Assembly: PresentationCore (in presentationcore.dll)
XML Namespace: http://schemas.microsoft.com/winfx/2006/xaml/presentation
When you use a RotateTransform, realize that the transformation rotates the coordinate system for a particular object about the point (0, 0). 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.
Freezable Features: Because it inherits from the Freezable class, the RotateTransform class provides several special features: RotateTransform 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 rotate an object. The example first creates a RotateTransform and then specifies its Angle in degrees.
The following example rotates a Polyline object 45 degrees about its upper-left corner.
<Canvas Height="200" Width="200"> <!-- Rotates the Polyline 45 degrees about the point (0,0). --> <Polyline Points="25,25 0,50 25,75 50,50 25,25 25,0" Stroke="Blue" StrokeThickness="10" Canvas.Left="75" Canvas.Top="50"> <Polyline.RenderTransform> <RotateTransform CenterX="0" CenterY="0" Angle="45" /> </Polyline.RenderTransform> </Polyline> </Canvas>
// Create a Polyline. Polyline polyline1 = new Polyline(); polyline1.Points.Add(new Point(25, 25)); polyline1.Points.Add(new Point(0, 50)); polyline1.Points.Add(new Point(25, 75)); polyline1.Points.Add(new Point(50, 50)); polyline1.Points.Add(new Point(25, 25)); polyline1.Points.Add(new Point(25, 0)); polyline1.Stroke = Brushes.Blue; polyline1.StrokeThickness = 10; // Create a RotateTransform to rotate // the Polyline 45 degrees about its // top-left corner. RotateTransform rotateTransform1 = new RotateTransform(45); polyline1.RenderTransform = rotateTransform1; // Create a Canvas to contain the Polyline. Canvas canvas1 = new Canvas(); canvas1.Width = 200; canvas1.Height = 200; Canvas.SetLeft(polyline1, 75); Canvas.SetTop(polyline1, 50); canvas1.Children.Add(polyline1);
The CenterX and CenterY properties of the RotateTransform specify the point about which the object is rotated. This center point is expressed in the coordinate space of the element that is transformed. By default, the rotation is applied to (0,0), which is the upper-left corner of the object to transform.
The next example rotates a Polyline object clockwise 45 degrees about the point (25,50).
<Canvas Height="200" Width="200"> <!-- Rotates the Polyline 45 degrees about the point (25,50). --> <Polyline Points="25,25 0,50 25,75 50,50 25,25 25,0" Stroke="Blue" StrokeThickness="10" Canvas.Left="75" Canvas.Top="50"> <Polyline.RenderTransform> <RotateTransform CenterX="25" CenterY="50" Angle="45" /> </Polyline.RenderTransform> </Polyline> </Canvas>
// Create a Polyline. Polyline polyline2 = new Polyline(); polyline2.Points = polyline1.Points; polyline2.Stroke = Brushes.Blue; polyline2.StrokeThickness = 10; // Create a RotateTransform to rotate // the Polyline 45 degrees about the // point (25,50). RotateTransform rotateTransform2 = new RotateTransform(45); rotateTransform2.CenterX = 25; rotateTransform2.CenterY = 50; polyline2.RenderTransform = rotateTransform2; // Create a Canvas to contain the Polyline. Canvas canvas2 = new Canvas(); canvas2.Width = 200; canvas2.Height = 200; Canvas.SetLeft(polyline2, 75); Canvas.SetTop(polyline2, 50); canvas2.Children.Add(polyline2);
The following illustration shows the results of applying a Transform to the two objects.
Two objects that rotate 45 degrees from different rotational centers
The Polyline in the previous examples is a UIElement. When you apply a Transform to the RenderTransform property of a UIElement, you can use the RenderTransformOrigin property to specify an origin for every Transform that you apply to the element. Because the RenderTransformOrigin property uses relative coordinates, you can apply a transformation to the center of the element even if you do not know its size. For more information and for an example, see How to: Specify the Origin of a Transform Using Relative Values.
For the complete sample, see 2-D Transforms Sample.
|How to: Make an Element Spin in Place|| |
This example shows how to make an element spin by using a RotateTransform and a DoubleAnimation.
|How to: Rotate an Object by Using a Geometric Path|| |
This example shows how to rotate (pivot) an object along a geometric path that is defined by a PathGeometry object.
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 EditionThe Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.