[ctypes-users] Sample ctypes Code -- Calling Windows Clipboard API w/ Global Memory

[Jack T. <jac...@pr...>]

###################################################################################
#
# The Python win32clipboard lib functions work well enough ... except that they
# can only cut and paste items from within one application, not across
# applications or processes.
#
# I've written a number of Python text filters I like to run on the contents of
# the clipboard so I need to call the Windows clipboard API with global memory
# for my filters to work properly.
#
# Here's some sample code solving this problem using ctypes.
#
# This is my first work with ctypes.  It's powerful stuff, but passing 
arguments
# in and out of functions is tricky.  More sample code would have been helpful,
# hence this contribution.
#
###################################################################################

from ctypes import *
from win32con import CF_TEXT, GHND

OpenClipboard = windll.user32.OpenClipboard
EmptyClipboard = windll.user32.EmptyClipboard
GetClipboardData = windll.user32.GetClipboardData
SetClipboardData = windll.user32.SetClipboardData
CloseClipboard = windll.user32.CloseClipboard
GlobalLock = windll.kernel32.GlobalLock
GlobalAlloc = windll.kernel32.GlobalAlloc
GlobalUnlock = windll.kernel32.GlobalUnlock
memcpy = cdll.msvcrt.memcpy

def GetClipboardText():
     text = ""
     if OpenClipboard(c_int(0)):
         hClipMem = GetClipboardData(c_int(CF_TEXT))
         GlobalLock.restype = c_char_p
         text = GlobalLock(c_int(hClipMem))
         GlobalUnlock(c_int(hClipMem))
         CloseClipboard()
     return text

def SetClipboardText(text):
     buffer = c_buffer(text)
     bufferSize = sizeof(buffer)
     hGlobalMem = GlobalAlloc(c_int(GHND), c_int(bufferSize))
     GlobalLock.restype = c_void_p
     lpGlobalMem = GlobalLock(c_int(hGlobalMem))
     memcpy(lpGlobalMem, addressof(buffer), c_int(bufferSize))
     GlobalUnlock(c_int(hGlobalMem))
     if OpenClipboard(0):
         EmptyClipboard()
         SetClipboardData(c_int(CF_TEXT), c_int(hGlobalMem))
         CloseClipboard()

if __name__ == '__main__':
     print GetClipboardText()                            # display last 
text clipped
     SetClipboardText("[Clipboard text replaced]")       # replace it
     print GetClipboardText()                            # display new 
clipboard