- Qt 6.6
- Qt Graphs
- Qt Graphs Migration from Qt DataVisualization
- Qt Graphs | Commercial or GPLv3

# Qt Graphs Migration from Qt DataVisualization

The API and functionality between Qt DataVisualization and Qt Graphs has been kept mostly unchanged. However, there are some differences that need to be taken into consideration when migrating your application from Qt DataVisualization to Qt Graphs:

- QML import statement
- CMake module inclusion
- qmake module inclusion
- Widget application creation
- Requirement to use OpenGL backend
- Removed APIs
- Changed APIs

## QML Import Statement

The import statement in Qt DataVisualization:

     import QtDataVisualization

has to be changed to:

     import QtGraphs

for Qt Graphs.

## CMake Module Inclusion

The inclusion in Qt DataVisualization:

     find_package(Qt6 REQUIRED COMPONENTS DataVisualization)
     target_link_libraries(mytarget PRIVATE Qt6::DataVisualization)

has to be changed to:

     find_package(Qt6 REQUIRED COMPONENTS Graphs)
     target_link_libraries(mytarget PRIVATE Qt6::Graphs)

for Qt Graphs.

## Qmake Module Inclusion

The inclusion in Qt DataVisualization:

     QT += datavisualization

has to be changed to:

     QT += graphs

for Qt Graphs.

## Widget Application Creation

Instead of creating your widget application like this:

     QGuiApplication app(argc, argv);
     Q3DScatter scatter;
     scatter.setFlags(scatter.flags() ^ Qt::FramelessWindowHint);

you should create it like this:

     QApplication app(argc, argv);
     Q3DScatter scatter;
     scatter.setMinimumSize(QSize(256, 256));
     scatter.setResizeMode(QQuickWidget::SizeRootObjectToView);

## Requirement to Use OpenGL Backend

Adding the forced OpenGL backend usage:

     qputenv("QSG_RHI_BACKEND", "opengl");

is no longer required. Qt Graphs uses Qt Quick 3D for rendering, and as such supports the rendering backends native to the platform it is being run on.

## Removed APIs

- hasContext
- shadowsSupported

## Changed APIs

- optimizationHints
- renderingMode

### optimizationHints

`OptimizationLegacy` is now the mode that was `OptimizationDefault` in QtDataVisualization. `OptimizationDefault` uses instancing, and should be used for all targets that support it.

### renderingMode

`RenderDirectToBackground_NoClear` has been removed, as it was already obsolete in QtDataVisualization in Qt 6.