How to use the pyqtgraph.GraphicsLayoutWidget function in pyqtgraph

"""
Demonstrates very basic use of ImageItem to display image data inside a ViewBox.
"""

## Add path to library (just for examples; you do not need this)
import initExample

from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
import pyqtgraph as pg
import pyqtgraph.ptime as ptime

app = QtGui.QApplication([])

## Create window with GraphicsView widget
win = pg.GraphicsLayoutWidget()
win.show()  ## show widget alone in its own window
win.setWindowTitle('pyqtgraph example: ImageItem')
view = win.addViewBox()

## lock the aspect ratio so pixels are always square
view.setAspectLocked(True)

## Create image item
img = pg.ImageItem(border='w')
view.addItem(img)

## Set initial view bounds
view.setRange(QtCore.QRectF(0, 0, 600, 600))

## Create random image
data = np.random.normal(size=(15, 600, 600), loc=1024, scale=64).astype(np.uint16)

def init_plt( self ) :

		# Initialize the "GraphicsLayoutWidget" for this widget.  This
		# will allow a grid of "GraphicsItem" objects, which will
		# include the plots themselves, the axes, and the axis labels.

		# Note.  The "QGridLayout" object given to this widget as its
		#        layout is essentially a dummy.  I tried to just having
		#        this widget be an extention of "GraphicsLayoutWidget"
		#        (i.e., having it inheret that type), but I couldn't get
		#        it to display anything at all.

		self.setLayout( QGridLayout( ) )

		self.grd = GraphicsLayoutWidget( )
		self.grd.setBackground( 'w' )
		self.layout( ).addWidget( self.grd )

		self.layout().setContentsMargins( 0, 0, 0, 0 )

		# Initialize the text for the x- and y-axis labels.  Then,
		# create the labels themselves and add them to the grid.

		self.txt_axs_x = 'Time [s]'
		self.txt_axs_y = 'Magnetic Field [nT]'

		if ( self.core.app.res_lo ) :
			size =  '8pt'
		else :
			size = '10pt'

def create_display_widget(self):
        self._display_widget = QtWidgets.QFrame(self)
        self._display_layout = QtWidgets.QVBoxLayout()
        self._display_layout.setContentsMargins(0, 0, 0, 0)
        self.img_layout_widget = GraphicsLayoutWidget()
        self.img_widget = MaskImgWidget(self.img_layout_widget)

        self._display_layout.addWidget(self.img_layout_widget)

        self._status_layout = QtWidgets.QHBoxLayout()
        self._status_layout.addSpacerItem(HorizontalSpacerItem())

        self.pos_lbl = LabelAlignRight('')
        self._status_layout.addWidget(self.pos_lbl)
        self._display_layout.addLayout(self._status_layout)

        self._display_widget.setLayout(self._display_layout)

def __init__(self, *args, **kwargs):
        super(CalibrationDisplayWidget, self).__init__(*args, **kwargs)

        self._layout = QtWidgets.QVBoxLayout(self)
        self._layout.setContentsMargins(0, 0, 0, 0)

        self.img_layout_widget = GraphicsLayoutWidget()
        self.cake_layout_widget = GraphicsLayoutWidget()
        self.pattern_layout_widget = GraphicsLayoutWidget()

        self.img_widget = MaskImgWidget(self.img_layout_widget)
        self.cake_widget = CalibrationCakeWidget(self.cake_layout_widget)
        self.pattern_widget = PatternWidget(self.pattern_layout_widget)

        self.tab_widget = QtWidgets.QTabWidget()
        self.tab_widget.addTab(self.img_layout_widget, 'Image')
        self.tab_widget.addTab(self.cake_layout_widget, 'Cake')
        self.tab_widget.addTab(self.pattern_layout_widget, 'Pattern')
        self._layout.addWidget(self.tab_widget)

        self._status_layout = QtWidgets.QHBoxLayout()
        self.calibrate_btn = FlatButton("Calibrate")
        self.refine_btn = FlatButton("Refine")
        self.position_lbl = QtWidgets.QLabel("position_lbl")

def __init__(self, sandbox, *args, **kwargs):
        pg.GraphicsLayoutWidget.__init__(self, **kwargs)
        self.sandbox = sandbox

        self.plots = [
            DisplacementPlot(
                sandbox,
                title='Scene Displacement',
                component=lambda m: m.reference.scene.displacement),
            DisplacementPlot(
                sandbox,
                title='Model Residual',
                component=lambda m: m.reference.difference)]
        self.plots[-1].addHintText()

        self._mov_sig = pg.SignalProxy(
            self.scene().sigMouseMoved,
            rateLimit=60, slot=self.mouseMoved)

def init_figure(self):
        """Init figures"""
        self.canvas2d_cartesian = pg.GraphicsLayoutWidget()
        self.canvas2d_polar = pg.GraphicsLayoutWidget()
        self.canvas3d = gl.GLViewWidget()
        self.canvas3d_array = pg.GraphicsLayoutWidget()

        self.ui.layout_canvas.addWidget(self.canvas3d)
        self.ui.layout_canvas.addWidget(self.canvas3d_array)
        self.ui.layout_canvas.addWidget(self.canvas2d_cartesian)
        self.ui.layout_canvas.addWidget(self.canvas2d_polar)

        self.plot_type_changed(self.ui.cb_plottype.currentIndex())

        """Surface view"""
        self.cmap = cm.get_cmap('jet')
        self.minZ = -100
        self.maxZ = 0

        self.surface_plot = gl.GLSurfacePlotItem(computeNormals=False)

return int(self.UI.dilate_kernelX_spinbox.value())

    @property
    def dilate_kernelY(self):
        return int(self.UI.dilate_kernelY_spinbox.value())

    @property
    def dilate_iters(self):
        return int(self.UI.dilate_iters_spinbox.value())

    @property
    def num_largest_components(self):
        return int(self.UI.n_largest_component_spinbox.value())


class QImshow(pg.GraphicsLayoutWidget):
    emitter = pyqtSignal(object)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.emitter.connect(lambda x: self.update_figure(x))

        self._view = self.addViewBox()
        self._view.setAspectLocked(True)
        self._img = pg.ImageItem(border='w')
        self._view.addItem(self._img)
        self._view.setRange(QRectF(0, 0, 128, 128))

        self.lock = time.time()
        self.fps = 25
        self.freq = 1/self.fps

def draw_buffer(self):
        self.buff_win = pg.GraphicsLayoutWidget()
        self.buff_win.setWindowTitle('Buffer Status')
        self.buff_win.resize(800, 700)

        self.total_peers = self.number_of_monitors + self.number_of_peers + self.number_of_malicious
        self.p4 = self.buff_win.addPlot()
        self.p4.showGrid(x=True, y=True, alpha=100)   # To show grid lines across x axis and y axis
        leftaxis = self.p4.getAxis('left')  # get left axis i.e y axis
        leftaxis.setTickSpacing(5, 1)    # to set ticks at a interval of 5 and grid lines at 1 space

        # Get different colors using matplotlib library
        if self.total_peers < 8:
            colors = cm.Set2(np.linspace(0, 1, 8))
        elif self.total_peers < 12:
            colors = cm.Set3(np.linspace(0, 1, 12))
        else:
            colors = cm.rainbow(np.linspace(0, 1, self.total_peers+1))

def init_figure(self):
        """Init figures"""
        self.canvas2d_cartesian = pg.GraphicsLayoutWidget()
        self.canvas2d_polar = pg.GraphicsLayoutWidget()
        self.canvas3d = gl.GLViewWidget()
        self.canvas3d_array = pg.GraphicsLayoutWidget()

        self.ui.layout_canvas.addWidget(self.canvas3d)
        self.ui.layout_canvas.addWidget(self.canvas3d_array)
        self.ui.layout_canvas.addWidget(self.canvas2d_cartesian)
        self.ui.layout_canvas.addWidget(self.canvas2d_polar)

        self.plot_type_changed(self.ui.cb_plottype.currentIndex())

        """Surface view"""
        self.cmap = cm.get_cmap('jet')
        self.minZ = -100
        self.maxZ = 0

self.overlay_graphicsView_03.setFrameShape(QtGui.QFrame.NoFrame)
        self.overlay_graphicsView_03.setAlignment(QtCore.Qt.AlignCenter)
        self.overlay_graphicsView_03.setObjectName(_fromUtf8("overlay_graphicsView_03"))
        self.overlay_graphicsView_08 = GraphicsLayoutWidget(self.overlays_groupBox)
        self.overlay_graphicsView_08.setGeometry(QtCore.QRect(220, 285, 192, 64))
        sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Preferred)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.overlay_graphicsView_08.sizePolicy().hasHeightForWidth())
        self.overlay_graphicsView_08.setSizePolicy(sizePolicy)
        self.overlay_graphicsView_08.setMinimumSize(QtCore.QSize(192, 64))
        self.overlay_graphicsView_08.setMaximumSize(QtCore.QSize(192, 64))
        self.overlay_graphicsView_08.setFrameShape(QtGui.QFrame.NoFrame)
        self.overlay_graphicsView_08.setAlignment(QtCore.Qt.AlignCenter)
        self.overlay_graphicsView_08.setObjectName(_fromUtf8("overlay_graphicsView_08"))
        self.overlay_graphicsView_05 = GraphicsLayoutWidget(self.overlays_groupBox)
        self.overlay_graphicsView_05.setGeometry(QtCore.QRect(10, 200, 192, 64))
        sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Preferred)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.overlay_graphicsView_05.sizePolicy().hasHeightForWidth())
        self.overlay_graphicsView_05.setSizePolicy(sizePolicy)
        self.overlay_graphicsView_05.setMinimumSize(QtCore.QSize(192, 64))
        self.overlay_graphicsView_05.setMaximumSize(QtCore.QSize(192, 64))
        self.overlay_graphicsView_05.setFrameShape(QtGui.QFrame.NoFrame)
        self.overlay_graphicsView_05.setAlignment(QtCore.Qt.AlignCenter)
        self.overlay_graphicsView_05.setObjectName(_fromUtf8("overlay_graphicsView_05"))
        self.overlay_graphicsView_02 = GraphicsLayoutWidget(self.overlays_groupBox)
        self.overlay_graphicsView_02.setGeometry(QtCore.QRect(220, 30, 192, 64))
        sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Preferred)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)