public static int AlphaBlend( 
   int sa,
   int sr,
   int sg,
   int sb,
   int destPixel
)

Parameters

sa

Source alpha color component

sr

Premultiplied source red color component

sg

Premultiplied source green color component

sb

Premultiplied source blue color component

destPixel

Premultiplied destination color

Return Value

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

WriteableBitmapExtensions Class
WriteableBitmapExtensions Members