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#!/usr/bin/env python
# coding: utf-8
# /*##########################################################################
#
# Copyright (c) 2012 University of North Carolina at Chapel Hill, Luke Campagnola
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# ###########################################################################*/
"""This module contains utils relative to qt Signal
"""
from silx.gui import qt
import weakref
from time import time
from silx.gui.utils import concurrent
__all__ = ['SignalProxy']
__authors__ = ['L. Campagnola', 'M. Liberty']
__license__ = "MIT"
class SignalProxy(qt.QObject):
"""
This peace of code come from pyqtgraph
Object which collects rapid-fire signals and condenses them
into a single signal or a rate-limited stream of signals.
Used, for example, to prevent a SpinBox from generating multiple
signals when the mouse wheel is rolled over it.
Emits sigDelayed after input signals have stopped for a certain period of time.
"""
sigDelayed = qt.Signal(object)
def __init__(self, signal, delay=0.3, rateLimit=0, slot=None):
"""Initialization arguments:
signal - a bound Signal or pyqtSignal instance
delay - Time (in seconds) to wait for signals to stop before emitting (default 0.3s)
slot - Optional function to connect sigDelayed to.
rateLimit - (signals/sec) if greater than 0, this allows signals to stream out at a
steady rate while they are being received.
"""
qt.QObject.__init__(self)
signal.connect(self.signalReceived)
self.signal = signal
self.delay = delay
self.rateLimit = rateLimit
self.args = None
self.timer = qt.QTimer()
self.timer.timeout.connect(self.flush)
self.blockSignal = False
self.slot = weakref.ref(slot)
self.lastFlushTime = None
if slot is not None:
self.sigDelayed.connect(slot)
def setDelay(self, delay):
self.delay = delay
def signalReceived(self, *args):
"""Received signal. Cancel previous timer and store args to be forwarded later."""
if self.blockSignal:
return
self.args = args
if self.rateLimit == 0:
concurrent.submitToQtMainThread(self.timer.stop)
concurrent.submitToQtMainThread(self.timer.start, (self.delay * 1000) + 1)
else:
now = time()
if self.lastFlushTime is None:
leakTime = 0
else:
lastFlush = self.lastFlushTime
leakTime = max(0, (lastFlush + (1.0 / self.rateLimit)) - now)
concurrent.submitToQtMainThread(self.timer.stop)
concurrent.submitToQtMainThread(self.timer.start, (min(leakTime, self.delay) * 1000) + 1)
# self.timer.stop()
# self.timer.start((min(leakTime, self.delay) * 1000) + 1)
def flush(self):
"""If there is a signal queued up, send it now."""
if self.args is None or self.blockSignal:
return False
args, self.args = self.args, None
concurrent.submitToQtMainThread(self.timer.stop)
self.lastFlushTime = time()
# self.emit(self.signal, *self.args)
concurrent.submitToQtMainThread(self.sigDelayed.emit, args)
# self.sigDelayed.emit(args)
return True
def disconnect(self):
self.blockSignal = True
try:
self.signal.disconnect(self.signalReceived)
except:
pass
try:
self.sigDelayed.disconnect(self.slot)
except:
pass
if __name__ == '__main__':
app = qt.QApplication([])
win = qt.QMainWindow()
spin = qt.QSpinBox()
win.setCentralWidget(spin)
win.show()
def fn(*args):
print("Raw signal:", args)
def fn2(*args):
print("Delayed signal:", args)
spin.valueChanged.connect(fn)
# proxy = proxyConnect(spin, QtCore.SIGNAL('valueChanged(int)'), fn)
proxy = SignalProxy(spin.valueChanged, delay=0.5, slot=fn2)
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