Commit 5786a627 authored by Luke Campagnola's avatar Luke Campagnola
Browse files

Added deprecation warning for Node.__getattr__

Expanded flowchart.Node docstrings
Added custom node example
parent 4cbc0124
......@@ -21,21 +21,24 @@ import pyqtgraph.metaarray as metaarray
app = QtGui.QApplication([])
## Create main window with grid layout
win = QtGui.QMainWindow()
cw = QtGui.QWidget()
layout = QtGui.QGridLayout()
## Create flowchart, define input/output terminals
fc = Flowchart(terminals={
'dataIn': {'io': 'in'},
'dataOut': {'io': 'out'}
w = fc.widget()
## Add flowchart control panel to the main window
layout.addWidget(fc.widget(), 0, 0, 2, 1)
## Add two plot widgets
pw1 = pg.PlotWidget()
pw2 = pg.PlotWidget()
layout.addWidget(pw1, 0, 1)
......@@ -43,14 +46,17 @@ layout.addWidget(pw2, 1, 1)
## generate signal data to pass through the flowchart
data = np.random.normal(size=1000)
data[200:300] += 1
data += np.sin(np.linspace(0, 100, 1000))
data = metaarray.MetaArray(data, info=[{'name': 'Time', 'values': np.linspace(0, 1.0, len(data))}, {}])
## Feed data into the input terminal of the flowchart
## populate the flowchart with a basic set of processing nodes.
## (usually we let the user do this)
pw1Node = fc.createNode('PlotWidget', pos=(0, -150))
......@@ -59,41 +65,11 @@ pw2Node.setPlot(pw2)
fNode = fc.createNode('GaussianFilter', pos=(0, 0))
fc.connectTerminals(fc.dataIn, fNode.In)
fc.connectTerminals(fc.dataIn, pw1Node.In)
fc.connectTerminals(fNode.Out, pw2Node.In)
fc.connectTerminals(fNode.Out, fc.dataOut)
#n1 = fc.createNode('Add', pos=(0,-80))
#n2 = fc.createNode('Subtract', pos=(140,-10))
#n3 = fc.createNode('Abs', pos=(0, 80))
#n4 = fc.createNode('Add', pos=(140,100))
#fc.connectTerminals(fc.dataIn, n1.A)
#fc.connectTerminals(fc.dataIn, n1.B)
#fc.connectTerminals(fc.dataIn, n2.A)
#fc.connectTerminals(n1.Out, n4.A)
#fc.connectTerminals(n1.Out, n2.B)
#fc.connectTerminals(n2.Out, n3.In)
#fc.connectTerminals(n3.Out, n4.B)
#fc.connectTerminals(n4.Out, fc.dataOut)
#def process(**kargs):
#return fc.process(**kargs)
#print process(dataIn=7)
#s = fc.saveState()
fc.connectTerminals(fc['dataIn'], fNode['In'])
fc.connectTerminals(fc['dataIn'], pw1Node['In'])
fc.connectTerminals(fNode['Out'], pw2Node['In'])
fc.connectTerminals(fNode['Out'], fc['dataOut'])
## Start Qt event loop unless running in interactive mode or using pyside.
# -*- coding: utf-8 -*-
This example demonstrates writing a custom Node subclass for use with flowcharts.
We implement a couple of simple image processing nodes.
import initExample ## Add path to library (just for examples; you do not need this)
from pyqtgraph.flowchart import Flowchart, Node
import pyqtgraph.flowchart.library as fclib
from pyqtgraph.flowchart.library.common import CtrlNode
from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph as pg
import numpy as np
import scipy.ndimage
app = QtGui.QApplication([])
## Create main window with a grid layout inside
win = QtGui.QMainWindow()
cw = QtGui.QWidget()
layout = QtGui.QGridLayout()
## Create an empty flowchart with a single input and output
fc = Flowchart(terminals={
'dataIn': {'io': 'in'},
'dataOut': {'io': 'out'}
w = fc.widget()
layout.addWidget(fc.widget(), 0, 0, 2, 1)
## Create two ImageView widgets to display the raw and processed data with contrast
## and color control.
v1 = pg.ImageView()
v2 = pg.ImageView()
layout.addWidget(v1, 0, 1)
layout.addWidget(v2, 1, 1)
## generate random input data
data = np.random.normal(size=(100,100))
data = 25 * scipy.ndimage.gaussian_filter(data, (5,5))
data += np.random.normal(size=(100,100))
data[40:60, 40:60] += 15.0
data[30:50, 30:50] += 15.0
#data += np.sin(np.linspace(0, 100, 1000))
#data = metaarray.MetaArray(data, info=[{'name': 'Time', 'values': np.linspace(0, 1.0, len(data))}, {}])
## Set the raw data as the input value to the flowchart
## At this point, we need some custom Node classes since those provided in the library
## are not sufficient. Each node will define a set of input/output terminals, a
## processing function, and optionally a control widget (to be displayed in the
## flowchart control panel)
class ImageViewNode(Node):
"""Node that displays image data in an ImageView widget"""
nodeName = 'ImageView'
def __init__(self, name):
self.view = None
## Initialize node with only a single input terminal
Node.__init__(self, name, terminals={'data': {'io':'in'}})
def setView(self, view): ## setView must be called by the program
self.view = view
def process(self, data, display=True):
## if process is called with display=False, then the flowchart is being operated
## in batch processing mode, so we should skip displaying to improve performance.
if display and self.view is not None:
## the 'data' argument is the value given to the 'data' terminal
if data is None:
self.view.setImage(np.zeros((1,1))) # give a blank array to clear the view
## register the class so it will appear in the menu of node types.
## It will appear in the 'display' sub-menu.
fclib.registerNodeType(ImageViewNode, [('Display',)])
## We will define an unsharp masking filter node as a subclass of CtrlNode.
## CtrlNode is just a convenience class that automatically creates its
## control widget based on a simple data structure.
class UnsharpMaskNode(CtrlNode):
"""Return the input data passed through scipy.ndimage.gaussian_filter."""
nodeName = "UnsharpMask"
uiTemplate = [
('sigma', 'spin', {'value': 1.0, 'step': 1.0, 'range': [0.0, None]}),
('strength', 'spin', {'value': 1.0, 'dec': True, 'step': 0.5, 'minStep': 0.01, 'range': [0.0, None]}),
def __init__(self, name):
## Define the input / output terminals available on this node
terminals = {
'dataIn': dict(io='in'), # each terminal needs at least a name and
'dataOut': dict(io='out'), # to specify whether it is input or output
} # other more advanced options are available
# as well..
CtrlNode.__init__(self, name, terminals=terminals)
def process(self, dataIn, display=True):
# CtrlNode has created self.ctrls, which is a dict containing {ctrlName: widget}
sigma = self.ctrls['sigma'].value()
strength = self.ctrls['strength'].value()
output = dataIn - (strength * scipy.ndimage.gaussian_filter(dataIn, (sigma,sigma)))
return {'dataOut': output}
## register the class so it will appear in the menu of node types.
## It will appear in a new 'image' sub-menu.
fclib.registerNodeType(UnsharpMaskNode, [('Image',)])
## Now we will programmatically add nodes to define the function of the flowchart.
## Normally, the user will do this manually or by loading a pre-generated
## flowchart file.
v1Node = fc.createNode('ImageView', pos=(0, -150))
v2Node = fc.createNode('ImageView', pos=(150, -150))
fNode = fc.createNode('UnsharpMask', pos=(0, 0))
fc.connectTerminals(fc['dataIn'], fNode['dataIn'])
fc.connectTerminals(fc['dataIn'], v1Node['data'])
fc.connectTerminals(fNode['dataOut'], v2Node['data'])
fc.connectTerminals(fNode['dataOut'], fc['dataOut'])
## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
import sys
if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
......@@ -13,6 +13,18 @@ def strDict(d):
return dict([(str(k), v) for k, v in d.items()])
class Node(QtCore.QObject):
Node represents the basic processing unit of a flowchart.
A Node subclass implements at least:
1) A list of input / ouptut terminals and their properties
2) a process() function which takes the names of input terminals as keyword arguments and returns a dict with the names of output terminals as keys.
A flowchart thus consists of multiple instances of Node subclasses, each of which is connected
to other by wires between their terminals. A flowchart is, itself, also a special subclass of Node.
This allows Nodes within the flowchart to connect to the input/output nodes of the flowchart itself.
Optionally, a node class can implement the ctrlWidget() method, which must return a QWidget (usually containing other widgets) that will be displayed in the flowchart control panel. Some nodes implement fairly complex control widgets, but most nodes follow a simple form-like pattern: a list of parameter names and a single value (represented as spin box, check box, etc..) for each parameter. To make this easier, the CtrlNode subclass allows you to instead define a simple data structure that CtrlNode will use to automatically generate the control widget. """
sigOutputChanged = QtCore.Signal(object) # self
sigClosed = QtCore.Signal(object)
......@@ -23,6 +35,31 @@ class Node(QtCore.QObject):
def __init__(self, name, terminals=None, allowAddInput=False, allowAddOutput=False, allowRemove=True):
============== ============================================================
name The name of this specific node instance. It can be any
string, but must be unique within a flowchart. Usually,
we simply let the flowchart decide on a name when calling
terminals Dict-of-dicts specifying the terminals present on this Node.
Terminal specifications look like::
'inputTerminalName': {'io': 'in'}
'outputTerminalName': {'io': 'out'}
There are a number of optional parameters for terminals:
multi, pos, renamable, removable, multiable, bypass. See
the Terminal class for more information.
allowAddInput bool; whether the user is allowed to add inputs by the
context menu.
allowAddOutput bool; whether the user is allowed to add outputs by the
context menu.
allowRemove bool; whether the user is allowed to remove this node by the
context menu.
============== ============================================================
self._name = name
self._bypass = False
......@@ -52,15 +89,25 @@ class Node(QtCore.QObject):
return name2
def addInput(self, name="Input", **args):
"""Add a new input terminal to this Node with the given name. Extra
keyword arguments are passed to Terminal.__init__.
This is a convenience function that just calls addTerminal(io='in', ...)"""
#print "Node.addInput called."
return self.addTerminal(name, io='in', **args)
def addOutput(self, name="Output", **args):
"""Add a new output terminal to this Node with the given name. Extra
keyword arguments are passed to Terminal.__init__.
This is a convenience function that just calls addTerminal(io='out', ...)"""
return self.addTerminal(name, io='out', **args)
def removeTerminal(self, term):
## term may be a terminal or its name
"""Remove the specified terminal from this Node. May specify either the
terminal's name or the terminal itself.
Causes sigTerminalRemoved to be emitted."""
if isinstance(term, Terminal):
name =
......@@ -80,7 +127,9 @@ class Node(QtCore.QObject):
def terminalRenamed(self, term, oldName):
"""Called after a terminal has been renamed"""
"""Called after a terminal has been renamed
Causes sigTerminalRenamed to be emitted."""
newName =
for d in [self.terminals, self._inputs, self._outputs]:
if oldName not in d:
......@@ -92,6 +141,10 @@ class Node(QtCore.QObject):
self.sigTerminalRenamed.emit(term, oldName)
def addTerminal(self, name, **opts):
"""Add a new terminal to this Node with the given name. Extra
keyword arguments are passed to Terminal.__init__.
Causes sigTerminalAdded to be emitted."""
name = self.nextTerminalName(name)
term = Terminal(self, name, **opts)
self.terminals[name] = term
......@@ -105,38 +158,60 @@ class Node(QtCore.QObject):
def inputs(self):
"""Return dict of all input terminals.
Warning: do not modify."""
return self._inputs
def outputs(self):
"""Return dict of all output terminals.
Warning: do not modify."""
return self._outputs
def process(self, **kargs):
"""Process data through this node. Each named argument supplies data to the corresponding terminal."""
"""Process data through this node. This method is called any time the flowchart
wants the node to process data. It will be called with one keyword argument
corresponding to each input terminal, and must return a dict mapping the name
of each output terminal to its new value.
This method is also called with a 'display' keyword argument, which indicates
whether the node should update its display (if it implements any) while processing
this data. This is primarily used to disable expensive display operations
during batch processing.
return {}
def graphicsItem(self):
"""Return a (the?) graphicsitem for this node"""
#print "Node.graphicsItem called."
"""Return the GraphicsItem for this node. Subclasses may re-implement
this method to customize their appearance in the flowchart."""
if self._graphicsItem is None:
#print "Creating NodeGraphicsItem..."
self._graphicsItem = NodeGraphicsItem(self)
#print "Node.graphicsItem is returning ", self._graphicsItem
return self._graphicsItem
## this is just bad planning. Causes too many bugs.
def __getattr__(self, attr):
"""Return the terminal with the given name"""
if attr not in self.terminals:
raise AttributeError(attr)
import traceback
print("Warning: use of node.terminalName is deprecated; use node['terminalName'] instead.")
return self.terminals[attr]
def __getitem__(self, item):
return getattr(self, item)
#return getattr(self, item)
"""Return the terminal with the given name"""
if item not in self.terminals:
raise KeyError(item)
return self.terminals[item]
def name(self):
"""Return the name of this node."""
return self._name
def rename(self, name):
"""Rename this node. This will cause sigRenamed to be emitted."""
oldName = self._name
self._name = name
#self.emit(QtCore.SIGNAL('renamed'), self, oldName)
......@@ -154,15 +229,25 @@ class Node(QtCore.QObject):
return "<Node %s @%x>" % (, id(self))
def ctrlWidget(self):
"""Return this Node's control widget."""
return None
def bypass(self, byp):
"""Set whether this node should be bypassed.
When bypassed, a Node's process() method is never called. In some cases,
data is automatically copied directly from specific input nodes to
output nodes instead (see the bypass argument to Terminal.__init__).
This is usually called when the user disables a node from the flowchart
control panel.
self._bypass = byp
if self.bypassButton is not None:
def isBypassed(self):
"""Return True if this Node is currently bypassed."""
return self._bypass
def setInput(self, **args):
......@@ -179,12 +264,14 @@ class Node(QtCore.QObject):
def inputValues(self):
"""Return a dict of all input values currently assigned to this node."""
vals = {}
for n, t in self.inputs().items():
vals[n] = t.value()
return vals
def outputValues(self):
"""Return a dict of all output values currently generated by this node."""
vals = {}
for n, t in self.outputs().items():
vals[n] = t.value()
......@@ -195,11 +282,15 @@ class Node(QtCore.QObject):
def disconnected(self, localTerm, remoteTerm):
"""Called whenever one of this node's terminals is connected elsewhere."""
"""Called whenever one of this node's terminals is disconnected from another."""
def update(self, signal=True):
"""Collect all input values, attempt to process new output values, and propagate downstream."""
"""Collect all input values, attempt to process new output values, and propagate downstream.
Subclasses should call update() whenever thir internal state has changed
(such as when the user interacts with the Node's control widget). Update
is automatically called when the inputs to the node are changed.
vals = self.inputValues()
#print " inputs:", vals
......@@ -227,6 +318,9 @@ class Node(QtCore.QObject):
self.sigOutputChanged.emit(self) ## triggers flowchart to propagate new data
def processBypassed(self, args):
"""Called when the flowchart would normally call Node.process, but this node is currently bypassed.
The default implementation looks for output terminals with a bypass connection and returns the
corresponding values. Most Node subclasses will _not_ need to reimplement this method."""
result = {}
for term in list(self.outputs().values()):
byp = term.bypassValue()
......@@ -266,6 +360,13 @@ class Node(QtCore.QObject):
self.graphicsItem().setPen(QtGui.QPen(QtGui.QColor(150, 0, 0), 3))
def saveState(self):
"""Return a dictionary representing the current state of this node
(excluding input / output values). This is used for saving/reloading
flowcharts. The default implementation returns this Node's position,
bypass state, and information about each of its terminals.
Subclasses may want to extend this method, adding extra keys to the returned
pos = self.graphicsItem().pos()
state = {'pos': (pos.x(), pos.y()), 'bypass': self.isBypassed()}
termsEditable = self._allowAddInput | self._allowAddOutput
......@@ -276,6 +377,8 @@ class Node(QtCore.QObject):
return state
def restoreState(self, state):
"""Restore the state of this node from a structure previously generated
by saveState(). """
pos = state.get('pos', (0,0))
self.bypass(state.get('bypass', False))
......@@ -24,6 +24,8 @@ class Terminal(object):
renamable (bool) Whether the terminal can be renamed by the user
removable (bool) Whether the terminal can be removed by the user
multiable (bool) Whether the user may toggle the *multi* option for this terminal
bypass (str) Name of the terminal from which this terminal's value is derived
when the Node is in bypass mode.
============== =================================================================================
self._io = io
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