How to position node’s port

12 Nov 202413 minutes to read

Diagram allows you to customize the position and appearance of the port efficiently. Ports can be aligned relative to the node boundaries. It has Margin, Offset, Horizontal, and Vertical alignment settings. It is quite tricky when all four alignments are used together but gives more control over alignments properties of the PointPort class. Ports of a node can be positioned using the following properties of PointPort.

  • Offset
  • HorizontalAlignment
  • VerticalAlignment
  • Margin

How to change offset at runtime

The Offset property is used to align the ports based on fractions. 0 represents top/left corner, 1 represents bottom/right corner, and 0.5 represents half of width/height.

@using Syncfusion.Blazor.Diagram

<SfDiagramComponent Height="600px" Nodes="@nodes"/>

@code
{
    DiagramObjectCollection<Node> nodes;

    protected override void OnInitialized()
    {
        nodes = new DiagramObjectCollection<Node>();
        // A node is created and stored in nodes collection.
        Node node = new Node()
        {
            // Position of the node.
            OffsetX = 250,
            OffsetY = 250,
            // Size of the node.
            Width = 100,
            Height = 100,
            Style = new ShapeStyle() { Fill = "#6495ED", StrokeColor = "white" },
            // Initialize port collection.
            Ports = new DiagramObjectCollection<PointPort>()
            {
                new PointPort() 
                {
                    ID = "port1",
                    // Sets the offset for the port.
                    Offset = new DiagramPoint() { X = 0, Y = 0.5 },
                    Visibility = PortVisibility.Visible,
                    //Set the style for the port.
                    Style= new ShapeStyle() { Fill = "gray", StrokeColor = "black" },
                    Width = 12,
                    Height = 12,
                    // Sets the shape of the port as Square .
                    Shape = PortShapes.Square
                }
            }
        };
        nodes.Add(node);
    }
}

You can download a complete working sample from GitHub

Blazor Diagram with Port based on Offset

The following table shows the relationship between the shape port position and path port offset (fraction values).

Offset values Output
(0,0) Blazor Diagram Port in Left Top Offset Values
(0,0.5) Blazor Diagram Port in Left Center Offset Values
(0,1) Blazor Diagram Port in Left Bottom Offset Values
(0.5,0) Blazor Diagram Port in Center Top Offset Values
(0.5,0.5) Blazor Diagram Port in Center Offset Values
(0.5,1) Blazor Diagram Port in Center Bottom Offset Values
(1,0) Blazor Diagram Port in Right Top Offset Values
(1,0.5) Blazor Diagram Port in Right Center Offset Values
(1,1) Blazor Diagram Port in Right Bottom Offset Values

How to change Horizontal and Vertical alignment

The HorizontalAlignment property of the port is used to set how the port is horizontally aligned at the port position determined from the fraction values. The VerticalAlignment property is used to set how the port is vertically aligned at the port position.

The following table shows all the possible alignments visually with offset (0, 0).

Horizontal Alignment Vertical Alignment Output with Offset(0,0)
Left Top Blazor Diagram Port in Left Top Position
Center Top Blazor Diagram Port in Center Top Position
Right Top Blazor Diagram Port in Right Top Position
Left Center Blazor Diagram Port in Left Center Position
Center Center Blazor Diagram Port in Center Center Position
Right Center Blazor Diagram Port in Right Center Position
Left Bottom Blazor Diagram Port in Left Bottom Position
Center Bottom Blazor Diagram Port in Center Bottom Position
Right Bottom Blazor Diagram Port in Right Bottom Position

The following code explains how to align ports.

@using Syncfusion.Blazor.Diagram

<SfDiagramComponent Height="600px" Nodes="@nodes"/>

@code
{
    DiagramObjectCollection<Node> nodes;

    protected override void OnInitialized()
    {
        nodes = new DiagramObjectCollection<Node>();
        // A node is created and stored in nodes array.
        Node node = new Node()
        {
            // Position of the node.
            OffsetX = 250,
            OffsetY = 250,
            // Size of the node.
            Width = 100,
            Height = 100,
            Style = new ShapeStyle() { Fill = "#6495ED", StrokeColor = "white" },
            // Initialize port collection.
            Ports = new DiagramObjectCollection<PointPort>() 
            {
                new PointPort() 
                {
                    ID = "port1",
                    Offset = new DiagramPoint() { X = 0, Y = 0 },
                    Visibility = PortVisibility.Visible,
                    //Set the style for the port.
                    Style = new ShapeStyle(){ Fill="gray", StrokeColor="black"},
                    Width = 12, 
                    Height = 12, 
                    // Sets the shape of the port as Square.                    
                    Shape = PortShapes.Square,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    VerticalAlignment = VerticalAlignment.Center
                }
            }
        };
        nodes.Add(node);
    }
}

You can download a complete working sample from GitHub

Changing Port Position in Blazor Diagram

NOTE

By default, the value of the HorizontalAlignment and VerticalAlignment is Center. The alignment is positioned based on the offset value.

How to update margin for port

Margin is an absolute value used to add some blank space to any one of its four sides. The ports can be displaced with the margin property. The following code example explains how to align a port based on its Offset, HorizontalAlignment, VerticalAlignment, and Margin values.

@using Syncfusion.Blazor.Diagram

<SfDiagramComponent Height="600px" Nodes="@nodes"/>

@code
{
    DiagramObjectCollection<Node> nodes;

    protected override void OnInitialized()
    {
        nodes = new DiagramObjectCollection<Node>();
        // A node is created and stored in nodes array.
        Node node = new Node()
        {
            // Position of the node.
            OffsetX = 250,
            OffsetY = 250,
            // Size of the node.
            Width = 100,
            Height = 100,
            Style = new ShapeStyle() { Fill = "#6495ED", StrokeColor = "white" },
            // Initialize port collection.
            Ports = new DiagramObjectCollection<PointPort>() 
            {
                new PointPort() 
                {
                    ID = "port1",
                    Offset = new DiagramPoint() { X = 0.5, Y = 1 },
                    Visibility = PortVisibility.Visible,
                    //Set the style for the port.
                    Style= new ShapeStyle() { Fill = "gray", StrokeColor = "black" },
                    Width = 12,
                    Height = 12, 
                    // Sets the shape of the port as Square.
                    Shape = PortShapes.Square,
                    HorizontalAlignment = HorizontalAlignment.Left,
                    VerticalAlignment = VerticalAlignment.Top,
                    Margin = new DiagramThickness() { Top = 20 }
                }
            }
        };
        nodes.Add(node);
    }
}

You can download a complete working sample from GitHub

Blazor Diagram Port with Margin

See also