本主题介绍如何使用ImageBrush、DrawingBrush和VisualBrush对象来将一个区域用图像、Drawing或Visual进行绘制。
先决条件
若要了解本主题，应熟悉 Windows Presentation Foundation（WPF）提供的不同类型的画笔及其基本功能。 有关简介，请参阅 WPF 画笔概述。
使用图像绘制区域
使用 ImageBrush 绘制一个有 ImageSource 的区域。 与 an ImageBrush 一起使用的最常用类型ImageSource是描述BitmapImage位图图形的一种。 可以使用对象 DrawingImage 进行绘制 Drawing ，但改用 DrawingBrush 更简单。 有关对象的详细信息 ImageSource ，请参阅 映像概述。
若要使用 a ImageBrush进行绘制，请创建一个 BitmapImage 并使用它来加载位图内容。 然后，使用BitmapImage设置ImageBrush的ImageSource属性。 最后，将 ImageBrush 对象应用于要绘制的对象。 在可扩展应用程序标记语言（XAML）中，还可以仅设置ImageSource的ImageBrush属性以加载图像的路径。
与所有 Brush 对象一样，可以使用对象 ImageBrush 绘制对象，如形状、面板、控件和文本。 下图显示了可以通过 ImageBrush 达到的一些效果。
由 ImageBrush 绘制的对象
默认情况下， ImageBrush 拉伸图像以完全填充所绘制的区域，如果绘制区域与图像的纵横比不同，则可能会扭曲图像。 可以通过将Stretch属性的默认值Fill更改为None、Uniform或UniformToFill来改变这种行为。 由于 ImageBrush 是一种类型 TileBrush，因此可以确切地指定图像画笔如何填充输出区域，甚至创建模式。 有关高级 TileBrush 功能的详细信息，请参阅 TileBrush 概述。
示例：使用位图图像绘制对象
下面的示例使用ImageBrush来绘制一个Canvas的Background。
<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="Microsoft.Samples.BrushExamples.ImageBrushExample"
WindowTitle="ImageBrush Example"
Background="White">
<StackPanel>
<Canvas
Height="200" Width="300">
<Canvas.Background>
<ImageBrush ImageSource="sampleImages\Waterlilies.jpg" />
</Canvas.Background>
</Canvas>
</StackPanel>
</Page>
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;
namespace Microsoft.Samples.BrushExamples
{
public class ImageBrushExample : Page
{
public ImageBrushExample()
{
StackPanel mainPanel = new StackPanel();
canvasBackgroundExample(mainPanel);
this.Content = mainPanel;
}
private void canvasBackgroundExample(Panel mainPanel)
{
BitmapImage theImage = new BitmapImage
(new Uri("sampleImages\\Waterlilies.jpg", UriKind.Relative));
ImageBrush myImageBrush = new ImageBrush(theImage);
Canvas myCanvas = new Canvas();
myCanvas.Width = 300;
myCanvas.Height = 200;
myCanvas.Background = myImageBrush;
mainPanel.Children.Add(myCanvas);
}
}
}
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Namespace Microsoft.Samples.BrushExamples
Public Class ImageBrushExample
Inherits Page
Public Sub New()
Dim mainPanel As New StackPanel()
canvasBackgroundExample(mainPanel)
Me.Content = mainPanel
End Sub
Private Sub canvasBackgroundExample(ByVal mainPanel As Panel)
Dim theImage As New BitmapImage(New Uri("sampleImages\Waterlilies.jpg", UriKind.Relative))
Dim myImageBrush As New ImageBrush(theImage)
Dim myCanvas As New Canvas()
myCanvas.Width = 300
myCanvas.Height = 200
myCanvas.Background = myImageBrush
mainPanel.Children.Add(myCanvas)
End Sub
End Class
End Namespace
使用绘图绘制区域
使用 A DrawingBrush ，可以使用形状、文本、图像和视频绘制区域。 绘图画笔内的形状可以用纯色、渐变、图像甚至其他颜色 DrawingBrush绘制。 下图演示了一 DrawingBrush些用法。
DrawingBrush 绘制的对象
DrawingBrush绘制具有Drawing对象的区域。 对象 Drawing 描述可见内容，如形状、位图、视频或文本行。 不同类型的绘图描述了不同类型的内容。 下面是不同类型的绘图对象的列表。
GeometryDrawing – 绘制形状。
ImageDrawing – 绘制图像。
GlyphRunDrawing – 绘制文本。
VideoDrawing – 播放音频或视频文件。
DrawingGroup – 绘制其他绘图。 使用绘图组将其他绘图合并成单个复合绘图。
有关 Drawing 对象的详细信息，请参阅 绘图对象概述。
就像ImageBrush，DrawingBrush拉伸其Drawing以填充其输出区域。 可以通过将Stretch属性从默认设置Fill更改来覆盖此行为。 有关详细信息，请参阅 Stretch 属性。
示例：使用绘图绘制对象
以下示例演示如何使用三个省略号的绘图绘制对象。 A GeometryDrawing 用于描述椭圆。
<Button Content="A Button">
<Button.Background>
<DrawingBrush>
<DrawingBrush.Drawing>
<GeometryDrawing Brush="LightBlue">
<GeometryDrawing.Geometry>
<GeometryGroup>
<EllipseGeometry RadiusX="12.5" RadiusY="25" Center="25,50" />
<EllipseGeometry RadiusX="12.5" RadiusY="25" Center="50,50" />
<EllipseGeometry RadiusX="12.5" RadiusY="25" Center="75,50" />
</GeometryGroup>
</GeometryDrawing.Geometry>
<GeometryDrawing.Pen>
<Pen Thickness="1" Brush="Gray" />
</GeometryDrawing.Pen>
</GeometryDrawing>
</DrawingBrush.Drawing>
</DrawingBrush>
</Button.Background>
</Button>
// Create a DrawingBrush.
DrawingBrush myDrawingBrush = new DrawingBrush();
// Create a drawing.
GeometryDrawing myGeometryDrawing = new GeometryDrawing();
myGeometryDrawing.Brush = Brushes.LightBlue;
myGeometryDrawing.Pen = new Pen(Brushes.Gray, 1);
GeometryGroup ellipses = new GeometryGroup();
ellipses.Children.Add(new EllipseGeometry(new Point(25,50), 12.5, 25));
ellipses.Children.Add(new EllipseGeometry(new Point(50,50), 12.5, 25));
ellipses.Children.Add(new EllipseGeometry(new Point(75,50), 12.5, 25));
myGeometryDrawing.Geometry = ellipses;
myDrawingBrush.Drawing = myGeometryDrawing;
Button myButton = new Button();
myButton.Content = "A Button";
// Use the DrawingBrush to paint the button's background.
myButton.Background = myDrawingBrush;
' Create a DrawingBrush.
Dim myDrawingBrush As New DrawingBrush()
' Create a drawing.
Dim myGeometryDrawing As New GeometryDrawing()
myGeometryDrawing.Brush = Brushes.LightBlue
myGeometryDrawing.Pen = New Pen(Brushes.Gray, 1)
Dim ellipses As New GeometryGroup()
ellipses.Children.Add(New EllipseGeometry(New Point(25,50), 12.5, 25))
ellipses.Children.Add(New EllipseGeometry(New Point(50,50), 12.5, 25))
ellipses.Children.Add(New EllipseGeometry(New Point(75,50), 12.5, 25))
myGeometryDrawing.Geometry = ellipses
myDrawingBrush.Drawing = myGeometryDrawing
Dim myButton As New Button()
myButton.Content = "A Button"
' Use the DrawingBrush to paint the button's background.
myButton.Background = myDrawingBrush
使用视觉对象绘制区域
在所有画笔中，VisualBrush是最多才多艺且最强大的，它能够用Visual涂色一个区域。 A Visual 是一种低级图形类型，充当许多有用图形组件的上级。 例如，WindowFrameworkElement和Control类是所有类型的Visual对象。 使用 VisualBrush，您可以在几乎任何 Windows Presentation Foundation（WPF）图形对象上进行区域绘制。
注释
虽然 VisualBrush 它是一种对象类型 Freezable ，但当对象的 Visual 属性设置为非 null值时，它不能被冻结（设为只读）。
有两种方法可以指定 VisualBrush 的 Visual 内容。
创建一个新的Visual，并使用它设置VisualBrush的Visual属性。 请参阅后续的 示例：使用视觉效果绘制对象 部分了解示例。
使用现有的 Visual，这将创建目标 Visual的重复映像。 然后可以使用 VisualBrush 来创建有趣的效果，例如反射和放大。 有关示例，请参阅 示例：创建反射 部分。
当您为VisualBrush定义新的Visual且该Visual是UIElement（例如面板或控件）时，布局系统将在AutoLayoutContent属性设置为true时运行于UIElement及其子元素。 但是，根 UIElement 基本上与系统的其余部分隔离：样式和外部布局不能渗透到此边界。 因此，应显式指定根 UIElement的大小，因为其唯一的父级是 VisualBrush ，因此它无法自动将自身大小调整到要绘制的区域。 有关 Windows Presentation Foundation 中布局的详细信息（WPF），请参阅 布局。
类似于 ImageBrush 和 DrawingBrush，VisualBrush 拉伸其内容以填充其输出区域。 可以通过将Stretch属性从默认设置Fill更改来覆盖此行为。 有关详细信息，请参阅 Stretch 属性。
示例：使用视觉效果装饰对象
在以下示例中，多个控件和面板用于绘制矩形。
<Rectangle Width="150" Height="150" Stroke="Black" Margin="5,0,5,0">
<Rectangle.Fill>
<VisualBrush>
<VisualBrush.Visual>
<StackPanel Background="White">
<Rectangle Width="25" Height="25" Fill="Red" Margin="2" />
<TextBlock FontSize="10pt" Margin="2">Hello, World!</TextBlock>
<Button Margin="2">A Button</Button>
</StackPanel>
</VisualBrush.Visual>
</VisualBrush>
</Rectangle.Fill>
</Rectangle>
VisualBrush myVisualBrush = new VisualBrush();
// Create the visual brush's contents.
StackPanel myStackPanel = new StackPanel();
myStackPanel.Background = Brushes.White;
Rectangle redRectangle = new Rectangle();
redRectangle.Width = 25;
redRectangle.Height =25;
redRectangle.Fill = Brushes.Red;
redRectangle.Margin = new Thickness(2);
myStackPanel.Children.Add(redRectangle);
TextBlock someText = new TextBlock();
FontSizeConverter myFontSizeConverter = new FontSizeConverter();
someText.FontSize = (double)myFontSizeConverter.ConvertFrom("10pt");
someText.Text = "Hello, World!";
someText.Margin = new Thickness(2);
myStackPanel.Children.Add(someText);
Button aButton = new Button();
aButton.Content = "A Button";
aButton.Margin = new Thickness(2);
myStackPanel.Children.Add(aButton);
// Use myStackPanel as myVisualBrush's content.
myVisualBrush.Visual = myStackPanel;
// Create a rectangle to paint.
Rectangle myRectangle = new Rectangle();
myRectangle.Width = 150;
myRectangle.Height = 150;
myRectangle.Stroke = Brushes.Black;
myRectangle.Margin = new Thickness(5,0,5,0);
// Use myVisualBrush to paint myRectangle.
myRectangle.Fill = myVisualBrush;
Dim myVisualBrush As New VisualBrush()
' Create the visual brush's contents.
Dim myStackPanel As New StackPanel()
myStackPanel.Background = Brushes.White
Dim redRectangle As New Rectangle()
With redRectangle
.Width = 25
.Height = 25
.Fill = Brushes.Red
.Margin = New Thickness(2)
End With
myStackPanel.Children.Add(redRectangle)
Dim someText As New TextBlock()
Dim myFontSizeConverter As New FontSizeConverter()
someText.FontSize = CDbl(myFontSizeConverter.ConvertFrom("10pt"))
someText.Text = "Hello, World!"
someText.Margin = New Thickness(2)
myStackPanel.Children.Add(someText)
Dim aButton As New Button()
aButton.Content = "A Button"
aButton.Margin = New Thickness(2)
myStackPanel.Children.Add(aButton)
' Use myStackPanel as myVisualBrush's content.
myVisualBrush.Visual = myStackPanel
' Create a rectangle to paint.
Dim myRectangle As New Rectangle()
With myRectangle
.Width = 150
.Height = 150
.Stroke = Brushes.Black
.Margin = New Thickness(5, 0, 5, 0)
End With
' Use myVisualBrush to paint myRectangle.
myRectangle.Fill = myVisualBrush
示例：创建反射
前面的示例演示了如何新建一个 Visual 用作背景的用途。 还可以使用 a VisualBrush 来显示现有视觉对象;此功能使你能够产生有趣的视觉效果，如反射和放大。 以下示例使用VisualBrush创建包含多个元素的Border反射效果。 下图显示了此示例生成的输出。
反射的视觉对象
using System;
using System.Windows;
using System.Windows.Data;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Effects;
using System.Windows.Media.Imaging;
using System.IO;
using System.Collections.ObjectModel;
using System.Windows.Shapes;
namespace SDKSample
{
public partial class ReflectionExample : Page
{
public ReflectionExample()
{
// Create a name scope for the page.
NameScope.SetNameScope(this, new NameScope());
this.Background = Brushes.Black;
StackPanel myStackPanel = new StackPanel();
myStackPanel.Margin = new Thickness(50);
Border myReflectedBorder = new Border();
this.RegisterName("ReflectedVisual", myReflectedBorder);
// Create a gradient background for the border.
GradientStop firstStop = new GradientStop();
firstStop.Offset = 0.0;
Color firstStopColor = new Color();
firstStopColor.R = 204;
firstStopColor.G = 204;
firstStopColor.B = 255;
firstStopColor.A = 255;
firstStop.Color = firstStopColor;
GradientStop secondStop = new GradientStop();
secondStop.Offset = 1.0;
secondStop.Color = Colors.White;
GradientStopCollection myGradientStopCollection = new GradientStopCollection();
myGradientStopCollection.Add(firstStop);
myGradientStopCollection.Add(secondStop);
LinearGradientBrush myLinearGradientBrush = new LinearGradientBrush();
myLinearGradientBrush.StartPoint = new Point(0, 0.5);
myLinearGradientBrush.EndPoint = new Point(1, 0.5);
myLinearGradientBrush.GradientStops = myGradientStopCollection;
myReflectedBorder.Background = myLinearGradientBrush;
// Add contents to the border.
StackPanel borderStackPanel = new StackPanel();
borderStackPanel.Orientation = Orientation.Horizontal;
borderStackPanel.Margin = new Thickness(10);
TextBlock myTextBlock = new TextBlock();
myTextBlock.TextWrapping = TextWrapping.Wrap;
myTextBlock.Width = 200;
myTextBlock.Text = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit." +
" Suspendisse vel ante. Donec luctus tortor sit amet est." +
" Nullam pulvinar odio et wisi." +
" Pellentesque quis magna. Sed pellentesque." +
" Nulla euismod." +
"Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas.";
borderStackPanel.Children.Add(myTextBlock);
StackPanel ellipseStackPanel = new StackPanel();
Ellipse ellipse1 = new Ellipse();
ellipse1.Margin = new Thickness(10);
ellipse1.Height = 50;
ellipse1.Width = 50;
ellipse1.Fill = Brushes.Black;
ellipseStackPanel.Children.Add(ellipse1);
Ellipse ellipse2 = new Ellipse();
ellipse2.Margin = new Thickness(10);
ellipse2.Height = 50;
ellipse2.Width = 50;
ellipse2.Fill = Brushes.Black;
ellipseStackPanel.Children.Add(ellipse2);
Ellipse ellipse3 = new Ellipse();
ellipse3.Margin = new Thickness(10);
ellipse3.Height = 50;
ellipse3.Width = 50;
ellipse3.Fill = Brushes.Black;
ellipseStackPanel.Children.Add(ellipse3);
borderStackPanel.Children.Add(ellipseStackPanel);
myReflectedBorder.Child = borderStackPanel;
// Create divider rectangle
Rectangle dividerRectangle = new Rectangle();
dividerRectangle.Height = 1;
dividerRectangle.Fill = Brushes.Gray;
dividerRectangle.HorizontalAlignment = HorizontalAlignment.Stretch;
// Create the object to contain the reflection.
Rectangle reflectionRectangle = new Rectangle();
// Bind the height of the rectangle to the border height.
Binding heightBinding = new Binding();
heightBinding.ElementName = "ReflectedVisual";
heightBinding.Path = new PropertyPath(Rectangle.HeightProperty);
BindingOperations.SetBinding(reflectionRectangle, Rectangle.HeightProperty, heightBinding);
// Bind the width of the rectangle to the border width.
Binding widthBinding = new Binding();
widthBinding.ElementName = "ReflectedVisual";
widthBinding.Path = new PropertyPath(Rectangle.WidthProperty);
BindingOperations.SetBinding(reflectionRectangle, Rectangle.WidthProperty, widthBinding);
// Creates the reflection.
VisualBrush myVisualBrush = new VisualBrush();
myVisualBrush.Opacity = 0.75;
myVisualBrush.Stretch = Stretch.None;
Binding reflectionBinding = new Binding();
reflectionBinding.ElementName = "ReflectedVisual";
BindingOperations.SetBinding(myVisualBrush, VisualBrush.VisualProperty, reflectionBinding);
ScaleTransform myScaleTransform = new ScaleTransform();
myScaleTransform.ScaleX = 1;
myScaleTransform.ScaleY = -1;
TranslateTransform myTranslateTransform = new TranslateTransform();
myTranslateTransform.Y = 1;
TransformGroup myTransformGroup = new TransformGroup();
myTransformGroup.Children.Add(myScaleTransform);
myTransformGroup.Children.Add(myTranslateTransform);
myVisualBrush.RelativeTransform = myTransformGroup;
reflectionRectangle.Fill = myVisualBrush;
// Create a gradient background for the border.
GradientStop firstStop2 = new GradientStop();
firstStop2.Offset = 0.0;
Color c1 = new Color();
c1.R = 0;
c1.G = 0;
c1.B = 0;
c1.A = 255;
firstStop2.Color = c1;
GradientStop secondStop2 = new GradientStop();
secondStop2.Offset = 0.5;
Color c2 = new Color();
c2.R = 0;
c2.G = 0;
c2.B = 0;
c2.A = 51;
firstStop2.Color = c2;
GradientStop thirdStop = new GradientStop();
thirdStop.Offset = 0.75;
Color c3 = new Color();
c3.R = 0;
c3.G = 0;
c3.B = 0;
c3.A = 0;
thirdStop.Color = c3;
GradientStopCollection myGradientStopCollection2 = new GradientStopCollection();
myGradientStopCollection2.Add(firstStop2);
myGradientStopCollection2.Add(secondStop2);
myGradientStopCollection2.Add(thirdStop);
LinearGradientBrush myLinearGradientBrush2 = new LinearGradientBrush();
myLinearGradientBrush2.StartPoint = new Point(0.5, 0);
myLinearGradientBrush2.EndPoint = new Point(0.5, 1);
myLinearGradientBrush2.GradientStops = myGradientStopCollection2;
reflectionRectangle.OpacityMask = myLinearGradientBrush2;
BlurBitmapEffect myBlurBitmapEffect = new BlurBitmapEffect();
myBlurBitmapEffect.Radius = 1.5;
reflectionRectangle.BitmapEffect = myBlurBitmapEffect;
myStackPanel.Children.Add(myReflectedBorder);
myStackPanel.Children.Add(dividerRectangle);
myStackPanel.Children.Add(reflectionRectangle);
this.Content = myStackPanel;
}
/*
<Rectangle
Height="{Binding Path=ActualHeight, ElementName=ReflectedVisual}"
Width="{Binding Path=ActualWidth, ElementName=ReflectedVisual}">
<Rectangle.OpacityMask>
<LinearGradientBrush StartPoint="0.5,0" EndPoint="0.5,1">
<GradientStop Color="#FF000000" Offset="0.0" />
<GradientStop Color="#33000000" Offset="0.5" />
<GradientStop Color="#00000000" Offset="0.75" />
</LinearGradientBrush>
</Rectangle.OpacityMask>
<Rectangle.BitmapEffect>
<BlurBitmapEffect Radius="1.5" />
</Rectangle.BitmapEffect>
</Rectangle>
</StackPanel>
</Page>
*/
}
}
Imports System.Windows
Imports System.Windows.Data
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Media.Effects
Imports System.Windows.Media.Imaging
Imports System.IO
Imports System.Collections.ObjectModel
Imports System.Windows.Shapes
Namespace SDKSample
Partial Public Class ReflectionExample
Inherits Page
Public Sub New()
' Create a name scope for the page.
NameScope.SetNameScope(Me, New NameScope())
Me.Background = Brushes.Black
Dim myStackPanel As New StackPanel()
myStackPanel.Margin = New Thickness(50)
Dim myReflectedBorder As New Border()
Me.RegisterName("ReflectedVisual", myReflectedBorder)
' Create a gradient background for the border.
Dim firstStop As New GradientStop()
firstStop.Offset = 0.0
Dim firstStopColor As New Color()
firstStopColor.R = 204
firstStopColor.G = 204
firstStopColor.B = 255
firstStopColor.A = 255
firstStop.Color = firstStopColor
Dim secondStop As New GradientStop()
secondStop.Offset = 1.0
secondStop.Color = Colors.White
Dim myGradientStopCollection As New GradientStopCollection()
myGradientStopCollection.Add(firstStop)
myGradientStopCollection.Add(secondStop)
Dim myLinearGradientBrush As New LinearGradientBrush()
myLinearGradientBrush.StartPoint = New Point(0, 0.5)
myLinearGradientBrush.EndPoint = New Point(1, 0.5)
myLinearGradientBrush.GradientStops = myGradientStopCollection
myReflectedBorder.Background = myLinearGradientBrush
' Add contents to the border.
Dim borderStackPanel As New StackPanel()
borderStackPanel.Orientation = Orientation.Horizontal
borderStackPanel.Margin = New Thickness(10)
Dim myTextBlock As New TextBlock()
myTextBlock.TextWrapping = TextWrapping.Wrap
myTextBlock.Width = 200
myTextBlock.Text = "Lorem ipsum dolor sit amet, consectetuer adipiscing elit." & " Suspendisse vel ante. Donec luctus tortor sit amet est." & " Nullam pulvinar odio et wisi." & " Pellentesque quis magna. Sed pellentesque." & " Nulla euismod." & "Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas."
borderStackPanel.Children.Add(myTextBlock)
Dim ellipseStackPanel As New StackPanel()
Dim ellipse1 As New Ellipse()
ellipse1.Margin = New Thickness(10)
ellipse1.Height = 50
ellipse1.Width = 50
ellipse1.Fill = Brushes.Black
ellipseStackPanel.Children.Add(ellipse1)
Dim ellipse2 As New Ellipse()
ellipse2.Margin = New Thickness(10)
ellipse2.Height = 50
ellipse2.Width = 50
ellipse2.Fill = Brushes.Black
ellipseStackPanel.Children.Add(ellipse2)
Dim ellipse3 As New Ellipse()
ellipse3.Margin = New Thickness(10)
ellipse3.Height = 50
ellipse3.Width = 50
ellipse3.Fill = Brushes.Black
ellipseStackPanel.Children.Add(ellipse3)
borderStackPanel.Children.Add(ellipseStackPanel)
myReflectedBorder.Child = borderStackPanel
' Create divider rectangle
Dim dividerRectangle As New Rectangle()
dividerRectangle.Height = 1
dividerRectangle.Fill = Brushes.Gray
dividerRectangle.HorizontalAlignment = HorizontalAlignment.Stretch
' Create the object to contain the reflection.
Dim reflectionRectangle As New Rectangle()
' Bind the height of the rectangle to the border height.
Dim heightBinding As New Binding()
heightBinding.ElementName = "ReflectedVisual"
heightBinding.Path = New PropertyPath(Rectangle.HeightProperty)
BindingOperations.SetBinding(reflectionRectangle, Rectangle.HeightProperty, heightBinding)
' Bind the width of the rectangle to the border width.
Dim widthBinding As New Binding()
widthBinding.ElementName = "ReflectedVisual"
widthBinding.Path = New PropertyPath(Rectangle.WidthProperty)
BindingOperations.SetBinding(reflectionRectangle, Rectangle.WidthProperty, widthBinding)
' Creates the reflection.
Dim myVisualBrush As New VisualBrush()
myVisualBrush.Opacity = 0.75
myVisualBrush.Stretch = Stretch.None
Dim reflectionBinding As New Binding()
reflectionBinding.ElementName = "ReflectedVisual"
BindingOperations.SetBinding(myVisualBrush, VisualBrush.VisualProperty, reflectionBinding)
Dim myScaleTransform As New ScaleTransform()
myScaleTransform.ScaleX = 1
myScaleTransform.ScaleY = -1
Dim myTranslateTransform As New TranslateTransform()
myTranslateTransform.Y = 1
Dim myTransformGroup As New TransformGroup()
myTransformGroup.Children.Add(myScaleTransform)
myTransformGroup.Children.Add(myTranslateTransform)
myVisualBrush.RelativeTransform = myTransformGroup
reflectionRectangle.Fill = myVisualBrush
' Create a gradient background for the border.
Dim firstStop2 As New GradientStop()
firstStop2.Offset = 0.0
Dim c1 As New Color()
c1.R = 0
c1.G = 0
c1.B = 0
c1.A = 255
firstStop2.Color = c1
Dim secondStop2 As New GradientStop()
secondStop2.Offset = 0.5
Dim c2 As New Color()
c2.R = 0
c2.G = 0
c2.B = 0
c2.A = 51
firstStop2.Color = c2
Dim thirdStop As New GradientStop()
thirdStop.Offset = 0.75
Dim c3 As New Color()
c3.R = 0
c3.G = 0
c3.B = 0
c3.A = 0
thirdStop.Color = c3
Dim myGradientStopCollection2 As New GradientStopCollection()
myGradientStopCollection2.Add(firstStop2)
myGradientStopCollection2.Add(secondStop2)
myGradientStopCollection2.Add(thirdStop)
Dim myLinearGradientBrush2 As New LinearGradientBrush()
myLinearGradientBrush2.StartPoint = New Point(0.5, 0)
myLinearGradientBrush2.EndPoint = New Point(0.5, 1)
myLinearGradientBrush2.GradientStops = myGradientStopCollection2
reflectionRectangle.OpacityMask = myLinearGradientBrush2
Dim myBlurBitmapEffect As New BlurBitmapEffect()
myBlurBitmapEffect.Radius = 1.5
reflectionRectangle.BitmapEffect = myBlurBitmapEffect
myStackPanel.Children.Add(myReflectedBorder)
myStackPanel.Children.Add(dividerRectangle)
myStackPanel.Children.Add(reflectionRectangle)
Me.Content = myStackPanel
End Sub
End Class
End Namespace
<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Background="Black">
<StackPanel Margin="50">
<!-- The object to reflect. -->
<Border Name="ReflectedVisual" Width="400">
<Border.Background>
<LinearGradientBrush StartPoint="0,0.5" EndPoint="1,0.5">
<GradientStop Offset="0.0" Color="#CCCCFF" />
<GradientStop Offset="1.0" Color="White" />
</LinearGradientBrush>
</Border.Background>
<StackPanel Orientation="Horizontal" Margin="10">
<TextBlock TextWrapping="Wrap" Width="200" Margin="10">
Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
Suspendisse vel ante. Donec luctus tortor sit amet est.
Nullam pulvinar odio et wisi.
Pellentesque quis magna. Sed pellentesque.
Nulla euismod.
Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas.
</TextBlock>
<StackPanel>
<Ellipse Margin="10" Height="50" Width="50" Fill="Black" />
<Ellipse Margin="10" Height="50" Width="50" Fill="Black" />
<Ellipse Margin="10" Height="50" Width="50" Fill="Black" />
</StackPanel>
</StackPanel>
</Border>
<Rectangle Height="1" Fill="Gray" HorizontalAlignment="Stretch" />
<!-- The object to contain the reflection.-->
<Rectangle
Height="{Binding Path=ActualHeight, ElementName=ReflectedVisual}"
Width="{Binding Path=ActualWidth, ElementName=ReflectedVisual}">
<Rectangle.Fill>
<!-- Creates the reflection. -->
<VisualBrush
Opacity="0.75" Stretch="None"
Visual="{Binding ElementName=ReflectedVisual}">
<VisualBrush.RelativeTransform>
<!-- Flip the reflection. -->
<TransformGroup>
<ScaleTransform ScaleX="1" ScaleY="-1" />
<TranslateTransform Y="1" />
</TransformGroup>
</VisualBrush.RelativeTransform>
</VisualBrush>
</Rectangle.Fill>
<Rectangle.OpacityMask>
<LinearGradientBrush StartPoint="0.5,0" EndPoint="0.5,1">
<GradientStop Color="#FF000000" Offset="0.0" />
<GradientStop Color="#33000000" Offset="0.5" />
<GradientStop Color="#00000000" Offset="0.75" />
</LinearGradientBrush>
</Rectangle.OpacityMask>
<Rectangle.BitmapEffect>
<BlurBitmapEffect Radius="1.5" />
</Rectangle.BitmapEffect>
</Rectangle>
</StackPanel>
</Page>
有关演示如何放大屏幕部分以及如何创建反射的其他示例，请参阅 VisualBrush 示例。
TileBrush 功能
ImageBrush、DrawingBrush和VisualBrush 是TileBrush类型的对象。 TileBrush 对象赋予你极大的控制权，决定如何使用图像、绘图或视觉效果来绘制区域。 例如，不使用单个拉伸图像绘制区域，而是使用创建图案的一系列平铺图像绘制区域。
A TileBrush 有三个主要组件：内容、磁贴和输出区域。
具有单个图块的 TileBrush 的组成部分
具有多个磁贴的 TileBrush 组件
有关 TileBrush 对象的平铺功能的更多详细信息，请参阅 TileBrush 概述。
