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DropShadowBitmapEffect Class

Applies a shadow behind a visual object at a slight offset. The offset is determined by mimicking a casting shadow from an imaginary light source.

Namespace:  System.Windows.Media.Effects
Assembly:  PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public sealed class DropShadowBitmapEffect : BitmapEffect
<DropShadowBitmapEffect .../>

NoteNote:

WPF bitmap effects are software rendered. Any object that applies an effect will also be rendered in software. Bitmap effects should not be applied to large visuals or animations because this can degrade performance.

The DropShadowBitmapEffect can be used to create what looks like a shadow behind a visible object. Below are a series of examples that show the following:

  • How to use simple markup to apply the effect to an object

  • How to use a Style to apply the effect to one or more objects

  • How to use code to apply the effect to an object

  • How to use an animation to animate the properties of an effect applied to an object

Note: All of the examples below apply only a single effect to an object. To apply multiple effects, you can use BitmapEffectGroup. See How to: Create Multiple Visual Effects for examples.

The following example shows how to use a DropShadowBitmapEffect to create the appearance of a shadow behind a Button.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

  <StackPanel>

    <Button Margin="50" Width="200">DropShadow Under this Button
      <Button.BitmapEffect>

      <!-- <BitmapEffectGroup> would go here if you wanted to apply more 
             then one effect to the TextBox. However, in this example only  
             one effect is being applied so BitmapEffectGroup does not need  
             to be included. -->

        <!-- The DropShadowBitmapEffect has several important properties that
             determine characteristics of the drop shadow: 
             - Color: Specifies the color of the drop shadow (in this example black).
             - ShadowDepth: Specifies how far displaced the shadow is from the object
               casting the shadow. Default is 20.
             - Direction: Specifies in what direction the shadow is cast from the object. 
               It is an angle between 0 and 360 with 0 starting on the right hand side 
               and moving counter-clockwise around the object. The value of 320 in this 
               example casts the shadow on the lower right hand side of the button.
             - Noise: Specifies how grainy the drop-shadow is. Range is between 0 and 1.
               Default is 0.
             - Softness: Specifies how soft the shadow. The range is between 0 and 1 with 1
               being the softest. Default is 0.5. 
             - Opacity: Specifies how transparent the shadow is. The range is between 0 
               and 1 with 1 being fully opaque and 0 fully transparent (not visible). The
               default is 1. -->
        <DropShadowBitmapEffect Color="Black" Direction="320" ShadowDepth="25" Softness="1" 
         Opacity="0.5"/>

      </Button.BitmapEffect>
    </Button>

  </StackPanel>

</Page>

The following illustration shows the effect created in the previous example.

Screenshot: DropShadowBitmapEffect

The following example shows how to use a Style to apply a DropShadowBitmapEffect to any Button on the page while it is pressed.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://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 drop shadow. -->
        <Trigger Property="IsPressed" Value="true">
          <Setter Property = "BitmapEffect" >
            <Setter.Value>
              <DropShadowBitmapEffect Color="Black" Direction="320"  
               ShadowDepth="25" Softness="1" Opacity="0.5"/>
            </Setter.Value>
          </Setter>
        </Trigger>
      </Style.Triggers>
    </Style>
  </Page.Resources>

  <StackPanel>

    <!-- The Style defined above applies to this Button which creates
         a drop shadow when the button is pressed down. -->
    <Button Width="200" >Press Me!</Button>

  </StackPanel>

</Page>

The following example shows how to use code to apply a DropShadowBitmapEffect to a Button when it is clicked.

This following is the Extensible Application Markup Language (XAML) for the example.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="SDKSample.DropShadowExample" >

  <StackPanel>

    <Button Click="OnClickDropShadowButton" Margin="50"  Width="200">
    Click to Create Drop Shadow!</Button>

  </StackPanel>

</Page>

The following is the code that handles the event for the example markup.

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 DropShadowExample : Page
	{

        // Add Blur effect.
        void OnClickDropShadowButton(object sender, RoutedEventArgs args)
        {

            // Get a reference to the Button.
            Button myButton = (Button)sender;

            // Initialize a new DropShadowBitmapEffect that will be applied
            // to the Button.
            DropShadowBitmapEffect myDropShadowEffect = new DropShadowBitmapEffect();

            // Set the color of the shadow to Black.
            Color myShadowColor = new Color();
            myShadowColor.ScA = 1; // Note that the alpha value is ignored by Color property. The Opacity property is used to control the alpha.
            myShadowColor.ScB = 0;
            myShadowColor.ScG = 0;
            myShadowColor.ScR = 0;
            myDropShadowEffect.Color = myShadowColor;

            // Set the direction of where the shadow is cast to 320 degrees.
            myDropShadowEffect.Direction = 320;

            // Set the depth of the shadow being cast.
            myDropShadowEffect.ShadowDepth = 25;

            // Set the shadow softness to the maximum (range of 0-1).
            myDropShadowEffect.Softness = 1;

            // Set the shadow opacity to half opaque or in other words - half transparent.
            // The range is 0-1.
            myDropShadowEffect.Opacity = 0.5;

            // Apply the bitmap effect to the Button.
            myButton.BitmapEffect = myDropShadowEffect;

        }

    }
}

The following example shows how to animate the ShadowDepth and Softness of the DropShadowBitmapEffect to make it appear like the Button is lifting off of the surface of the screen after it is clicked.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >

  <StackPanel>

    <Button Margin="50" Width="200" Name="myButton">
      Click Me to Animate Drop Shadow!
      <Button.BitmapEffect>

        <!-- This BitmapEffect is targeted by the animation. -->
        <DropShadowBitmapEffect x:Name="myDropShadowBitmapEffect" Color="Black"   
         ShadowDepth="0" />
      </Button.BitmapEffect>
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Click">
          <BeginStoryboard>
            <Storyboard>

              <!-- Animate the movement of the button. -->
              <ThicknessAnimation
               Storyboard.TargetProperty="Margin" Duration="0:0:0.5" 
               From="50,50,50,50" To="0,0,50,50" AutoReverse="True" />

              <!-- Animate shadow depth of the effect. -->
              <DoubleAnimation
               Storyboard.TargetName="myDropShadowBitmapEffect"
               Storyboard.TargetProperty="ShadowDepth"
               From="0" To="30" Duration="0:0:0.5"
               AutoReverse="True" />

              <!-- Animate shadow softness of the effect. As 
                   the Button appears to get farther from the shadow,  
                   the shadow gets softer. -->
              <DoubleAnimation
               Storyboard.TargetName="myDropShadowBitmapEffect"
               Storyboard.TargetProperty="Softness"
               From="0" To="1" Duration="0:0:0.5"
               AutoReverse="True" />
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Button.Triggers>
    </Button>

  </StackPanel>

</Page>

More Code

How to: Animate a Drop Shadow Visual Effect The following example shows how to animate the ShadowDepth and Softness of the DropShadowBitmapEffect to make it appear like the Button is lifting off of the surface of the screen after it is clicked.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0

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