Chart Data Label

Data labels on a chart show details about the chart data series or individual data points. They allow readers to quickly identify data series and they also make charts easier to understand.

Set Precision of Data in Chart Data Label

This C++ code shows you how to set the data precision in a chart data label:

	// The path to the documents directory
	const String outPath = u"../out/SettingPrecisionOfDataLabel_out.pptx";

	// Instantiates a Presentation class that represents a PPTX file
	SharedPtr<Presentation> pres = MakeObject<Presentation>();

	// Gets the first slide
	SharedPtr<ISlide> slide = pres->get_Slides()->idx_get(0);

	// Adds chart with default data
	SharedPtr<IChart> chart = slide->get_Shapes()->AddChart(Aspose::Slides::Charts::ChartType::Line, 0, 0, 500, 500);

	// Sets series number format
	chart->set_HasDataTable( true);
	chart->get_ChartData()->get_Series()->idx_get(0)->set_NumberFormatOfValues (u"#,##0.00");

	// Writes the presentation file to disk
	pres->Save(outPath, Aspose::Slides::Export::SaveFormat::Pptx);

Display Percentage as Labels

Aspose.Slides for C++ allows you to set percentage labels on displayed charts. This C++ code demonstrates the operation:

	// The path to the documents directory
	const String outPath = u"../out/DisplayPercentageAsLabels_out.pptx";

	// Creates an instance of the Presentation class
	System::SharedPtr<Presentation> presentation = System::MakeObject<Presentation>();

	System::SharedPtr<ISlide> slide = presentation->get_Slides()->idx_get(0);
	System::SharedPtr<IChart> chart = slide->get_Shapes()->AddChart(Aspose::Slides::Charts::ChartType::StackedColumn, 20, 20, 400, 400);
	System::SharedPtr<IChartSeries> series = chart->get_ChartData()->get_Series()->idx_get(0);
	System::SharedPtr<IChartCategory> cat;
	System::ArrayPtr<double> total_for_Cat = System::MakeObject<System::Array<double>>(chart->get_ChartData()->get_Categories()->get_Count(), 0);
	for (int32_t k = 0; k < chart->get_ChartData()->get_Categories()->get_Count(); k++)
	{
		cat = chart->get_ChartData()->get_Categories()->idx_get(k);

		for (int32_t i = 0; i < chart->get_ChartData()->get_Series()->get_Count(); i++)
		{
			total_for_Cat[k] = total_for_Cat[k] + System::Convert::ToDouble(chart->get_ChartData()->get_Series()->idx_get(i)->get_DataPoints()->idx_get(k)->get_Value()->get_Data());
		}
	}

	double dataPontPercent = 0.f;

	for (int32_t x = 0; x < chart->get_ChartData()->get_Series()->get_Count(); x++)
	{
		series = chart->get_ChartData()->get_Series()->idx_get(x);
		series->get_Labels()->get_DefaultDataLabelFormat()->set_ShowLegendKey(false);

		for (int32_t j = 0; j < series->get_DataPoints()->get_Count(); j++)
		{
			System::SharedPtr<IDataLabel> lbl = series->get_DataPoints()->idx_get(j)->get_Label();
			dataPontPercent = (System::Convert::ToDouble(series->get_DataPoints()->idx_get(j)->get_Value()->get_Data()) / total_for_Cat[j]) * 100;

			System::SharedPtr<IPortion> port = System::MakeObject<Portion>();
			port->set_Text(System::String::Format(u"{0:F2} %", dataPontPercent));
			port->get_PortionFormat()->set_FontHeight(8.f);
			lbl->get_TextFrameForOverriding()->set_Text(u"");
			System::SharedPtr<IParagraph> para = lbl->get_TextFrameForOverriding()->get_Paragraphs()->idx_get(0);
			para->get_Portions()->Add(port);

			lbl->get_DataLabelFormat()->set_ShowSeriesName(false);
			lbl->get_DataLabelFormat()->set_ShowPercentage(false);
			lbl->get_DataLabelFormat()->set_ShowLegendKey(false);
			lbl->get_DataLabelFormat()->set_ShowCategoryName(false);
			lbl->get_DataLabelFormat()->set_ShowBubbleSize(false);

		}

	}

	// Saves the presentation containing the chart
	presentation->Save(outPath, Aspose::Slides::Export::SaveFormat::Pptx);

Set Percentage Sign with Chart Data Label

This C++ code shows you to set the percentage sign for a chart data label:

	// The path to the documents directory.
	const String outPath = u"../out/DataLabelsPercentageSign_out.pptx";

	// Creates an instance of the Presentation class
	SharedPtr<Presentation> pres = MakeObject<Presentation>();

	// Gets a slide's reference through its index
	SharedPtr<ISlide> slide = pres->get_Slides()->idx_get(0);

	// Creates the PercentsStackedColumn chart on a slide
	SharedPtr<IChart> chart = slide->get_Shapes()->AddChart(Aspose::Slides::Charts::ChartType::PercentsStackedColumn, 0, 0, 500, 500);

	// Sets the NumberFormatLinkedToSource to false
	chart->get_Axes()->get_VerticalAxis()->set_IsNumberFormatLinkedToSource ( false);
	chart->get_Axes()->get_VerticalAxis()->set_NumberFormat(u"0.00%");


	// Sets the index of chart data sheet
	int defaultWorksheetIndex = 0;

	// Gets the chart data worksheet
	SharedPtr<IChartDataWorkbook> fact = chart->get_ChartData()->get_ChartDataWorkbook();


	// Deletes default generated series 
	chart->get_ChartData()->get_Series()->Clear();
	

	// Adds a new series
	chart->get_ChartData()->get_Series()->Add(fact->GetCell(defaultWorksheetIndex, 0, 2, ObjectExt::Box<System::String>(u"Series 2")), chart->get_Type());


	// Takes the first chart series
	SharedPtr<IChartSeries> series=chart->get_ChartData()->get_Series()->Add(fact->GetCell(defaultWorksheetIndex, 0, 1, ObjectExt::Box<System::String>(u"Red")), chart->get_Type());
	// Populates the series data
	series->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 1, 1, ObjectExt::Box<double>(0.50)));
	series->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 2, 1, ObjectExt::Box<double>(0.50)));
	series->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 3, 1, ObjectExt::Box<double>(0.80)));
	series->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 4, 1, ObjectExt::Box<double>(0.65)));

	// Sets fill color for series
	series->get_Format()->get_Fill()->set_FillType(FillType::Solid);
	series->get_Format()->get_Fill()->get_SolidFillColor()->set_Color(System::Drawing::Color::get_Red());

	// Sets LabelFormat properties
	series->get_Labels()->get_DefaultDataLabelFormat()->set_ShowValue(true);
	series->get_Labels()->get_DefaultDataLabelFormat()->set_IsNumberFormatLinkedToSource ( false);
	series->get_Labels()->get_DefaultDataLabelFormat()->set_NumberFormat (u"0.0%");
	series->get_Labels()->get_DefaultDataLabelFormat()->get_TextFormat()->get_PortionFormat()->set_FontHeight ( 10);
	series->get_Labels()->get_DefaultDataLabelFormat()->get_TextFormat()->get_PortionFormat()->get_FillFormat()->set_FillType(FillType::Solid);
	series->get_Labels()->get_DefaultDataLabelFormat()->get_TextFormat()->get_PortionFormat()->get_FillFormat()->get_SolidFillColor()->set_Color(System::Drawing::Color::get_White());
	series->get_Labels()->get_DefaultDataLabelFormat()->set_ShowValue(true);

	// Takes the second chart series
	SharedPtr<IChartSeries> series2 = chart->get_ChartData()->get_Series()->Add(fact->GetCell(defaultWorksheetIndex, 0, 2, ObjectExt::Box<System::String>(u"Blues")), chart->get_Type());
	// Populates series data
	series2->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 1, 2, ObjectExt::Box<double>(0.70)));
	series2->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 2, 2, ObjectExt::Box<double>(0.50)));
	series2->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 3, 2, ObjectExt::Box<double>(0.20)));
	series2->get_DataPoints()->AddDataPointForBarSeries(fact->GetCell(defaultWorksheetIndex, 4, 2, ObjectExt::Box<double>(0.35)));

	// Sets fill color for series
	series2->get_Format()->get_Fill()->set_FillType(FillType::Solid);
	series2->get_Format()->get_Fill()->get_SolidFillColor()->set_Color(System::Drawing::Color::get_Blue());

	// Sets LabelFormat properties
	series2->get_Labels()->get_DefaultDataLabelFormat()->set_ShowValue(true);
	series2->get_Labels()->get_DefaultDataLabelFormat()->set_IsNumberFormatLinkedToSource(false);
	series2->get_Labels()->get_DefaultDataLabelFormat()->set_NumberFormat(u"0.0%");
	series2->get_Labels()->get_DefaultDataLabelFormat()->get_TextFormat()->get_PortionFormat()->set_FontHeight(10);
	series2->get_Labels()->get_DefaultDataLabelFormat()->get_TextFormat()->get_PortionFormat()->get_FillFormat()->set_FillType(FillType::Solid);
	series2->get_Labels()->get_DefaultDataLabelFormat()->get_TextFormat()->get_PortionFormat()->get_FillFormat()->get_SolidFillColor()->set_Color(System::Drawing::Color::get_White());
	series2->get_Labels()->get_DefaultDataLabelFormat()->set_ShowValue(true);

	// Writes the presentation file to disk
	pres->Save(outPath, Aspose::Slides::Export::SaveFormat::Pptx);

Set Label Distance From Axis

This C++ code shows you how to set the label distance from a category axis when you are dealing with a chart plotted from axes:

	// The path to the documents directory
	const String outPath = u"../out/CategoryAxisLabelDistance_out.pptx";

	// Creates an instance of the Presentation class
	SharedPtr<Presentation> pres = MakeObject<Presentation>();

	// Gets a slide's reference
	SharedPtr<ISlide> slide = pres->get_Slides()->idx_get(0);

	// Creates a chart on the slide
	SharedPtr<IChart> chart = slide->get_Shapes()->AddChart(Aspose::Slides::Charts::ChartType::ClusteredColumn, 0, 0, 500, 500);


	// Gets the chart series collection
	SharedPtr<IChartSeriesCollection> seriesCollection = chart->get_ChartData()->get_Series();

	// Sets the label distance from an axis
	chart->get_Axes()->get_HorizontalAxis()->set_LabelOffset ( 500);

	// Writes the presentation file to disk
	pres->Save(outPath, Aspose::Slides::Export::SaveFormat::Pptx);

Adjust Label Location

When you create a chart that does not rely on any axis such as a pie chart, the chart’s data labels may end up being too close to its edge. In such a case, you have to adjust the location of the data label so that the leader lines get displayed clearly.

This C++ code shows you how to adjust the label location on a pie chart:

System::SharedPtr<Presentation> pres = System::MakeObject<Presentation>();

System::SharedPtr<IChart> chart = pres->get_Slide(0)->get_Shapes()->AddChart(ChartType::Pie, 50.0f, 50.0f, 200.0f, 200.0f);

System::SharedPtr<IChartSeriesCollection> series = chart->get_ChartData()->get_Series();
System::SharedPtr<IDataLabel> label = series->idx_get(0)->get_Label(0);
System::SharedPtr<IDataLabelFormat> dataLabelFormat = label->get_DataLabelFormat();

dataLabelFormat->set_ShowValue(true);
dataLabelFormat->set_Position(LegendDataLabelPosition::OutsideEnd);
label->set_X(0.71f);
label->set_Y(0.04f);

pres->Save(u"pres.pptx", SaveFormat::Pptx);