（未完成）Pyglet实现SideBar

import pyglet

class Window(pyglet.window.Window):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    def attach(self, widget):
        def __on_draw():
            self.clear()

            widget.on_draw(self.width, self.height)

        def __on_mouse_press(x, y, button, modifiers):
            widget.on_mouse_press(x, self.height-y, button, modifiers)

        def __on_mouse_motion(x, y, dx, dy):
            widget.on_mouse_motion(x, self.height-y, dx, -dy)

        def __on_key_press(symbol, modifiers):
            widget.on_key_press(symbol, modifiers)

        self.push_handlers(on_draw = __on_draw)
        self.push_handlers(on_mouse_press = __on_mouse_press)
        self.push_handlers(on_mouse_motion = __on_mouse_motion)
        self.push_handlers(on_key_press = __on_key_press)

class Color():
    White = (255, 255, 255)
    Black = (0, 0, 0)
    Green = (0, 255, 0)
    Blue = (0, 0, 255)

class BaseWidget():
    def __init__(self):
        self.x = 0
        self.y = 0
        self.width = 0
        self.height = 0
        self.text = ""
        self.text_x = 0
        self.visible = True
        self.active = True
        self.color = Color.White

    def __del__(self):
        pass

    def __draw(self, mode, window_width, window_height):
        ny = window_height - self.y
        points = (self.x, ny, self.x+self.width, ny, self.x+self.width, ny-self.height, self.x, ny-self.height)

        colors = []
        for i in range(4):
            colors.extend(self.color)

        pyglet.graphics.draw(4, mode, ("v2i", points), ("c3B", colors))

    # def draw_line_loop(self, ):
    #     self.draw(pyglet.gl.GL_LINE_LOOP)

    def draw_rectangle(self, window_width, window_height):
        self.__draw(pyglet.gl.GL_QUADS, window_width, window_height)

    def is_within_area(self, x, y):
        if x >= self.x and x <= self.x+self.width:
            if y >= self.y and y <= self.y+self.height:
                return True

        return False

    def on_draw(self, window_width, window_height):
        pass

    def on_mouse_press(self, x, y, button, modifiers):
        pass

    def on_mouse_motion(self, x, y, dx, dy):
        pass

    def on_key_press(self, symbol, modifiers):
        pass

class PaneWidget(BaseWidget):
    def __init__(self):
        super().__init__()

        self.widgets = []
        # self.selected_widget = None

    def add(self, widget):
        self.widgets.append(widget)

    def on_draw(self, window_width, window_height):
        for widget in self.widgets:
            widget.on_draw(window_width, window_height)

    def on_mouse_press(self, x, y, button, modifiers):
        for widget in self.widgets:
            widget.on_mouse_press(x, y, button, modifiers)

    def on_mouse_motion(self, x, y, dx, dy):
        for widget in self.widgets:
            widget.on_mouse_motion(x, y, dx, dy)

    def on_key_press(self, symbol, modifiers):
        for widget in self.widgets:
            widget.on_key_press(symbol, modifiers)

class Node():
    def __init__(self):
        self.widget = None
        self.nodes = []

class TreeWidget(BaseWidget):
    def __init__(self):
        super().__init__()

        self.root = Node()
        self.selected_node = self.root

    def add(self, widget):
        node = Node()
        node.widget = widget

        self.selected_node.nodes.append(node)

        height = self.update() * widget.height

        if height > self.height:
            self.height = height

    def update(self):
        return self.__update(self.root, 0, 0)

    def on_draw(self, window_width, window_height):
        if self.selected_node != self.root:
            self.selected_node.widget.color = Color.Blue

        self.__on_draw(self.root, window_width, window_height)

    def on_mouse_press(self, x, y, button, modifiers):
        self.__on_mouse_press(self.root, x, y, button, modifiers)

    def on_mouse_motion(self, x, y, dx, dy):
        self.__on_mouse_motion(self.root, x, y, dx, dy)

    def __update(self, next_node, depth, height):
        for node in next_node.nodes:
            # node.widget.x = self.x + depth*20
            node.widget.text_x = self.x + depth*20
            node.widget.y = self.y + height*node.widget.height
            # node.widget.width = self.width
            # node.widget.height = 20

            height = self.__update(node, depth + 1, height + 1)

        return height

    def __on_draw(self, next_node, window_width, window_height):
        for node in next_node.nodes:
            node.widget.on_draw(window_width, window_height)

            self.__on_draw(node, window_width, window_height)

    def __on_mouse_press(self, next_node, x, y, button, modifiers):
        for node in next_node.nodes:
            if node.widget.on_mouse_press(x, y, button, modifiers):
                if self.selected_node != self.root:
                    self.selected_node.widget.color = Color.White

                self.selected_node = node

            self.__on_mouse_press(node, x, y, button, modifiers)

    def __on_mouse_motion(self, next_node, x, y, dx, dy):
        for node in next_node.nodes:
            node.widget.on_mouse_motion(x, y, dx, dy)

            self.__on_mouse_motion(node, x, y, dx, dy)

class Item(BaseWidget):
    def __init__(self):
        super().__init__()

    def on_draw(self, window_width, window_height):
        self.draw_rectangle(window_width, window_height)

    def on_mouse_press(self, x, y, button, modifiers):
        if self.is_within_area(x, y):
            if button == pyglet.window.mouse.LEFT or button == pyglet.window.mouse.RIGHT:
                return True

        return False

    def on_mouse_motion(self, x, y, dx, dy):
        if self.is_within_area(x, y):
            self.color = Color.Green
        else:
            self.color = Color.White

class Sidebar(TreeWidget):
    def __init__(self):
        super().__init__()

    def add(self, widget):
        widget.x = self.x
        widget.y = self.y
        widget.width = self.width
        widget.height = 20

        super().add(widget)

    def on_draw(self, window_width, window_height):
        self.draw_rectangle(window_width, window_height)

        super().on_draw(window_width, window_height)

class Form(PaneWidget):
    def __init__(self):
        super().__init__()

        self.sidebar = None
        # self.menu = None

        self.init_component()

        self.test()

    def init_component(self):
        self.sidebar = Sidebar()
        self.sidebar.x = 10
        self.sidebar.y = 10
        self.sidebar.width = 100
        self.sidebar.height = 200
        self.add(self.sidebar)

        # self.menu = Menu()
        # self.menu.width = 80
        # self.menu.active = False
        # self.add(self.menu)

    def on_mouse_press(self, x, y, button, modifiers):
        super().on_mouse_press(x, y, button, modifiers)

        # if button == pyglet.window.mouse.RIGHT:
        #     widget = self.sidebar.selected_node.widget

        #     if widget != None and widget.is_within_area(x, y):
        #         if self.menu.active:
        #             if self.menu.is_within_area(x, y) == False:
        #                 self.menu.x = x
        #                 self.menu.y = y
        #         else:
        #             self.menu.x = x
        #             self.menu.y = y
        #             self.menu.active = True

    def on_key_press(self, symbol, modifiers):
        super().on_key_press(symbol, modifiers)

        if symbol == pyglet.window.key.N:
            self.sidebar.add(Item())

    def test(self):
        self.sidebar.add(Item())
        self.sidebar.add(Item())
        self.sidebar.add(Item())

from widget import *

if __name__ == "__main__":
    window = Window()

    form = Form()

    window.attach(form)

    pyglet.app.run()