[Tkinter] scrolling text in tkinter

[nilamo]

I tossed this together to give you an example of one way it can be done.  Basically, you find out the current index, and repeatedly increment that until the index points somewhere that isn't currently visible, and then move the widget to display that index.

from tkinter import scrolledtext as st
from tkinter import constants as const

def scroll_textbox(elem):
    # get the current index
    current = float(elem.index(const.CURRENT))
    new = current
    # keep incrementing the index until it's not visible
    while elem.bbox(new):
        new += 1
    # make sure the new index is visible
    elem.see(new)
    # move the index again in 250ms
    elem.after(250, lambda: scroll_textbox(elem))

if __name__ == "__main__":
    # a little setup to demonstrate...
    stext = st.ScrolledText(bg='white', height=10)
    # kick off our callback
    stext.after(1000, lambda: scroll_textbox(stext))
    # shove a large amount of text in there
    stext.insert(const.END, ''' here's a very large block of text.
    
    it just keeps going...
    ''' + ('...and going...\n\n'*100))
    stext.pack(fill=const.BOTH, side=const.LEFT, expand=True)
    stext.focus_set()
    stext.mainloop()