[PyKDE] PyQt 4 doesn't allow to create an application, given an already open display. How to solve it?

Ulrich Berning ulrich.berning at denviso.de
Thu Mar 8 08:07:34 GMT 2007


mikos at centrum.cz wrote:

>Eh, I have just realized that I have replied directly to Phil Thompson, not to this list
>(this is because I have used unfamiliar webmail client). So this is our conversation:
>
>*** Me: ***
>You can look at that example by Zack Rusin, it is very simple, here is code:
>http://ktown.kde.org/~zrusin/examples/argb.tar.bz2 (look at main.cpp)
>
>That Display instance come directly from xlib, it is created by XOpenDisplay:
>http://lxr.freedesktop.org/ident?i=XOpenDisplay
>
>In Python, I am using ctypes module to directly access xlib (libX11)
>and call XOpenDisplay.
>
>*** Phil: ***
>I meant, in the context of PyQt. PyQt needs to know about the type.
>
>*** Me: *** 
>I can't help you much in this, I don't know much about ctypes, I have only learned it
>because I want to create ARGB windows with PyQt (and then I realized that I can't do it
>because PyQt doesn't support it). But you can try this code:
>
>### Python code ###
>import ctypes
>
>class Display(ctypes.Structure):
>pass
>
>xlib = ctypes.CDLL('libX11.so.6')
>xlib.XOpenDisplay.restype = ctypes.POINTER(Display)
>xlib.XOpenDisplay.argtypes = [ctypes.c_char_p]
>
>display = xlib.XOpenDisplay(':0.0')
>### End of Python code ###
>
>This will create 'display' object, which is pointer to 'Display' structure
>(which is derived from standard ctypes.Structure).
>
>But this is all I can tell you, as I said I don't know any details about this
>process, only that it works (I have tried creating window with pure xlib).
>
>Ctypes are standard module in python 2.5 (for Python 2.4 it is external
>module), so I think PyQt should support it.
>
>  
>
The ctypes extension doesn't build on AIX, HP-UX, IRIX and Solaris. With 
some changes, it may build on IRIX and Solaris, because libffi has been 
ported to these platforms. On AIX and HP-UX, you have definitely lost. 
I've never understood, why ctypes became a standard module.

PyQt works on the above platforms. Making it dependent on the ctypes 
extension seems to be a bad idea.

Ulli




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