Turtle Viewer

Run Python turtle programs directly inside VS Code. No Tkinter window, no popups — every drawing command renders live on an HTML5 canvas in a panel beside your code.

Features

Inline rendering Every forward(), circle(), goto(), and dot() call draws on a real canvas in a VS Code webview. No external window ever opens.

Re-run & speed control Click Re-run to instantly restart the script. Drag the Speed slider from slow step-through all the way to instant playback.

Zoom & pan Scroll to zoom in or out. Drag the canvas to pan. Double-click to reset the view.

Interactive mode onclick, onkey, onkeypress, mainloop, and exitonclick all work. Enable the Interactive checkbox in the toolbar to send mouse clicks and keypresses to your script in real time.

Input dialogs turtle.textinput(), turtle.numinput(), and Python's built-in input() all pop up a VS Code input box and return the result to your script.

Console panel print() output appears in a console panel below the canvas. Input prompts and responses are echoed there too.

Error highlighting Runtime errors appear as an overlay on the canvas with a Go to line button that jumps your cursor to the failing line.

End button If your script gets stuck in an infinite loop, click End to kill it cleanly — no error overlay.

Multiple turtles t1 = turtle.Turtle(); t2 = turtle.Turtle() creates independent turtles, each with its own position, color, pen, and shape.

Quick Start

1. Open any .py file that contains import turtle or from turtle import …
2. A play button appears in the editor toolbar (top-right)
3. Click it — a Turtle Viewer panel opens beside your code and starts drawing

Tip: Use the Speed slider to slow down drawing and watch each step, or keep it at max for instant output.

Requirements

• VS Code 1.85 or newer
• Python 3 available on your PATH (or configured via the Python extension)
• No Python packages needed — the shim is bundled with the extension

Supported API

Examples

Basic drawing

import turtle

turtle.speed(0)
turtle.bgcolor("black")
turtle.pencolor("cyan")

for i in range(36):
    turtle.forward(200)
    turtle.right(170)

turtle.hideturtle()
turtle.done()

Multiple turtles

import turtle

t1 = turtle.Turtle()
t1.color("red")
t1.shape("turtle")

t2 = turtle.Turtle()
t2.color("blue")
t2.shape("circle")
t2.penup()
t2.goto(100, 0)
t2.pendown()

for _ in range(4):
    t1.forward(100)
    t1.left(90)
    t2.forward(100)
    t2.right(90)

turtle.done()

Animation with ontimer

import turtle

screen = turtle.Screen()
t = turtle.Turtle()
t.speed(0)
angle = 0

def step():
    global angle
    t.setheading(angle)
    t.forward(3)
    angle += 7
    screen.ontimer(step, 30)

screen.ontimer(step, 30)
screen.mainloop()

Interactive clicks

import turtle

screen = turtle.Screen()
screen.bgcolor("black")

def draw_dot(x, y):
    t = turtle.Turtle()
    t.hideturtle()
    t.penup()
    t.goto(x, y)
    t.dot(20, "yellow")

screen.onclick(draw_dot)
# Enable "Interactive" in the toolbar, then click the canvas
screen.mainloop()

User input

import turtle

name = input("What is your name? ")
turtle.write(f"Hello, {name}!", font=("Arial", 24, "bold"))
turtle.done()

Known Limitations

• stamp() / clearstamp() are no-ops
• undo() is not implemented
• bgpic() (background image) is not supported
• setworldcoordinates() is not supported
• write(move=True) estimates text width rather than measuring it precisely
• ontimer uses a select-based loop — works on macOS and Linux; on Windows it falls back to blocking (timers still fire, but between events only)