How to use the nanogui.Window function in nanogui

popup.setLayout(GroupLayout())
        Label(popup, "Arbitrary widgets can be placed here")
        CheckBox(popup, "A check box")
        # popup right
        popupBtn = PopupButton(popup, "Recursive popup", entypo.ICON_FLASH)
        popupRight = popupBtn.popup()
        popupRight.setLayout(GroupLayout())
        CheckBox(popupRight, "Another check box")
        # popup left
        popupBtn = PopupButton(popup, "Recursive popup", entypo.ICON_FLASH)
        popupBtn.setSide(Popup.Side.Left)
        popupLeft = popupBtn.popup()
        popupLeft.setLayout(GroupLayout())
        CheckBox(popupLeft, "Another check box");

        window = Window(self, "Basic widgets")
        window.setPosition((200, 15))
        window.setLayout(GroupLayout())

        Label(window, "Message dialog", "sans-bold")
        tools = Widget(window)
        tools.setLayout(BoxLayout(Orientation.Horizontal,
                                  Alignment.Middle, 0, 6))

        def cb2(result):
            print("Dialog result: %i" % result)

        b = Button(tools, "Info")

        def cb():
            dlg = MessageDialog(self, MessageDialog.Type.Information, "Title",
                                "This is an information message")

graphDyn.setFooter("Iteration {0}".format(index*counter))
                valuesDyn = [0.5 * abs((0.5 * math.sin(i / 10.0 + counter)) +
                                       (0.5 * math.cos(i / 23.0 + 1 + counter)))
                             for i in range(100)]
                graphDyn.setValues(valuesDyn)
                counter += 1
                # We must invoke perform layout from the screen instance to keep everything in order.
                # This is essential when creating tabs dynamically.
                self.performLayout()
                # Ensure that the newly added header is visible on screen
                tabWidget.ensureTabVisible(index)

        tabWidget.setCallback(tab_cb)
        tabWidget.setActiveTab(0);

        window = Window(self, "Grid of small widgets")
        window.setPosition((425, 300))
        layout = GridLayout(Orientation.Horizontal, 2,
                            Alignment.Middle, 15, 5)
        layout.setColAlignment(
            [Alignment.Maximum, Alignment.Fill])
        layout.setSpacing(0, 10)
        window.setLayout(layout)

        Label(window, "Floating point :", "sans-bold")
        floatBox = TextBox(window)
        floatBox.setEditable(True)
        floatBox.setFixedSize((100, 20))
        floatBox.setValue("50")
        floatBox.setUnits("GiB")
        floatBox.setDefaultValue("0.0")
        floatBox.setFontSize(16)

def __init__(self):
        super(TestApp, self).__init__((1024, 768), "NanoGUI Test")

        window = Window(self, "Button demo")
        window.setPosition((15, 15))
        window.setLayout(GroupLayout())

        Label(window, "Push buttons", "sans-bold")
        b = Button(window, "Plain button")

        def cb():
            print("pushed!")
        b.setCallback(cb)

        b = Button(window, "Styled", entypo.ICON_ROCKET)
        b.setBackgroundColor(Color(0, 0, 1.0, 0.1))
        b.setCallback(cb)

        Label(window, "Toggle buttons", "sans-bold")
        b = Button(window, "Toggle me")

try:
                icons = nanogui.loadImageDirectory(self.nvgContext(), "../icons")
            except:
                icons = nanogui.loadImageDirectory(self.nvgContext(), "../resources/icons")


        Label(window, "Image panel & scroll panel", "sans-bold")
        imagePanelBtn = PopupButton(window, "Image Panel")
        imagePanelBtn.setIcon(entypo.ICON_FOLDER)
        popup = imagePanelBtn.popup()
        vscroll = VScrollPanel(popup)
        imgPanel = ImagePanel(vscroll)
        imgPanel.setImages(icons)
        popup.setFixedSize((245, 150))

        img_window = Window(self, "Selected image")
        img_window.setPosition((710, 15))
        img_window.setLayout(GroupLayout())

        imgView = ImageView(img_window, icons[0][0])

        def cb(i):
            print("Selected item %i" % i)
            imgView.bindImage(icons[i][0])
        imgPanel.setCallback(cb)

        imgView.setGridThreshold(3)

        Label(window, "File dialog", "sans-bold")
        tools = Widget(window)
        tools.setLayout(BoxLayout(Orientation.Horizontal,
                                  Alignment.Middle, 0, 6))

textBox = TextBox(panel)
        textBox.setFixedSize((60, 25))
        textBox.setValue("50")
        textBox.setUnits("%")
        textBox.setFontSize(20)
        textBox.setAlignment(TextBox.Alignment.Right)

        def cb(value):
            textBox.setValue("%i" % int(value * 100))
        slider.setCallback(cb)

        def cb(value):
            print("Final slider value: %i" % int(value * 100))
        slider.setFinalCallback(cb)

        window = Window(self, "Misc. widgets")
        window.setPosition((425, 15))
        window.setLayout(GroupLayout())

        tabWidget = TabWidget(window)
        layer = tabWidget.createTab("Color Wheel")
        layer.setLayout(GroupLayout())

        Label(layer, "Color wheel widget", "sans-bold")
        ColorWheel(layer)

        layer = tabWidget.createTab("Function Graph")
        layer.setLayout(GroupLayout())
        Label(layer, "Function graph widget", "sans-bold")

        graph = Graph(layer, "Some function")
        graph.setHeader("E = 2.35e-3")

try:
                icons = nanogui.loadImageDirectory(self.nvgContext(), "../icons")
            except:
                icons = nanogui.loadImageDirectory(self.nvgContext(), "../resources/icons")


        Label(window, "Image panel & scroll panel", "sans-bold")
        imagePanelBtn = PopupButton(window, "Image Panel")
        imagePanelBtn.setIcon(entypo.ICON_FOLDER)
        popup = imagePanelBtn.popup()
        vscroll = VScrollPanel(popup)
        imgPanel = ImagePanel(vscroll)
        imgPanel.setImages(icons)
        popup.setFixedSize((245, 150))

        img_window = Window(self, "Selected image")
        img_window.setPosition((710, 15))
        img_window.setLayout(GroupLayout())

        imgView = ImageView(img_window, icons[0][0])

        def cb(i):
            if i < len(icons):
                print("Selected item %i" % i)
                imgView.bindImage(icons[i][0])
        imgPanel.setCallback(cb)

        imgView.setGridThreshold(3)

        Label(window, "File dialog", "sans-bold")
        tools = Widget(window)
        tools.setLayout(BoxLayout(Orientation.Horizontal,

def __init__(self):
        super(TestApp, self).__init__((1024, 768), "NanoGUI Test")

        window = Window(self, "Button demo")
        window.setPosition((15, 15))
        window.setLayout(GroupLayout())

        Label(window, "Push buttons", "sans-bold")
        b = Button(window, "Plain button")

        def cb():
            print("pushed!")
        b.setCallback(cb)

        b = Button(window, "Styled", entypo.ICON_ROCKET)
        b.setBackgroundColor(Color(0, 0, 1.0, 0.1))
        b.setCallback(cb)

        Label(window, "Toggle buttons", "sans-bold")
        b = Button(window, "Toggle me")

def __init__(self):
        super(TestApp, self).__init__((800, 600), "NanoGUI Test", False)

        window = Window(self, "GLCanvas Demo")
        window.setPosition((15, 15))
        window.setLayout(GroupLayout())

        self.canvas = MyGLCanvas(window)
        self.canvas.setBackgroundColor(Color(0.5, 0.5, 0.5, 1.0))
        self.canvas.setSize((400, 400))

        self.canvas.rotation = [0.25, 0.5, 0.33]

        tools = Widget(window)
        tools.setLayout(BoxLayout(Orientation.Horizontal,
                                  Alignment.Middle, 0, 5))

        b0 = Button(tools, "Random Color")
        def cb0():
            self.canvas.setBackgroundColor(Color(random.random(), random.random(), random.random(), 1.0))

graphDyn.setFooter("Iteration {0}".format(index*counter))
                valuesDyn = [0.5 * abs((0.5 * math.sin(i / 10.0 + counter)) +
                                       (0.5 * math.cos(i / 23.0 + 1 + counter)))
                             for i in range(100)]
                graphDyn.setValues(valuesDyn)
                counter += 1
                # We must invoke perform layout from the screen instance to keep everything in order.
                # This is essential when creating tabs dynamically.
                self.performLayout()
                # Ensure that the newly added header is visible on screen
                tabWidget.ensureTabVisible(index)

        tabWidget.setCallback(tab_cb)
        tabWidget.setActiveTab(0);

        window = Window(self, "Grid of small widgets")
        window.setPosition((425, 300))
        layout = GridLayout(Orientation.Horizontal, 2,
                            Alignment.Middle, 15, 5)
        layout.setColAlignment(
            [Alignment.Maximum, Alignment.Fill])
        layout.setSpacing(0, 10)
        window.setLayout(layout)

        Label(window, "Floating point :", "sans-bold")
        floatBox = TextBox(window)
        floatBox.setEditable(True)
        floatBox.setFixedSize((100, 20))
        floatBox.setValue("50")
        floatBox.setUnits("GiB")
        floatBox.setDefaultValue("0.0")
        floatBox.setFontSize(16)

cp = ColorPicker(window, Color(255, 120, 0, 255));
        cp.setFixedSize((100, 20));

        def cp_final_cb(color):
            print(
                "ColorPicker Final Callback: [{0}, {1}, {2}, {3}]".format(color.r,
                                                                          color.g,
                                                                          color.b,
                                                                          color.w)
            )

        cp.setFinalCallback(cp_final_cb)

        # setup a fast callback for the color picker widget on a new window
        # for demonstrative purposes
        window = Window(self, "Color Picker Fast Callback")
        window.setPosition((425, 300))
        layout = GridLayout(Orientation.Horizontal, 2,
                            Alignment.Middle, 15, 5)
        layout.setColAlignment(
            [Alignment.Maximum, Alignment.Fill])
        layout.setSpacing(0, 10)
        window.setLayout(layout)
        window.setPosition((425, 500))
        Label(window, "Combined: ");
        b = Button(window, "ColorWheel", entypo.ICON_500PX)
        Label(window, "Red: ")
        redIntBox = IntBox(window)
        redIntBox.setEditable(False)
        Label(window, "Green: ")
        greenIntBox = IntBox(window)
        greenIntBox.setEditable(False)