Re: [matplotlib-devel] help request: wx, tk, qt backend leave event

[Darren D. <dsd...@gm...>]

On Tue, Dec 2, 2008 at 10:41 AM, John Hunter <jd...@gm...> wrote:

> On Tue, Dec 2, 2008 at 8:34 AM, Gregor Thalhammer
> <gre...@gm...> wrote:
>
> > If a mouse button is pressed while leaving the figure the behaviour is
> > somewhat strange. First, a figure_leave_event is emitted. Then, further
> > moving the mouse outside the figure a new figure_enter_event is created.
> > This is the case since all mouse events, also movements outside the
> window,
> > are captured as long as a mouse button is pressed. This is a very
> convenient
> > behaviour for panning/zooming. However, when finally releasing the mouse
> > button no figure_leave_event is triggered. With the GTK backend such an
> > event is created.
> > So what should be the desired behaviour?
>
> Ahh, I hadn't considered this problem.  It arises because I am using
> mpl location events to trigger the figure enter event.  The solution
> is to use the gui event for the figure enter event too -- basically
> the gui needs to call the canvas.enter_notify_event.  I added your
> patch and modified gtk to handle the enter_notify_event in svn r6468.
> Can you update, repatch wx to use it (and Darren qt)?


This is done for qt and qt4. In qt, if you hold the  button, leave the
figure, enter the second figure, and release the button, the old  figure
receives the leave event, but the new figure does not receive the enter
event. This seems like an issue with qt3, the new figure does receive the
enter event with qt4.

I noticed that if one moves the cursor rapidly through the figure and axes,
some events are not captured. For example, the cursor is in an axes but the
last event the axes received was a leave event. I'm not sure how that could
be improved, do you see it as well?

Finally, off topic, I committed the improved version checking in
mpl.__init__, using subprocess instead of popen*, which were deprecated in
python-2.6. This has been tested on two separate windows machines, hopefully
there are no lurking issues. But its something to keep in mind when we cut
the next release for windows.

Darren