如何旋转对象
此示例演示如何旋转对象。 该示例首先创建一个 RotateTransform，然后指定其 Angle 的角度。
以下示例将一个 Polyline 对象围绕其的左上角旋转 45 度。
例
<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);
' Create a Polyline.
Dim polyline1 As 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.
Dim rotateTransform1 As New RotateTransform(45)
polyline1.RenderTransform = rotateTransform1
' Create a Canvas to contain the Polyline.
Dim canvas1 As New Canvas()
canvas1.Width = 200
canvas1.Height = 200
Canvas.SetLeft(polyline1, 75)
Canvas.SetTop(polyline1, 50)
canvas1.Children.Add(polyline1)
RotateTransform 的 CenterX 和 CenterY 属性指定对象旋转的点。 此中心点以转换的元素的坐标空间表示。 默认情况下，将围绕着要转换的对象的左上角 (0,0) 进行旋转。
下一个示例将 Polyline 对象围绕点（25,50）顺时针旋转 45 度。
<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);
' Create a Polyline.
Dim polyline2 As 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).
Dim rotateTransform2 As New RotateTransform(45)
rotateTransform2.CenterX = 25
rotateTransform2.CenterY = 50
polyline2.RenderTransform = rotateTransform2
' Create a Canvas to contain the Polyline.
Dim canvas2 As New Canvas()
canvas2.Width = 200
canvas2.Height = 200
Canvas.SetLeft(polyline2, 75)
Canvas.SetTop(polyline2, 50)
canvas2.Children.Add(polyline2)
下图显示了向两个对象应用 Transform 的结果。
两个从不同旋转中心旋转 45 度的对象
前面的示例中的 Polyline 是一个 UIElement。 当你将 Transform 应用于 UIElement的 RenderTransform 属性时，可以使用 RenderTransformOrigin 属性为应用到元素的每个 Transform 指定一个出处。 由于 RenderTransformOrigin 属性使用相对坐标，因此即使不知道其大小，也可以将转换应用到元素的中心。 有关详细信息和示例，请参阅 使用相对值指定变换的原点。
有关完整示例，请参阅 二维转换示例。
