Matrix.RotateAt Method

Definition

Namespace:

System.Drawing.Drawing2D

Assembly:

System.Drawing.Common.dll

Applies a clockwise rotation about the specified point to this Matrix by prepending the rotation.

Overloads

RotateAt(Single, PointF)	Applies a clockwise rotation to this Matrix around the point specified in the point parameter, and by prepending the rotation.
RotateAt(Single, PointF, MatrixOrder)	Applies a clockwise rotation about the specified point to this Matrix in the specified order.

RotateAt(Single, PointF)

Source:

Matrix.cs

Applies a clockwise rotation to this Matrix around the point specified in the point parameter, and by prepending the rotation.

public:
 void RotateAt(float angle, System::Drawing::PointF point);

public void RotateAt (float angle, System.Drawing.PointF point);

member this.RotateAt : single * System.Drawing.PointF -> unit

Public Sub RotateAt (angle As Single, point As PointF)

Parameters

angle

Single

The angle (extent) of the rotation, in degrees.

point

PointF

A PointF that represents the center of the rotation.

Examples

The following code example demonstrates using a Matrix and the Transform method to rotate a string. This example is designed to be used with Windows Forms. Create a form and paste the following code into it. Call the DrawVerticalStringFromBottomUp method in the form's Paint event handler, passing e as PaintEventArgs.

private:
   void DrawVerticalStringFromBottomUp( PaintEventArgs^ e )
   {
      // Create the string to draw on the form.
      String^ text = "Can you read this?";

      // Create a GraphicsPath.
      System::Drawing::Drawing2D::GraphicsPath^ path = gcnew System::Drawing::Drawing2D::GraphicsPath;

      // Add the string to the path; declare the font, font style, size, and
      // vertical format for the string.
      path->AddString( text, this->Font->FontFamily, 1, 15, PointF(0.0F,0.0F), gcnew StringFormat( StringFormatFlags::DirectionVertical ) );

      // Declare a matrix that will be used to rotate the text.
      System::Drawing::Drawing2D::Matrix^ rotateMatrix = gcnew System::Drawing::Drawing2D::Matrix;

      // Set the rotation angle and starting point for the text.
      rotateMatrix->RotateAt( 180.0F, PointF(10.0F,100.0F) );

      // Transform the text with the matrix.
      path->Transform(rotateMatrix);

      // Set the SmoothingMode to high quality for best readability.
      e->Graphics->SmoothingMode = System::Drawing::Drawing2D::SmoothingMode::HighQuality;

      // Fill in the path to draw the string.
      e->Graphics->FillPath( Brushes::Red, path );

      // Dispose of the path.
      delete path;
   }

public void DrawVerticalStringFromBottomUp(PaintEventArgs e)
{

    // Create the string to draw on the form.
    string text = "Can you read this?";

    // Create a GraphicsPath.
    System.Drawing.Drawing2D.GraphicsPath path = 
        new System.Drawing.Drawing2D.GraphicsPath();

    // Add the string to the path; declare the font, font style, size, and
    // vertical format for the string.
    path.AddString(text, this.Font.FontFamily, 1, 15, 
        new PointF(0.0F, 0.0F), 
        new StringFormat(StringFormatFlags.DirectionVertical));

    // Declare a matrix that will be used to rotate the text.
    System.Drawing.Drawing2D.Matrix rotateMatrix = 
        new System.Drawing.Drawing2D.Matrix();

    // Set the rotation angle and starting point for the text.
    rotateMatrix.RotateAt(180.0F, new PointF(10.0F, 100.0F));

    // Transform the text with the matrix.
    path.Transform(rotateMatrix);

    // Set the SmoothingMode to high quality for best readability.
    e.Graphics.SmoothingMode = 
        System.Drawing.Drawing2D.SmoothingMode.HighQuality;

    // Fill in the path to draw the string.
    e.Graphics.FillPath(Brushes.Red, path);

    // Dispose of the path.
    path.Dispose();
}

Public Sub DrawVerticalStringFromBottomUp(ByVal e As PaintEventArgs)

    ' Create the string to draw on the form.
    Dim text As String = "Can you read this?"

    ' Create a GraphicsPath.
    Dim path As New System.Drawing.Drawing2D.GraphicsPath

    ' Add the string to the path; declare the font, font style, size, and
    ' vertical format for the string.
    path.AddString(text, Me.Font.FontFamily, 1, 15, New PointF(0.0F, 0.0F), _
        New StringFormat(StringFormatFlags.DirectionVertical))

    ' Declare a matrix that will be used to rotate the text.
    Dim rotateMatrix As New System.Drawing.Drawing2D.Matrix

    ' Set the rotation angle and starting point for the text.
    rotateMatrix.RotateAt(180.0F, New PointF(10.0F, 100.0F))

    ' Transform the text with the matrix.
    path.Transform(rotateMatrix)

    ' Set the SmoothingMode to high quality for best readability.
    e.Graphics.SmoothingMode = Drawing2D.SmoothingMode.HighQuality

    ' Fill in the path to draw the string.
    e.Graphics.FillPath(Brushes.Red, path)

    ' Dispose of the path.
    path.Dispose()

End Sub

RotateAt(Single, PointF, MatrixOrder)

Source:

Matrix.cs

Applies a clockwise rotation about the specified point to this Matrix in the specified order.

public:
 void RotateAt(float angle, System::Drawing::PointF point, System::Drawing::Drawing2D::MatrixOrder order);

public void RotateAt (float angle, System.Drawing.PointF point, System.Drawing.Drawing2D.MatrixOrder order);

member this.RotateAt : single * System.Drawing.PointF * System.Drawing.Drawing2D.MatrixOrder -> unit

Public Sub RotateAt (angle As Single, point As PointF, order As MatrixOrder)

Parameters

angle

Single

The angle of the rotation, in degrees.

point

PointF

A PointF that represents the center of the rotation.

order

MatrixOrder

A MatrixOrder that specifies the order (append or prepend) in which the rotation is applied.

Examples

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

• Draws a rectangle to the screen prior to applying a rotation transform (the blue rectangle).

• Creates a matrix and rotates it 45 degrees around a specified point.

• Applies this matrix transform is to the rectangle.

• Draws the transformed rectangle to the screen (the red rectangle).

Notice that the red rectangle has been rotated around the upper left-hand corner of the rectangle (the rotation point specified the RotateAt method).

public:
   void RotateAtExample( PaintEventArgs^ e )
   {
      Pen^ myPen = gcnew Pen( Color::Blue,1.0f );
      Pen^ myPen2 = gcnew Pen( Color::Red,1.0f );
      PointF rotatePoint = PointF(150.0f,50.0f);

      // Draw the rectangle to the screen before applying the
      // transform.
      e->Graphics->DrawRectangle( myPen, 150, 50, 200, 100 );

      // Create a matrix and rotate it 45 degrees.
      Matrix^ myMatrix = gcnew Matrix;
      myMatrix->RotateAt( 45, rotatePoint, MatrixOrder::Append );

      // Draw the rectangle to the screen again after applying the
      // transform.
      e->Graphics->Transform = myMatrix;
      e->Graphics->DrawRectangle( myPen2, 150, 50, 200, 100 );
   }

public void RotateAtExample(PaintEventArgs e)
{
    Pen myPen = new Pen(Color.Blue, 1);
    Pen myPen2 = new Pen(Color.Red, 1);
    PointF rotatePoint = new PointF(150.0f, 50.0f);
             
    // Draw the rectangle to the screen before applying the
    // transform.
    e.Graphics.DrawRectangle(myPen, 150, 50, 200, 100);
             
    // Create a matrix and rotate it 45 degrees.
    Matrix myMatrix = new Matrix();
    myMatrix.RotateAt(45, rotatePoint, MatrixOrder.Append);
             
    // Draw the rectangle to the screen again after applying the
    // transform.
    e.Graphics.Transform = myMatrix;
    e.Graphics.DrawRectangle(myPen2, 150, 50, 200, 100);
}

Public Sub RotateAtExample(ByVal e As PaintEventArgs)
    Dim myPen As New Pen(Color.Blue, 1)
    Dim myPen2 As New Pen(Color.Red, 1)
    Dim rotatePoint As New PointF(150.0F, 50.0F)

    ' Draw the rectangle to the screen before applying the
    ' transform.
    e.Graphics.DrawRectangle(myPen, 150, 50, 200, 100)

    ' Create a matrix and rotate it 45 degrees.
    Dim myMatrix As New Matrix
    myMatrix.RotateAt(45, rotatePoint, MatrixOrder.Append)

    ' Draw the rectangle to the screen again after applying the
    ' transform.
    e.Graphics.Transform = myMatrix
    e.Graphics.DrawRectangle(myPen2, 150, 50, 200, 100)
End Sub