PythonQt properties shadowing methods

[fbordignon (Fernando Bordignon (LTrace))]

For this example, the user needs to have the python3.dll fix, alternatively one can temporarily download and install WinPython 3.6.7 and copy python3.dll from winpython/python-3.6.7.amd64/python3.dll to Slicer/bin/python3.dll
Slicer can crash if one does not have PythonQt compiled with this fix. It works without it, but Slicer can become unstable.

Working example based on plotting example of pyqtgraph:

# Copy and paste this on Slicer's python terminal
pip_install('pyside2==5.15.1') # must be important to match pyside2 version to slicer's qt version
pip_install('pyqtgraph')

import textwrap
from PySide2.QtWidgets import QVBoxLayout
import shiboken2
import numpy as np
from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph as pg

# Custom layout base class
class BaseLayout:
    TAG = "EmptyScreen"
    UID = 1010
    LAYOUT = textwrap.dedent(
        f"""
        <layout type="vertical">
            <item>
                <{TAG}></{TAG}>
            </item>
        </layout>
    """
    )
    @classmethod
    def register(cls):
        viewFactory = slicer.qSlicerSingletonViewFactory()
        viewFactory.setTagName(cls.TAG)
        if slicer.app.layoutManager() is not None:
            slicer.app.layoutManager().registerViewFactory(viewFactory)
        container = cls.build(viewFactory)
        layoutManager = slicer.app.layoutManager()
        layoutManager.layoutLogic().GetLayoutNode().AddLayoutDescription(cls.UID, cls.LAYOUT)
        return container
    @classmethod
    def build(cls, factory):
        viewWidget = qt.QWidget()
        viewWidget.setAutoFillBackground(True)
        factory.setWidget(viewWidget)
        viewLayout = qt.QVBoxLayout()
        viewWidget.setLayout(viewLayout)
        return viewWidget
    @classmethod
    def show(cls):
        slicer.app.layoutManager().setLayout(cls.UID)

#my plot layout class
class PlotLayout(BaseLayout):
    TAG = "MyPlotWidget"
    UID = 1019
    LAYOUT = textwrap.dedent(f"""
        <layout type="vertical">
            <item>
                <{TAG}></{TAG}>
            </item>
        </layout>
    """)

lw = PlotLayout.register().layout()
PlotLayout.show()

# wrap pythonQt instance with shiboken2 (pyside2)
pysidelayout = shiboken2.wrapInstance(hash(lw), QVBoxLayout)

pg.mkQApp()

# start of pyqtgraph plotting example https://github.com/pyqtgraph/pyqtgraph/blob/master/examples/Plotting.py
win = pg.GraphicsLayoutWidget(show=True, title="Basic plotting examples")
pysidelayout.addWidget(win)

# Enable antialiasing for prettier plots
pg.setConfigOptions(antialias=True)

p1 = win.addPlot(title="Basic array plotting", y=np.random.normal(size=100))

p2 = win.addPlot(title="Multiple curves")
p2.plot(np.random.normal(size=100), pen=(255,0,0), name="Red curve")
p2.plot(np.random.normal(size=110)+5, pen=(0,255,0), name="Green curve")
p2.plot(np.random.normal(size=120)+10, pen=(0,0,255), name="Blue curve")

p3 = win.addPlot(title="Drawing with points")
p3.plot(np.random.normal(size=100), pen=(200,200,200), symbolBrush=(255,0,0), symbolPen='w')

win.nextRow()

p4 = win.addPlot(title="Parametric, grid enabled")
x = np.cos(np.linspace(0, 2*np.pi, 1000))
y = np.sin(np.linspace(0, 4*np.pi, 1000))
p4.plot(x, y)
p4.showGrid(x=True, y=True)

p5 = win.addPlot(title="Scatter plot, axis labels, log scale")
x = np.random.normal(size=1000) * 1e-5
y = x*1000 + 0.005 * np.random.normal(size=1000)
y -= y.min()-1.0
mask = x > 1e-15
x = x[mask]
y = y[mask]
p5.plot(x, y, pen=None, symbol='t', symbolPen=None, symbolSize=10, symbolBrush=(100, 100, 255, 50))
p5.setLabel('left', "Y Axis", units='A')
p5.setLabel('bottom', "Y Axis", units='s')
p5.setLogMode(x=True, y=False)

p6 = win.addPlot(title="Updating plot")
curve = p6.plot(pen='y')
data = np.random.normal(size=(10,1000))
ptr = 0

def update():
    global curve, data, ptr, p6
    curve.setData(data[ptr%10])
    if ptr == 0:
        p6.enableAutoRange('xy', False)  ## stop auto-scaling after the first data set is plotted
    ptr += 1

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(50)


win.nextRow()

p7 = win.addPlot(title="Filled plot, axis disabled")
y = np.sin(np.linspace(0, 10, 1000)) + np.random.normal(size=1000, scale=0.1)
p7.plot(y, fillLevel=-0.3, brush=(50,50,200,100))
p7.showAxis('bottom', False)


x2 = np.linspace(-100, 100, 1000)
data2 = np.sin(x2) / x2
p8 = win.addPlot(title="Region Selection")
p8.plot(data2, pen=(255,255,255,200))
lr = pg.LinearRegionItem([400,700])
lr.setZValue(-10)
p8.addItem(lr)

p9 = win.addPlot(title="Zoom on selected region")
p9.plot(data2)

def updatePlot():
    p9.setXRange(*lr.getRegion(), padding=0)

def updateRegion():
    lr.setRegion(p9.getViewBox().viewRange()[0])

lr.sigRegionChanged.connect(updatePlot)
p9.sigXRangeChanged.connect(updateRegion)
updatePlot()