[Out]  out WTS_ALPHATYPE pat

        [In]  WTS_ALPHATYPE wtsAT

WTS_ALPHATYPE

            out WTS_ALPHATYPE pdwAlpha

    enum WTS_ALPHATYPE {

        Sub GetThumbnail(cx As Integer, ByRef phbmp As IntPtr, ByRef pdwAlpha As WTS_ALPHATYPE)

    Enum WTS_ALPHATYPE

public enum WTS_ALPHATYPE : uint

Enum WTS_ALPHATYPE