Gets or sets the y-coordinate of the rotation center point.
Assembly: PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/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 of the RotateTransform to the center of the object to rotate.
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>
The CenterX and 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>
The following illustration shows the results of applying a Transform to the two objects.
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 by Using Relative Values.
For the complete sample, see 2-D Transforms Sample.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2