How to have text next to an arrow in tkinter

Question

I am trying to draw an arrow in python's tkinter package which has text written along the arrow. How does one do this? I haven't found a method online

Answer 1

Here is an example by using a Canvas

import numpy as np
from tkinter import *


# Calculation from https://stackoverflow.com/questions/2827393/angles-between-two-n-dimensional-vectors-in-python
def calc_angle(x1, y1, x2, y2):
    p0 = [x1, y1]
    p1 = [x2, y2]
    p2 = [0, y2]

    ''' 
    compute angle (in degrees) for p0p1p2 corner
    Inputs:
        p0,p1,p2 - points in the form of [x,y]
    '''

    v0 = np.array(p0) - np.array(p1)
    v1 = np.array(p2) - np.array(p1)

    angle = np.math.atan2(np.linalg.det([v0, v1]), np.dot(v0, v1))
    return round(np.degrees(angle), 2)


def create_line_with_text(x1, y1, x2, y2, text):
    # line creation
    canvas.create_line(x1, y1, x2, y2, arrow=LAST)

    # angle calculation of given pos
    angle = calc_angle(x1, y1, x2, y2)

    # text rotation if arrow form right to left
    if x1 > x2:
        angle += 180

    # creates text
    canvas.create_text(x2, y2, anchor=S, angle=angle, text=text)

root = Tk()
root.geometry("800x600")

canvas = Canvas(root, bg="white", height=800, width=600) # Creating a Canvas to draw on
canvas.pack(fill=BOTH)
#                    ( x1,  y1,  x2,  y2)
create_line_with_text(200, 100, 500, 400, "MyText")
create_line_with_text(100, 200, 300, 500, "MyText2")
create_line_with_text(400, 200, 100, 300, "MyText3")

# Manual Line and Text Creation
# canvas.create_line(200, 100, 500, 400, arrow=LAST) # Draws a Line with an Arrow at the End
# - the angle of the text should be calculated out of the x's and y's of the line
# canvas.create_text(340, 190, anchor=NW, angle=-44.99, text="My Text") # Creates Text
root.mainloop()

Then the output looks like this:

Note: The create_line has no in-build text parameter. So you need to work with create_text.