#SingleInstance Force
    #UseHook
    SurfacePenBegin()
    Return

; trap pen taps with the top button pressed
#If (SurfacePenState = "tap down with upper side button pressed (seen in AutoHotkey as RButton event)")
RButton::{WheelUp 1}

; trap pen taps with the bottom button pressed
#If (SurfacePenState = "tap down with bottom side button pressed (seen in AutoHotkey as LButton event)")
LButton::{WheelDown 1}

; initialize to trap input messages
  SurfacePenBegin( )
  {
    Global SurfacePenState
    SurfacePenState := ""
    AHKHID_Register(1, 2, A_ScriptHwnd, RIDEV_INPUTSINK := 0x00000100)
    OnMessage(WM_INPUT := 0xFF, "SurfacePenEvent")
  }

; trap wm_input messages and analyze them
  SurfacePenEvent( wParam, lParam, msg, hwnd )
  {
    Global SurfacePenState
    Critical
    AnyType := AHKHID_GetInputInfo(lParam, II_DEVTYPE := 0)
    AnyFlag := AHKHID_GetInputInfo(lParam, II_MSE_FLAGS := (08 + A_PtrSize * 2) | 0x0100)
    AnyButt := AHKHID_GetInputInfo(lParam, II_MSE_BUTTONFLAGS := ((12 + A_PtrSize * 2) | 0x0100))
    AnyData := AHKHID_GetInputInfo(lParam, II_MSE_EXTRAINFO := 28 + A_PtrSize * 2)
    SurfacePenState := ""
    If (AnyType = 0 And AnyFlag <> 0 And AnyButt <> 0)
    {
      If (AnyButt = 1 And (AnyData & 3) = 2)
        SurfacePenState := "tap down with no side button pressed (seen in AutoHotkey as LButton event)"
      If (AnyButt = 2 And (AnyData & 3) = 2)
        SurfacePenState := "tap up with no side button pressed (seen in AutoHotkey as LButton up event)"
      If (AnyButt = 1 And (AnyData & 3) = 3)
        SurfacePenState := "tap down with bottom side button pressed (seen in AutoHotkey as LButton event)"
      If (AnyButt = 2 And (AnyData & 3) = 3)
        SurfacePenState := "tap up with bottom side button pressed (seen in AutoHotkey as LButton up event)"
      If (AnyButt = 4)
        SurfacePenState := "tap down with upper side button pressed (seen in AutoHotkey as RButton event)"
      If (AnyButt = 8)
        SurfacePenState := "tap up with upper side button pressed (seen in AutoHotkey as RButton up event)"
      OutputDebug, SurfacePenEvent [%SurfacePenState%]
    }
  }


#Include <hidfuncs>