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BitmapDecoder Class

Represents a container for bitmap frames. Each bitmap frame is a BitmapSource. This abstract class provides a base set of functionality for all derived decoder objects.

Namespace:  System.Windows.Media.Imaging
Assembly:  PresentationCore (in PresentationCore.dll)

'Declaration
Public MustInherit Class BitmapDecoder _
	Inherits DispatcherObject
'Usage
Dim instance As BitmapDecoder
This class is abstract; see Inheritance Hierarchy for derived non-abstract classes usable in XAML.

BitmapDecoder is not a BitmapFrame itself; rather, it is a container for BitmapFrame objects. Each BitmapFrame in the container can potentially have different attributes, including different sizes, resolutions, or palettes.

Unless a specific codec is selected, Windows Presentation Foundation (WPF) uses automatic run-time discovery to identify the format of an image and match it with the appropriate codec. This discovery process allows a codec developed by an independent software vendor (ISV) to be automatically discoverable by the system. To select a specific codec, the derived BitmapDecoder or BitmapEncoder, such as the TiffBitmapDecoder class, should be used.

Tagged Image File Format (TIFF) and Graphics Interchange Format (GIF) are the only implemented image formats that support multiple frames.

The following example demonstrates how to use the Create(Uri, BitmapCreateOptions, BitmapCacheOption) method to create a decoder for a given image. The first BitmapFrame of the image is used as the source of an Image control.

Dim uriBitmap As BitmapDecoder = BitmapDecoder.Create(New Uri("sampleImages/waterlilies.jpg", UriKind.Relative), BitmapCreateOptions.None, BitmapCacheOption.Default)

' Create an image element; 
Dim uriImage As New Image()
uriImage.Width = 200
' Set image source.
uriImage.Source = uriBitmap.Frames(0)

The following code example demonstrates how to use the built in TiffBitmapDecoder to open and decode a Tagged Image File Format (TIFF) bitmap. The resulting BitmapSource is used as the Source of an Image element.

' Open a Stream and decode a TIFF image 
Dim imageStreamSource As New FileStream("tulipfarm.tif", FileMode.Open, FileAccess.Read, FileShare.Read)
Dim decoder As New TiffBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default)
Dim bitmapSource As BitmapSource = decoder.Frames(0)

' Draw the Image 
Dim myImage1 As New Image()
myImage1.Source = bitmapSource
myImage1.Stretch = Stretch.None
myImage1.Margin = New Thickness(20)

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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