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ScaleTransform Class

Scales an object in the 2-D x-y coordinate system.

Namespace: System.Windows.Media
Assembly: PresentationCore (in presentationcore.dll)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

public sealed class ScaleTransform : Transform
public final class ScaleTransform extends Transform
public final class ScaleTransform extends Transform
<ScaleTransform .../>

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

Freezable Features: Because it inherits from the Freezable class, the ScaleTransform class provides several special features: ScaleTransform objects can be declared as resources, shared among multiple objects, made read-only to improve performance, cloned, and made thread-safe. For more information about the different features provided by Freezable objects, see the Freezable Objects Overview.

This example shows how to use a ScaleTransform to scale an element.

Use the ScaleX and ScaleY properties to resize the element by the factor you specify. For example, a ScaleX value of 1.5 stretches the element to 150 percent of its original width. A ScaleY value of 0.5 shrinks the height of an element by 50 percent.

Use the CenterX and CenterY properties to specify the point that is the center of the scale operation. By default, a ScaleTransform is centered at the point (0,0). This has the effect of moving the element and also of making it appear larger, because when you apply a Transform, you change the coordinate space in which the object resides.

The following example uses a ScaleTransform to double the size of a 50 by 50 Rectangle. The ScaleTransform has a value of 0 (the default) for both CenterX and CenterY.

<!-- Scales a rectangle by 200% from a center of (0,0).-->
<Rectangle Height="50" Width="50" Fill="#CCCCCCFF" 
  Stroke="Blue" StrokeThickness="2"
  Canvas.Left="100" Canvas.Top="100">
  <Rectangle.RenderTransform>
    <ScaleTransform CenterX="0" CenterY="0" ScaleX="2" ScaleY="2" />
  </Rectangle.RenderTransform>
</Rectangle>

Typically, you set CenterX and CenterY to the center of the object that is scaled: (Width/2, Height/2).

The following example shows another Rectangle that is doubled in size; however, this ScaleTransform has a value of 25 for both CenterX and CenterY, which corresponds to the center of the rectangle.

<!-- Scales a rectangle by 200% from a center of (25,25).-->
<Rectangle Height="50" Width="50" Fill="#CCCCCCFF"
  Canvas.Left="100" Canvas.Top="100" Stroke="Blue" StrokeThickness="2">
  <Rectangle.RenderTransform>
    <ScaleTransform CenterX="25" CenterY="25" ScaleX="2" ScaleY="2" />
  </Rectangle.RenderTransform>
</Rectangle>

The following illustration shows the difference between the two ScaleTransform operations. The dotted line shows the size and position of the rectangle before scaling.

Two ScaleTransform operations with identical ScaleX and ScaleY values but different centers


2x scales with different center points

For the complete sample, see 2-D Transforms Sample.

More Code

How to: Flip a UIElement Horizontally or Vertically

This example shows how to use a ScaleTransform to flip a UIElement horizontally or vertically. In this example, a Button control (a type of UIElement) is flipped by applying a ScaleTransform to its RenderTransform property.

How to: Animate the Size of a FrameworkElement

To animate the size of a FrameworkElement, you can either animate its Width and Height properties or use an animated ScaleTransform.

How to: Apply a Transform to an Element When an Event Occurs

This example shows how to apply a ScaleTransform when an event occurs. The concept that is shown here is the same that you use for applying other types of transformations. For more information about the available types of transformations, see the Transform class.

System.Object
   System.Windows.Threading.DispatcherObject
     System.Windows.DependencyObject
       System.Windows.Freezable
         System.Windows.Media.Animation.Animatable
           System.Windows.Media.GeneralTransform
             System.Windows.Media.Transform
              System.Windows.Media.ScaleTransform

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

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0

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