Python GUI programming platforms for Windows
[Edit]
By popular demand, I've added a section on PyGTK. See bottom of post.
There are several platforms for programming Windows GUI applications in Python. Below I outline a few of them, with a simple "hello world" example for each. Where I've lifted the example from another site, there's a link to the source.
Contents
- Tkinter
- wxPython
- IronPython
- PyQT
- Pyglet
- Win32 with ctypes (warning: long!)
- Venster
- PyGTK
Tkinter
Tkinter is the ubiquitous GUI toolkit for Python. It's cross platform and easy to use, but it looks non-native on just about every platform. There are various add-ons and improvements you can find to improve the look and feel, but the basic problem is that the toolkit implements its own widgets, rather than using the native ones provided on the platform.
Pros
- Most portable GUI toolkit for Python
- Very easy to use, with pythonic API
Cons
- Non-native look and feel out of the box
Hello world example (code source):
la = Tk.Label(None, text='Hello World!', font=('Times', '18'))
la.pack()
la.mainloop()
wxPython
wxPython is probably the most popular GUI toolkit for Python. It's a wrapper for the wxWidgets C++ toolkit, and as such it betrays a few unpythonic edges (like lumpy case, getters and setters, and funky C++ errors creeping up occasionally). There are a few pythonification efforts on top of wxPython, such as dabo and (the now apparently moribund) wax.
Pros
- Highly cross platform
- Relatively mature and robust
- Uses native Windows widgets for authentic look and feel
Cons
- Must include large wx runtime when packaging with py2exe (adds ~7 MB)
- Cross platform nature makes accessing some native platform features (like ActiveX) difficult to impossible
Hello world example (code source):
class Application(wx.Frame):
def __init__(self, parent):
wx.Frame.__init__(self, parent, -1, 'My GUI', size=(300, 200))
panel = wx.Panel(self)
sizer = wx.BoxSizer(wx.VERTICAL)
panel.SetSizer(sizer)
txt = wx.StaticText(panel, -1, 'Hello World!')
sizer.Add(txt, 0, wx.TOP|wx.LEFT, 20)
self.Centre()
self.Show(True)
app = wx.App(0)
Application(None)
app.MainLoop()
.NET with IronPython
IronPython is a .NET implementation of Python. As of 1.0 it has full support for Python 2.4 features, and the 2.0 version will duplicate the Python 2.5 feature set. Although there are many CPython libraries/modules that won't run under IronPython (namely, the ones relying on compiled extensions that have not yet been ported), this lack is partially made up by the huge .NET library.
One cool thing about IronPython is that you can easily create lightweight .exe files that you can ship off to your friends — although you pay for this with a dependency on the .NET runtime, which you can't count on random Windows users to have installed.
Of course, when you go the IronPython route, you take all that comes with it: the good things, like access to .NET libraries and possibly the easiest/cleanest optimization path of any Python implementation (C#); and the bad things, like dependence on the .NET runtime and danger of getting caught on the MS upgrade treadmill.
Another way of getting at the .NET libraries is Python.NET, which adds two files to your Python directory to enable you to call the CLR from CPython.
Pros
- Leverage .NET libraries
- Easily create .exe files
Cons
- Depends on .NET runtime
Hello world example (code source):
sys.path.append(r'C:\Python24\Lib')
import clr
clr.AddReference("System.Windows.Forms")
from System.Windows.Forms import Application, Form
class HelloWorldForm(Form):
def __init__(self):
self.Text = 'Hello World'
self.Name = 'Hello World'
form = HelloWorldForm()
Application.Run(form)
PyQT
PyQT is probably the third most widely used GUI toolkit, after wxPython and Tkinter. It has a dual commercial/GPL license (Edit: but it does let you use other open-source licenses; see comments below). I have to admit that this made it a non-starter for me: I don't want to pay for my toolkit when there are others just as good or better that are free; and when I do release open-source software, I want to choose my own license. For others, the GPL might be a non-issue or a plus, so I've left it off my pro/con list.
[Edit] PyQT will be available under the LGPL as of March 2009. Fantastic news.
Pros
- Highly cross platform
- Very easy to use
- Highly mature
- Decent looking widgets
Cons
- Somewhat non-native look and feel (though much better than Tkinter)
- Must include large runtime when packaging with py2exe
Hello world example (from PyQT docs):
from PyQt4 import QtGui
app = QtGui.QApplication(sys.argv)
hello = QtGui.QPushButton("Hello world!")
hello.resize(100, 30)
hello.show()
sys.exit(app.exec_())
Pyglet
Pyglet is kind of the new kid on the block in terms of GUI toolkits, but it sure made a splash. It implements its own windowing system, but with no dependencies other than Python (for Python 2.5 users). You will need OpenGL to do decent 3D graphics, but that's hardly a black mark for pyglet — other libraries would love to make it this easy.
Pros
- High degree of freedom for GUI creation
- Only depends on Python
- Large number of widgets
Cons
- Purposely doesn't duplicate the native platform look and feel
- Although there are a lot of widgets, you'll have to roll your own for many things the platform gives you for free.
Hello world example (slightly modified from code source):
from pyglet import window
win = window.Window(width=300, height=150, caption="Hello World")
ft = font.load('Arial', 36)
text = font.Text(ft, 'Hello, World!')
while not win.has_exit:
win.dispatch_events()
win.clear()
text.draw()
win.flip()
Win32 with ctypes
Of course, all you really need to write GUI applications on Windows with Python is your trusty ctypes module and a well worn copy of Petzold. The benefit of this style is that you're working right down at the system API level, with nothing to get in your way. The disadvantage is that you're working right down at the system API level, with nothing to relieve you from all that boilerplate (unless you write your own abstraction layer on top; see Venster, below…).
Pros
- Enables high level of control
- Straightforward if familiar with Win32 API
- No added complexity or buried functionality due to need to be cross-platform
- Lightest of all Windows GUI programming methods using Python
Cons
- All the complexity and inconsistency of Win32 API in gory detail
- Lack of high-level libraries (have to write more code)
Hello world example (long, ain't it?):
import win32con
WNDPROC = WINFUNCTYPE(c_long, c_int, c_uint, c_int, c_int)
NULL = c_int(win32con.NULL)
_user32 = windll.user32
def ErrorIfZero(handle):
if handle == 0:
raise WinError()
else:
return handle
CreateWindowEx = _user32.CreateWindowExW
CreateWindowEx.argtypes = [c_int,
c_wchar_p,
c_wchar_p,
c_int,
c_int,
c_int,
c_int,
c_int,
c_int,
c_int,
c_int,
c_int]
CreateWindowEx.restype = ErrorIfZero
class WNDCLASS(Structure):
_fields_ = [('style', c_uint),
('lpfnWndProc', WNDPROC),
('cbClsExtra', c_int),
('cbWndExtra', c_int),
('hInstance', c_int),
('hIcon', c_int),
('hCursor', c_int),
('hbrBackground', c_int),
('lpszMenuName', c_wchar_p),
('lpszClassName', c_wchar_p)]
def __init__(self,
wndProc,
style=win32con.CS_HREDRAW | win32con.CS_VREDRAW,
clsExtra=0,
wndExtra=0,
menuName=None,
className=u"PythonWin32",
instance=None,
icon=None,
cursor=None,
background=None,
):
if not instance:
instance = windll.kernel32.GetModuleHandleW(c_int(win32con.NULL))
if not icon:
icon = _user32.LoadIconW(c_int(win32con.NULL),
c_int(win32con.IDI_APPLICATION))
if not cursor:
cursor = _user32.LoadCursorW(c_int(win32con.NULL),
c_int(win32con.IDC_ARROW))
if not background:
background = windll.gdi32.GetStockObject(c_int(win32con.WHITE_BRUSH))
self.lpfnWndProc=wndProc
self.style=style
self.cbClsExtra=clsExtra
self.cbWndExtra=wndExtra
self.hInstance=instance
self.hIcon=icon
self.hCursor=cursor
self.hbrBackground=background
self.lpszMenuName=menuName
self.lpszClassName=className
class RECT(Structure):
_fields_ = [('left', c_long),
('top', c_long),
('right', c_long),
('bottom', c_long)]
def __init__(self, left=0, top=0, right=0, bottom=0 ):
self.left = left
self.top = top
self.right = right
self.bottom = bottom
class PAINTSTRUCT(Structure):
_fields_ = [('hdc', c_int),
('fErase', c_int),
('rcPaint', RECT),
('fRestore', c_int),
('fIncUpdate', c_int),
('rgbReserved', c_wchar * 32)]
class POINT(Structure):
_fields_ = [('x', c_long),
('y', c_long)]
def __init__( self, x=0, y=0 ):
self.x = x
self.y = y
class MSG(Structure):
_fields_ = [('hwnd', c_int),
('message', c_uint),
('wParam', c_int),
('lParam', c_int),
('time', c_int),
('pt', POINT)]
def pump_messages():
"""Calls message loop"""
msg = MSG()
pMsg = pointer(msg)
while _user32.GetMessageW(pMsg, NULL, 0, 0):
_user32.TranslateMessage(pMsg)
_user32.DispatchMessageW(pMsg)
return msg.wParam
class Window(object):
"""Wraps an HWND handle"""
def __init__(self, hwnd=NULL):
self.hwnd = hwnd
self._event_handlers = {}
# Register event handlers
for key in dir(self):
method = getattr(self, key)
if hasattr(method, "win32message") and callable(method):
self._event_handlers[method.win32message] = method
def GetClientRect(self):
rect = RECT()
_user32.GetClientRect(self.hwnd, byref(rect))
return rect
def Create(self,
exStyle=0 , # DWORD dwExStyle
className=u"WndClass",
windowName=u"Window",
style=win32con.WS_OVERLAPPEDWINDOW,
x=win32con.CW_USEDEFAULT,
y=win32con.CW_USEDEFAULT,
width=win32con.CW_USEDEFAULT,
height=win32con.CW_USEDEFAULT,
parent=NULL,
menu=NULL,
instance=NULL,
lparam=NULL,
):
self.hwnd = CreateWindowEx(exStyle,
className,
windowName,
style,
x,
y,
width,
height,
parent,
menu,
instance,
lparam)
return self.hwnd
def Show(self, flag):
return _user32.ShowWindow(self.hwnd, flag)
def Update(self):
if not _user32.UpdateWindow(self.hwnd):
raise WinError()
def WndProc(self, hwnd, message, wParam, lParam):
event_handler = self._event_handlers.get(message, None)
if event_handler:
return event_handler(message, wParam, lParam)
return _user32.DefWindowProcW(c_int(hwnd),
c_int(message),
c_int(wParam),
c_int(lParam))
## Lifted shamelessly from WCK (effbot)'s wckTkinter.bind
def EventHandler(message):
"""Decorator for event handlers"""
def decorator(func):
func.win32message = message
return func
return decorator
class HelloWindow(Window):
"""The application window"""
@EventHandler(win32con.WM_PAINT)
def OnPaint(self, message, wParam, lParam):
"""Draw 'Hello World' in center of window"""
ps = PAINTSTRUCT()
rect = self.GetClientRect()
hdc = _user32.BeginPaint(c_int(self.hwnd), byref(ps))
rect = self.GetClientRect()
flags = win32con.DT_SINGLELINE|win32con.DT_CENTER|win32con.DT_VCENTER
_user32.DrawTextW(c_int(hdc),
u"Hello, world!",
c_int(-1),
byref(rect),
flags)
_user32.EndPaint(c_int(self.hwnd), byref(ps))
return 0
@EventHandler(win32con.WM_DESTROY)
def OnDestroy(self, message, wParam, lParam):
"""Quit app when window is destroyed"""
_user32.PostQuitMessage(0)
return 0
def RunHello():
"""Create window and start message loop"""
# two-stage creation for Win32 windows
hello = HelloWindow()
# register window class…
wndclass = WNDCLASS(WNDPROC(hello.WndProc))
wndclass.lpszClassName = u"HelloWindow"
if not _user32.RegisterClassW(byref(wndclass)):
raise WinError()
# …then create Window
hello.Create( className=wndclass.lpszClassName,
instance=wndclass.hInstance,
windowName=u"Hello World")
# Show Window
hello.Show(win32con.SW_SHOWNORMAL)
hello.Update()
pump_messages()
RunHello()
Venster
Venster was a very promising wrapper over the Win32 API, borrowing heavily from WTL and ATL windowing techniques. Unfortunately, the project hasn't been updated in several years, and doesn't support the latest versions of Python (especially after ctypes.com was dropped).
Pros
- Rational abstraction layer on top of Win32
- Use to write native, lightweight (relatively speaking) GUI applications
- Has most of the cool Win32 tricks like hosting ActiveX and Coolbars
Cons
- Out of date; not updated in several years
Hello world example (code source):
from venster.wtl import *
from venster import gdi
class MyWindow(Window):
_window_title_ = "Hello World"
_window_background_ = gdi.GetStockObject(WHITE_BRUSH)
_window_class_style_ = CS_HREDRAW | CS_VREDRAW
def OnPaint(self, event):
ps = PAINTSTRUCT()
hdc = self.BeginPaint(ps)
rc = self.GetClientRect()
msg = "Hello World"
gdi.TextOut(hdc, rc.width / 2, rc.height / 2, msg, len(msg))
self.EndPaint(ps)
msg_handler(WM_PAINT)(OnPaint)
def OnDestroy(self, event):
PostQuitMessage(NULL)
msg_handler(WM_DESTROY)(OnDestroy)
myWindow = MyWindow()
application = Application()
application.Run()
PyGTK
PyGTK seems to have a lot going for it as a cross-platform toolkit. It's also licensed under the LGPL, which I like a lot more than the GPL of PyQT. Unfortunately, it doesn't use native Windows widgets; it does a pretty good job of faking it, but it stands out like a Win32, .NET, or wxPython app wouldn't.
Pros
- Cross platform
- Lots of widgets
- Voluminous (if somewhat disorganized) documenation
Cons
- Native Win32 widgets not used (looks good, but not quite all the way there)
- Must include large runtime when packaging with py2exe
Hello world example (code source):
pygtk.require('2.0')
import gtk
class HelloWorld:
def hello(self, widget, data=None):
print "Hello World"
def delete_event(self, widget, event, data=None):
print "delete event occurred"
return False
def destroy(self, widget, data=None):
print "destroy signal occurred"
gtk.main_quit()
def __init__(self):
self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
self.window.connect("delete_event", self.delete_event)
self.window.connect("destroy", self.destroy)
self.window.set_border_width(10)
self.button = gtk.Button("Hello World")
self.button.connect("clicked", self.hello, None)
self.button.connect_object("clicked", gtk.Widget.destroy, self.window)
self.window.add(self.button)
self.button.show()
self.window.show()
def main(self):
gtk.main()
if __name__ == "__main__":
hello = HelloWorld()
hello.main()