Feature request: decorator for setting streamline Source position
The decorator should allow to set the position of the two source types: Line and Sphere. Line is two vertices, Sphere is 1 vertex and 1 radius.
Changing the position of the source in the visualisation pane should update the decorator widgets.
The widget implementation can be similar to sdm-modeler/preprocessing/view-canvas/slices : last 3 widgets for controlling the 3 slices. This is implemented in dtkVisualizationWidgetsSliceControls, instantiated in dtkVisualizationDecoratorSlices.