CroppedBitmap Class

CroppedBitmap implements the ISupportInitialize interface to optimize initialization on multiple properties. Property changes can occur only during object initialization. Call BeginInit to signal that initialization has begun and EndInit to signal that initialization has completed. After initialization, property changes are ignored.

CroppedBitmap objects created by using the CroppedBitmap(BitmapSource, Int32Rect) constructor are automatically initialized, and properties cannot be changed.

Metadata tags related to image data must be updated if an image is saved to a file after a transform is applied.

Use the SourceRect property of this class to define the area of the bitmap that is to be cropped.

This example shows how to crop an image using CroppedBitmap.

CroppedBitmap is primarily used when encoding a cropped version of an image to save out to a file. To crop an image for display purposes see the How to: Create a Clip Region topic.

The following Extensible Application Markup Language (XAML) defines resources used within the samples below.

<Page.Resources>
   <!-- Define some image resources, for use as the image element source. -->
   <BitmapImage x:Key="masterImage" UriSource="/sampleImages/gecko.jpg" />
   <CroppedBitmap x:Key="croppedImage" 
      Source="{StaticResource masterImage}" SourceRect="30 20 105 50"/>
</Page.Resources>

The following example creates an image using a CroppedBitmap as its source.

<!-- Use the cropped image resource as the images source -->
<Image Width="200" Source="{StaticResource croppedImage}" 
   Margin="5" Grid.Column="0" Grid.Row="1" />

// Create an Image element.
Image croppedImage = new Image();
croppedImage.Width = 200;
croppedImage.Margin = new Thickness(5);

// Create a CroppedBitmap based off of a xaml defined resource.
CroppedBitmap cb = new CroppedBitmap(     
   (BitmapSource)this.Resources["masterImage"],
   new Int32Rect(30, 20, 105, 50));       //select region rect
croppedImage.Source = cb;                 //set image source to cropped

The CroppedBitmap can also be used as the source of another CroppedBitmap, chaining the cropping. Note that the SourceRect uses values that are relative to the source cropped bitmap and not the initial image.

<!-- Chain a cropped bitmap off a previosly defined cropped image -->
<Image Width="200" Grid.Column="0" Grid.Row="3" Margin="5">
   <Image.Source>
      <CroppedBitmap Source="{StaticResource croppedImage}" 
         SourceRect="30 0 75 50"/>
   </Image.Source>
</Image>

// Create an Image element.
Image chainImage = new Image();
chainImage.Width = 200;
chainImage.Margin = new Thickness(5);

// Create the cropped image based on previous CroppedBitmap.
CroppedBitmap chained = new CroppedBitmap(cb,
   new Int32Rect(30, 0, (int)cb.Width-30, (int)cb.Height)); 
// Set the image's source.
chainImage.Source = chained;

More Code

.NET Framework

.NET Framework Client Profile

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

Reference

Other Resources