Customize Error Bars in Presentation Charts with Python

Add Error Bar

Aspose.Slides for Python via .NET provides a simple API for managing error bar values. The sample code applies when using a custom value type. To specify a value, use the ErrorBarCustomValues property of a specific data point in the DataPoints collection of series:

  1. Create an instance of the Presentation class.
  2. Add a bubble chart on desired slide.
  3. Access the first chart series and set the error bar X format.
  4. Access the first chart series and set the error bar Y format.
  5. Setting bars values and format.
  6. Write the modified presentation to a PPTX file.
import aspose.slides.charts as charts
import aspose.slides as slides

# Creating empty presentation
with slides.Presentation() as presentation:
    # Creating a bubble chart
    chart = presentation.slides[0].shapes.add_chart(charts.ChartType.BUBBLE, 50, 50, 400, 300, True)

    # Adding Error bars and setting its format
    errBarX = chart.chart_data.series[0].error_bars_x_format
    errBarY = chart.chart_data.series[0].error_bars_y_format
    errBarX.is_visible = True
    errBarY.is_visible = True
    errBarX.value_type = charts.ErrorBarValueType.FIXED
    errBarX.value = 0.1
    errBarY.value_type = charts.ErrorBarValueType.PERCENTAGE
    errBarY.value = 5
    errBarX.type = charts.ErrorBarType.PLUS
    errBarY.format.line.width = 2
    errBarX.has_end_cap = True

    # Saving presentation
    presentation.save("ErrorBars_out.pptx", slides.export.SaveFormat.PPTX)

Add Custom Error Bar Value

Aspose.Slides for Python via .NET provides a simple API for managing custom error bar values. The sample code applies when the IErrorBarsFormat.ValueType property is equal to Custom. To specify a value, use the ErrorBarCustomValues property of a specific data point in the DataPoints collection of series:

  1. Create an instance of the Presentation class.
  2. Add a bubble chart on desired slide.
  3. Access the first chart series and set the error bar X format.
  4. Access the first chart series and set the error bar Y format.
  5. Access the chart series individual data points and setting the Error Bar values for individual series data point.
  6. Setting bars values and format.
  7. Write the modified presentation to a PPTX file.
import aspose.slides.charts as charts
import aspose.slides as slides

# Creating empty presentation
with slides.Presentation() as presentation:
    # Creating a bubble chart
    chart = presentation.slides[0].shapes.add_chart(charts.ChartType.BUBBLE, 50, 50, 400, 300, True)

    # Adding custom Error bars and setting its format
    series = chart.chart_data.series[0]
    errBarX = series.error_bars_x_format
    errBarY = series.error_bars_y_format
    errBarX.is_visible = True
    errBarY.is_visible = True
    errBarX.value_type = charts.ErrorBarValueType.CUSTOM
    errBarY.value_type = charts.ErrorBarValueType.CUSTOM

    # Accessing chart series data point and setting error bars values for individual point
    points = series.data_points
    points.data_source_type_for_error_bars_custom_values.data_source_type_for_x_plus_values = charts.DataSourceType.DOUBLE_LITERALS
    points.data_source_type_for_error_bars_custom_values.data_source_type_for_x_minus_values = charts.DataSourceType.DOUBLE_LITERALS
    points.data_source_type_for_error_bars_custom_values.data_source_type_for_y_plus_values = charts.DataSourceType.DOUBLE_LITERALS
    points.data_source_type_for_error_bars_custom_values.data_source_type_for_y_minus_values = charts.DataSourceType.DOUBLE_LITERALS

    # Setting error bars for chart series points
    for i in range(len(points)):
        points[i].error_bars_custom_values.x_minus.as_literal_double = i + 1
        points[i].error_bars_custom_values.x_plus.as_literal_double = i + 1
        points[i].error_bars_custom_values.y_minus.as_literal_double = i + 1
        points[i].error_bars_custom_values.y_plus.as_literal_double = i + 1

    # Saving presentation
    presentation.save("ErrorBarsCustomValues_out.pptx", slides.export.SaveFormat.PPTX)

FAQ

What happens to error bars when exporting a presentation to PDF or images?

They are rendered as part of the chart and preserved during conversion along with the rest of the chart formatting, assuming a compatible version or renderer.

Can error bars be combined with markers and data labels?

Yes. Error bars are a separate element and are compatible with markers and data labels; if elements overlap, you may need to adjust formatting.

Where can I find the list of properties and enums for working with error bars in the API?

In the API reference: the ErrorBarsFormat class and the related enums ErrorBarType and ErrorBarValueType.