PlotNode control widget now displays combo box to let user select plots to connect to

Flowchart example updated to use this feature.

examples/Flowchart.py

@@ -58,11 +58,15 @@ fc.setInput(dataIn=data)
 
 ## populate the flowchart with a basic set of processing nodes. 
 ## (usually we let the user do this)
+plotList = {'Top Plot': pw1, 'Bottom Plot': pw2}
+
 pw1Node = fc.createNode('PlotWidget', pos=(0, -150))
+pw1Node.setPlotList(plotList)
 pw1Node.setPlot(pw1)
 
 pw2Node = fc.createNode('PlotWidget', pos=(150, -150))
 pw2Node.setPlot(pw2)
+pw2Node.setPlotList(plotList)
 
 fNode = fc.createNode('GaussianFilter', pos=(0, 0))
 fNode.ctrls['sigma'].setValue(5)

pyqtgraph/flowchart/library/Display.py

@@ -4,7 +4,7 @@ import weakref
 from ...Qt import QtCore, QtGui
 from ...graphicsItems.ScatterPlotItem import ScatterPlotItem
 from ...graphicsItems.PlotCurveItem import PlotCurveItem
-from ... import PlotDataItem
+from ... import PlotDataItem, ComboBox
 
 from .common import *
 import numpy as np
@@ -16,7 +16,9 @@ class PlotWidgetNode(Node):
     
     def __init__(self, name):
         Node.__init__(self, name, terminals={'In': {'io': 'in', 'multi': True}})
-        self.plot = None
+        self.plot = None  # currently selected plot 
+        self.plots = {}   # list of available plots user may select from
+        self.ui = None 
         self.items = {}
         
     def disconnected(self, localTerm, remoteTerm):
@@ -26,16 +28,27 @@ class PlotWidgetNode(Node):
         
     def setPlot(self, plot):
         #print "======set plot"
+        if plot == self.plot:
+            return
+        
+        # clear data from previous plot
+        if self.plot is not None:
+            for vid in list(self.items.keys()):
+                self.plot.removeItem(self.items[vid])
+                del self.items[vid]
+
         self.plot = plot
+        self.updateUi()
+        self.update()
         self.sigPlotChanged.emit(self)
         
     def getPlot(self):
         return self.plot
         
     def process(self, In, display=True):
-        if display:
+        if display and self.plot is not None:
-            #self.plot.clearPlots()
             items = set()
+            # Add all new input items to selected plot
             for name, vals in In.items():
                 if vals is None:
                     continue
@@ -45,14 +58,13 @@ class PlotWidgetNode(Node):
                 for val in vals:
                     vid = id(val)
                     if vid in self.items and self.items[vid].scene() is self.plot.scene():
+                        # Item is already added to the correct scene
+                        #   possible bug: what if two plots occupy the same scene? (should
+                        #   rarely be a problem because items are removed from a plot before
+                        #   switching).
                         items.add(vid)
                     else:
-                        #if isinstance(val, PlotCurveItem):
+                        # Add the item to the plot, or generate a new item if needed.
-                            #self.plot.addItem(val)
-                            #item = val
-                        #if isinstance(val, ScatterPlotItem):
-                            #self.plot.addItem(val)
-                            #item = val
                         if isinstance(val, QtGui.QGraphicsItem):
                             self.plot.addItem(val)
                             item = val
@@ -60,21 +72,47 @@ class PlotWidgetNode(Node):
                             item = self.plot.plot(val)
                         self.items[vid] = item
                         items.add(vid)
+                        
+            # Any left-over items that did not appear in the input must be removed
             for vid in list(self.items.keys()):
                 if vid not in items:
-                    #print "remove", self.items[vid]
                     self.plot.removeItem(self.items[vid])
                     del self.items[vid]
             
     def processBypassed(self, args):
+        if self.plot is None:
+            return
         for item in list(self.items.values()):
             self.plot.removeItem(item)
         self.items = {}
         
-    #def setInput(self, **args):
+    def ctrlWidget(self):
-        #for k in args:
+        if self.ui is None:
-            #self.plot.plot(args[k])
+            self.ui = ComboBox()
+            self.ui.currentIndexChanged.connect(self.plotSelected)
+            self.updateUi()
+        return self.ui
     
+    def plotSelected(self, index):
+        self.setPlot(self.ui.value())
+    
+    def setPlotList(self, plots):
+        """
+        Specify the set of plots (PlotWidget or PlotItem) that the user may
+        select from.
+        
+        *plots* must be a dictionary of {name: plot} pairs.
+        """
+        self.plots = plots
+        self.updateUi()
+    
+    def updateUi(self):
+        # sets list and automatically preserves previous selection
+        self.ui.setItems(self.plots)
+        try:
+            self.ui.setValue(self.plot)
+        except ValueError:
+            pass
         
 
 class CanvasNode(Node):

pyqtgraph/graphicsItems/PlotItem/PlotItem.py

@@ -95,7 +95,6 @@ class PlotItem(GraphicsWidget):
     
     
     lastFileDir = None
-    managers = {}
     
     def __init__(self, parent=None, name=None, labels=None, title=None, viewBox=None, axisItems=None, enableMenu=True, **kargs):
         """
@@ -369,28 +368,6 @@ class PlotItem(GraphicsWidget):
         self.scene().removeItem(self.vb)
         self.vb = None
         
-        ## causes invalid index errors:
-        #for i in range(self.layout.count()):
-            #self.layout.removeAt(i)
-            
-        #for p in self.proxies:
-            #try:
-                #p.setWidget(None)
-            #except RuntimeError:
-                #break
-            #self.scene().removeItem(p)
-        #self.proxies = []
-        
-        #self.menuAction.releaseWidget(self.menuAction.defaultWidget())
-        #self.menuAction.setParent(None)
-        #self.menuAction = None
-        
-        #if self.manager is not None:
-            #self.manager.sigWidgetListChanged.disconnect(self.updatePlotList)
-            #self.manager.removeWidget(self.name)
-        #else:
-            #print "no manager"
-
     def registerPlot(self, name):   ## for backward compatibility
         self.vb.register(name)