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)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

'Declaration
Public MustInherit Class BitmapDecoder
	Inherits DispatcherObject
'Usage
Dim instance As BitmapDecoder

public abstract class BitmapDecoder extends DispatcherObject
public abstract class BitmapDecoder extends DispatcherObject
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 an independent software vendor (ISV) developed codec 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)

System.Object
   System.Windows.Threading.DispatcherObject
    System.Windows.Media.Imaging.BitmapDecoder
       Derived Classes

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 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0

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