BitmapSourceExtensionsBeginConvertPixelFormat(BitmapSource, PixelFormat, IQuantizer, IDitherer, AsyncConfig) Method

Begins to convert the specified bitmap to a WriteableBitmap of the desired PixelFormat asynchronously.


Namespace: KGySoft.Drawing.Wpf
Assembly: KGySoft.Drawing.Wpf (in KGySoft.Drawing.Wpf.dll) Version: 8.1.0
public static IAsyncResult BeginConvertPixelFormat(
	this BitmapSource bitmap,
	PixelFormat newPixelFormat,
	IQuantizer? quantizer,
	IDitherer? ditherer = null,
	AsyncConfig? asyncConfig = null


bitmap  BitmapSource
The original image to convert.
newPixelFormat  PixelFormat
The desired new pixel format.
quantizer  IQuantizer
An optional IQuantizer instance to determine the colors of the result. If and newPixelFormat is an indexed format, then a default palette and quantization logic will be used.
ditherer  IDitherer  (Optional)
The ditherer to be used. Might be ignored if quantizer is not specified and newPixelFormat represents an at least 24 bits-per-pixel size. This parameter is optional.
Default value: .
asyncConfig  AsyncConfig  (Optional)
The configuration of the asynchronous operation such as parallelization, cancellation, reporting progress, etc. When Progress is set in this parameter, then this library always passes a DrawingOperation instance to the generic methods of the IAsyncProgress interface. This parameter is optional.
Default value: .

Return Value

An IAsyncResult that represents the asynchronous operation, which could still be pending.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type BitmapSource. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).


In .NET Framework 4.0 and above you can use also the ConvertPixelFormatAsync(BitmapSource, PixelFormat, IQuantizer, IDitherer, TaskConfig) method.

To get the result or the exception that occurred during the operation you have to call the EndConvertPixelFormat method.

This method is not a blocking call even if the MaxDegreeOfParallelism property of the asyncConfig parameter is 1.


  • This method can be called from any thread but if it is called from a different one from the thread of the source bitmap's dispatcher, then the result WriteableBitmap will be created by using a synchronized callback. To avoid possible deadlocks, the thread of the source bitmap must not be blocked and the dispatcher must run. The result will be usable in the same thread as the source bitmap. To avoid blocking waiting for the result set the CompletedCallback parameter of the asyncConfig parameter and call the EndConvertPixelFormat method from there.
  • If quantizer is not a PredefinedColorsQuantizer, then the result WriteableBitmap is created by a synchronized callback on the thread of the source bitmap even if you call this method from the same thread. Do not block the thread of the source bitmap; otherwise, a deadlock may occur.


ArgumentNullExceptionbitmap is .
ArgumentOutOfRangeExceptionnewPixelFormat does not specify a valid format.
ArgumentExceptionThe quantizer palette contains too many colors for the indexed format specified by newPixelFormat.

See Also