From b323065a216c9273a903d616a1baa726316d17d8 Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauld.mccarthy@gmail.com>
Date: Wed, 27 Jul 2016 17:14:03 +0100
Subject: [PATCH] I have just discovered that wx will sometimes stop generating
idle events (if user stops moving the mouse), meaning that idle tasks can get
stuck in the idle queue, and not processed until the next UI event.
Therefore, the idle loop now gets periodically called by a wx.Timer, in
addition to via EVT_IDLE events.
---
fsl/utils/async.py | 49 ++++++++++++++++++++++++++++++++++++++++------
1 file changed, 43 insertions(+), 6 deletions(-)
diff --git a/fsl/utils/async.py b/fsl/utils/async.py
index 67e0bf65e..60734afb4 100644
--- a/fsl/utils/async.py
+++ b/fsl/utils/async.py
@@ -163,7 +163,7 @@ def run(task, onFinish=None, onError=None, name=None):
_idleRegistered = False
-"""Boolean flag indicating whether the :func:`wxIdleLoop` function has
+"""Boolean flag indicating whether the :func:`_wxIdleLoop` function has
been registered as a ``wx.EVT_IDLE`` event handler. Checked and set
in the :func:`idle` function.
"""
@@ -182,6 +182,20 @@ currently queued on the idle loop (see the ``name`` parameter to the
"""
+_idleTimer = None
+"""A ``wx.Timer`` instance which is used to periodically trigger the
+:func:`_wxIdleLoop` in circumstances where ``wx.EVT_IDLE`` events may not
+be generated. This is created in the first call to :func:`idle`.
+"""
+
+
+_idleCallRate = 200
+"""Minimum time (in milliseconds) between consecutive calls to
+:func:`_wxIdleLoop`. If ``wx.EVT_IDLE`` events are not being fired, the
+:attr:`_idleTimer` is used to maintain the idle loop at this rate.
+"""
+
+
class IdleTask(object):
"""Container object used by the :func:`idle` and :func:`_wxIdleLoop`
functions.
@@ -204,20 +218,35 @@ class IdleTask(object):
self.kwargs = kwargs
-
def _wxIdleLoop(ev):
- """Function which is called on ``wx.EVT_IDLE`` events. If there
+ """Function which is called on ``wx.EVT_IDLE`` events, and occasionally
+ on ``wx.EVT_TIMER` events via the :attr:`_idleTimer`. If there
is a function on the :attr:`_idleQueue`, it is popped and called.
+
+ .. note:: The ``wx.EVT_IDLE`` event is only triggered on user interaction
+ (e.g. mouse movement). This means that a situation may arise
+ whereby a function is queued via the :func:`idle` function, but
+ no ``EVT_IDLE`` event gets generated. Therefore, the
+ :attr:`_idleTimer` object is occasionally used to call this
+ function as well.
"""
+ import wx
global _idleQueue
global _idleQueueSet
-
+ global _idleTimer
+ global _idleCallRate
+
ev.Skip()
try:
task = _idleQueue.get_nowait()
+
except queue.Empty:
+
+ # Make sure that we get called periodically,
+ # if EVT_IDLE decides to stop firing.
+ _idleTimer.Start(_idleCallRate, wx.TIMER_ONE_SHOT)
return
now = time.time()
@@ -243,6 +272,8 @@ def _wxIdleLoop(ev):
if _idleQueue.qsize() > 0:
ev.RequestMore()
+ else:
+ _idleTimer.Start(_idleCallRate, wx.TIMER_ONE_SHOT)
def inIdle(taskName):
@@ -288,6 +319,7 @@ def idle(task, *args, **kwargs):
"""
global _idleRegistered
+ global _idleTimer
global _idleQueue
global _idleQueueSet
@@ -300,9 +332,14 @@ def idle(task, *args, **kwargs):
import wx
if not _idleRegistered:
- wx.GetApp().Bind(wx.EVT_IDLE, _wxIdleLoop)
+ app = wx.GetApp()
+ app.Bind(wx.EVT_IDLE, _wxIdleLoop)
+
+ _idleTimer = wx.Timer(app)
_idleRegistered = True
+ _idleTimer.Bind(wx.EVT_TIMER, _wxIdleLoop)
+
log.debug('Scheduling idle task ({}) on wx idle '
'loop'.format(getattr(task, '__name__', '<unknown>')))
@@ -558,7 +595,7 @@ class TaskThread(threading.Thread):
getattr(task.func, '__name__', '<unknown>')))
except Exception as e:
- log.debug('Task crashed: {} [{}]: {}: {}'.format(
+ log.warning('Task crashed: {} [{}]: {}: {}'.format(
task.name,
getattr(task.func, '__name__', '<unknown>'),
type(e).__name__,
--
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