怎么获取鼠标所指处的颜色？

[e4snake]

怎么获取鼠标所指处的颜色？
鼠标不在自己的程序窗口中，比如在桌面上或者其他程序窗口中？

[online]

Option Explicit

Private Type POINTAPI
x As Long
y As Long
End Type
Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long
Private Declare Function GetCursorPos Lib "user32" (lpPoint As POINTAPI) As Long
Private Declare Function GetDC Lib "user32" (ByVal hwnd As Long) As Long
Private Declare Function GetPixel Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function ScreenToClient Lib "user32" (ByVal hwnd As Long, lpPoint As POINTAPI) As Long
Private Declare Function WindowFromPoint Lib "user32" (ByVal xPoint As Long, ByVal yPoint As Long) As Long

Private Sub Timer1_Timer()
Static lX As Long, lY As Long
On Local Error Resume Next
Dim P As POINTAPI, h As Long, hD As Long, r As Long
GetCursorPos P
If P.x = lX And P.y = lY Then Exit Sub
lX = P.x: lY = P.y
lblData(0).Caption = lX & "," & lY
h = WindowFromPoint(lX, lY)
lblData(1).Caption = h
hD = GetDC(h)
lblData(2).Caption = hD
ScreenToClient h, P
lblData(3).Caption = P.x & "," & P.y
r = GetPixel(hD, P.x, P.y)
If r = -1 Then
BitBlt Picture1.hdc, 0, 0, 1, 1, hD, P.x, P.y, vbSrcCopy
r = Picture1.Point(0, 0)
Else
Picture1.PSet (0, 0), r
End If
lblData(4).Caption = Hex$(r)
Picture1.BackColor = r
End Sub