pyqtgraph/canvas/CanvasManager.py

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# -*- coding: utf-8 -*-
from pyqtgraph.Qt import QtCore, QtGui
if not hasattr(QtCore, 'Signal'):
QtCore.Signal = QtCore.pyqtSignal
import weakref
class CanvasManager(QtCore.QObject):
SINGLETON = None
sigCanvasListChanged = QtCore.Signal()
def __init__(self):
if CanvasManager.SINGLETON is not None:
raise Exception("Can only create one canvas manager.")
CanvasManager.SINGLETON = self
QtCore.QObject.__init__(self)
self.canvases = weakref.WeakValueDictionary()
@classmethod
def instance(cls):
return CanvasManager.SINGLETON
def registerCanvas(self, canvas, name):
n2 = name
i = 0
while n2 in self.canvases:
n2 = "%s_%03d" % (name, i)
i += 1
self.canvases[n2] = canvas
self.sigCanvasListChanged.emit()
return n2
def unregisterCanvas(self, name):
c = self.canvases[name]
del self.canvases[name]
self.sigCanvasListChanged.emit()
def listCanvases(self):
return list(self.canvases.keys())
def getCanvas(self, name):
return self.canvases[name]
manager = CanvasManager()
class CanvasCombo(QtGui.QComboBox):
def __init__(self, parent=None):
QtGui.QComboBox.__init__(self, parent)
man = CanvasManager.instance()
man.sigCanvasListChanged.connect(self.updateCanvasList)
self.hostName = None
self.updateCanvasList()
def updateCanvasList(self):
canvases = CanvasManager.instance().listCanvases()
canvases.insert(0, "")
if self.hostName in canvases:
canvases.remove(self.hostName)
sel = self.currentText()
if sel in canvases:
self.blockSignals(True) ## change does not affect current selection; block signals during update
self.clear()
for i in canvases:
self.addItem(i)
if i == sel:
self.setCurrentIndex(self.count())
self.blockSignals(False)
def setHostName(self, name):
self.hostName = name
self.updateCanvasList()