Develop Reference

Why does window title get truncated? [Windows API] [duplicate]

I been trying to create Win32 Application by using python (2.7) and ctypes module. Window is created and shown but title of window gets truncated. I got 'M' instead of 'My test window'. What I am doing wrong?
Thanks in advance
P.S. Here follows the code and screenshot:
# -*- coding: utf-8 -*-
from sys import platform, exit
from ctypes import *
from ctypes.wintypes import DWORD, HWND, HANDLE, LPCWSTR, WPARAM, LPARAM, RECT, POINT, MSG
WNDPROCTYPE = WINFUNCTYPE(c_int, HWND, c_uint, WPARAM, LPARAM)
WS_EX_APPWINDOW = 0x40000
WS_OVERLAPPEDWINDOW = 0xcf0000
WS_CAPTION = 0xc00000
SW_SHOWNORMAL = 1
SW_SHOW = 5
CS_HREDRAW = 2
CS_VREDRAW = 1
CW_USEDEFAULT = 0x80000000
WM_DESTROY = 2
WHITE_BRUSH = 0
class WNDCLASSEX(Structure):
_fields_ = [("cbSize", c_uint),
("style", c_uint),
("lpfnWndProc", WNDPROCTYPE),
("cbClsExtra", c_int),
("cbWndExtra", c_int),
("hInstance", HANDLE),
("hIcon", HANDLE),
("hCursor", HANDLE),
("hBrush", HANDLE),
("lpszMenuName", LPCWSTR),
("lpszClassName", LPCWSTR),
("hIconSm", HANDLE)]
def PyWndProcedure(hWnd, Msg, wParam, lParam):
if Msg == WM_DESTROY:
windll.user32.PostQuitMessage(0)
else:
return windll.user32.DefWindowProcA(hWnd, Msg, wParam, lParam)
return 0
WndProc = WNDPROCTYPE(PyWndProcedure)
hInst = windll.kernel32.GetModuleHandleW(0)
print(hInst)
wclassName = u'My Python Win32 Class'
wndClass = WNDCLASSEX()
wndClass.cbSize = sizeof(WNDCLASSEX)
wndClass.style = CS_HREDRAW | CS_VREDRAW
wndClass.lpfnWndProc = WndProc
wndClass.cbClsExtra = 0
wndClass.cbWndExtra = 0
wndClass.hInstance = hInst
wndClass.hIcon = 0
wndClass.hCursor = 0
wndClass.hBrush = windll.gdi32.GetStockObject(WHITE_BRUSH)
wndClass.lpszMenuName = 0
wndClass.lpszClassName = wclassName
wndClass.hIconSm = 0
print(wndClass)
regRes = windll.user32.RegisterClassExW(byref(wndClass))
print(regRes)
wname = u'My test window'
hWnd = windll.user32.CreateWindowExW(
0,
wclassName,
wname,
WS_OVERLAPPEDWINDOW | WS_CAPTION,
CW_USEDEFAULT,
CW_USEDEFAULT,
300,
300,
0,
0,
hInst,
0)
print('hWnd', hWnd)
if not hWnd:
print('Failed to create window')
exit(0)
print('ShowWindow', windll.user32.ShowWindow(hWnd, SW_SHOW))
print('UpdateWindow', windll.user32.UpdateWindow(hWnd))
msg = MSG()
lpmsg = pointer(msg)
print('Entering message loop')
while windll.user32.GetMessageA(lpmsg, 0, 0, 0) != 0:
windll.user32.TranslateMessage(lpmsg)
windll.user32.DispatchMessageA(lpmsg)
print('done.')

It is because you are creating a Unicode window with CreateWindowExW but then calling the ANSI DefWindowProcA. You are passing Unicode strings which typically have zero for every other byte since your text is in the ASCII range which explains what you observe.
The solution? Call DefWindowProcW instead.
Actually, a better solution would be to use win32gui instead which wraps this up a bit more for you.

If you provide a regular string rather than an unicode string, the text is displayed properly.
wname = 'My test window'
It looks strange to me because you are using the Unicode API (CreateWindowExW). Maybe the root cause is somewhere else.
I hope it helps

which argtypes for NetShareAdd

The win32 function NetShareDel takes three arguments, LPCWSTR LPCWSTR and DWORD.
So I use the following list for argtypes:
import ctypes as C
C.windll.Netapi32.NetShareDel.argtypes = [LPCWSTR, LPCWSTR, c_int]
C.windll.Netapi32.NetShareDel.restype = c_int
C.windll.Netapi32.NetShareDel(server, shareName, 0)
That works fine, but I can't figure out what to use for NetShareAdd, especialle the byte array for NET_SHARE_INFO struct and the last byref(c_int) argument.
Here's the code:
def Share(server, shareName, dir):
info = SHARE_INFO_2()
STYPE_DISKTREE = 0
info.shi2_netname = shareName
info.shi2_path = dir
info.shi2_type = STYPE_DISKTREE
info.shi2_remark = "Shared: " + time.strftime("%Y%m%d-%H:%M")
info.shi2_max_uses = -1
info.shi2_passwd = ""
info.shi2_current_uses = 0
info.shi2_permissions = 0xFFFFFFFF
i = c_int()
bytearray = buffer(info)[:]
windll.Netapi32.NetShareAdd.argtypes = [LPCWSTR, c_int, ????, ????]
windll.Netapi32.NetShareAdd(server, 2, bytearray, C.byref(i))
What would be the correct argtypes list for NetShareAdd?

Got it working finally
First the line
bytearray = buffer(info)[:]
was changed into byte pointer type
byteptr = C.POINTER(C.wintypes.BYTE)(info)
and then the argtypes and call will become POINTER(BYTE) too of course:
C.windll.Netapi32.NetShareAdd.argtypes = [LPCWSTR, c_int, C.POINTER(C.wintypes.BYTE), C.POINTER(c_int)]
C.windll.Netapi32.NetShareAdd.restype = c_int
windll.Netapi32.NetShareAdd(server, 2, byteptr, C.byref(i))

OS X and ctypes: how to retrieve raw pixels from CGDataProviderCopyData()?

I am trying to capture the screen using only the ctypes modules. Unfortunately I cannot retrieve raw pixel from CGDataProviderCopyData. I need to get an access to raw data:
#!/usr/bin/env python
# coding: utf-8
from sys import maxsize
from ctypes import POINTER, Structure, c_double, byref, c_void_p, c_int32, c_uint32, c_float, cdll
from ctypes.util import find_library
CGFloat = c_double if maxsize > 2 ** 32 else c_float
class CGPoint(Structure):
_fields_ = [('x', CGFloat), ('y', CGFloat)]
class CGSize(Structure):
_fields_ = [('width', CGFloat), ('height', CGFloat)]
class CGRect(Structure):
_fields_ = [('origin', CGPoint), ('size', CGSize)]
# Library
cgs = cdll.LoadLibrary(find_library('CoreGraphics'))
# Argtypes
cgs.CGGetActiveDisplayList.argtypes = [c_uint32, POINTER(c_uint32), POINTER(c_uint32)]
cgs.CGDisplayBounds.argtypes = [c_uint32]
cgs.CGRectStandardize.argtypes = [CGRect]
cgs.CGDisplayRotation.argtypes = [c_uint32]
cgs.CGWindowListCreateImage.argtypes = [CGRect, c_uint32, c_uint32, c_uint32]
cgs.CGImageGetWidth.argtypes = [c_void_p]
cgs.CGImageGetHeight.argtypes = [c_void_p]
cgs.CGImageGetDataProvider.argtypes = [c_void_p]
cgs.CGDataProviderCopyData.argtypes = [c_void_p]
cgs.CGDataProviderRelease.argtypes = [c_void_p]
# Restypes
cgs.CGGetActiveDisplayList.restype = c_int32
cgs.CGDisplayBounds.restype = CGRect
cgs.CGRectStandardize.restype = CGRect
cgs.CGDisplayRotation.restype = c_float
cgs.CGWindowListCreateImage.restype = c_void_p
cgs.CGImageGetWidth.restype = c_uint32
cgs.CGImageGetHeight.restype = c_uint32
cgs.CGImageGetDataProvider.restype = c_void_p
cgs.CGDataProviderCopyData.restype = c_void_p
cgs.CGDataProviderRelease.restype = c_void_p
# Monitors
max_displays = 32
display_count = c_uint32(0)
active_displays = (c_uint32 * max_displays)()
cgs.CGGetActiveDisplayList(max_displays, active_displays, byref(display_count))
for idx in range(display_count.value):
display = active_displays[idx]
rect = cgs.CGDisplayBounds(display)
rect = cgs.CGRectStandardize(rect)
image_ref = cgs.CGWindowListCreateImage(rect, 1, 0, 0)
width = int(cgs.CGImageGetWidth(image_ref))
height = int(cgs.CGImageGetHeight(image_ref))
prov = cgs.CGImageGetDataProvider(image_ref)
data = cgs.CGDataProviderCopyData(prov)
# How to get raw pixels from data`?
MacOS X version 10.11.3.
Python versions 2.7.10 and 2.6.9.

I have no experience with the CoreGraphics API, but looking at the documentation it looks like CGDataProviderCopyData returns a CFDataRef object. The documentat for CFDataRef has a section on "Examining a CFData Object" which describes a CFDataGetLength function and a CFDataGetBytePtr function which return the length of the data and a UInt8*.
https://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGDataProvider/#//apple_ref/c/func/CGDataProviderCopyData
https://developer.apple.com/library/ios/documentation/CoreFoundation/Reference/CFDataRef/index.html

Thanks to Snorfalorpagus, I finally succeed:
#...
data = cgs.CGDataProviderCopyData(prov)
data_ref = cgs.CFDataGetBytePtr(data)
buf_len = cgs.CFDataGetLength()
image_data = cast(data_ref, POINTER(c_ubyte * buf_len))
cgs.CGDataProviderRelease(prov)
# Raw pixels are in image_data.contents

ctypes: passing and reading an enum pointer

This page says:
Enumeration types are not implemented. You can do it easily yourself,
using c_int as the base class.
If it were easy, why isn't it implemented yet? How do I get the current color temperature of my monitor, for instance?
BOOL GetMonitorColorTemperature(
_In_ HANDLE hMonitor,
_Out_ LPMC_COLOR_TEMPERATURE pctCurrentColorTemperature
);
Parameters
hMonitor [in]
Handle to a physical monitor. To get the monitor handle, call GetPhysicalMonitorsFromHMONITOR or GetPhysicalMonitorsFromIDirect3DDevice9.
pctCurrentColorTemperature [out]
Receives the monitor's current color temperature, specified as a member of the MC_COLOR_TEMPERATURE enumeration.
Return value
If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. To get extended error information, call GetLastError.
This is the closest i was able to get:
from ctypes import *
import win32api # http://sourceforge.net/projects/pywin32/files/pywin32/
for idx, (hMon, hDC, (left, top, right, bottom)) in enumerate(win32api.EnumDisplayMonitors(None, None)):
print(hMon.handle) # or int(hMon)
class MyEnum(c_int):
MC_COLOR_TEMPERATURE_UNKNOWN = 0
MC_COLOR_TEMPERATURE_4000K = 1
MC_COLOR_TEMPERATURE_5000K = 2
MC_COLOR_TEMPERATURE_6500K = 3
MC_COLOR_TEMPERATURE_7500K = 4
MC_COLOR_TEMPERATURE_8200K = 5
MC_COLOR_TEMPERATURE_9300K = 6
MC_COLOR_TEMPERATURE_10000K = 7
MC_COLOR_TEMPERATURE_11500K = 8
o = MyEnum()
print(o)
po = pointer(o)
t = windll.dxva2.GetMonitorColorTemperature(hMon.handle, po) #byref(o))
#print(dir(o))
print(o)
print(po.contents)
print(t)
print(windll.kernel32.GetLastError()) # ERROR_GRAPHICS_INVALID_PHYSICAL_MONITOR_HANDLE = -1071241844 # Variable c_long '-0x03fd9da74'
...returns this:
65537
65539
<MyEnum object at 0x006F6DA0>
<MyEnum object at 0x006F6DA0>
<MyEnum object at 0x0234FAD0>
0
-1071241844
It's the same for either monitor handle. What am I doing wrong?

Using this answer, I somehow found out that it works using None as physical monitor handle:
from ctypes import *
from ctypes.wintypes import BOOL, HMONITOR, HDC, RECT, LPARAM, DWORD, BYTE, WCHAR, HANDLE
import win32api # http://sourceforge.net/projects/pywin32/files/pywin32/
_MONITORENUMPROC = WINFUNCTYPE(BOOL, HMONITOR, HDC, POINTER(RECT), LPARAM)
class _PHYSICAL_MONITOR(Structure):
_fields_ = [('handle', HANDLE),
('description', WCHAR * 128)]
def _iter_physical_monitors(close_handles=True):
"""Iterates physical monitors.
The handles are closed automatically whenever the iterator is advanced.
This means that the iterator should always be fully exhausted!
If you want to keep handles e.g. because you need to store all of them and
use them later, set `close_handles` to False and close them manually."""
def callback(hmonitor, hdc, lprect, lparam):
monitors.append(hmonitor)
return True
monitors = []
if not windll.user32.EnumDisplayMonitors(None, None, _MONITORENUMPROC(callback), None):
raise WinError('EnumDisplayMonitors failed')
for monitor in monitors:
# Get physical monitor count
count = DWORD()
if not windll.dxva2.GetNumberOfPhysicalMonitorsFromHMONITOR(monitor, byref(count)):
raise WinError()
# Get physical monitor handles
physical_array = (_PHYSICAL_MONITOR * count.value)()
if not windll.dxva2.GetPhysicalMonitorsFromHMONITOR(monitor, count.value, physical_array):
raise WinError()
for physical in physical_array:
yield physical.handle
if close_handles:
if not windll.dxva2.DestroyPhysicalMonitor(physical.handle):
raise WinError()
mons = [m for m in _iter_physical_monitors(False)]
#for idx, (hMon, hDC, (left, top, right, bottom)) in enumerate(win32api.EnumDisplayMonitors(None, None)):
# print(hMon.handle) # or int(hMon)
temps = (
'UNKNOWN',
'4000K',
'5000K',
'6500K',
'7500K',
'8200K',
'9300K',
'10000K',
'11500K'
)
class MyEnum(c_int):
MC_COLOR_TEMPERATURE_UNKNOWN = 0
MC_COLOR_TEMPERATURE_4000K = 1
MC_COLOR_TEMPERATURE_5000K = 2
MC_COLOR_TEMPERATURE_6500K = 3
MC_COLOR_TEMPERATURE_7500K = 4
MC_COLOR_TEMPERATURE_8200K = 5
MC_COLOR_TEMPERATURE_9300K = 6
MC_COLOR_TEMPERATURE_10000K = 7
MC_COLOR_TEMPERATURE_11500K = 8
o = MyEnum()
print(o)
po = pointer(o)
pm = mons[0]
print("physical %r" % pm)
t = windll.dxva2.GetMonitorColorTemperature(pm, po) #byref(o))
if t:
#print(o)
#print(dir(po.contents))
print(temps[po.contents.value])
else:
print("Err: %s" % windll.kernel32.GetLastError()) # ERROR_GRAPHICS_INVALID_PHYSICAL_MONITOR_HANDLE = -1071241844 # Variable c_long '-0x03fd9da74'
Result:
<MyEnum object at 0x005D6120>
physical None
6500K

How to use ctypes to call 'AU3_WinGetTitle' in AutoIt?

I'm trying to make a python wrapper for AutoIt using ctypes.
Here is my problem:
e.g. The prototype for AU3_WinGetText is:
void AU3_WinGetTitle(LPCWSTR szTitle, LPCWSTR szText, LPWSTR szRetText, int nBufSize);
I'm using flowing code to call the function:
import ctypes
from ctypes.wintypes import *
AUTOIT = ctypes.windll.LoadLibrary("AutoItX3.dll")
def win_get_title(title, text="", buf_size=200):
AUTOIT.AU3_WinGetTitle.argtypes = (LPCWSTR, LPCWSTR, LPWSTR, INT)
AUTOIT.AU3_WinGetTitle.restypes = None
rec_text = LPWSTR()
AUTOIT.AU3_WinGetTitle(LPCWSTR(title), LPCWSTR(text),
ctypes.cast(ctypes.byref(rec_text), LPWSTR),
INT(buf_size))
res = rec_text.value
return res
print win_get_title("[CLASS:Notepad]")
I'm getting an exception after run these codes:
res = rec_text.value
ValueError: invalid string pointer 0x680765E0

szRetText is used to receive the output text buffer
import ctypes
from ctypes.wintypes import *
AUTOIT = ctypes.windll.LoadLibrary("AutoItX3.dll")
def win_get_title(title, text="", buf_size=200):
# AUTOIT.AU3_WinGetTitle.argtypes = (LPCWSTR, LPCWSTR, LPWSTR, INT)
# AUTOIT.AU3_WinGetTitle.restypes = None
rec_text = ctypes.create_unicode_buffer(buf_size)
AUTOIT.AU3_WinGetTitle(LPCWSTR(title), LPCWSTR(text),
rec_text, INT(buf_size))
res = rec_text.value.rstrip()
return res
print win_get_title("[CLASS:Notepad]")