SyncTk/classes/custom/scrollable_frame.py

from tkinter import E, N, NSEW, S, Canvas, Event, ttk

from classes.custom.themed_frame import ThemedFrame

FIT_WIDTH = "fit_width"
FIT_HEIGHT = "fit_height"


class ScrollableFrame(ThemedFrame):
    """
    There is no way to scroll <tkinter.Frame> so we are
    going to create a canvas and place the frame there.
    Scrolling the canvas will give the illusion of scrolling
    the frame
    Partly taken from:
        https://blog.tecladocode.com/tkinter-scrollable-frames/
        https://stackoverflow.com/a/17457843/11106801
    master_frame---------------------------------------------------------
    | dummy_canvas-----------------------------------------  y_scroll--  |
    | | self---------------------------------------------  | |         | |
    | | |                                                | | |         | |
    | | |                                                | | |         | |
    | | |                                                | | |         | |
    | |  ------------------------------------------------  | |         | |
    |  ----------------------------------------------------   ---------  |
    | x_scroll---------------------------------------------              |
    | |                                                    |             |
    |  ----------------------------------------------------              |
     --------------------------------------------------------------------
    """
    def __init__(self, master=None, scroll_speed:int=2, hscroll:bool=False, vscroll:bool=True, scrollbar_kwargs={}, **kwargs):
        assert isinstance(scroll_speed, int), "`scroll_speed` must be an int"
        self.scroll_speed = scroll_speed

        self.master_frame = ThemedFrame(master)
        # self.master_frame["borderwidth"] = 1
        # self.master_frame["relief"] = "solid"
        self.master_frame.grid_rowconfigure(0, weight=1)
        self.master_frame.grid_columnconfigure(0, weight=1)
        self.dummy_canvas = Canvas(self.master_frame, highlightthickness=0, **kwargs)
        super().__init__(self.dummy_canvas)

        # Create the 2 scrollbars
        if vscroll:
            self.v_scrollbar = ttk.Scrollbar(self.master_frame, orient="vertical", command=self.dummy_canvas.yview, **scrollbar_kwargs)
            self.v_scrollbar.grid(row=0, column=1, sticky=N+S+E)
            self.dummy_canvas.configure(yscrollcommand=self.v_scrollbar.set)
        if hscroll:
            self.h_scrollbar = ttk.Scrollbar(self.master_frame, orient="horizontal", command=self.dummy_canvas.xview, **scrollbar_kwargs)
            self.h_scrollbar.grid(row=1, column=0, sticky=NSEW)
            self.dummy_canvas.configure(xscrollcommand=self.h_scrollbar.set)

        # Bind to the mousewheel scrolling
        self.dummy_canvas.bind_all("<MouseWheel>", self.scrolling_windows, add=True)
        self.dummy_canvas.bind_all("<Button-4>", self.scrolling_linux, add=True)
        self.dummy_canvas.bind_all("<Button-5>", self.scrolling_linux, add=True)
        self.bind("<Configure>", self.scrollbar_scrolling, add=True)

        # Place `self` inside `dummy_canvas`
        self.dummy_canvas.create_window((0, 0), window=self, anchor="nw")
        # Place `dummy_canvas` inside `master_frame`
        self.dummy_canvas.grid(row=0, column=0, sticky=NSEW)

        self.pack = self.master_frame.pack
        self.grid = self.master_frame.grid
        self.place = self.master_frame.place
        self.pack_forget = self.master_frame.pack_forget
        self.grid_forget = self.master_frame.grid_forget
        self.place_forget = self.master_frame.place_forget

    def scrolling_windows(self, event:Event) -> None:
        assert event.delta != 0, "On Windows, `event.delta` should never be 0"
        y_steps = int(-event.delta/abs(event.delta)*self.scroll_speed)
        self.dummy_canvas.yview_scroll(y_steps, "units")

    def scrolling_linux(self, event:Event) -> None:
        y_steps = self.scroll_speed
        if event.num == 4:
            y_steps *= -1
        self.dummy_canvas.yview_scroll(y_steps, "units")

    def scrollbar_scrolling(self, event:Event) -> None:
        region = list(self.dummy_canvas.bbox("all"))
        region[2] = max(self.dummy_canvas.winfo_width(), region[2])
        region[3] = max(self.dummy_canvas.winfo_height(), region[3])
        self.dummy_canvas.configure(scrollregion=region)

    def resize(self, fit:str=None, height:int=None, width:int=None) -> None:
        """
        Resizes the frame to fit the widgets inside. You must either
        specify (the `fit`) or (the `height` or/and the `width`) parameter.
        Parameters:
            fit:str       `fit` can be either `FIT_WIDTH` or `FIT_HEIGHT`.
                          `FIT_WIDTH` makes sure that the frame's width can
                           fit all of the widgets. `FIT_HEIGHT` is simmilar
            height:int     specifies the height of the frame in pixels
            width:int      specifies the width of the frame in pixels
        To do:
            ALWAYS_FIT_WIDTH
            ALWAYS_FIT_HEIGHT
        """
        if height is not None:
            self.dummy_canvas.config(height=height)
        if width is not None:
            self.dummy_canvas.config(width=width)
        if fit == FIT_WIDTH:
            super().update()
            self.dummy_canvas.config(width=super().winfo_width())
        elif fit == FIT_HEIGHT:
            super().update()
            self.dummy_canvas.config(height=super().winfo_height())
        else:
            raise ValueError("Unknow value for the `fit` parameter.")
    fit = resize

# import tkinter as tk
# from tkinter import ttk
# from classes.custom.themed_frame import ThemedFrame

# class ScrollableFrame(ThemedFrame):

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

#         super().__init__(container, *args, **kwargs)

#         self.canvas = tk.Canvas(self)
#         scrollbar = ttk.Scrollbar(self, orient="vertical", command=self.canvas.yview)
        
#         self.canvas.bind_all("<MouseWheel>", self._on_mousewheel)

#         self.scrollable_frame = ThemedFrame(self.canvas)

#         self.scrollable_frame.bind(
#             "<Configure>",
#             lambda e: self.canvas.configure(
#                 scrollregion=self.canvas.bbox("all")
#             )
#         )

#         self.canvas.create_window((0, 0), window=self.scrollable_frame, anchor="nw")

#         self.canvas.configure(yscrollcommand=scrollbar.set)

#         self.canvas.pack(side="left", fill="both", expand=True)
#         scrollbar.pack(side="right", fill="y")

#     def _on_mousewheel(self, event):
#         shift = (event.state & 0x1) != 0
#         scroll = -1 if event.delta > 0 else 1
#         if shift:
#             self.canvas.xview_scroll(scroll, "units")
#         else:
#             self.canvas.yview_scroll(scroll, "units")