如何清除或覆盖 tkinter 画布？

Question

下面的代码显示了我目前正在处理的 tkinter GUI 的一页。

我想要“清除绘图字段”按钮做的就是它所说的：清除画布，因为如果我再次绘图，新的绘图会在下面打包。

或者：我怎样才能覆盖现有的情节，这样我就可以摆脱按钮本身？

class PlotPage(tk.Frame):
"""Page containing the matplotlib graphs"""

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        label = ttk.Label(self, text="PlotPage", font=LARGE_FONT)
        label.pack(pady=5)

        button1 = ttk.Button(self, text="Back to Start Page", command=lambda: controller.show_frame(StartPage))
        button1.pack(pady=5)

        buttonPlot = ttk.Button(self, text="Show Plot", command=self.plot)
        buttonPlot.pack(pady=5)

        buttonClear = ttk.Button(self, text="Clear Plot Field", command=lambda: controller.show_frame(PlotPage))
        buttonClear.pack(pady=5)

    def plot(self):
    """generate a simple matplotlib graph for multiple profiles"""

        f = Figure(figsize=(8,4), dpi=100)   
        a = f.add_subplot(111)

        for profile in listofProfiles:
            X_list=profile.indexList
            Y_list=profile.VL_List

            [...] Some lines related to plotting [...]

            a.plot(X_list, Y_list, lw=0.3,)

        canvas = FigureCanvasTkAgg(f, self)
        canvas.show()
        canvas.get_tk_widget().pack(side=tk.TOP, fill=tk.BOTH, expand=True)

        toolbar = NavigationToolbar2TkAgg(canvas, self)
        toolbar.update()
        canvas._tkcanvas.pack(side=tk.TOP, fill=tk.BOTH, expand=True)

        print("Stuff has been plotted")

    def clearPlotPage(self):
    """cleares the whole plot field"""     

        # ???

        print("Plot Page has been cleared")

Answer 1

只需在谷歌上搜索“clear tkinter canvas”即可获得this、this、this 和this。

简答：调用canvas.delete('all') 将清除整个画布。

Answer 2

我会 destroy() 画布，然后重新运行 plot()。为此，您需要将canvas 设为类似self.canvas 的类属性。现在我们有了一个类属性，您的任何方法都可以毫无问题地使用self.canvas。

看看我根据你的问题修改的这段代码，如果你有任何问题，请告诉我。

class PlotPage(tk.Frame):
    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)

        self.canvas = None

        label = ttk.Label(self, text="PlotPage", font=LARGE_FONT)
        label.pack(pady=5)
        button1 = ttk.Button(self, text="Back to Start Page", command=lambda: controller.show_frame(StartPage))
        button1.pack(pady=5)
        buttonPlot = ttk.Button(self, text="Show Plot", command=self.plot)
        buttonPlot.pack(pady=5)
        buttonClear = ttk.Button(self, text="Clear Plot Field", command=lambda: controller.show_frame(PlotPage))
        buttonClear.pack(pady=5)

    def plot(self):
        if self.canvas == None:
            f = Figure(figsize=(8,4), dpi=100)   
            a = f.add_subplot(111)

            for profile in listofProfiles:
                X_list=profile.indexList
                Y_list=profile.VL_List
                # [...] Some lines related to plotting [...]
                a.plot(X_list, Y_list, lw=0.3,)

            self.canvas = FigureCanvasTkAgg(f, self)
            self.canvas.show()
            self.canvas.get_tk_widget().pack(side=tk.TOP, fill=tk.BOTH, expand=True)

            toolbar = NavigationToolbar2TkAgg(self.canvas, self)
            toolbar.update()
            self.canvas._tkcanvas.pack(side=tk.TOP, fill=tk.BOTH, expand=True)

            print("Stuff has been plotted")
        else:
            print("Plot already plotted please clear first")

    def clearPlotPage(self):
        self.canvas.destroy()
        self.canvas = None
        self.plot()
        print("Plot Page has been cleared")

Answer 3

对于仍在处理 AttributeError 的任何人：“FigureCanvasTkAgg”对象没有“destroy”属性。

我通过创建一个“虚拟”容器框架来包装可以被破坏的 FigureCanvas 来解决这个问题，进而破坏 FigureCanvas。