turtle.ondrag() function in Python

20 Sep turtle.ondrag() function in Python

Posted at 11:02h in Python Turtle by Studyopedia Editorial Staff 0 Comments

The turtle.ondrag() function binds a function to a mouse-move event on the turtle while a button is held down. This lets you drag the turtle around the screen.

Syntax: turtle.ondrag(fun, btn=1, add=None)
Parameters: fun – a function with two arguments (x, y coordinates); btn – mouse button number.

Let us see an example to implement the turtle.ondrag() function in Python:

Demo36.py

# turtle.ondrag() function in Python
# Code by Studyopedia

import turtle

window = turtle.Screen()
t = turtle.Turtle()

def drag_handler(x, y):
    t.ondrag(None)  # Disable drag during processing
    t.goto(x, y)
    t.ondrag(drag_handler)  # Re-enable drag

t.ondrag(drag_handler)  # Bind drag event

window.mainloop()

The following is the output:

turtle.ondrag() function in Python

In the above code, we followed the below steps:

Import module: import turtle loads the turtle graphics library.
Create screen: window = turtle.Screen() opens the drawing window.
Create turtle: t = turtle.Turtle() creates the turtle you’ll control.
Define drag handler: def drag_handler(x, y): processes drag events.
- Temporarily disable drag: t.ondrag(None) prevents recursive re-entry while moving the turtle.
- Move turtle: t.goto(x, y) moves to the current mouse position (draws if the pen is down).
- Re-enable drag: t.ondrag(drag_handler) restores the handler so dragging continues smoothly.
Bind drag event: t.ondrag(drag_handler) triggers the handler while you drag the turtle with the mouse held down.
Run event loop: window.mainloop() keeps the window open and responsive to drag events.