Region.Union Method

Definition

Namespace:

System.Drawing

Assembly:

System.Drawing.Common.dll

Updates this Region to the union of itself and the specified GraphicsPath.

Overloads

Union(GraphicsPath)	Updates this Region to the union of itself and the specified GraphicsPath.
Union(Rectangle)	Updates this Region to the union of itself and the specified Rectangle structure.
Union(RectangleF)	Updates this Region to the union of itself and the specified RectangleF structure.
Union(Region)	Updates this Region to the union of itself and the specified Region.

Union(GraphicsPath)

Updates this Region to the union of itself and the specified GraphicsPath.

public:
 void Union(System::Drawing::Drawing2D::GraphicsPath ^ path);

public void Union (System.Drawing.Drawing2D.GraphicsPath path);

member this.Union : System.Drawing.Drawing2D.GraphicsPath -> unit

Public Sub Union (path As GraphicsPath)

Parameters

path

GraphicsPath

The GraphicsPath to unite with this Region.

Exceptions

ArgumentNullException

path is null.

Examples

For a code example, see the Union(RectangleF) and Complement(GraphicsPath) methods.

Union(Rectangle)

Updates this Region to the union of itself and the specified Rectangle structure.

public:
 void Union(System::Drawing::Rectangle rect);

public void Union (System.Drawing.Rectangle rect);

member this.Union : System.Drawing.Rectangle -> unit

Public Sub Union (rect As Rectangle)

Parameters

rect

Rectangle

The Rectangle structure to unite with this Region.

Examples

For a code example, see the Union(RectangleF) method.

Union(RectangleF)

Updates this Region to the union of itself and the specified RectangleF structure.

public:
 void Union(System::Drawing::RectangleF rect);

public void Union (System.Drawing.RectangleF rect);

member this.Union : System.Drawing.RectangleF -> unit

Public Sub Union (rect As RectangleF)

Parameters

rect

RectangleF

The RectangleF structure to unite with this Region.

Examples

The following code example is designed for use with Windows Forms, and it requires PaintEventArgs e. The code performs the following actions:

• Creates the first rectangle and draws it to the screen in black.

• Creates a second rectangle and draws it to the screen in red.

• Creates a region using the first rectangle.

• Gets the area of union for myRegion when combined with complementRect.

• Fills the fills the area of union with blue and draws it to the screen.

Notice that both rectangles are filled with blue, including the area of overlap.

void Union_RectF_Example( PaintEventArgs^ e )
{
   // Create the first rectangle and draw it to the screen in black.
   Rectangle regionRect = Rectangle(20,20,100,100);
   e->Graphics->DrawRectangle( Pens::Black, regionRect );

   // create the second rectangle and draw it to the screen in red.
   RectangleF unionRect = RectangleF(90,30,100,100);
   e->Graphics->DrawRectangle( Pens::Red, Rectangle::Round( unionRect ) );

   // Create a region using the first rectangle.
   System::Drawing::Region^ myRegion = gcnew System::Drawing::Region( regionRect );

   // Get the area of union for myRegion when combined with
   // complementRect.
   myRegion->Union( unionRect );

   // Fill the union area of myRegion with blue.
   SolidBrush^ myBrush = gcnew SolidBrush( Color::Blue );
   e->Graphics->FillRegion( myBrush, myRegion );
}

public void Union_RectF_Example(PaintEventArgs e)
{
             
    // Create the first rectangle and draw it to the screen in black.
    Rectangle regionRect = new Rectangle(20, 20, 100, 100);
    e.Graphics.DrawRectangle(Pens.Black, regionRect);
             
    // create the second rectangle and draw it to the screen in red.
    RectangleF unionRect = new RectangleF(90, 30, 100, 100);
    e.Graphics.DrawRectangle(Pens.Red,
        Rectangle.Round(unionRect));
             
    // Create a region using the first rectangle.
    Region myRegion = new Region(regionRect);
             
    // Get the area of union for myRegion when combined with
             
    // complementRect.
    myRegion.Union(unionRect);
             
    // Fill the union area of myRegion with blue.
    SolidBrush myBrush = new SolidBrush(Color.Blue);
    e.Graphics.FillRegion(myBrush, myRegion);
}

Public Sub Union_RectF_Example(ByVal e As PaintEventArgs)

    ' Create the first rectangle and draw it to the screen in black.
    Dim regionRect As New Rectangle(20, 20, 100, 100)
    e.Graphics.DrawRectangle(Pens.Black, regionRect)

    ' create the second rectangle and draw it to the screen in red.
    Dim unionRect As New RectangleF(90, 30, 100, 100)
    e.Graphics.DrawRectangle(Pens.Red, Rectangle.Round(unionRect))

    ' Create a region using the first rectangle.
    Dim myRegion As New [Region](regionRect)

    ' Get the area of union for myRegion when combined with
    ' complementRect.
    myRegion.Union(unionRect)

    ' Fill the intersection area of myRegion with blue.
    Dim myBrush As New SolidBrush(Color.Blue)
    e.Graphics.FillRegion(myBrush, myRegion)
End Sub

Union(Region)

Updates this Region to the union of itself and the specified Region.

public:
 void Union(System::Drawing::Region ^ region);

public void Union (System.Drawing.Region region);

member this.Union : System.Drawing.Region -> unit

Public Sub Union (region As Region)

Parameters

region

Region

The Region to unite with this Region.

Exceptions

ArgumentNullException

region is null.

Examples

For a code example, see the Union(RectangleF) and Complement(GraphicsPath) method.