Re: [matplotlib-devel] Direction keys not recognized in Qt4 backend

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

On Fri, May 14, 2010 at 2:39 PM, Tony S Yu <to...@mi...> wrote:
> I'm running the Qt4 backend, and I noticed that I'd frequently get error messages saying I was pressing unrecognized keys. It turns out that the direction keys aren't recognized in the qt4 backend. (I'm using direction keys to switch between spaces in OSX, so this error gets triggered quite frequently)
>
> One possible fix is to just add the direction keys to the list of valid keys (see patch below). Alternatively, the key event code could just ignore unrecognized keys (i.e. `key == None`). This change could be made in FigureCanvasQT.keyPressEvent (in backends.backend_qt4.py) or, more generally, in FigureCanvasBase.key_press_event (in backend_bases.py).
>
> -Tony
>
> %---Diff
>
> Index: lib/matplotlib/backends/backend_qt4.py
> ===================================================================
> --- lib/matplotlib/backends/backend_qt4.py      (revision 8315)
> +++ lib/matplotlib/backends/backend_qt4.py      (working copy)
> @@ -129,6 +129,10 @@
>     keyvald = { QtCore.Qt.Key_Control : 'control',
>                 QtCore.Qt.Key_Shift : 'shift',
>                 QtCore.Qt.Key_Alt : 'alt',
> +                QtCore.Qt.Key_Up : 'up',
> +                QtCore.Qt.Key_Right : 'right',
> +                QtCore.Qt.Key_Down : 'down',
> +                QtCore.Qt.Key_Left : 'left',
>                }
>     # left 1, middle 2, right 3
>     buttond = {1:1, 2:3, 4:2}
>
>
> %---Full traceback
>
> Traceback (most recent call last):
>  File "/Users/Tony/python/devel/mpl/lib/matplotlib/backends/backend_qt4.py", line 198, in keyPressEvent
>    FigureCanvasBase.key_press_event( self, key )
>  File "/Users/Tony/python/devel/mpl/lib/matplotlib/backend_bases.py", line 1459, in key_press_event
>    self.callbacks.process(s, event)
>  File "/Users/Tony/python/devel/mpl/lib/matplotlib/cbook.py", line 169, in process
>    func(*args, **kwargs)
>  File "/Users/Tony/python/devel/mpl/lib/matplotlib/backend_bases.py", line 2079, in key_press
>    if event.key in fullscreen_keys:
> TypeError: 'in <string>' requires string as left operand, not NoneType

I can commit the change to backend_qt4, but I need to run the change
to backendbases by the other devs. Is there any reason not to do the
following?:

===================================================================
--- lib/matplotlib/backend_bases.py	(revision 8306)
+++ lib/matplotlib/backend_bases.py	(working copy)
@@ -1,4 +1,3 @@
-
 """
 Abstract base classes define the primitives that renderers and
 graphics contexts must implement to serve as a matplotlib backend
@@ -1450,9 +1449,11 @@

     def key_press_event(self, key, guiEvent=None):
         """
-        This method will be call all functions connected to the
+        This method will call all functions connected to the
         'key_press_event' with a :class:`KeyEvent`
         """
+        if key is None:
+            return
         self._key = key
         s = 'key_press_event'
         event = KeyEvent(s, self, key, self._lastx, self._lasty,
guiEvent=guiEvent)