Tkinter Scrollable canvas create additional scroll area on top

Question

I'm quite new to Tkinter on python3, and trying to make a scrollable frame on top of a canvas. I'm able to create it for default windows size, with no problem. But when the windows maximized, the canvas suddenly add extra scrollable area on top and I have been looking for way to remove it / keep my scrollable frame on top.

import tkinter as tk


class MainWindow(tk.Tk):

    def __init__(self, *args, **kwargs):
        super().__init__()
        self.geometry("1500x800")
        self.configure(background="#303030")


class Table(tk.Frame):

    def __init__(self, master, rows=2, columns=2):

        tk.Frame.__init__(self, master, background="#36363d")

        # Set table as list of rows
        self.table = []
        for row in range(rows):

            # Create list to store cell info in a rows
            current_row = []
            for column in range(columns):

                label = tk.Label(self, text="", borderwidth=0, width=columns, bg="#474756", )
                label.grid(row=row, column=column, sticky="nsew", padx=1, pady=1, )

                # Append cell (column) into rows
                current_row.append(label)

            # Append rows into whole table
            self.table.append(current_row)

        for column in range(columns):
            self.grid_columnconfigure(column, weight=1)


class ScrollablePage(tk.Frame):

    def __init__(self, master, *args, **kw):
        super().__init__(master)

        self.canvas = tk.Canvas(self, borderwidth=0, highlightthickness=0, bg="red")    # THIS TO EMPHASIZE THE CANVAS,

        self.frame = tk.Frame(self.canvas, *args, **kw)
        self.vsb = tk.Scrollbar(self, orient="vertical", command=self.canvas.yview)
        self.canvas.configure(yscrollcommand=self.vsb.set)

        self.vsb.pack(side="right", fill="y")
        self.canvas.pack(side="left", fill="both", expand=True)
        self.canvas_frame = self.canvas.create_window((0, 0), window=self.frame, anchor="nw", tags="self.frame")

        # Dynamic frame setup
        self.frame.bind("<Configure>", self.frame_conf)
        self.canvas.bind("<Configure>", self.frame_width)

        # Bind canvas to mousewheel
        self.canvas.bind("<Enter>", self.bound_to_mousewheel)
        self.canvas.bind("<Leave>", self.unbound_to_mousewheel)

    def frame_conf(self, event):
        """
        Reset the scroll region to encompass the inner frame
        """

        self.canvas.configure(scrollregion=self.canvas.bbox("all"))

    def frame_width(self, event):
        """
        Function to adjust canvas's frame upon expand (can't use pack)
        """

        self.canvas.itemconfig(self.canvas_frame, width=event.width)

    def mouse_wheel(self, event):
        """
        Capture mouse wheel changes to scroll page
        """
        self.canvas.yview_scroll(-1 * int(event.delta / 60), "units")

    def bound_to_mousewheel(self, event):
        self.canvas.bind_all("<MouseWheel>", self.mouse_wheel)

    def unbound_to_mousewheel(self, event):
        self.canvas.unbind_all("<MouseWheel>")


class PageTwo(ScrollablePage):

    def __init__(self, master):

        # Create page
        super().__init__(master, bg="#36363d")

        # EXAMPLE CONTENT
        controller = tk.Frame(self.frame, bg="#474756", width=0.9 * 1500, height=200, bd=0,)
        controller.pack(side="top", fill="x", padx=20, pady=10)

        self.table = Table(self.frame, rows=20, columns=10)
        self.table.pack(side="top", fill="both", padx=20, expand=1)


class MainContent(tk.Frame):

    # Setup main content's stacked-frame
    frames = {}

    # main_content_classes = [PageOne, PageTwo, PageThree, PageFour, PageFive, PageSix, PageDefault]  # << ORIGINAL ONE
    main_content_classes = [PageTwo]

    def __init__(self, master):

        # Create main content's frame
        super().__init__(master)

        # Place main content's frame in main window
        self.place(x=150, y=130, relwidth=0.9, relheight=0.83)

        # Create grid inside main content frame
        self.grid_rowconfigure(0, weight=1)
        self.grid_columnconfigure(0, weight=1)

        # Stacking pages in main content
        for FrameClass in MainContent.main_content_classes:
            page_name = FrameClass.__name__
            frame = FrameClass(self)
            frame.grid(row=0, column=0, sticky="nsew")
            MainContent.frames[page_name] = frame


class Datalab:

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

        main_window = MainWindow()
        MainContent(main_window)
        main_window.mainloop()

if __name__ == "__main__":
    app = Datalab()

I Include some link to image (can't post directly) to illustrate

• default window size - scrollable canvas on top

• maximized window - canvas created additional scroll area on bottom (marked red : canvas)

• maximized window - canvas created additional scroll area on top (marked red : canvas)

Thanks in advance

Answer 1

I faced the same problem and found that vsb.get() method returns tuple (0.0, 1.0) when everything is shown in the window (maximized, or not many items within scroll area). Don't know how dirty this solution is, but this worked for me.

Mousewheel should take effect only when scrollbar is scrollable:

def mouse_wheel(self, event):
    """
    Capture mouse wheel changes to scroll page
    """
    if self.vsb.get() != (0.0, 1.0):
        self.canvas.yview_scroll(-1 * int(event.delta / 60), "units")