To set which DiagramView instance is shown in a ruler, add it as a child to the Ruler by placing the <DiagramView> tag within the <Ruler> tag in XAML.

The ruler tracks mouse movements and modifications being performed on an item, and displays markers over the scales indicating the current position in diagram's coordinate system. The colors of these markers can be changed using the PointerColor and ProjectionColor properties.

If EnableGuides is set to true, the ruler allows aligning several items by clicking on a scale and dragging. That displays alignment guides which follow the mouse pointer and move all selected items on their way. If no diagram elements are selected, all items are moved.

System.Object
    System.Windows.Threading.DispatcherObject
        System.Windows.DependencyObject
            System.Windows.Media.Visual
                System.Windows.UIElement
                    System.Windows.FrameworkElement
                        System.Windows.Controls.Control
                            System.Windows.Controls.ContentControl
                                MindFusion.Diagramming.Wpf.Ruler

Ruler Members
MindFusion.Diagramming.Wpf Namespace