Artikel
11/18/2011

RotateTransform Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Rotates an object clockwise about a specified point in a two-dimensional x-y coordinate system.

Inheritance Hierarchy

System.Object
  System.Windows.DependencyObject
    System.Windows.Media.GeneralTransform
      System.Windows.Media.Transform
        System.Windows.Media.RotateTransform

Namespace: System.Windows.Media
Assembly: System.Windows (in System.Windows.dll)

Syntax

'Declaration
Public NotInheritable Class RotateTransform _
    Inherits Transform

public sealed class RotateTransform : Transform

<RotateTransform .../>

The RotateTransform type exposes the following members.

Constructors

	Name	Description
	RotateTransform	Initializes a new instance of the RotateTransform class.

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Properties

	Name	Description
	Angle	Gets or sets the angle, in degrees, of clockwise rotation.
	CenterX	Gets or sets the x-coordinate of the rotation center point.
	CenterY	Gets or sets the y-coordinate of the rotation center point.
	Dispatcher	Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
	Inverse	Gets the inverse of this transform, if it exists. (Inherited from Transform.)

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Methods

	Name	Description
	CheckAccess	Determines whether the calling thread has access to this object. (Inherited from DependencyObject.)
	ClearValue	Clears the local value of a dependency property. (Inherited from DependencyObject.)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetAnimationBaseValue	Returns any base value established for a Silverlight dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetValue	Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ReadLocalValue	Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject.)
	SetValue	Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	Transform	Transforms the specified point and returns the result. (Inherited from GeneralTransform.)
	TransformBounds	Transforms the specified bounding box and returns an axis-aligned bounding box that is exactly large enough to contain it. (Inherited from Transform.)
	TryTransform	Attempts to transform the specified point and returns a value that indicates whether the transformation was successful. (Inherited from Transform.)

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Fields

	Name	Description
	AngleProperty	Identifies the Angle dependency property.
	CenterXProperty	Identifies the CenterX dependency property.
	CenterYProperty	Identifies the CenterY dependency property.

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Remarks

A RotateTransform is defined by the following properties: Angle rotates an object by a specified angle about the point CenterX, CenterY.

When you use a RotateTransform, the transformation rotates the coordinate system for a particular object about the origin point for its frame of reference. Therefore, depending on the position of the object, it might not rotate in place (around its center). For example, if an object is positioned 200 units from 0 along the x-axis, a rotation of 30 degrees can swing the object 30 degrees along a circle that has a radius of 200, which is drawn around the origin. To rotate an object in place, set the CenterX and CenterY of the RotateTransform to the center of the object to rotate.

The local 0,0 for an object can be offset on a Canvas using Canvas.Left and Canvas.Top, but this does not count as a transform; the object retains its own local 0,0 in this case for transform purposes.

Multiple transforms can be applied with a TransformGroup.

Examples

Transforms can alter the display of text in your application to create a decorative effect. The following example shows text rotated 90 degrees using a RotateTransform.

TextBlock using a RotateTransform

Diagram showing rotated text.

The following example uses a RotateTransform to rotate text. An Angle value of 90 rotates the element 90 degrees clockwise.

<!-- Rotate the text 90 degrees using a RotateTransform. -->
<TextBlock Text="Rotated Text" FontSize="32" Foreground="Teal">
  <TextBlock.RenderTransform>
    <RotateTransform Angle="90" />
  </TextBlock.RenderTransform>
</TextBlock>

Transform objects can be accessed and manipulated by using code. One way to do this is to name the Transform and then access it by using its name. The following example shows how to increase the ScaleX and ScaleY property values of a ScaleTransform applied to a Rectangle every time the Rectangle is clicked.

Run this sample

<StackPanel>
  <Rectangle MouseLeftButtonDown="HandleMouseButtonDown"
    Width="50" Height="50" Fill="RoyalBlue">
    <Rectangle.RenderTransform>

      <!-- If you give the transform a name you can 
        access it easily from code. -->
      <ScaleTransform x:Name="myScaleTransform" />
    </Rectangle.RenderTransform>
  </Rectangle>
</StackPanel>

Private Sub HandleMouseButtonDown(ByVal sender As Object, ByVal e As MouseButtonEventArgs)
    ' Increase ScaleX and ScaleY by 25%.
    myScaleTransform.ScaleX = (myScaleTransform.ScaleX * 1.25)
    myScaleTransform.ScaleY = (myScaleTransform.ScaleY * 1.25)
End Sub

private void HandleMouseButtonDown(object sender, MouseButtonEventArgs e)
{
    // Increase ScaleX and ScaleY by 25%.
    myScaleTransform.ScaleX = myScaleTransform.ScaleX * 1.25;
    myScaleTransform.ScaleY = myScaleTransform.ScaleY * 1.25;
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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