pptでドラッグインタラクションを作成する方法

Option Explicit
Declare Function GetKeyState Lib "user32" (ByVal nVirtKey As Long) As Integer
Private Declare Function WindowFromPoint Lib "user32" (ByVal xPoint As Long, ByVal yPoint As Long) As Long
Private Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long
Private Declare Function GetCursorPos Lib "user32" (lpPoint As PointAPI) As Long
Private Declare Function SetCursorPos Lib "user32" (ByVal x As Long, ByVal y As Long) As Long
Public Declare Function MonitorFromPoint Lib "user32.dll" (ByVal x As Long, ByVal y As Long, ByVal dwFlags As Long) As Long
Private Declare Function GetSystemMetrics Lib "user32" (ByVal nIndex As Long) As Long
Private Const SM_SCREENX = 0
Private Const SM_SCREENY = 1
Private Const sigProc = "Drag & Drop"
Public Const VK_SHIFT = &H10
Public Const VK_CTRL = &H11
Public Const VK_ALT = &H12
Private Type PointAPI
    x As Long
    y As Long
End Type
Public Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type
Public mPoint As PointAPI, dPoint As PointAPI
Public ActiveShape As Shape
Dim dragMode As Boolean
Dim dx As Double, dy As Double
Sub DragandDrop(sh As Shape)
dragMode = Not dragMode
If dragMode Then Drag sh
End Sub
Private Sub Drag(sh As Shape)
Dim i As Integer, sx As Integer, sy As Integer
Dim mWnd As Long, WR As RECT
dx = GetSystemMetrics(SM_SCREENX): dPoint.x = dx
dy = GetSystemMetrics(SM_SCREENY): dPoint.y = dy
GetCursorPos mPoint
With ActivePresentation.SlideShowWindow
    mWnd = WindowFromPoint(mPoint.x, mPoint.y)
    GetWindowRect mWnd, WR
    sx = WR.Left
    sy = WR.Top
    dx = (WR.Right - WR.Left) / ActivePresentation.PageSetup.SlideWidth
    dy = (WR.Bottom - WR.Top) / ActivePresentation.PageSetup.SlideHeight
End With
If dx > dy Then
    sx = sx + (dx - dy) * ActivePresentation.PageSetup.SlideWidth / 2
    dx = dy
End If
If dy > dx Then
    sy = sy + (dy - dx) * ActivePresentation.PageSetup.SlideHeight / 2
    dy = dx
End If
While dragMode
    GetCursorPos mPoint
    sh.Left = (mPoint.x - sx) / dx - sh.Width / 2
    sh.Top = (mPoint.y - sy) / dy - sh.Height / 2
    DoEvents
    i = i + 1: If i > 2000 Then dragMode = False: Exit Sub
Wend
End Sub