Bugs item #834351, was opened at 2003-11-02 00:37
Message generated for change (Comment added) made by orthorim
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=834351&group_id=5470
Category: Tkinter
Group: Python 2.2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Gary Richardson (garyrxx)
Assigned to: Martin v. Löwis (loewis)
Summary: Mouse wheel crashes program
Initial Comment:
The following program (by Michael Peuser) crashes as
soon as the mouse wheel is moved. See my post to
c.l.p. on Oct 29.
Gary Richardson
#-------------------------
from Tkinter import *
def _onMouseWheel(event):
print event
root = Tk()
root.bind('<MouseWheel>',_onMouseWheel)
root.mainloop()
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Comment By: nikolaus heger (orthorim)
Date: 2005-05-12 14:41
Message:
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sdati, thanks for this workaround. it's awesome. i am now
happily mouse-wheeling :)
I did make a small improvement to it so it works for all
MouseWheel type events. Instead of
if sequence == "<MouseWheel>":
i say
if type(sequence) == str and
sequence.__contains__("MouseWheel"):
This way, all permutations of mouse events are covered, e.g.
"<Control-MouseWheel>"
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Comment By: Steve Davis (sdati)
Date: 2005-02-08 02:40
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I have determined the root cause of this problem. It actually does lie in
Tk, but is only revealed by Python Tkinter because of the way Python
deals with events.
>From Tk source -- tkWinX.c:
case WM_MOUSEWHEEL:
...
event.xany.send_event = -1
...
This line causes Tk to call TkpGetString() when ExpandPercents() is
called with '%A' (which is done by Python for ALL events, including
<MouseWheel>). This, in turn, causes segmentation fault because
event.xkey.trans_chars and event.xkey.nbytes are not initialized.
So, the workaround from the Python side is pretty ugly, but I have
tested it and verified that it works. There is probably a better way, but
this was the obvious solution to me, since I have never needed to look at
the Tkinter interface before:
In Tkinter.py, define a new _subst_format and _subst_format_str:
_subst_format_workaround = ('%#', '%b', '%f', '%h', '%k',
'%s', '%t', '%w', '%x', '%y',
'%D', '%E', '%K', '%N', '%W', '%T', '%X', '%Y', '%D')
_subst_format_str_workaround = " ".join(_subst_format_workaround)
Note that '%A' entry in _subst_format is replaced with '%D' entry in
_subst_format_workaround.
Now, in Misc._bind(),
if sequence == "<MouseWheel>":
cmd = ('%sif {"[%s %s]" == "break"} break\n'
%
(add and '+' or '',
funcid, self._subst_format_str_workaround))
else:
cmd = ('%sif {"[%s %s]" == "break"} break\n'
%
(add and '+' or '',
funcid, self._subst_format_str))
I am submitting this bug to Tcl/Tk maintainers to request that they fix
(Project: Tk Toolkit Request ID 1118340), but in the meantime (and for
all older versions of Tk), it seems like a workaround in the Tkinter code
might be appropriate.
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Comment By: John Speno (corvus)
Date: 2005-01-04 15:40
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I wasn't able to reproduce this in pure Tcl/Tk (under Wish). No surprise
there. In wish, I used this:
toplevel .top
bind .top <MouseWheel> {puts 'foo'}
And mouse wheeling in the Toplevel widget made a bunch of 'foo's appear in
the wish console without crashing.
HTH.
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Comment By: John Speno (corvus)
Date: 2005-01-04 15:02
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Me too. Python 2.3.4 with Tcl/Tk 8.4.9. Crash on Scroll Wheeling in WinXP
SP 1. (users report it happening in SP 2 also).
I'll try to make this happen in pure Tcl/Tk rather than Tkinter too.
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Comment By: John Fouhy (johnfouhy)
Date: 2004-10-26 04:13
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I can reproduce this bug. I am running Python 2.3.4 on
WinXP SP2.
tk84.dll is version 8.4.3; tcl84.dll is also 8.4.3.
The mousewheel works correctly with a Tkinter.Text object
with no additional bindings.
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Comment By: Jon Ashley (ash101)
Date: 2003-12-04 17:02
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Happens for me too, on Win2K with python 2.3.2. The fault is
in TCL84.DLL at an offset of 1002a58c, if that means
anything to anyone.
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Comment By: Gary Richardson (garyrxx)
Date: 2003-11-03 02:42
Message:
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I'm using Win98SE.
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Comment By: Martin v. Löwis (loewis)
Date: 2003-11-02 18:37
Message:
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What operating system are you using?
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You can respond by visiting:
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