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如何：变换画笔

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此示例演示如何使用两个转换属性转换 Brush 对象：RelativeTransform 和 Transform。

以下示例使用 RotateTransform 将 ImageBrush 的内容旋转 45 度。

下图显示了没有 RotateTransform的 ImageBrush，其中 RotateTransform 应用于 RelativeTransform 属性，RotateTransform 应用于 Transform 属性。

画笔的 RelativeTransform 和 Transform 设置

例

第一个示例将 RotateTransform 应用于 ImageBrush的 RelativeTransform 属性。 RotateTransform 对象的 CenterX 和 CenterY 属性都设置为 0.5，这是此内容的中心点的相对坐标。 因此，ImageBrush 的内容绕其中心旋转。

//
// Create an ImageBrush with a relative transform and
// use it to paint a rectangle.
//
ImageBrush relativeTransformImageBrush = new ImageBrush();
relativeTransformImageBrush.ImageSource =
    new BitmapImage(new Uri(@"sampleImages\pinkcherries.jpg", UriKind.Relative));

// Create a 45 rotate transform about the brush's center
// and apply it to the brush's RelativeTransform property.
RotateTransform aRotateTransform = new RotateTransform();
aRotateTransform.CenterX = 0.5;
aRotateTransform.CenterY = 0.5;
aRotateTransform.Angle = 45;
relativeTransformImageBrush.RelativeTransform = aRotateTransform;

// Use the brush to paint a rectangle.
Rectangle relativeTransformImageBrushRectangle = new Rectangle();
relativeTransformImageBrushRectangle.Width = 175;
relativeTransformImageBrushRectangle.Height = 90;
relativeTransformImageBrushRectangle.Stroke = Brushes.Black;
relativeTransformImageBrushRectangle.Fill = relativeTransformImageBrush;


'
' Create an ImageBrush with a relative transform and
' use it to paint a rectangle.
'
Dim relativeTransformImageBrush As New ImageBrush()
relativeTransformImageBrush.ImageSource = New BitmapImage(New Uri("sampleImages\pinkcherries.jpg", UriKind.Relative))

' Create a 45 rotate transform about the brush's center
' and apply it to the brush's RelativeTransform property.
Dim aRotateTransform As New RotateTransform()
aRotateTransform.CenterX = 0.5
aRotateTransform.CenterY = 0.5
aRotateTransform.Angle = 45
relativeTransformImageBrush.RelativeTransform = aRotateTransform

' Use the brush to paint a rectangle.
Dim relativeTransformImageBrushRectangle As New Rectangle()
relativeTransformImageBrushRectangle.Width = 175
relativeTransformImageBrushRectangle.Height = 90
relativeTransformImageBrushRectangle.Stroke = Brushes.Black
relativeTransformImageBrushRectangle.Fill = relativeTransformImageBrush


<Rectangle Width="175" Height="90" Stroke="Black">
  <Rectangle.Fill>
    <ImageBrush ImageSource="sampleImages\pinkcherries.jpg">
      <ImageBrush.RelativeTransform>
        <RotateTransform CenterX="0.5" CenterY="0.5" Angle="45" />
      </ImageBrush.RelativeTransform>
    </ImageBrush>
  </Rectangle.Fill>
</Rectangle>

第二个示例还对 ImageBrush应用 RotateTransform;但是，此示例使用 Transform 属性而不是 RelativeTransform 属性。

若要围绕其中心旋转画笔，本示例将 CenterX 和 CenterYRotateTransform 对象的属性设置为绝对坐标。 由于画笔绘制的矩形为 175 x 90 像素，因此矩形的中心点为 （87.5， 45）。

//
// Create an ImageBrush with a transform and
// use it to paint a rectangle.
//
ImageBrush transformImageBrush = new ImageBrush();
transformImageBrush.ImageSource =
    new BitmapImage(new Uri(@"sampleImages\pinkcherries.jpg", UriKind.Relative));

// Create a 45 rotate transform about the brush's center
// and apply it to the brush's Transform property.
RotateTransform anotherRotateTransform = new RotateTransform();
anotherRotateTransform.CenterX = 87.5;
anotherRotateTransform.CenterY = 45;
anotherRotateTransform.Angle = 45;
transformImageBrush.Transform = anotherRotateTransform;

// Use the brush to paint a rectangle.
Rectangle transformImageBrushRectangle = new Rectangle();
transformImageBrushRectangle.Width = 175;
transformImageBrushRectangle.Height = 90;
transformImageBrushRectangle.Stroke = Brushes.Black;
transformImageBrushRectangle.Fill = transformImageBrush;


'
' Create an ImageBrush with a transform and
' use it to paint a rectangle.
'
Dim transformImageBrush As New ImageBrush()
transformImageBrush.ImageSource = New BitmapImage(New Uri("sampleImages\pinkcherries.jpg", UriKind.Relative))

' Create a 45 rotate transform about the brush's center
' and apply it to the brush's Transform property.
Dim anotherRotateTransform As New RotateTransform()
anotherRotateTransform.CenterX = 87.5
anotherRotateTransform.CenterY = 45
anotherRotateTransform.Angle = 45
transformImageBrush.Transform = anotherRotateTransform

' Use the brush to paint a rectangle.
Dim transformImageBrushRectangle As New Rectangle()
transformImageBrushRectangle.Width = 175
transformImageBrushRectangle.Height = 90
transformImageBrushRectangle.Stroke = Brushes.Black
transformImageBrushRectangle.Fill = transformImageBrush


<Rectangle Width="175" Height="90" Stroke="Black">
  <Rectangle.Fill>
    <ImageBrush ImageSource="sampleImages\pinkcherries.jpg">
      <ImageBrush.Transform>
        <RotateTransform CenterX="87.5" CenterY="45" Angle="45" />
      </ImageBrush.Transform>
    </ImageBrush>
  </Rectangle.Fill>
</Rectangle>

有关 RelativeTransform 和 Transform 属性的工作原理的说明，请参阅 画笔转换概述。

有关完整示例，请参阅画笔示例。 有关画笔的详细信息，请参阅 纯色和渐变绘制概述。

另请参阅