119 lines
3.8 KiB
Python
119 lines
3.8 KiB
Python
# -*- coding: utf-8 -*-
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from .Qt import QtCore
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from .ptime import time
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from . import ThreadsafeTimer
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import weakref
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__all__ = ['SignalProxy']
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class SignalProxy(QtCore.QObject):
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"""Object which collects rapid-fire signals and condenses them
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into a single signal or a rate-limited stream of signals.
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Used, for example, to prevent a SpinBox from generating multiple
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signals when the mouse wheel is rolled over it.
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Emits sigDelayed after input signals have stopped for a certain period of time.
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"""
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sigDelayed = QtCore.Signal(object)
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def __init__(self, signal, delay=0.3, rateLimit=0, slot=None):
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"""Initialization arguments:
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signal - a bound Signal or pyqtSignal instance
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delay - Time (in seconds) to wait for signals to stop before emitting (default 0.3s)
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slot - Optional function to connect sigDelayed to.
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rateLimit - (signals/sec) if greater than 0, this allows signals to stream out at a
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steady rate while they are being received.
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"""
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QtCore.QObject.__init__(self)
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signal.connect(self.signalReceived)
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self.signal = signal
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self.delay = delay
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self.rateLimit = rateLimit
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self.args = None
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self.timer = ThreadsafeTimer.ThreadsafeTimer()
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self.timer.timeout.connect(self.flush)
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self.block = False
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self.slot = weakref.ref(slot)
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self.lastFlushTime = None
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if slot is not None:
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self.sigDelayed.connect(slot)
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def setDelay(self, delay):
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self.delay = delay
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def signalReceived(self, *args):
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"""Received signal. Cancel previous timer and store args to be forwarded later."""
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if self.block:
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return
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self.args = args
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if self.rateLimit == 0:
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self.timer.stop()
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self.timer.start((self.delay*1000)+1)
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else:
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now = time()
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if self.lastFlushTime is None:
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leakTime = 0
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else:
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lastFlush = self.lastFlushTime
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leakTime = max(0, (lastFlush + (1.0 / self.rateLimit)) - now)
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self.timer.stop()
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self.timer.start((min(leakTime, self.delay)*1000)+1)
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def flush(self):
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"""If there is a signal queued up, send it now."""
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if self.args is None or self.block:
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return False
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#self.emit(self.signal, *self.args)
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self.sigDelayed.emit(self.args)
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self.args = None
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self.timer.stop()
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self.lastFlushTime = time()
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return True
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def disconnect(self):
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self.block = True
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try:
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self.signal.disconnect(self.signalReceived)
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except:
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pass
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try:
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self.sigDelayed.disconnect(self.slot())
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except:
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pass
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#def proxyConnect(source, signal, slot, delay=0.3):
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#"""Connect a signal to a slot with delay. Returns the SignalProxy
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#object that was created. Be sure to store this object so it is not
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#garbage-collected immediately."""
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#sp = SignalProxy(source, signal, delay)
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#if source is None:
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#sp.connect(sp, QtCore.SIGNAL('signal'), slot)
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#else:
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#sp.connect(sp, signal, slot)
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#return sp
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if __name__ == '__main__':
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from .Qt import QtGui
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app = QtGui.QApplication([])
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win = QtGui.QMainWindow()
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spin = QtGui.QSpinBox()
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win.setCentralWidget(spin)
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win.show()
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def fn(*args):
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print("Raw signal:", args)
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def fn2(*args):
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print("Delayed signal:", args)
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spin.valueChanged.connect(fn)
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#proxy = proxyConnect(spin, QtCore.SIGNAL('valueChanged(int)'), fn)
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proxy = SignalProxy(spin.valueChanged, delay=0.5, slot=fn2)
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