In the name of improving performance over SSH, SliceCanvas._refresh now

calls the _draw method directly, and LocationPanel calls
wx.Refresh/Update when its location changes.

fsl/fslview/controls/locationpanel.py

@@ -260,15 +260,14 @@ class LocationPanel(fslpanel.FSLViewPanel):
         wloc = transform.transform(
             [dloc], display.getTransform('display', 'world'))[0]
 
-        import fsl.utils.trace as trace
-        trace.trace('LocationPanel')
-
         log.debug('Updating location ({} -> vox {}, world {})'.format(
             dloc, vloc, wloc))
         
         self            .disableListener('voxelLocation', self._name)
         self            .disableListener('worldLocation', self._name)
         self._displayCtx.disableListener('location',      self._name)
+
+        self.Freeze()
         
         self.voxelLocation.xyz       = np.round(vloc)
         self.worldLocation.xyz       = wloc
@@ -279,6 +278,10 @@ class LocationPanel(fslpanel.FSLViewPanel):
 
         self._updateVoxelValue()
 
+        self.Thaw()
+        self.Refresh()
+        self.Update()
+
 
     def _voxelLocationChanged(self, *a):
         """

fsl/fslview/gl/__init__.py

@@ -396,8 +396,13 @@ class WXGLCanvasTarget(object):
 
         
     def _refresh(self, *a):
-        """Triggers a redraw via the :mod:`wx` `Refresh` method."""
-        self.Refresh()
+        """Triggers a redraw via the :meth:`_draw` method."""
+        
+        # NOTE I'm not drawing via wx.Refresh/Update
+        # because, when running over ssh under X11,
+        # this doesn't seem to force a redraw. Calling
+        # the draw code directly seems to do the trick
+        self._draw()
 
         
     def _postDraw(self):

fsl/fslview/gl/slicecanvas.py

@@ -692,6 +692,10 @@ class SliceCanvas(props.HasProperties):
         :func:`fsl.fslview.gl.slicecanvas_draw.drawScene` function, which does
         the actual drawing.
         """
+        
+        width, height = self._getSize()
+        if width == 0 or height == 0:
+            return
 
         self._setGLContext()
         self._setViewport()