X display visual

[Ivan Van Laningham]

Hi All--

Randall Hopper wrote:
> 
[snip]
>  |so I guess that means python took the first color visual type it
>  |found... is there a way to force it to use my 24 bit visual?
> 
> Yes.  Frame and Toplevel widgets have visual and colormap resources which
> can be set.  Here is some simple code that just deals with 8bpp pseudo and
> 24bpp true.
> 
>   ---------------------------------------------------------------------------
>   root     = Tk()
>   root.wm_withdraw()
> 
>   # Determine the depth, if non specified
>   if depth: assert depth in [ 8, 24 ]
>   else:     depth = root.winfo_depth()
> 
>   # Just force 24-bit
>   depth = 24
> 
>   if depth == 8: visual = "pseudocolor 8"
>   else:          visual = "truecolor  24"
> 
>   main     = Toplevel( root, visual=visual )
>   ---------------------------------------------------------------------------
> 
> Stack your widgets under 'main' rather than 'root'.
> 
> To be more robust, pick a visual returned by:
> 
>   root.winfo_visualsavailable()
> 
> As you suggested, selecting the proper visual is the best solution (as
> opposed to forcing the user to reconfigure the default depth of their X
> server).
> 

1)  I don't follow the logic in solution 1, above:  it looks like you're
forcing the depth to 24 regardless of whatever you find out.

2)  winfo_visualsavailable() doesn't work on Windows.  I can find out
the depth and get the visual string back, but I can't use
winfo_visualsavailable().  Here's the traceback:

Traceback (innermost last):
  File ".\ccube.py", line 212, in ?
    x = root.winfo_visualsavailable()
  File ".\Tkinter.py", line 429, in winfo_visualsavailable
    return map(parseitem, data)
  File ".\Tkinter.py", line 428, in parseitem
    return x[:1] + tuple(map(getint, x[1:]))
TypeError: illegal argument type for built-in operation


I put a temporary print into Tkinter.py: 

def winfo_visualsavailable(self, includeids=0):
		data = self.tk.split(
			self.tk.call('winfo', 'visualsavailable', self._w,
				     includeids and 'includeids' or None))
                print data #        <== Temp print
		def parseitem(x, self=self):
			return x[:1] + tuple(map(getint, x[1:]))
		return map(parseitem, data)

Before getting the exception, it prints "truecolor 16" for the
data--i.e., just a plain old string.

On Linux, the same call returns a list of tuples:

	[('pseudocolor', 8), ('directcolor', 8), ....

and works fine. 


I ended up just putting a quick check in to find out the depth, and if
it's less than 16 I modify the number of colors the program asks for.

<plain-ol-string>-ly y'rs,
Ivan
----------------------------------------------
Ivan Van Laningham
Callware Technologies, Inc.
ivanlan at callware.com
ivanlan at home.com
http://www.pauahtun.org
See also: 
http://www.foretec.com/python/workshops/1998-11/proceedings.html
Army Signal Corps:  Cu Chi, Class of '70
Author:  Teach Yourself Python in 24 Hours
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