如何：向 Visual 应用模糊效果
更新：2007 年 11 月
BlurBitmapEffect 可用于使可见对象模糊。下面是关于以下主题的一系列示例：
如何使用简单的标记将效果应用于对象
如何使用 Style 将效果应用于一个或多个对象
如何使用代码将效果应用于对象
如何使用动画对应用于对象的效果的属性进行动画处理
**注意：**下面的所有示例都只将单一效果应用于对象。若要应用多个效果，请使用 BitmapEffectGroup。请参见如何：创建多个可视化效果中的示例。
示例
下面的示例演示如何使用 BlurBitmapEffect 来创建模糊 Button。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml">
<StackPanel>
<Button Width="200">You Can't Read This!
<Button.BitmapEffect>
<!-- <BitmapEffectGroup> would go here if you wanted to apply more
then one effect to the Button. However, in this example only
one effect is being applied so BitmapEffectGroup does not need
to be included. -->
<!-- The larger the Radius, the more blurring. The default range is 20.
In addition, the KernelType is set to a box kernel. A box kernel
creates less disruption (less blur) then the default Gaussian kernel. -->
<BlurBitmapEffect Radius="10" KernelType="Box" />
</Button.BitmapEffect>
</Button>
</StackPanel>
</Page>
下面的插图演示了上一示例中创建的效果。
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下面的示例演示在按下页面上的任何 Button 时，如何使用 Style 向该按钮应用 BlurBitmapEffect。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml">
<!-- Resources define Styles for the entire page. -->
<Page.Resources>
<!-- This style applies to any Button on the page. -->
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<!-- When the Button is pressed, apply the blur. -->
<Trigger Property="IsPressed" Value="true">
<Setter Property = "BitmapEffect" >
<Setter.Value>
<BlurBitmapEffect Radius="10" />
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</Page.Resources>
<StackPanel>
<!-- The Style defined above applies to this Button which makes
the Button appear blurred while it is pressed. -->
<Button Width="200" >Blurning down the House!</Button>
</StackPanel>
</Page>
下面的示例演示在单击 Button 时，如何使用代码向该按钮应用 BlurBitmapEffect。
下面是该示例的可扩展应用程序标记语言 (XAML) 版本。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SDKSample.BlurExample" >
<StackPanel>
<Button Click="OnClickBlurButton" Width="200">Click to Blur!</Button>
</StackPanel>
</Page>
下面的代码示例是用来为可扩展应用程序标记语言 (XAML) 处理事件的代码。
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Input;
using System.Windows.Media.Effects;
namespace SDKSample
{
public partial class BlurExample : Page
{
// Add Blur effect.
void OnClickBlurButton(object sender, RoutedEventArgs args)
{
// Toggle effect
if (((Button)sender).BitmapEffect != null)
{
((Button)sender).BitmapEffect = null;
}
else
{
// Get a reference to the Button.
Button myButton = (Button)sender;
// Initialize a new BlurBitmapEffect that will be applied
// to the Button.
BlurBitmapEffect myBlurEffect = new BlurBitmapEffect();
// Set the Radius property of the blur. This determines how
// blurry the effect will be. The larger the radius, the more
// blurring.
myBlurEffect.Radius = 10;
// Set the KernelType property of the blur. A KernalType of "Box"
// creates less blur than the Gaussian kernal type.
myBlurEffect.KernelType = KernelType.Box;
// Apply the bitmap effect to the Button.
myButton.BitmapEffect = myBlurEffect;
}
}
}
}
下面的示例演示如何对 BlurBitmapEffect 的 Radius 属性进行动画处理，以便 Button 在被单击之后变得模糊。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml" >
<StackPanel>
<Button Width="200">
Click to Blur ME!
<Button.BitmapEffect>
<!-- This BitmapEffect is targeted by the animation. -->
<BlurBitmapEffect x:Name="myBlurBitmapEffect" Radius="0" />
</Button.BitmapEffect>
<Button.Triggers>
<EventTrigger RoutedEvent="Button.Click">
<BeginStoryboard>
<Storyboard>
<!-- Blur the Button and then animate back to normal. -->
<DoubleAnimation
Storyboard.TargetName="myBlurBitmapEffect"
Storyboard.TargetProperty="Radius"
From="0" To="40" Duration="0:0:0.3"
AutoReverse="True" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Button.Triggers>
</Button>
</StackPanel>
</Page>