lambdas which reference self prevent GC

pyqtgraph/graphicsItems/GradientEditorItem.py

@@ -446,10 +446,10 @@ class GradientEditorItem(TickSliderItem):
         
         self.rgbAction = QtGui.QAction(translate("GradiantEditorItem", 'RGB'), self)
         self.rgbAction.setCheckable(True)
-        self.rgbAction.triggered.connect(lambda: self.setColorMode('rgb'))
+        self.rgbAction.triggered.connect(self.setColorModeToRGB)
         self.hsvAction = QtGui.QAction(translate("GradiantEditorItem", 'HSV'), self)
         self.hsvAction.setCheckable(True)
-        self.hsvAction.triggered.connect(lambda: self.setColorMode('hsv'))
+        self.hsvAction.triggered.connect(self.setColorModeToHSV)
             
         self.menu = QtGui.QMenu()
         
@@ -493,7 +493,7 @@ class GradientEditorItem(TickSliderItem):
         self.updateGradient()
         self.linkedGradients = {}
         
-        self.sigTicksChanged.connect(lambda *args, **kwargs: self.updateGradient())
+        self.sigTicksChanged.connect(self.updateGradientIgnoreArgs)
         self.sigTicksChangeFinished.connect(self.sigGradientChangeFinished.emit)
 
     def showTicks(self, show=True):
@@ -567,6 +567,12 @@ class GradientEditorItem(TickSliderItem):
         self.sigTicksChanged.emit(self)
         self.sigGradientChangeFinished.emit(self)
 
+    def setColorModeToRGB(self):
+        self.setColorMode("rgb")
+
+    def setColorModeToHSV(self):
+        self.setColorMode("hsv")
+
     def colorMap(self):
         """Return a ColorMap object representing the current state of the editor."""
         if self.colorMode == 'hsv':
@@ -585,6 +591,9 @@ class GradientEditorItem(TickSliderItem):
         self.gradRect.setBrush(QtGui.QBrush(self.gradient))
         self.sigGradientChanged.emit(self)
 
+    def updateGradientIgnoreArgs(self, *args, **kwargs):
+        self.updateGradient()
+
     def setLength(self, newLen):
         #private (but maybe public)
         TickSliderItem.setLength(self, newLen)

pyqtgraph/graphicsItems/LinearRegionItem.py

@@ -110,8 +110,8 @@ class LinearRegionItem(GraphicsObject):
         for l in self.lines:
             l.setParentItem(self)
             l.sigPositionChangeFinished.connect(self.lineMoveFinished)
-        self.lines[0].sigPositionChanged.connect(lambda: self.lineMoved(0))
+        self.lines[0].sigPositionChanged.connect(self.line0Moved)
-        self.lines[1].sigPositionChanged.connect(lambda: self.lineMoved(1))
+        self.lines[1].sigPositionChanged.connect(self.line1Moved)
             
         if brush is None:
             brush = QtGui.QBrush(QtGui.QColor(0, 0, 255, 50))
@@ -242,6 +242,12 @@ class LinearRegionItem(GraphicsObject):
         self.prepareGeometryChange()
         self.sigRegionChanged.emit(self)
 
+    def line0Moved(self):
+        self.lineMoved(0)
+
+    def line1Moved(self):
+        self.lineMoved(1)
+
     def lineMoveFinished(self):
         self.sigRegionChangeFinished.emit(self)
 

pyqtgraph/graphicsItems/ROI.py

@@ -785,7 +785,10 @@ class ROI(GraphicsObject):
 
     def removeClicked(self):
         ## Send remove event only after we have exited the menu event handler
-        QtCore.QTimer.singleShot(0, lambda: self.sigRemoveRequested.emit(self))
+        QtCore.QTimer.singleShot(0, self.emitRemoveRequest)
+
+    def emitRemoveRequest(self):
+        self.sigRemoveRequested.emit(self)
 
     def mouseDragEvent(self, ev):
         self.mouseDragHandler.mouseDragEvent(ev)

pyqtgraph/parametertree/Parameter.py

@@ -203,15 +203,15 @@ class Parameter(QtCore.QObject):
             self.opts['default'] = None
     
         ## Connect all state changed signals to the general sigStateChanged
-        self.sigValueChanged.connect(lambda param, data: self.emitStateChanged('value', data))
+        self.sigValueChanged.connect(self.emitValueChanged)
-        self.sigChildAdded.connect(lambda param, *data: self.emitStateChanged('childAdded', data))
+        self.sigChildAdded.connect(self.emitChildAddedChanged)
-        self.sigChildRemoved.connect(lambda param, data: self.emitStateChanged('childRemoved', data))
+        self.sigChildRemoved.connect(self.emitChildRemovedChanged)
-        self.sigParentChanged.connect(lambda param, data: self.emitStateChanged('parent', data))
+        self.sigParentChanged.connect(self.emitParentChanged)
-        self.sigLimitsChanged.connect(lambda param, data: self.emitStateChanged('limits', data))
+        self.sigLimitsChanged.connect(self.emitLimitsChanged)
-        self.sigDefaultChanged.connect(lambda param, data: self.emitStateChanged('default', data))
+        self.sigDefaultChanged.connect(self.emitDefaultChanged)
-        self.sigNameChanged.connect(lambda param, data: self.emitStateChanged('name', data))
+        self.sigNameChanged.connect(self.emitNameChanged)
-        self.sigOptionsChanged.connect(lambda param, data: self.emitStateChanged('options', data))
+        self.sigOptionsChanged.connect(self.emitOptionsChanged)
-        self.sigContextMenu.connect(lambda param, data: self.emitStateChanged('contextMenu', data))
+        self.sigContextMenu.connect(self.emitContextMenuChanged)
 
         
         #self.watchParam(self)  ## emit treechange signals if our own state changes
@@ -511,6 +511,33 @@ class Parameter(QtCore.QObject):
         self.treeStateChanges.append((self, changeDesc, data))
         self.emitTreeChanges()
 
+    def emitValueChanged(self, param, data):
+        self.emitStateChanged("value", data)
+
+    def emitChildAddedChanged(self, param, *data):
+        self.emitStateChanged("childAdded", data)
+
+    def emitchildRemovedChanged(self, param, data):
+        self.emitStateChanged("childRemoved", data)
+
+    def emitParentChanged(self, param, data):
+        self.emitStateChanged("parent", data)
+
+    def emitLimitsChanged(self, param, data):
+        self.emitStateChanged("limits", data)
+
+    def emitDefaultChanged(self, param, data):
+        self.emitStateChanged("default", data)
+
+    def emitNameChanged(self, param, data):
+        self.emitStateChanged("name", data)
+
+    def emitOptionsChanged(self, param, data):
+        self.emitStateChanged("options", data)
+
+    def emitContextMenuChanged(self, param, data):
+        self.emitStateChanged("contextMenu", data)
+
     def makeTreeItem(self, depth):
         """
         Return a TreeWidgetItem suitable for displaying/controlling the content of