Optimize Chart Calculations for Presentations in C++

Calculate Actual Values of Chart Elements

Aspose.Slides for C++ provides a simple API for getting these properties. This will help you to calculate actual values of chart elements. The actual values include position of elements that implement IActualLayout interface (IActualLayout::get_ActualX(), IActualLayout::get_ActualY(), IActualLayout::get_ActualWidth(), IActualLayout::get_ActualHeight()) and actual axes values (IAxis::get_ActualMaxValue(), IAxis::get_ActualMinValue(), IAxis::get_ActualMajorUnit(), IAxis::get_ActualMinorUnit(), IAxis::get_ActualMajorUnitScale(), IAxis::get_ActualMinorUnitScale()).

auto pres = System::MakeObject<Presentation>(u"test.pptx");
    
auto chart = System::ExplicitCast<Chart>(pres->get_Slides()->idx_get(0)->get_Shapes()->AddChart(ChartType::ClusteredColumn, 100.0f, 100.0f, 500.0f, 350.0f));
chart->ValidateChartLayout();

double x = chart->get_PlotArea()->get_ActualX();
double y = chart->get_PlotArea()->get_ActualY();
double w = chart->get_PlotArea()->get_ActualWidth();
double h = chart->get_PlotArea()->get_ActualHeight();

// Saving presentation
pres->Save(u"Result.pptx", SaveFormat::Pptx);

Calculate the Actual Position of Parent Chart Elements

Aspose.Slides for C++ provides a simple API for getting these properties. Methods of IActualLayout provide information about actual position of parent chart element. It is necessary to call method IChart::ValidateChartLayout() previously to fill properties with actual values.

// Creating empty presentation
auto pres = System::MakeObject<Presentation>();

auto chart = System::ExplicitCast<Chart>(pres->get_Slides()->idx_get(0)->get_Shapes()->AddChart(ChartType::ClusteredColumn, 100.0f, 100.0f, 500.0f, 350.0f));
chart->ValidateChartLayout();

double x = chart->get_PlotArea()->get_ActualX();
double y = chart->get_PlotArea()->get_ActualY();
double w = chart->get_PlotArea()->get_ActualWidth();
double h = chart->get_PlotArea()->get_ActualHeight();

Hide Chart Elements

This topic helps you to understand how to hide information from chart. Using Aspose.Slides for C++ you can hide Title, Vertical Axis, Horizontal Axis and Grid Lines from chart. Below code example shows how to use these properties.

Set a Data Range for a Chart

Aspose.Slides for C++ has provided the simplest API to set the data range for chart in an easiest way. To set the data range for chart:

  • Open an instance of Presentation class containing chart.
  • Obtain the reference of a slide by using its Index.
  • Traverse through all shapes to find desired chart.
  • Access the chart data and set the range.
  • Save the modified presentation as a PPTX file.

The code examples that follow how to update a chart.

FAQ

Do external Excel workbooks work as a data source, and how does that affect recalculation?

Yes. A chart can reference an external workbook: when you connect or refresh the external source, formulas and values are taken from that workbook, and the chart reflects the updates during open/edit operations. The API lets you specify the external workbook path and manage the linked data.

Can I compute and display trendlines without implementing regression myself?

Yes. Trendlines (linear, exponential, and others) are added and updated by Aspose.Slides; their parameters are recalculated from the series data automatically, so you don’t need to implement your own calculations.

If a presentation has multiple charts with external links, can I control which workbook each chart uses for computed values?

Yes. Each chart can point to its own external workbook, or you can create/replace an external workbook per chart independently of the others.

Customize Presentation Chart Entities in С++ Format Presentation Charts in С++