Artikel
11/17/2011

ScaleTransform Class

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

Scales an object in the two-dimensional x-y coordinate system.

Inheritance Hierarchy

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

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

Syntax

'Declaration
Public NotInheritable Class ScaleTransform _
    Inherits Transform

public sealed class ScaleTransform : Transform

<ScaleTransform .../>

The ScaleTransform type exposes the following members.

Constructors

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

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Properties

	Name	Description
	CenterX	Gets or sets the x-coordinate of the center point of this ScaleTransform.
	CenterY	Gets or sets the y-coordinate of the center point of this ScaleTransform.
	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.)
	ScaleX	Gets or sets the x-axis scale factor.
	ScaleY	Gets or sets the y-axis scale factor.

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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
	CenterXProperty	Identifies the CenterX dependency property.
	CenterYProperty	Identifies the CenterY dependency property.
	ScaleXProperty	Identifies the ScaleX dependency property.
	ScaleYProperty	Identifies the ScaleY dependency property.

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Remarks

Use a ScaleTransform to stretch or shrink an object horizontally or vertically. The ScaleX property specifies the amount to stretch or shrink an object along the x-axis, and the ScaleY property specifies the amount to stretch or shrink an object along the y-axis. Scale operations are centered on the point specified by the CenterX and CenterY properties.

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. Custom transforms can be created with a MatrixTransform.

Transforms can alter the display of text in your application to create a decorative effect. The following illustration shows the second line of text scaled by 150% along the x-axis, and the third line of text scaled by 150% along the y-axis.

TextBlock using a ScaleTransform

Transformed text.

Note:
Scaling text is not the same as increasing the font size of text. Font sizes are calculated independently of each other in order to provide the best resolution at different sizes. Scaled text, on the other hand, preserves the proportions of the original-sized text.

Examples

The following XAML example uses a ScaleTransform to scale text from its original size.

Run this sample

<StackPanel>
<TextBlock
  FontFamily="Verdana"
  FontSize="32"
  FontWeight="Bold" 
  Foreground="SteelBlue"
  Text="Scaled Text" />

<!-- Scale the text width using a ScaleTransform. -->
<TextBlock
  FontFamily="Verdana"
  FontSize="32"
  FontWeight="Bold" 
  Foreground="SteelBlue"
  Text="Scaled Text">
  <TextBlock.RenderTransform>
    <ScaleTransform ScaleX="1.5" ScaleY="1.0" />
  </TextBlock.RenderTransform>
</TextBlock>

<!-- Scale the text height using a ScaleTransform. -->
<TextBlock
  FontFamily="Verdana"
  FontSize="32"
  FontWeight="Bold" 
  Foreground="SteelBlue"
  Text="Scaled Text">
  <TextBlock.RenderTransform>
    <ScaleTransform ScaleX="1.0" ScaleY="1.5" />
  </TextBlock.RenderTransform>
</TextBlock>
</StackPanel>

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 code. The following example shows how to increase the ScaleX and ScaleY property values of a ScaleTransform applied to a Rectangle every time that 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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