placed inside the SCIPieChartSurface at the same time.

Multi Pie Donut

NOTE: Examples of the Multi Pie Donut Chart can be found in the SciChart iOS Examples Suite as well as on GitHub.