Draw Rainbow using Turtle Graphics in Python

Turtle is an inbuilt module in Python. It provides: 

1. Drawing using a screen (cardboard).
2. Turtle (pen).

To draw something on the screen, we need to move the turtle (pen), and to move the turtle, there are some functions like the forward(), backward(), etc.

Prerequisite: Turtle Programming Basics

Draw Rainbow Using Turtle Graphics

In this section, we will discuss how to draw a Rainbow using two different ways using Turtle Graphics.

Approach:

1. Import Turtle.
2. Set screen
3. Make Turtle Object
4. Define colors used for drawing
5. Loop to draw semi-circles oriented by 180-degree position.

Example 1:

python3

# Import turtle package
import turtle

# Creating a turtle screen object
sc = turtle.Screen()

# Creating a turtle object(pen)
pen = turtle.Turtle()

# Defining a method to form a semicircle
# with a dynamic radius and color
def semi_circle(col, rad, val):

    # Set the fill color of the semicircle
    pen.color(col)

    # Draw a circle
    pen.circle(rad, -180)

    # Move the turtle to air
    pen.up()

    # Move the turtle to a given position
    pen.setpos(val, 0)

    # Move the turtle to the ground
    pen.down()

    pen.right(180)


# Set the colors for drawing
col = ['violet', 'indigo', 'blue',
       'green', 'yellow', 'orange', 'red']

# Setup the screen features
sc.setup(600, 600)

# Set the screen color to black
sc.bgcolor('black')

# Setup the turtle features
pen.right(90)
pen.width(10)
pen.speed(7)

# Loop to draw 7 semicircles
for i in range(7):
    semi_circle(col[i], 10*(
      i + 8), -10*(i + 1))

# Hide the turtle
pen.hideturtle()

Output:

Example 2:

Python3

import turtle

mypen= turtle.Turtle()
mypen.shape('turtle')
mypen.speed(10)

window= turtle.Screen()
window.bgcolor('white')
rainbow= ['red','orange','yellow','green','blue','indigo','violet']
size= 180
mypen.penup()
mypen.goto(0,-180)
for color in rainbow:
    mypen.color(color)
    mypen.fillcolor(color)
    mypen.begin_fill()
    mypen.circle(size)
    mypen.end_fill()
    size-=20

turtle.done()

Output: