Refactor the surface examples

- Introduce a Window class to unclutter main.py
- Port to snake case naming

Task-number: PYSIDE-1880
Pick-to: 6.2 6.3
Change-Id: I433c48904ccc9adbafceb6d51c86f551e405a10e
Reviewed-by: Christian Tismer <tismer@stackless.com>

4 files changed, 552 insertions, 540 deletions

diff --git a/examples/datavisualization/surface/main.py b/examples/datavisualization/surface/main.py
index 6ec717238..676e9942f 100644
--- a/examples/datavisualization/surface/main.py
+++ b/examples/datavisualization/surface/main.py
@@ -53,168 +53,174 @@ THEMES = ["Qt", "Primary Colors", "Digia", "Stone Moss", "Army Blue", "Retro",
           "Ebony", "Isabelle"]
 
 
+class Window(QWidget):
+    def __init__(self, graph, parent=None):
+        super().__init__(parent)
+        self._graph = graph
+        self._container = QWidget.createWindowContainer(self._graph, self,
+                                                        Qt.Widget)
+
+        screen_size = self._graph.screen().size()
+        self._container.setMinimumSize(QSize(screen_size.width() / 2,
+                                       screen_size.height() / 1.6))
+        self._container.setMaximumSize(screen_size)
+        self._container.setSizePolicy(QSizePolicy.Expanding,
+                                      QSizePolicy.Expanding)
+        self._container.setFocusPolicy(Qt.StrongFocus)
+
+        h_layout = QHBoxLayout(self)
+        v_layout = QVBoxLayout()
+        h_layout.addWidget(self._container, 1)
+        h_layout.addLayout(v_layout)
+        v_layout.setAlignment(Qt.AlignTop)
+
+        model_group_box = QGroupBox("Model")
+
+        sqrt_sin_model_rb = QRadioButton(self)
+        sqrt_sin_model_rb.setText("Sqrt& Sin")
+        sqrt_sin_model_rb.setChecked(False)
+
+        height_map_model_rb = QRadioButton(self)
+        height_map_model_rb.setText("Height Map")
+        height_map_model_rb.setChecked(False)
+
+        model_vbox = QVBoxLayout()
+        model_vbox.addWidget(sqrt_sin_model_rb)
+        model_vbox.addWidget(height_map_model_rb)
+        model_group_box.setLayout(model_vbox)
+
+        selection_group_box = QGroupBox("Selection Mode")
+
+        mode_none_rb = QRadioButton(self)
+        mode_none_rb.setText("No selection")
+        mode_none_rb.setChecked(False)
+
+        mode_item_rb = QRadioButton(self)
+        mode_item_rb.setText("Item")
+        mode_item_rb.setChecked(False)
+
+        mode_slice_row_rb = QRadioButton(self)
+        mode_slice_row_rb.setText("Row Slice")
+        mode_slice_row_rb.setChecked(False)
+
+        mode_slice_column_rb = QRadioButton(self)
+        mode_slice_column_rb.setText("Column Slice")
+        mode_slice_column_rb.setChecked(False)
+
+        selection_vbox = QVBoxLayout()
+        selection_vbox.addWidget(mode_none_rb)
+        selection_vbox.addWidget(mode_item_rb)
+        selection_vbox.addWidget(mode_slice_row_rb)
+        selection_vbox.addWidget(mode_slice_column_rb)
+        selection_group_box.setLayout(selection_vbox)
+
+        axis_min_slider_x = QSlider(Qt.Horizontal, self)
+        axis_min_slider_x.setMinimum(0)
+        axis_min_slider_x.setTickInterval(1)
+        axis_min_slider_x.setEnabled(True)
+        axis_max_slider_x = QSlider(Qt.Horizontal, self)
+        axis_max_slider_x.setMinimum(1)
+        axis_max_slider_x.setTickInterval(1)
+        axis_max_slider_x.setEnabled(True)
+        axis_min_slider_z = QSlider(Qt.Horizontal, self)
+        axis_min_slider_z.setMinimum(0)
+        axis_min_slider_z.setTickInterval(1)
+        axis_min_slider_z.setEnabled(True)
+        axis_max_slider_z = QSlider(Qt.Horizontal, self)
+        axis_max_slider_z.setMinimum(1)
+        axis_max_slider_z.setTickInterval(1)
+        axis_max_slider_z.setEnabled(True)
+
+        theme_list = QComboBox(self)
+        theme_list.addItems(THEMES)
+
+        color_group_box = QGroupBox("Custom gradient")
+
+        gr_bto_y = QLinearGradient(0, 0, 1, 100)
+        gr_bto_y.setColorAt(1.0, Qt.black)
+        gr_bto_y.setColorAt(0.67, Qt.blue)
+        gr_bto_y.setColorAt(0.33, Qt.red)
+        gr_bto_y.setColorAt(0.0, Qt.yellow)
+
+        pm = QPixmap(24, 100)
+        pmp = QPainter(pm)
+        pmp.setBrush(QBrush(gr_bto_y))
+        pmp.setPen(Qt.NoPen)
+        pmp.drawRect(0, 0, 24, 100)
+        pmp.end()
+
+        gradient_bto_ypb = QPushButton(self)
+        gradient_bto_ypb.setIcon(QIcon(pm))
+        gradient_bto_ypb.setIconSize(QSize(24, 100))
+
+        gr_gto_r = QLinearGradient(0, 0, 1, 100)
+        gr_gto_r.setColorAt(1.0, Qt.darkGreen)
+        gr_gto_r.setColorAt(0.5, Qt.yellow)
+        gr_gto_r.setColorAt(0.2, Qt.red)
+        gr_gto_r.setColorAt(0.0, Qt.darkRed)
+        pmp.begin(pm)
+        pmp.setBrush(QBrush(gr_gto_r))
+        pmp.drawRect(0, 0, 24, 100)
+        pmp.end()
+
+        gradient_gto_rpb = QPushButton(self)
+        gradient_gto_rpb.setIcon(QIcon(pm))
+        gradient_gto_rpb.setIconSize(QSize(24, 100))
+
+        color_hbox = QHBoxLayout()
+        color_hbox.addWidget(gradient_bto_ypb)
+        color_hbox.addWidget(gradient_gto_rpb)
+        color_group_box.setLayout(color_hbox)
+
+        v_layout.addWidget(model_group_box)
+        v_layout.addWidget(selection_group_box)
+        v_layout.addWidget(QLabel("Column range"))
+        v_layout.addWidget(axis_min_slider_x)
+        v_layout.addWidget(axis_max_slider_x)
+        v_layout.addWidget(QLabel("Row range"))
+        v_layout.addWidget(axis_min_slider_z)
+        v_layout.addWidget(axis_max_slider_z)
+        v_layout.addWidget(QLabel("Theme"))
+        v_layout.addWidget(theme_list)
+        v_layout.addWidget(color_group_box)
+
+        self._modifier = SurfaceGraph(self._graph)
+
+        height_map_model_rb.toggled.connect(self._modifier.enable_height_map_model)
+        sqrt_sin_model_rb.toggled.connect(self._modifier.enable_sqrt_sin_model)
+        mode_none_rb.toggled.connect(self._modifier.toggle_mode_none)
+        mode_item_rb.toggled.connect(self._modifier.toggle_mode_item)
+        mode_slice_row_rb.toggled.connect(self._modifier.toggle_mode_slice_row)
+        mode_slice_column_rb.toggled.connect(self._modifier.toggle_mode_slice_column)
+        axis_min_slider_x.valueChanged.connect(self._modifier.adjust_xmin)
+        axis_max_slider_x.valueChanged.connect(self._modifier.adjust_xmax)
+        axis_min_slider_z.valueChanged.connect(self._modifier.adjust_zmin)
+        axis_max_slider_z.valueChanged.connect(self._modifier.adjust_zmax)
+        theme_list.currentIndexChanged[int].connect(self._modifier.change_theme)
+        gradient_bto_ypb.pressed.connect(self._modifier.set_black_to_yellow_gradient)
+        gradient_gto_rpb.pressed.connect(self._modifier.set_green_to_red_gradient)
+
+        self._modifier.set_axis_min_slider_x(axis_min_slider_x)
+        self._modifier.set_axis_max_slider_x(axis_max_slider_x)
+        self._modifier.set_axis_min_slider_z(axis_min_slider_z)
+        self._modifier.set_axis_max_slider_z(axis_max_slider_z)
+
+        sqrt_sin_model_rb.setChecked(True)
+        mode_item_rb.setChecked(True)
+        theme_list.setCurrentIndex(2)
+
+
 if __name__ == "__main__":
     app = QApplication(sys.argv)
     graph = Q3DSurface()
-    container = QWidget.createWindowContainer(graph)
-
     if not graph.hasContext():
-        msgBox = QMessageBox()
-        msgBox.setText("Couldn't initialize the OpenGL context.")
-        msgBox.exec()
+        msg_box = QMessageBox()
+        msg_box.setText("Couldn't initialize the OpenGL context.")
+        msg_box.exec()
         sys.exit(-1)
 
-    screenSize = graph.screen().size()
-    container.setMinimumSize(QSize(screenSize.width() / 2,
-                                   screenSize.height() / 1.6))
-    container.setMaximumSize(screenSize)
-    container.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
-    container.setFocusPolicy(Qt.StrongFocus)
-
-    widget = QWidget()
-    hLayout = QHBoxLayout(widget)
-    vLayout = QVBoxLayout()
-    hLayout.addWidget(container, 1)
-    hLayout.addLayout(vLayout)
-    vLayout.setAlignment(Qt.AlignTop)
-
-    widget.setWindowTitle("Surface example")
-
-    modelGroupBox = QGroupBox("Model")
-
-    sqrtSinModelRB = QRadioButton(widget)
-    sqrtSinModelRB.setText("Sqrt& Sin")
-    sqrtSinModelRB.setChecked(False)
-
-    heightMapModelRB = QRadioButton(widget)
-    heightMapModelRB.setText("Height Map")
-    heightMapModelRB.setChecked(False)
-
-    modelVBox = QVBoxLayout()
-    modelVBox.addWidget(sqrtSinModelRB)
-    modelVBox.addWidget(heightMapModelRB)
-    modelGroupBox.setLayout(modelVBox)
-
-    selectionGroupBox = QGroupBox("Selection Mode")
-
-    modeNoneRB = QRadioButton(widget)
-    modeNoneRB.setText("No selection")
-    modeNoneRB.setChecked(False)
-
-    modeItemRB = QRadioButton(widget)
-    modeItemRB.setText("Item")
-    modeItemRB.setChecked(False)
-
-    modeSliceRowRB = QRadioButton(widget)
-    modeSliceRowRB.setText("Row Slice")
-    modeSliceRowRB.setChecked(False)
-
-    modeSliceColumnRB = QRadioButton(widget)
-    modeSliceColumnRB.setText("Column Slice")
-    modeSliceColumnRB.setChecked(False)
-
-    selectionVBox = QVBoxLayout()
-    selectionVBox.addWidget(modeNoneRB)
-    selectionVBox.addWidget(modeItemRB)
-    selectionVBox.addWidget(modeSliceRowRB)
-    selectionVBox.addWidget(modeSliceColumnRB)
-    selectionGroupBox.setLayout(selectionVBox)
-
-    axisMinSliderX = QSlider(Qt.Horizontal, widget)
-    axisMinSliderX.setMinimum(0)
-    axisMinSliderX.setTickInterval(1)
-    axisMinSliderX.setEnabled(True)
-    axisMaxSliderX = QSlider(Qt.Horizontal, widget)
-    axisMaxSliderX.setMinimum(1)
-    axisMaxSliderX.setTickInterval(1)
-    axisMaxSliderX.setEnabled(True)
-    axisMinSliderZ = QSlider(Qt.Horizontal, widget)
-    axisMinSliderZ.setMinimum(0)
-    axisMinSliderZ.setTickInterval(1)
-    axisMinSliderZ.setEnabled(True)
-    axisMaxSliderZ = QSlider(Qt.Horizontal, widget)
-    axisMaxSliderZ.setMinimum(1)
-    axisMaxSliderZ.setTickInterval(1)
-    axisMaxSliderZ.setEnabled(True)
-
-    themeList = QComboBox(widget)
-    themeList.addItems(THEMES)
-
-    colorGroupBox = QGroupBox("Custom gradient")
-
-    grBtoY = QLinearGradient(0, 0, 1, 100)
-    grBtoY.setColorAt(1.0, Qt.black)
-    grBtoY.setColorAt(0.67, Qt.blue)
-    grBtoY.setColorAt(0.33, Qt.red)
-    grBtoY.setColorAt(0.0, Qt.yellow)
-
-    pm = QPixmap(24, 100)
-    pmp = QPainter(pm)
-    pmp.setBrush(QBrush(grBtoY))
-    pmp.setPen(Qt.NoPen)
-    pmp.drawRect(0, 0, 24, 100)
-    pmp.end()
-
-    gradientBtoYPB = QPushButton(widget)
-    gradientBtoYPB.setIcon(QIcon(pm))
-    gradientBtoYPB.setIconSize(QSize(24, 100))
-
-    grGtoR = QLinearGradient(0, 0, 1, 100)
-    grGtoR.setColorAt(1.0, Qt.darkGreen)
-    grGtoR.setColorAt(0.5, Qt.yellow)
-    grGtoR.setColorAt(0.2, Qt.red)
-    grGtoR.setColorAt(0.0, Qt.darkRed)
-    pmp.begin(pm)
-    pmp.setBrush(QBrush(grGtoR))
-    pmp.drawRect(0, 0, 24, 100)
-    pmp.end()
-
-    gradientGtoRPB = QPushButton(widget)
-    gradientGtoRPB.setIcon(QIcon(pm))
-    gradientGtoRPB.setIconSize(QSize(24, 100))
-
-    colorHBox = QHBoxLayout()
-    colorHBox.addWidget(gradientBtoYPB)
-    colorHBox.addWidget(gradientGtoRPB)
-    colorGroupBox.setLayout(colorHBox)
-
-    vLayout.addWidget(modelGroupBox)
-    vLayout.addWidget(selectionGroupBox)
-    vLayout.addWidget(QLabel("Column range"))
-    vLayout.addWidget(axisMinSliderX)
-    vLayout.addWidget(axisMaxSliderX)
-    vLayout.addWidget(QLabel("Row range"))
-    vLayout.addWidget(axisMinSliderZ)
-    vLayout.addWidget(axisMaxSliderZ)
-    vLayout.addWidget(QLabel("Theme"))
-    vLayout.addWidget(themeList)
-    vLayout.addWidget(colorGroupBox)
-
-    widget.show()
-
-    modifier = SurfaceGraph(graph)
-
-    heightMapModelRB.toggled.connect(modifier.enableHeightMapModel)
-    sqrtSinModelRB.toggled.connect(modifier.enableSqrtSinModel)
-    modeNoneRB.toggled.connect(modifier.toggleModeNone)
-    modeItemRB.toggled.connect(modifier.toggleModeItem)
-    modeSliceRowRB.toggled.connect(modifier.toggleModeSliceRow)
-    modeSliceColumnRB.toggled.connect(modifier.toggleModeSliceColumn)
-    axisMinSliderX.valueChanged.connect(modifier.adjustXMin)
-    axisMaxSliderX.valueChanged.connect(modifier.adjustXMax)
-    axisMinSliderZ.valueChanged.connect(modifier.adjustZMin)
-    axisMaxSliderZ.valueChanged.connect(modifier.adjustZMax)
-    themeList.currentIndexChanged[int].connect(modifier.changeTheme)
-    gradientBtoYPB.pressed.connect(modifier.setBlackToYellowGradient)
-    gradientGtoRPB.pressed.connect(modifier.setGreenToRedGradient)
-
-    modifier.setAxisMinSliderX(axisMinSliderX)
-    modifier.setAxisMaxSliderX(axisMaxSliderX)
-    modifier.setAxisMinSliderZ(axisMinSliderZ)
-    modifier.setAxisMaxSliderZ(axisMaxSliderZ)
-
-    sqrtSinModelRB.setChecked(True)
-    modeItemRB.setChecked(True)
-    themeList.setCurrentIndex(2)
+    window = Window(graph)
+    window.setWindowTitle("Surface example")
+    window.show()
 
     sys.exit(app.exec())
diff --git a/examples/datavisualization/surface/surfacegraph.py b/examples/datavisualization/surface/surfacegraph.py
index 0a450fbc2..f98c419f9 100644
--- a/examples/datavisualization/surface/surfacegraph.py
+++ b/examples/datavisualization/surface/surfacegraph.py
@@ -49,230 +49,230 @@ from PySide6.QtDataVisualization import (Q3DTheme, QAbstract3DGraph,
 from PySide6.QtGui import QImage, QLinearGradient, QVector3D
 from PySide6.QtWidgets import QSlider
 
-sampleCountX = 50
-sampleCountZ = 50
-heightMapGridStepX = 6
-heightMapGridStepZ = 6
-sampleMin = -8.0
-sampleMax = 8.0
+SAMPLE_COUNT_X = 50
+SAMPLE_COUNT_Z = 50
+HEIGHT_MAP_GRID_STEP_X = 6
+HEIGHT_MAP_GRID_STEP_Z = 6
+SAMPLE_MIN = -8.0
+SAMPLE_MAX = 8.0
 
 
 class SurfaceGraph(QObject):
     def __init__(self, surface, parent=None):
         super().__init__(parent)
 
-        self.m_graph = surface
-        self.m_graph.setAxisX(QValue3DAxis())
-        self.m_graph.setAxisY(QValue3DAxis())
-        self.m_graph.setAxisZ(QValue3DAxis())
-
-        self.m_sqrtSinProxy = QSurfaceDataProxy()
-        self.m_sqrtSinSeries = QSurface3DSeries(self.m_sqrtSinProxy)
-        self.fillSqrtSinProxy()
-
-        imageFile = Path(__file__).parent / "mountain.png"
-        heightMapImage = QImage(imageFile)
-        self.m_heightMapProxy = QHeightMapSurfaceDataProxy(heightMapImage)
-        self.m_heightMapSeries = QSurface3DSeries(self.m_heightMapProxy)
-        self.m_heightMapSeries.setItemLabelFormat("(@xLabel, @zLabel): @yLabel")
-        self.m_heightMapProxy.setValueRanges(34.0, 40.0, 18.0, 24.0)
-
-        self.m_heightMapWidth = heightMapImage.width()
-        self.m_heightMapHeight = heightMapImage.height()
-
-        self.m_axisMinSliderX = QSlider()
-        self.m_axisMaxSliderX = QSlider()
-        self.m_axisMinSliderZ = QSlider()
-        self.m_axisMaxSliderZ = QSlider()
-        self.m_rangeMinX = 0.0
-        self.m_rangeMinZ = 0.0
-        self.m_stepX = 0.0
-        self.m_stepZ = 0.0
-
-    def fillSqrtSinProxy(self):
-        stepX = (sampleMax - sampleMin) / float(sampleCountX - 1)
-        stepZ = (sampleMax - sampleMin) / float(sampleCountZ - 1)
-
-        dataArray = []
-        for i in range(sampleCountZ):
-            newRow = []
+        self._graph = surface
+        self._graph.setAxisX(QValue3DAxis())
+        self._graph.setAxisY(QValue3DAxis())
+        self._graph.setAxisZ(QValue3DAxis())
+
+        self._sqrtSinProxy = QSurfaceDataProxy()
+        self._sqrtSinSeries = QSurface3DSeries(self._sqrtSinProxy)
+        self.fill_sqrt_sin_proxy()
+
+        image_file = Path(__file__).parent / "mountain.png"
+        height_map_image = QImage(image_file)
+        self._heightMapProxy = QHeightMapSurfaceDataProxy(height_map_image)
+        self._heightMapSeries = QSurface3DSeries(self._heightMapProxy)
+        self._heightMapSeries.setItemLabelFormat("(@xLabel, @zLabel): @yLabel")
+        self._heightMapProxy.setValueRanges(34.0, 40.0, 18.0, 24.0)
+
+        self._heightMapWidth = height_map_image.width()
+        self._heightMapHeight = height_map_image.height()
+
+        self._axisMinSliderX = QSlider()
+        self._axisMaxSliderX = QSlider()
+        self._axisMinSliderZ = QSlider()
+        self._axisMaxSliderZ = QSlider()
+        self._rangeMinX = 0.0
+        self._rangeMinZ = 0.0
+        self._stepX = 0.0
+        self._stepZ = 0.0
+
+    def fill_sqrt_sin_proxy(self):
+        step_x = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_X - 1)
+        step_z = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_Z - 1)
+
+        data_array = []
+        for i in range(SAMPLE_COUNT_Z):
+            new_row = []
             # Keep values within range bounds, since just adding step can cause
             # minor drift due to the rounding errors.
-            z = min(sampleMax, (i * stepZ + sampleMin))
-            for j in range(sampleCountX):
-                x = min(sampleMax, (j * stepX + sampleMin))
+            z = min(SAMPLE_MAX, (i * step_z + SAMPLE_MIN))
+            for j in range(SAMPLE_COUNT_X):
+                x = min(SAMPLE_MAX, (j * step_x + SAMPLE_MIN))
                 R = math.sqrt(z * z + x * x) + 0.01
                 y = (math.sin(R) / R + 0.24) * 1.61
-                newRow.append(QSurfaceDataItem(QVector3D(x, y, z)))
-            dataArray.append(newRow)
+                new_row.append(QSurfaceDataItem(QVector3D(x, y, z)))
+            data_array.append(new_row)
 
-        self.m_sqrtSinProxy.resetArray(dataArray)
+        self._sqrtSinProxy.resetArray(data_array)
 
-    def enableSqrtSinModel(self, enable):
+    def enable_sqrt_sin_model(self, enable):
         if enable:
-            self.m_sqrtSinSeries.setDrawMode(QSurface3DSeries.DrawSurfaceAndWireframe)
-            self.m_sqrtSinSeries.setFlatShadingEnabled(True)
+            self._sqrtSinSeries.setDrawMode(QSurface3DSeries.DrawSurfaceAndWireframe)
+            self._sqrtSinSeries.setFlatShadingEnabled(True)
 
-            self.m_graph.axisX().setLabelFormat("%.2f")
-            self.m_graph.axisZ().setLabelFormat("%.2f")
-            self.m_graph.axisX().setRange(sampleMin, sampleMax)
-            self.m_graph.axisY().setRange(0.0, 2.0)
-            self.m_graph.axisZ().setRange(sampleMin, sampleMax)
-            self.m_graph.axisX().setLabelAutoRotation(30)
-            self.m_graph.axisY().setLabelAutoRotation(90)
-            self.m_graph.axisZ().setLabelAutoRotation(30)
+            self._graph.axisX().setLabelFormat("%.2f")
+            self._graph.axisZ().setLabelFormat("%.2f")
+            self._graph.axisX().setRange(SAMPLE_MIN, SAMPLE_MAX)
+            self._graph.axisY().setRange(0.0, 2.0)
+            self._graph.axisZ().setRange(SAMPLE_MIN, SAMPLE_MAX)
+            self._graph.axisX().setLabelAutoRotation(30)
+            self._graph.axisY().setLabelAutoRotation(90)
+            self._graph.axisZ().setLabelAutoRotation(30)
 
-            self.m_graph.removeSeries(self.m_heightMapSeries)
-            self.m_graph.addSeries(self.m_sqrtSinSeries)
+            self._graph.removeSeries(self._heightMapSeries)
+            self._graph.addSeries(self._sqrtSinSeries)
 
             # Reset range sliders for Sqrt&Sin
-            self.m_rangeMinX = sampleMin
-            self.m_rangeMinZ = sampleMin
-            self.m_stepX = (sampleMax - sampleMin) / float(sampleCountX - 1)
-            self.m_stepZ = (sampleMax - sampleMin) / float(sampleCountZ - 1)
-            self.m_axisMinSliderX.setMaximum(sampleCountX - 2)
-            self.m_axisMinSliderX.setValue(0)
-            self.m_axisMaxSliderX.setMaximum(sampleCountX - 1)
-            self.m_axisMaxSliderX.setValue(sampleCountX - 1)
-            self.m_axisMinSliderZ.setMaximum(sampleCountZ - 2)
-            self.m_axisMinSliderZ.setValue(0)
-            self.m_axisMaxSliderZ.setMaximum(sampleCountZ - 1)
-            self.m_axisMaxSliderZ.setValue(sampleCountZ - 1)
-
-    def enableHeightMapModel(self, enable):
+            self._rangeMinX = SAMPLE_MIN
+            self._rangeMinZ = SAMPLE_MIN
+            self._stepX = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_X - 1)
+            self._stepZ = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_Z - 1)
+            self._axisMinSliderX.setMaximum(SAMPLE_COUNT_X - 2)
+            self._axisMinSliderX.setValue(0)
+            self._axisMaxSliderX.setMaximum(SAMPLE_COUNT_X - 1)
+            self._axisMaxSliderX.setValue(SAMPLE_COUNT_X - 1)
+            self._axisMinSliderZ.setMaximum(SAMPLE_COUNT_Z - 2)
+            self._axisMinSliderZ.setValue(0)
+            self._axisMaxSliderZ.setMaximum(SAMPLE_COUNT_Z - 1)
+            self._axisMaxSliderZ.setValue(SAMPLE_COUNT_Z - 1)
+
+    def enable_height_map_model(self, enable):
         if enable:
-            self.m_heightMapSeries.setDrawMode(QSurface3DSeries.DrawSurface)
-            self.m_heightMapSeries.setFlatShadingEnabled(False)
+            self._heightMapSeries.setDrawMode(QSurface3DSeries.DrawSurface)
+            self._heightMapSeries.setFlatShadingEnabled(False)
 
-            self.m_graph.axisX().setLabelFormat("%.1f N")
-            self.m_graph.axisZ().setLabelFormat("%.1f E")
-            self.m_graph.axisX().setRange(34.0, 40.0)
-            self.m_graph.axisY().setAutoAdjustRange(True)
-            self.m_graph.axisZ().setRange(18.0, 24.0)
+            self._graph.axisX().setLabelFormat("%.1f N")
+            self._graph.axisZ().setLabelFormat("%.1f E")
+            self._graph.axisX().setRange(34.0, 40.0)
+            self._graph.axisY().setAutoAdjustRange(True)
+            self._graph.axisZ().setRange(18.0, 24.0)
 
-            self.m_graph.axisX().setTitle("Latitude")
-            self.m_graph.axisY().setTitle("Height")
-            self.m_graph.axisZ().setTitle("Longitude")
+            self._graph.axisX().setTitle("Latitude")
+            self._graph.axisY().setTitle("Height")
+            self._graph.axisZ().setTitle("Longitude")
 
-            self.m_graph.removeSeries(self.m_sqrtSinSeries)
-            self.m_graph.addSeries(self.m_heightMapSeries)
+            self._graph.removeSeries(self._sqrtSinSeries)
+            self._graph.addSeries(self._heightMapSeries)
 
             # Reset range sliders for height map
-            mapGridCountX = self.m_heightMapWidth / heightMapGridStepX
-            mapGridCountZ = self.m_heightMapHeight / heightMapGridStepZ
-            self.m_rangeMinX = 34.0
-            self.m_rangeMinZ = 18.0
-            self.m_stepX = 6.0 / float(mapGridCountX - 1)
-            self.m_stepZ = 6.0 / float(mapGridCountZ - 1)
-            self.m_axisMinSliderX.setMaximum(mapGridCountX - 2)
-            self.m_axisMinSliderX.setValue(0)
-            self.m_axisMaxSliderX.setMaximum(mapGridCountX - 1)
-            self.m_axisMaxSliderX.setValue(mapGridCountX - 1)
-            self.m_axisMinSliderZ.setMaximum(mapGridCountZ - 2)
-            self.m_axisMinSliderZ.setValue(0)
-            self.m_axisMaxSliderZ.setMaximum(mapGridCountZ - 1)
-            self.m_axisMaxSliderZ.setValue(mapGridCountZ - 1)
-
-    def adjustXMin(self, minimum):
-        minX = self.m_stepX * float(minimum) + self.m_rangeMinX
-
-        maximum = self.m_axisMaxSliderX.value()
+            map_grid_count_x = self._heightMapWidth / HEIGHT_MAP_GRID_STEP_X
+            map_grid_count_z = self._heightMapHeight / HEIGHT_MAP_GRID_STEP_Z
+            self._rangeMinX = 34.0
+            self._rangeMinZ = 18.0
+            self._stepX = 6.0 / float(map_grid_count_x - 1)
+            self._stepZ = 6.0 / float(map_grid_count_z - 1)
+            self._axisMinSliderX.setMaximum(map_grid_count_x - 2)
+            self._axisMinSliderX.setValue(0)
+            self._axisMaxSliderX.setMaximum(map_grid_count_x - 1)
+            self._axisMaxSliderX.setValue(map_grid_count_x - 1)
+            self._axisMinSliderZ.setMaximum(map_grid_count_z - 2)
+            self._axisMinSliderZ.setValue(0)
+            self._axisMaxSliderZ.setMaximum(map_grid_count_z - 1)
+            self._axisMaxSliderZ.setValue(map_grid_count_z - 1)
+
+    def adjust_xmin(self, minimum):
+        min_x = self._stepX * float(minimum) + self._rangeMinX
+
+        maximum = self._axisMaxSliderX.value()
         if minimum >= maximum:
             maximum = minimum + 1
-            self.m_axisMaxSliderX.setValue(maximum)
-        maxX = self.m_stepX * maximum + self.m_rangeMinX
+            self._axisMaxSliderX.setValue(maximum)
+        max_x = self._stepX * maximum + self._rangeMinX
 
-        self.setAxisXRange(minX, maxX)
+        self.set_axis_xrange(min_x, max_x)
 
-    def adjustXMax(self, maximum):
-        maxX = self.m_stepX * float(maximum) + self.m_rangeMinX
+    def adjust_xmax(self, maximum):
+        max_x = self._stepX * float(maximum) + self._rangeMinX
 
-        minimum = self.m_axisMinSliderX.value()
+        minimum = self._axisMinSliderX.value()
         if maximum <= minimum:
             minimum = maximum - 1
-            self.m_axisMinSliderX.setValue(minimum)
-        minX = self.m_stepX * minimum + self.m_rangeMinX
+            self._axisMinSliderX.setValue(minimum)
+        min_x = self._stepX * minimum + self._rangeMinX
 
-        self.setAxisXRange(minX, maxX)
+        self.set_axis_xrange(min_x, max_x)
 
-    def adjustZMin(self, minimum):
-        minZ = self.m_stepZ * float(minimum) + self.m_rangeMinZ
+    def adjust_zmin(self, minimum):
+        min_z = self._stepZ * float(minimum) + self._rangeMinZ
 
-        maximum = self.m_axisMaxSliderZ.value()
+        maximum = self._axisMaxSliderZ.value()
         if minimum >= maximum:
             maximum = minimum + 1
-            self.m_axisMaxSliderZ.setValue(maximum)
-        maxZ = self.m_stepZ * maximum + self.m_rangeMinZ
+            self._axisMaxSliderZ.setValue(maximum)
+        max_z = self._stepZ * maximum + self._rangeMinZ
 
-        self.setAxisZRange(minZ, maxZ)
+        self.set_axis_zrange(min_z, max_z)
 
-    def adjustZMax(self, maximum):
-        maxX = self.m_stepZ * float(maximum) + self.m_rangeMinZ
+    def adjust_zmax(self, maximum):
+        max_x = self._stepZ * float(maximum) + self._rangeMinZ
 
-        minimum = self.m_axisMinSliderZ.value()
+        minimum = self._axisMinSliderZ.value()
         if maximum <= minimum:
             minimum = maximum - 1
-            self.m_axisMinSliderZ.setValue(minimum)
-        minX = self.m_stepZ * minimum + self.m_rangeMinZ
+            self._axisMinSliderZ.setValue(minimum)
+        min_x = self._stepZ * minimum + self._rangeMinZ
 
-        self.setAxisZRange(minX, maxX)
+        self.set_axis_zrange(min_x, max_x)
 
-    def setAxisXRange(self, minimum, maximum):
-        self.m_graph.axisX().setRange(minimum, maximum)
+    def set_axis_xrange(self, minimum, maximum):
+        self._graph.axisX().setRange(minimum, maximum)
 
-    def setAxisZRange(self, minimum, maximum):
-        self.m_graph.axisZ().setRange(minimum, maximum)
+    def set_axis_zrange(self, minimum, maximum):
+        self._graph.axisZ().setRange(minimum, maximum)
 
     @Slot()
-    def changeTheme(self, theme):
-        self.m_graph.activeTheme().setType(Q3DTheme.Theme(theme))
+    def change_theme(self, theme):
+        self._graph.activeTheme().setType(Q3DTheme.Theme(theme))
 
-    def setBlackToYellowGradient(self):
+    def set_black_to_yellow_gradient(self):
         gr = QLinearGradient()
         gr.setColorAt(0.0, Qt.black)
         gr.setColorAt(0.33, Qt.blue)
         gr.setColorAt(0.67, Qt.red)
         gr.setColorAt(1.0, Qt.yellow)
 
-        series = self.m_graph.seriesList()[0]
+        series = self._graph.seriesList()[0]
         series.setBaseGradient(gr)
         series.setColorStyle(Q3DTheme.ColorStyleRangeGradient)
 
-    def setGreenToRedGradient(self):
+    def set_green_to_red_gradient(self):
         gr = QLinearGradient()
         gr.setColorAt(0.0, Qt.darkGreen)
         gr.setColorAt(0.5, Qt.yellow)
         gr.setColorAt(0.8, Qt.red)
         gr.setColorAt(1.0, Qt.darkRed)
 
-        series = self.m_graph.seriesList()[0]
+        series = self._graph.seriesList()[0]
         series.setBaseGradient(gr)
         series.setColorStyle(Q3DTheme.ColorStyleRangeGradient)
 
-    def toggleModeNone(self):
-        self.m_graph.setSelectionMode(QAbstract3DGraph.SelectionNone)
+    def toggle_mode_none(self):
+        self._graph.setSelectionMode(QAbstract3DGraph.SelectionNone)
 
-    def toggleModeItem(self):
-        self.m_graph.setSelectionMode(QAbstract3DGraph.SelectionItem)
+    def toggle_mode_item(self):
+        self._graph.setSelectionMode(QAbstract3DGraph.SelectionItem)
 
-    def toggleModeSliceRow(self):
-        self.m_graph.setSelectionMode(
+    def toggle_mode_slice_row(self):
+        self._graph.setSelectionMode(
             QAbstract3DGraph.SelectionItemAndRow | QAbstract3DGraph.SelectionSlice
         )
 
-    def toggleModeSliceColumn(self):
-        self.m_graph.setSelectionMode(
+    def toggle_mode_slice_column(self):
+        self._graph.setSelectionMode(
             QAbstract3DGraph.SelectionItemAndColumn | QAbstract3DGraph.SelectionSlice
         )
 
-    def setAxisMinSliderX(self, slider):
-        self.m_axisMinSliderX = slider
+    def set_axis_min_slider_x(self, slider):
+        self._axisMinSliderX = slider
 
-    def setAxisMaxSliderX(self, slider):
-        self.m_axisMaxSliderX = slider
+    def set_axis_max_slider_x(self, slider):
+        self._axisMaxSliderX = slider
 
-    def setAxisMinSliderZ(self, slider):
-        self.m_axisMinSliderZ = slider
+    def set_axis_min_slider_z(self, slider):
+        self._axisMinSliderZ = slider
 
-    def setAxisMaxSliderZ(self, slider):
-        self.m_axisMaxSliderZ = slider
+    def set_axis_max_slider_z(self, slider):
+        self._axisMaxSliderZ = slider
diff --git a/examples/datavisualization/surface_numpy/main.py b/examples/datavisualization/surface_numpy/main.py
index 17e23a795..676e9942f 100644
--- a/examples/datavisualization/surface_numpy/main.py
+++ b/examples/datavisualization/surface_numpy/main.py
@@ -1,6 +1,6 @@
 #############################################################################
 ##
-## Copyright (C) 2022 The Qt Company Ltd.
+## Copyright (C) 2021 The Qt Company Ltd.
 ## Contact: https://www.qt.io/licensing/
 ##
 ## This file is part of the Qt for Python examples of the Qt Toolkit.
@@ -53,168 +53,174 @@ THEMES = ["Qt", "Primary Colors", "Digia", "Stone Moss", "Army Blue", "Retro",
           "Ebony", "Isabelle"]
 
 
+class Window(QWidget):
+    def __init__(self, graph, parent=None):
+        super().__init__(parent)
+        self._graph = graph
+        self._container = QWidget.createWindowContainer(self._graph, self,
+                                                        Qt.Widget)
+
+        screen_size = self._graph.screen().size()
+        self._container.setMinimumSize(QSize(screen_size.width() / 2,
+                                       screen_size.height() / 1.6))
+        self._container.setMaximumSize(screen_size)
+        self._container.setSizePolicy(QSizePolicy.Expanding,
+                                      QSizePolicy.Expanding)
+        self._container.setFocusPolicy(Qt.StrongFocus)
+
+        h_layout = QHBoxLayout(self)
+        v_layout = QVBoxLayout()
+        h_layout.addWidget(self._container, 1)
+        h_layout.addLayout(v_layout)
+        v_layout.setAlignment(Qt.AlignTop)
+
+        model_group_box = QGroupBox("Model")
+
+        sqrt_sin_model_rb = QRadioButton(self)
+        sqrt_sin_model_rb.setText("Sqrt& Sin")
+        sqrt_sin_model_rb.setChecked(False)
+
+        height_map_model_rb = QRadioButton(self)
+        height_map_model_rb.setText("Height Map")
+        height_map_model_rb.setChecked(False)
+
+        model_vbox = QVBoxLayout()
+        model_vbox.addWidget(sqrt_sin_model_rb)
+        model_vbox.addWidget(height_map_model_rb)
+        model_group_box.setLayout(model_vbox)
+
+        selection_group_box = QGroupBox("Selection Mode")
+
+        mode_none_rb = QRadioButton(self)
+        mode_none_rb.setText("No selection")
+        mode_none_rb.setChecked(False)
+
+        mode_item_rb = QRadioButton(self)
+        mode_item_rb.setText("Item")
+        mode_item_rb.setChecked(False)
+
+        mode_slice_row_rb = QRadioButton(self)
+        mode_slice_row_rb.setText("Row Slice")
+        mode_slice_row_rb.setChecked(False)
+
+        mode_slice_column_rb = QRadioButton(self)
+        mode_slice_column_rb.setText("Column Slice")
+        mode_slice_column_rb.setChecked(False)
+
+        selection_vbox = QVBoxLayout()
+        selection_vbox.addWidget(mode_none_rb)
+        selection_vbox.addWidget(mode_item_rb)
+        selection_vbox.addWidget(mode_slice_row_rb)
+        selection_vbox.addWidget(mode_slice_column_rb)
+        selection_group_box.setLayout(selection_vbox)
+
+        axis_min_slider_x = QSlider(Qt.Horizontal, self)
+        axis_min_slider_x.setMinimum(0)
+        axis_min_slider_x.setTickInterval(1)
+        axis_min_slider_x.setEnabled(True)
+        axis_max_slider_x = QSlider(Qt.Horizontal, self)
+        axis_max_slider_x.setMinimum(1)
+        axis_max_slider_x.setTickInterval(1)
+        axis_max_slider_x.setEnabled(True)
+        axis_min_slider_z = QSlider(Qt.Horizontal, self)
+        axis_min_slider_z.setMinimum(0)
+        axis_min_slider_z.setTickInterval(1)
+        axis_min_slider_z.setEnabled(True)
+        axis_max_slider_z = QSlider(Qt.Horizontal, self)
+        axis_max_slider_z.setMinimum(1)
+        axis_max_slider_z.setTickInterval(1)
+        axis_max_slider_z.setEnabled(True)
+
+        theme_list = QComboBox(self)
+        theme_list.addItems(THEMES)
+
+        color_group_box = QGroupBox("Custom gradient")
+
+        gr_bto_y = QLinearGradient(0, 0, 1, 100)
+        gr_bto_y.setColorAt(1.0, Qt.black)
+        gr_bto_y.setColorAt(0.67, Qt.blue)
+        gr_bto_y.setColorAt(0.33, Qt.red)
+        gr_bto_y.setColorAt(0.0, Qt.yellow)
+
+        pm = QPixmap(24, 100)
+        pmp = QPainter(pm)
+        pmp.setBrush(QBrush(gr_bto_y))
+        pmp.setPen(Qt.NoPen)
+        pmp.drawRect(0, 0, 24, 100)
+        pmp.end()
+
+        gradient_bto_ypb = QPushButton(self)
+        gradient_bto_ypb.setIcon(QIcon(pm))
+        gradient_bto_ypb.setIconSize(QSize(24, 100))
+
+        gr_gto_r = QLinearGradient(0, 0, 1, 100)
+        gr_gto_r.setColorAt(1.0, Qt.darkGreen)
+        gr_gto_r.setColorAt(0.5, Qt.yellow)
+        gr_gto_r.setColorAt(0.2, Qt.red)
+        gr_gto_r.setColorAt(0.0, Qt.darkRed)
+        pmp.begin(pm)
+        pmp.setBrush(QBrush(gr_gto_r))
+        pmp.drawRect(0, 0, 24, 100)
+        pmp.end()
+
+        gradient_gto_rpb = QPushButton(self)
+        gradient_gto_rpb.setIcon(QIcon(pm))
+        gradient_gto_rpb.setIconSize(QSize(24, 100))
+
+        color_hbox = QHBoxLayout()
+        color_hbox.addWidget(gradient_bto_ypb)
+        color_hbox.addWidget(gradient_gto_rpb)
+        color_group_box.setLayout(color_hbox)
+
+        v_layout.addWidget(model_group_box)
+        v_layout.addWidget(selection_group_box)
+        v_layout.addWidget(QLabel("Column range"))
+        v_layout.addWidget(axis_min_slider_x)
+        v_layout.addWidget(axis_max_slider_x)
+        v_layout.addWidget(QLabel("Row range"))
+        v_layout.addWidget(axis_min_slider_z)
+        v_layout.addWidget(axis_max_slider_z)
+        v_layout.addWidget(QLabel("Theme"))
+        v_layout.addWidget(theme_list)
+        v_layout.addWidget(color_group_box)
+
+        self._modifier = SurfaceGraph(self._graph)
+
+        height_map_model_rb.toggled.connect(self._modifier.enable_height_map_model)
+        sqrt_sin_model_rb.toggled.connect(self._modifier.enable_sqrt_sin_model)
+        mode_none_rb.toggled.connect(self._modifier.toggle_mode_none)
+        mode_item_rb.toggled.connect(self._modifier.toggle_mode_item)
+        mode_slice_row_rb.toggled.connect(self._modifier.toggle_mode_slice_row)
+        mode_slice_column_rb.toggled.connect(self._modifier.toggle_mode_slice_column)
+        axis_min_slider_x.valueChanged.connect(self._modifier.adjust_xmin)
+        axis_max_slider_x.valueChanged.connect(self._modifier.adjust_xmax)
+        axis_min_slider_z.valueChanged.connect(self._modifier.adjust_zmin)
+        axis_max_slider_z.valueChanged.connect(self._modifier.adjust_zmax)
+        theme_list.currentIndexChanged[int].connect(self._modifier.change_theme)
+        gradient_bto_ypb.pressed.connect(self._modifier.set_black_to_yellow_gradient)
+        gradient_gto_rpb.pressed.connect(self._modifier.set_green_to_red_gradient)
+
+        self._modifier.set_axis_min_slider_x(axis_min_slider_x)
+        self._modifier.set_axis_max_slider_x(axis_max_slider_x)
+        self._modifier.set_axis_min_slider_z(axis_min_slider_z)
+        self._modifier.set_axis_max_slider_z(axis_max_slider_z)
+
+        sqrt_sin_model_rb.setChecked(True)
+        mode_item_rb.setChecked(True)
+        theme_list.setCurrentIndex(2)
+
+
 if __name__ == "__main__":
     app = QApplication(sys.argv)
     graph = Q3DSurface()
-    container = QWidget.createWindowContainer(graph)
-
     if not graph.hasContext():
-        msgBox = QMessageBox()
-        msgBox.setText("Couldn't initialize the OpenGL context.")
-        msgBox.exec()
+        msg_box = QMessageBox()
+        msg_box.setText("Couldn't initialize the OpenGL context.")
+        msg_box.exec()
         sys.exit(-1)
 
-    screenSize = graph.screen().size()
-    container.setMinimumSize(QSize(screenSize.width() / 2,
-                                   screenSize.height() / 1.6))
-    container.setMaximumSize(screenSize)
-    container.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
-    container.setFocusPolicy(Qt.StrongFocus)
-
-    widget = QWidget()
-    hLayout = QHBoxLayout(widget)
-    vLayout = QVBoxLayout()
-    hLayout.addWidget(container, 1)
-    hLayout.addLayout(vLayout)
-    vLayout.setAlignment(Qt.AlignTop)
-
-    widget.setWindowTitle("Surface example")
-
-    modelGroupBox = QGroupBox("Model")
-
-    sqrtSinModelRB = QRadioButton(widget)
-    sqrtSinModelRB.setText("Sqrt& Sin")
-    sqrtSinModelRB.setChecked(False)
-
-    heightMapModelRB = QRadioButton(widget)
-    heightMapModelRB.setText("Height Map")
-    heightMapModelRB.setChecked(False)
-
-    modelVBox = QVBoxLayout()
-    modelVBox.addWidget(sqrtSinModelRB)
-    modelVBox.addWidget(heightMapModelRB)
-    modelGroupBox.setLayout(modelVBox)
-
-    selectionGroupBox = QGroupBox("Selection Mode")
-
-    modeNoneRB = QRadioButton(widget)
-    modeNoneRB.setText("No selection")
-    modeNoneRB.setChecked(False)
-
-    modeItemRB = QRadioButton(widget)
-    modeItemRB.setText("Item")
-    modeItemRB.setChecked(False)
-
-    modeSliceRowRB = QRadioButton(widget)
-    modeSliceRowRB.setText("Row Slice")
-    modeSliceRowRB.setChecked(False)
-
-    modeSliceColumnRB = QRadioButton(widget)
-    modeSliceColumnRB.setText("Column Slice")
-    modeSliceColumnRB.setChecked(False)
-
-    selectionVBox = QVBoxLayout()
-    selectionVBox.addWidget(modeNoneRB)
-    selectionVBox.addWidget(modeItemRB)
-    selectionVBox.addWidget(modeSliceRowRB)
-    selectionVBox.addWidget(modeSliceColumnRB)
-    selectionGroupBox.setLayout(selectionVBox)
-
-    axisMinSliderX = QSlider(Qt.Horizontal, widget)
-    axisMinSliderX.setMinimum(0)
-    axisMinSliderX.setTickInterval(1)
-    axisMinSliderX.setEnabled(True)
-    axisMaxSliderX = QSlider(Qt.Horizontal, widget)
-    axisMaxSliderX.setMinimum(1)
-    axisMaxSliderX.setTickInterval(1)
-    axisMaxSliderX.setEnabled(True)
-    axisMinSliderZ = QSlider(Qt.Horizontal, widget)
-    axisMinSliderZ.setMinimum(0)
-    axisMinSliderZ.setTickInterval(1)
-    axisMinSliderZ.setEnabled(True)
-    axisMaxSliderZ = QSlider(Qt.Horizontal, widget)
-    axisMaxSliderZ.setMinimum(1)
-    axisMaxSliderZ.setTickInterval(1)
-    axisMaxSliderZ.setEnabled(True)
-
-    themeList = QComboBox(widget)
-    themeList.addItems(THEMES)
-
-    colorGroupBox = QGroupBox("Custom gradient")
-
-    grBtoY = QLinearGradient(0, 0, 1, 100)
-    grBtoY.setColorAt(1.0, Qt.black)
-    grBtoY.setColorAt(0.67, Qt.blue)
-    grBtoY.setColorAt(0.33, Qt.red)
-    grBtoY.setColorAt(0.0, Qt.yellow)
-
-    pm = QPixmap(24, 100)
-    pmp = QPainter(pm)
-    pmp.setBrush(QBrush(grBtoY))
-    pmp.setPen(Qt.NoPen)
-    pmp.drawRect(0, 0, 24, 100)
-    pmp.end()
-
-    gradientBtoYPB = QPushButton(widget)
-    gradientBtoYPB.setIcon(QIcon(pm))
-    gradientBtoYPB.setIconSize(QSize(24, 100))
-
-    grGtoR = QLinearGradient(0, 0, 1, 100)
-    grGtoR.setColorAt(1.0, Qt.darkGreen)
-    grGtoR.setColorAt(0.5, Qt.yellow)
-    grGtoR.setColorAt(0.2, Qt.red)
-    grGtoR.setColorAt(0.0, Qt.darkRed)
-    pmp.begin(pm)
-    pmp.setBrush(QBrush(grGtoR))
-    pmp.drawRect(0, 0, 24, 100)
-    pmp.end()
-
-    gradientGtoRPB = QPushButton(widget)
-    gradientGtoRPB.setIcon(QIcon(pm))
-    gradientGtoRPB.setIconSize(QSize(24, 100))
-
-    colorHBox = QHBoxLayout()
-    colorHBox.addWidget(gradientBtoYPB)
-    colorHBox.addWidget(gradientGtoRPB)
-    colorGroupBox.setLayout(colorHBox)
-
-    vLayout.addWidget(modelGroupBox)
-    vLayout.addWidget(selectionGroupBox)
-    vLayout.addWidget(QLabel("Column range"))
-    vLayout.addWidget(axisMinSliderX)
-    vLayout.addWidget(axisMaxSliderX)
-    vLayout.addWidget(QLabel("Row range"))
-    vLayout.addWidget(axisMinSliderZ)
-    vLayout.addWidget(axisMaxSliderZ)
-    vLayout.addWidget(QLabel("Theme"))
-    vLayout.addWidget(themeList)
-    vLayout.addWidget(colorGroupBox)
-
-    widget.show()
-
-    modifier = SurfaceGraph(graph)
-
-    heightMapModelRB.toggled.connect(modifier.enableHeightMapModel)
-    sqrtSinModelRB.toggled.connect(modifier.enableSqrtSinModel)
-    modeNoneRB.toggled.connect(modifier.toggleModeNone)
-    modeItemRB.toggled.connect(modifier.toggleModeItem)
-    modeSliceRowRB.toggled.connect(modifier.toggleModeSliceRow)
-    modeSliceColumnRB.toggled.connect(modifier.toggleModeSliceColumn)
-    axisMinSliderX.valueChanged.connect(modifier.adjustXMin)
-    axisMaxSliderX.valueChanged.connect(modifier.adjustXMax)
-    axisMinSliderZ.valueChanged.connect(modifier.adjustZMin)
-    axisMaxSliderZ.valueChanged.connect(modifier.adjustZMax)
-    themeList.currentIndexChanged[int].connect(modifier.changeTheme)
-    gradientBtoYPB.pressed.connect(modifier.setBlackToYellowGradient)
-    gradientGtoRPB.pressed.connect(modifier.setGreenToRedGradient)
-
-    modifier.setAxisMinSliderX(axisMinSliderX)
-    modifier.setAxisMaxSliderX(axisMaxSliderX)
-    modifier.setAxisMinSliderZ(axisMinSliderZ)
-    modifier.setAxisMaxSliderZ(axisMaxSliderZ)
-
-    sqrtSinModelRB.setChecked(True)
-    modeItemRB.setChecked(True)
-    themeList.setCurrentIndex(2)
+    window = Window(graph)
+    window.setWindowTitle("Surface example")
+    window.show()
 
     sys.exit(app.exec())
diff --git a/examples/datavisualization/surface_numpy/surfacegraph.py b/examples/datavisualization/surface_numpy/surfacegraph.py
index 88ef7e36a..c95cec2a0 100644
--- a/examples/datavisualization/surface_numpy/surfacegraph.py
+++ b/examples/datavisualization/surface_numpy/surfacegraph.py
@@ -52,12 +52,12 @@ from PySide6.QtDataVisualization import (Q3DTheme, QAbstract3DGraph,
 from PySide6.QtGui import QImage, QLinearGradient
 from PySide6.QtWidgets import QSlider
 
-sampleCountX = 50
-sampleCountZ = 50
-heightMapGridStepX = 6
-heightMapGridStepZ = 6
-sampleMin = -8.0
-sampleMax = 8.0
+SAMPLE_COUNT_X = 50
+SAMPLE_COUNT_Z = 50
+HEIGHT_MAP_GRID_STEP_X = 6
+HEIGHT_MAP_GRID_STEP_Z = 6
+SAMPLE_MIN = -8.0
+SAMPLE_MAX = 8.0
 
 
 X_ROLE = Qt.UserRole + 1
@@ -69,20 +69,20 @@ class SqrtSinModel(QAbstractTableModel):
     def __init__(self, parent=None):
         super().__init__(parent)
 
-        self._x = np.zeros(sampleCountX)
-        self._z = np.zeros(sampleCountZ)
-        self._data = np.zeros((sampleCountZ, sampleCountX))
+        self._x = np.zeros(SAMPLE_COUNT_X)
+        self._z = np.zeros(SAMPLE_COUNT_Z)
+        self._data = np.zeros((SAMPLE_COUNT_Z, SAMPLE_COUNT_X))
 
-        stepX = (sampleMax - sampleMin) / float(sampleCountX - 1)
-        stepZ = (sampleMax - sampleMin) / float(sampleCountZ - 1)
+        step_x = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_X - 1)
+        step_z = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_Z - 1)
 
-        for i in range(sampleCountZ):
+        for i in range(SAMPLE_COUNT_Z):
             # Keep values within range bounds, since just adding step can cause
             # minor drift due to the rounding errors.
-            z = min(sampleMax, (i * stepZ + sampleMin))
+            z = min(SAMPLE_MAX, (i * step_z + SAMPLE_MIN))
             self._z[i] = z
-            for j in range(sampleCountX):
-                x = min(sampleMax, (j * stepX + sampleMin))
+            for j in range(SAMPLE_COUNT_X):
+                x = min(SAMPLE_MAX, (j * step_x + SAMPLE_MIN))
                 self._x[j] = x
                 R = math.sqrt(z * z + x * x) + 0.01
                 y = (math.sin(R) / R + 0.24) * 1.61
@@ -131,15 +131,15 @@ class SurfaceGraph(QObject):
 
         self.m_sqrtSinSeries = QSurface3DSeries(self.m_sqrtSinProxy)
 
-        imageFile = Path(__file__).parent.parent / "surface" / "mountain.png"
-        heightMapImage = QImage(imageFile)
-        self.m_heightMapProxy = QHeightMapSurfaceDataProxy(heightMapImage)
+        image_file = Path(__file__).parent.parent / "surface" / "mountain.png"
+        height_map_image = QImage(image_file)
+        self.m_heightMapProxy = QHeightMapSurfaceDataProxy(height_map_image)
         self.m_heightMapSeries = QSurface3DSeries(self.m_heightMapProxy)
         self.m_heightMapSeries.setItemLabelFormat("(@xLabel, @zLabel): @yLabel")
         self.m_heightMapProxy.setValueRanges(34.0, 40.0, 18.0, 24.0)
 
-        self.m_heightMapWidth = heightMapImage.width()
-        self.m_heightMapHeight = heightMapImage.height()
+        self.m_heightMapWidth = height_map_image.width()
+        self.m_heightMapHeight = height_map_image.height()
 
         self.m_axisMinSliderX = QSlider()
         self.m_axisMaxSliderX = QSlider()
@@ -150,16 +150,16 @@ class SurfaceGraph(QObject):
         self.m_stepX = 0.0
         self.m_stepZ = 0.0
 
-    def enableSqrtSinModel(self, enable):
+    def enable_sqrt_sin_model(self, enable):
         if enable:
             self.m_sqrtSinSeries.setDrawMode(QSurface3DSeries.DrawSurfaceAndWireframe)
             self.m_sqrtSinSeries.setFlatShadingEnabled(True)
 
             self.m_graph.axisX().setLabelFormat("%.2f")
             self.m_graph.axisZ().setLabelFormat("%.2f")
-            self.m_graph.axisX().setRange(sampleMin, sampleMax)
+            self.m_graph.axisX().setRange(SAMPLE_MIN, SAMPLE_MAX)
             self.m_graph.axisY().setRange(0.0, 2.0)
-            self.m_graph.axisZ().setRange(sampleMin, sampleMax)
+            self.m_graph.axisZ().setRange(SAMPLE_MIN, SAMPLE_MAX)
             self.m_graph.axisX().setLabelAutoRotation(30)
             self.m_graph.axisY().setLabelAutoRotation(90)
             self.m_graph.axisZ().setLabelAutoRotation(30)
@@ -168,20 +168,20 @@ class SurfaceGraph(QObject):
             self.m_graph.addSeries(self.m_sqrtSinSeries)
 
             # Reset range sliders for Sqrt&Sin
-            self.m_rangeMinX = sampleMin
-            self.m_rangeMinZ = sampleMin
-            self.m_stepX = (sampleMax - sampleMin) / float(sampleCountX - 1)
-            self.m_stepZ = (sampleMax - sampleMin) / float(sampleCountZ - 1)
-            self.m_axisMinSliderX.setMaximum(sampleCountX - 2)
+            self.m_rangeMinX = SAMPLE_MIN
+            self.m_rangeMinZ = SAMPLE_MIN
+            self.m_stepX = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_X - 1)
+            self.m_stepZ = (SAMPLE_MAX - SAMPLE_MIN) / float(SAMPLE_COUNT_Z - 1)
+            self.m_axisMinSliderX.setMaximum(SAMPLE_COUNT_X - 2)
             self.m_axisMinSliderX.setValue(0)
-            self.m_axisMaxSliderX.setMaximum(sampleCountX - 1)
-            self.m_axisMaxSliderX.setValue(sampleCountX - 1)
-            self.m_axisMinSliderZ.setMaximum(sampleCountZ - 2)
+            self.m_axisMaxSliderX.setMaximum(SAMPLE_COUNT_X - 1)
+            self.m_axisMaxSliderX.setValue(SAMPLE_COUNT_X - 1)
+            self.m_axisMinSliderZ.setMaximum(SAMPLE_COUNT_Z - 2)
             self.m_axisMinSliderZ.setValue(0)
-            self.m_axisMaxSliderZ.setMaximum(sampleCountZ - 1)
-            self.m_axisMaxSliderZ.setValue(sampleCountZ - 1)
+            self.m_axisMaxSliderZ.setMaximum(SAMPLE_COUNT_Z - 1)
+            self.m_axisMaxSliderZ.setValue(SAMPLE_COUNT_Z - 1)
 
-    def enableHeightMapModel(self, enable):
+    def enable_height_map_model(self, enable):
         if enable:
             self.m_heightMapSeries.setDrawMode(QSurface3DSeries.DrawSurface)
             self.m_heightMapSeries.setFlatShadingEnabled(False)
@@ -200,76 +200,76 @@ class SurfaceGraph(QObject):
             self.m_graph.addSeries(self.m_heightMapSeries)
 
             # Reset range sliders for height map
-            mapGridCountX = self.m_heightMapWidth / heightMapGridStepX
-            mapGridCountZ = self.m_heightMapHeight / heightMapGridStepZ
+            map_grid_count_x = self.m_heightMapWidth / HEIGHT_MAP_GRID_STEP_X
+            map_grid_count_z = self.m_heightMapHeight / HEIGHT_MAP_GRID_STEP_Z
             self.m_rangeMinX = 34.0
             self.m_rangeMinZ = 18.0
-            self.m_stepX = 6.0 / float(mapGridCountX - 1)
-            self.m_stepZ = 6.0 / float(mapGridCountZ - 1)
-            self.m_axisMinSliderX.setMaximum(mapGridCountX - 2)
+            self.m_stepX = 6.0 / float(map_grid_count_x - 1)
+            self.m_stepZ = 6.0 / float(map_grid_count_z - 1)
+            self.m_axisMinSliderX.setMaximum(map_grid_count_x - 2)
             self.m_axisMinSliderX.setValue(0)
-            self.m_axisMaxSliderX.setMaximum(mapGridCountX - 1)
-            self.m_axisMaxSliderX.setValue(mapGridCountX - 1)
-            self.m_axisMinSliderZ.setMaximum(mapGridCountZ - 2)
+            self.m_axisMaxSliderX.setMaximum(map_grid_count_x - 1)
+            self.m_axisMaxSliderX.setValue(map_grid_count_x - 1)
+            self.m_axisMinSliderZ.setMaximum(map_grid_count_z - 2)
             self.m_axisMinSliderZ.setValue(0)
-            self.m_axisMaxSliderZ.setMaximum(mapGridCountZ - 1)
-            self.m_axisMaxSliderZ.setValue(mapGridCountZ - 1)
+            self.m_axisMaxSliderZ.setMaximum(map_grid_count_z - 1)
+            self.m_axisMaxSliderZ.setValue(map_grid_count_z - 1)
 
-    def adjustXMin(self, minimum):
-        minX = self.m_stepX * float(minimum) + self.m_rangeMinX
+    def adjust_xmin(self, minimum):
+        min_x = self.m_stepX * float(minimum) + self.m_rangeMinX
 
         maximum = self.m_axisMaxSliderX.value()
         if minimum >= maximum:
             maximum = minimum + 1
             self.m_axisMaxSliderX.setValue(maximum)
-        maxX = self.m_stepX * maximum + self.m_rangeMinX
+        max_x = self.m_stepX * maximum + self.m_rangeMinX
 
-        self.setAxisXRange(minX, maxX)
+        self.set_axis_xrange(min_x, max_x)
 
-    def adjustXMax(self, maximum):
-        maxX = self.m_stepX * float(maximum) + self.m_rangeMinX
+    def adjust_xmax(self, maximum):
+        max_x = self.m_stepX * float(maximum) + self.m_rangeMinX
 
         minimum = self.m_axisMinSliderX.value()
         if maximum <= minimum:
             minimum = maximum - 1
             self.m_axisMinSliderX.setValue(minimum)
-        minX = self.m_stepX * minimum + self.m_rangeMinX
+        min_x = self.m_stepX * minimum + self.m_rangeMinX
 
-        self.setAxisXRange(minX, maxX)
+        self.set_axis_xrange(min_x, max_x)
 
-    def adjustZMin(self, minimum):
-        minZ = self.m_stepZ * float(minimum) + self.m_rangeMinZ
+    def adjust_zmin(self, minimum):
+        min_z = self.m_stepZ * float(minimum) + self.m_rangeMinZ
 
         maximum = self.m_axisMaxSliderZ.value()
         if minimum >= maximum:
             maximum = minimum + 1
             self.m_axisMaxSliderZ.setValue(maximum)
-        maxZ = self.m_stepZ * maximum + self.m_rangeMinZ
+        max_z = self.m_stepZ * maximum + self.m_rangeMinZ
 
-        self.setAxisZRange(minZ, maxZ)
+        self.set_axis_zrange(min_z, max_z)
 
-    def adjustZMax(self, maximum):
-        maxX = self.m_stepZ * float(maximum) + self.m_rangeMinZ
+    def adjust_zmax(self, maximum):
+        max_x = self.m_stepZ * float(maximum) + self.m_rangeMinZ
 
         minimum = self.m_axisMinSliderZ.value()
         if maximum <= minimum:
             minimum = maximum - 1
             self.m_axisMinSliderZ.setValue(minimum)
-        minX = self.m_stepZ * minimum + self.m_rangeMinZ
+        min_x = self.m_stepZ * minimum + self.m_rangeMinZ
 
-        self.setAxisZRange(minX, maxX)
+        self.set_axis_zrange(min_x, max_x)
 
-    def setAxisXRange(self, minimum, maximum):
+    def set_axis_xrange(self, minimum, maximum):
         self.m_graph.axisX().setRange(minimum, maximum)
 
-    def setAxisZRange(self, minimum, maximum):
+    def set_axis_zrange(self, minimum, maximum):
         self.m_graph.axisZ().setRange(minimum, maximum)
 
     @Slot()
-    def changeTheme(self, theme):
+    def change_theme(self, theme):
         self.m_graph.activeTheme().setType(Q3DTheme.Theme(theme))
 
-    def setBlackToYellowGradient(self):
+    def set_black_to_yellow_gradient(self):
         gr = QLinearGradient()
         gr.setColorAt(0.0, Qt.black)
         gr.setColorAt(0.33, Qt.blue)
@@ -280,7 +280,7 @@ class SurfaceGraph(QObject):
         series.setBaseGradient(gr)
         series.setColorStyle(Q3DTheme.ColorStyleRangeGradient)
 
-    def setGreenToRedGradient(self):
+    def set_green_to_red_gradient(self):
         gr = QLinearGradient()
         gr.setColorAt(0.0, Qt.darkGreen)
         gr.setColorAt(0.5, Qt.yellow)
@@ -291,30 +291,30 @@ class SurfaceGraph(QObject):
         series.setBaseGradient(gr)
         series.setColorStyle(Q3DTheme.ColorStyleRangeGradient)
 
-    def toggleModeNone(self):
+    def toggle_mode_none(self):
         self.m_graph.setSelectionMode(QAbstract3DGraph.SelectionNone)
 
-    def toggleModeItem(self):
+    def toggle_mode_item(self):
         self.m_graph.setSelectionMode(QAbstract3DGraph.SelectionItem)
 
-    def toggleModeSliceRow(self):
+    def toggle_mode_slice_row(self):
         self.m_graph.setSelectionMode(
             QAbstract3DGraph.SelectionItemAndRow | QAbstract3DGraph.SelectionSlice
         )
 
-    def toggleModeSliceColumn(self):
+    def toggle_mode_slice_column(self):
         self.m_graph.setSelectionMode(
             QAbstract3DGraph.SelectionItemAndColumn | QAbstract3DGraph.SelectionSlice
         )
 
-    def setAxisMinSliderX(self, slider):
+    def set_axis_min_slider_x(self, slider):
         self.m_axisMinSliderX = slider
 
-    def setAxisMaxSliderX(self, slider):
+    def set_axis_max_slider_x(self, slider):
         self.m_axisMaxSliderX = slider
 
-    def setAxisMinSliderZ(self, slider):
+    def set_axis_min_slider_z(self, slider):
         self.m_axisMinSliderZ = slider
 
-    def setAxisMaxSliderZ(self, slider):
+    def set_axis_max_slider_z(self, slider):
         self.m_axisMaxSliderZ = slider