Overview of Essential® WPF Diagram (SfDiagram)

16 Dec 20245 minutes to read

Overview control is used to display a preview (overall view) of the entire content of a Diagram. This helps you to look overall picture of large diagram and easy to navigate (pan or zoom) to a particular position of the page.

Usage scenario

When you work on a huge and complex diagram, you may not know the part where you are actually working, and navigating from one part to another might be difficult. To navigation, zoom out entire diagram and find where you are. This solution is not suitable when you need some frequent navigation.

Overview control solved this problem by displaying a preview (overall view) of the entire diagram with option to pan and zoom.

Define overview

Overview control can be added to the application by dragging it from the toolbox and dropping it in Designer view. The required assembly references will be added automatically.

Steps to add Overview control manually in XAML:

Add the following required assembly reference to the project, Syncfusion.SfDiagram.WPF
Import Syncfusion® WPF schema http://schemas.syncfusion.com/wpf or SfDiagram control namespace Syncfusion.UI.Xaml.Diagram.Controls in XAML page.

Declare Overview control in XAML page.

XAML
<Window x:Class="UserInteraction_Overview.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
        WindowStartupLocation="CenterScreen"
        Title="Overview" Height="720" Width="1200">
       
    <!--Initialize the overview control and bind the diagram control elements to overview-->
    <syncfusion:Overview Source="{Binding ElementName=diagram}" Height="300" Margin="0,25,0,0"/>
   
    <!--Initialize the SfDiagram-->
    <syncfusion:SfDiagram x:Name="diagram"/>
</Window>

Overview of WPF Diagram

View Sample in GitHub.

ZoomSlider

The ShowZoomSlider property is used to show or hide the zoom slider in the overview control. By default, the ShowZoomSlider is true.

You can zoom in or zoom out the overview as well as the diagram by changing the slider or click on the zoom in or zoom out button.

The following code example explains how to hide the zoom slider.

XAML
<Window x:Class="UserInteraction_Overview.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
        WindowStartupLocation="CenterScreen"
        Title="Overview" Height="720" Width="1200">
    
    <!--Initialize the overview control and bind the diagram control elements to overview-->
    <syncfusion:Overview Source="{Binding ElementName=diagram}" Height="300" Margin="0,25,0,0" ShowZoomSlider="False"/>

    <!--Initialize the SfDiagram-->
    <syncfusion:SfDiagram x:Name="diagram"/>
</Window>

WPF Diagram displays ZoomSlider

Interaction

Overview control allows Zoom and Pan interactions. The red rectangle indicates the area currently displayed on the diagram page. The red box can be moved within the panel to pan around the diagram. You can click and drag the corner of the rectangle to change the level of zooming on the diagram page or you can draw a new rectangle by clicking and dragging anywhere within the panel to zoom an area.

XAML
<!--Initialize the overview control with its constraint-->
<syncfusion:Overview Source="{Binding ElementName=diagram}" 
                     Constraint="Default" 
                     Height="300" Margin="0,25,0,0"/>

<!--Initialize the SfDiagram-->
<syncfusion:SfDiagram x:Name="diagram"/>

The Constraint property of the Overview class allows you to control the Pan and Zoom interactions based the value assigned to that property. The following table explains the various values and their behaviors:

OverviewConstraints	Description	Output
Pan	Allows users to pan the diagram page by dragging the focused rectangle.
Zoom	Allows users to perform zoom by resizing the corners of the focused rectangle.
DrawFocus	Allows users to draw new focused rectangle anywhere within the overview panel, that is corresponding region in the diagram will be brought into the view.
TapFocus	Allows users move the focused rectangle to any area within the panel by just tapping it.
Default	Allows users to perform drag, resize, draw, and tap the overview control.
None	No interaction can be performed on the focused rectangle.

Deferred scrolling

Diagram supports the deferred scrolling behaviour to improve the zoom and pan performances.

To learn more about deferred scrolling, refer to Deferred Scrolling.

Event

The OverviewChangedEvent will notify the interactions in Overview control with OverviewChangedEventArgs as argument. This argument will provide the dragging and interaction state value of the overview.