name	description	author	image
Rangoli	Rangoli with python turtle!	Sid672	https://github.com/Sid672/Rangoli/blob/main/rangoli.PNG?raw=true

Rangoli

Hey!, Have you heard of Rangoli?

If yes, great!. If no, don't worry I am here for you.

Rangoli is an art form, originating in the Indian subcontinent, in which patterns are created on the floor or the ground using materials such as colored rice, colored sand, quartz powder, flower petals, and colored rocks. And today we are going to create this beautiful pattern in just a few clicks.

Demo Link

Let's start

Let me introduce " repl. it " to you, its an online platform that runs code in all languages. It's a friendly platform to test code.
Now, create a new python project on repl.it.

• Follow steps in the demo video to create your own repl.

Functions

• Before any project, everyone needs some knowledge. But that doesn't mean you have to remember all the keywords. All you need is an understanding about the needful functions.
• The functions that we use in this program are given below. Lets go through them once:

Method	Parameter	Description
turtle()	None	Creates and returns a new turtle object
right()	value of angle is degree	Turns the turtle clockwise
left()	value of angle is degree	Turns the turtle counter clockwise
forward()	distance – a number (integer or float)	Moves the turtle forward by the specified amount
pencolor()	Color name	Changes the color of the turtle’s pen
fillcolor()	Color name	Changes the color of the turtle will use to fill a polygon
goto()	x, y	Move the turtle to position x,y
up()	None	Picks up the turtle’s Pen
down()	None	Puts down the turtle’s Pen
bgpic()	image name	Changes the background
stamp()	None	Leaves an impression of a turtle shape at the current location
shape()	shapename	Should be ‘arrow’, ‘classic’, ‘turtle’ or ‘circle’
setup()	width, height	Sets screen size
speed()	value in integer	Increases turtle speed. fastest: 0, fast: 10, normal: 6, slow: 3, slowest: 1
done()	None	This function is used to starts event loop – calling Tkinter’s main loop function

Steps:

The program is divided into four parts:  

• Background
• Outer pattern
• Inner pattern
• Combination: outer + inner patterns

Background

Python turtle library

• Python turtle library is a popular way to introduce programming to young minds. One can create shapes, patterns, learn about functions, loops, variables and a lot more while programming.

Programming is the building block for all coders. Like while drawing we need paper, pen and colors. In the python turtle, screen becomes your paper, turtle your pen and colors are all in the pen.

• To import python turtle library write import turtle.
• To set up a screen(paper) we need a variable s = turtle.Screen(). By this variable, we can set background colors, add images on the screen and change the size of the screen. In the same way a variable for pen t = turtle.Turtle() is used to draw.
• turtle. done() is used to pause the screen after the execution of code. Otherwise, one can't see the pattern after execution.
• One can start with this simple code and run it to get warmed up with the programming environment of python turtle.

import turtle
s = turtle.Screen()
t = turtle.Turtle()
turtle.done()

• The programming environment for python turtle looks like this:

• Now it's time to choose a background image either from your system or from online sources after download. Upload this image on your repl.

• Link of the image used in the project : link

• To upload an image click on the last option of Files which is above main.py and then choose 'Upload file'.

• After uploading image, setup screen size s.setup(width, height).

• To set background s.bgpic("imagename.png/jpg") is used.

• Since the pattern is large, we need to move the turtle as fast as possible.

• To do this we use t.speed(0), 0 implies fastest speed.

s.setup(626, 313)
s.bgpic("back.jpg")
t.speed(0)

Add these lines before turtle. done() then run it to get your background.

Outer Pattern

Let's draw

• Tip: Before drawing anything on python turtle, you should draw it on paper.

These are my rough creations of Rangoli. Well don't worry if it doesn't turn out to look beautiful, it's ok. This is a rough figure, basically used for calculations of length (in pixels) and angles (in degrees).

• We can design outer patterns in a lot of variations. In this project we are using only one variation, you can try other variations also.

• Other variations look like.

• Now focusing back on the project design with a simple code change we can achieve other variations too.

• Since all patterns are colorful, we would need some colors.

• Original color of the pen is black. We can change the color by using a list.

• List is like a container in which colors are stored. col = ["red","orange","yellow","green","blue","purple"]. We also need a varible to access the colors j = 0. 

Example- col[j] = red, when j = 0
col[j] = orange, when j = 1

• By changing the value of j, we can change the color of the pen.
• We can initialize the color of the pen using t.pencolor("purple").

#Colours :
col = ["red","orange","yellow","green","blue","purple"]
j = 0
t.pencolor("purple")

• It would not be a good idea to draw an outer pattern from the center because that could make the outer and inner pattern intersect.
• To manage it use t.up().This moves the pen on the paper. Otherwise, if we change coordinates from (0, 0)(initial coordinates) to (x, y)(new position) the pen will trace the path between two points.
• So, set coordinates using t.goto(x, y) and put pen down  by t.down().
• To get the coordinate we need to run the code two to three times after both patterns codes are completed.

t.up()
t.goto(80, -100)
t.down()

Terms we need to understand before drawing:

• Pixel is the smallest measurable unit on screen.
• Nested loop
  • loop inside loop.

Outer loop:
   Inner loop:
     #body

• You can see that the same pattern is being repeated. If count, you would find that the pattern is repeated 36 times. So we need a variable n = 36.
• According to the rough diagram we require to turn the turtle upward t.right(270) then move it 25 pixels t.forward(25).

n = 36                                          
t.right(270)
t.forward(25)

• Next we use loops, the main loop will repeat 36 times because n = 36.
• We fill color in turtle(pen) by t.fillcolor(col[j]) and change its shape from arrow --> circle   after that we print pen shape on paper t.stamp().
• Nested loop repeat int((3 * n) / 4) = 21 times.
• Then t.forward(0.8)means pen will move 0.8 pixel , t.left(360/ n) turn left 10 degrees because 360/ n = 10 degrees.
• To join the circle and arrow, we require forward(25) and change its shape circle --> arrow to print it again.
• We then repeat the next loop in right direction to create a circular path.
• To change the color of the pen use t.pencolor(color name).
• But remember our color container col = ["red","orange","yellow","green","blue","purple"] contains only 6 colors numbered from (col[j = 0] = red,.... col[j = 5] = purple).
• Therefore, j can't be greater than and equal to 6.
• To maintain j we can use condition if (j >= 6 ): j = 0.

#main loop
for i in range(n):
   t.fillcolor(col[j])
   t.shape('circle')
   t.stamp()
   
   #nested loop
   for i in range(int((3 * n) / 4)):
       t.forward(0.8)
       t.left(360/ n)
   
   #line to join partterns 
   t.forward(25)
   t.shape('arrow')
   t.stamp()
   
   for i in range(int((3 * n) / 4)):
        t.forward(0.8)
        t.right(360/ n)
        
   #line to join patterns     
   t.left(10)
   t.forward(25)
   
   #colour change of pen
   t.pencolor(col[j])
   j = j + 1
   if (j >= 6 ):
      j = 0

Inner pattern

• It is better to draw the inner patterns separately so that we can try different combinations with outer patterns.
• First, we set coordinates of the inner pattern since the outer pattern coordinates are not (0, 0).
• Now correcting the coordinates, we again use t.up(), t.goto(0, 0) and t.down().

t.up()
t.goto(0, 0)
t.down()

• Now we change the shape of the pen by t.shape('arrow').
• It's time to decide the shape of the inner pattern, for this we can use a triangle, a square, a rectangle, or any other (n - sided) polygon.
• For this project, we are using a 10 sided polygon.
• We use a loop to draw a polygon for i in range(n): then repeat the same polygon in a circular path for i in range(m):.
• To draw a polygon we move t.forward(24), then turn t.right(360.0/ n).
• Since we need some colors again, so we set t.pencolor("blue").
• To make the pattern more beautiful we fill colors in the pen and then print(t.stamp()) the shape of the pen at the edges.
• We need to turn the pen to draw the same polygon at different angles. In this way a circular path can be achieved.

#for 10 sided polygon
n = 10

#to move in circular path
m = 10

for i in range(m):
   for i in range (n):
       t.forward(24)
       t.right(360.0/(n))
       t.pencolor("blue")
       t.fillcolor("blue")
       t.stamp()
   t.right(360.0/n)

• Similarly, we can draw two more designs with t.pencolor("green") and t.pencolor("red").

for i in range (m):

  for i in range(n):
       t.pencolor("green")
       t.fillcolor("green")
       t.forward(26)
       t.left(360.0/(n))
       t.stamp()
  
  t.left(360.0/n)


for i in range(m):

   for i in range(n):
       t.pencolor("red")
       t.fillcolor("red")
       t.forward(28)
       t.right(360.0/(n))
       t.stamp()
   
   t.right(360.0/n)

• Now we combine all designs.

Your final design looks like

• If you need an outline in the inner the design, we use the same polygon loop but this time without printing the pen's shape.
• To make the design more interesting we use a different shapes of the pen t.shape('turtle').

t.shape('turtle')
for i in range(m): 

  for i in range(n):
    t.pencolor("black")
    t.forward(30)
    t.right(360.0/(n))
    
  t.right(360.0/n)

Combination

• For combination we need to write both codes together.

Your code looks like this:

import turtle

#background
s = turtle.Screen()
t = turtle.Turtle()
s.setup(626, 313)
s.bgpic("back.jpg")
t.speed(0)

#colour
col = ["red","orange","yellow","green","blue","purple"]
j = 0
t.pencolor("purple")

#coordinates
t.up()
t.goto(80, -100)
t.down()

#outer pattern:
n = 36
t.right(270)
t.forward(25)
for i in range(n):
   t.fillcolor(col[j])
   t.shape('circle')
   t.stamp()
   for i in range(int((3 * n) / 4)):
       t.forward(0.8)
       t.left(360 / n)
   t.forward(25)
   t.shape('arrow')
   t.stamp()
   for i in range(int((3 * n) / 4)):
        t.forward(0.8)
        t.right(360/ n)
   t.left(10)
   t.forward(25)
   t.pencolor(col[j])
   j = j + 1
   if (j >= 6 ):
      j = 0

#inner pattern:
t.up()
t.goto(0, 0)
t.down()
t.shape('arrow')
n = 10
m = 10

#blue design:
for i in range(m):
   for i in range (n):
       t.forward(24)
       t.right(360.0/(n))
       t.pencolor("blue")
       t.fillcolor("blue")
       t.stamp()
   t.right(360.0/n)
   
#green design:
for i in range (m):
  for i in range(n):
       t.pencolor("green")
       t.fillcolor("green")
       t.forward(26)
       t.left(360.0/(n))
       t.stamp()
  t.left(360.0/n)
  
#red design:
for i in range(m):
   for i in range(n):
       t.pencolor("red")
       t.fillcolor("red")
       t.forward(28)
       t.right(360.0/(n))
       t.stamp()
   t.right(360.0/n)

#outline:
t.shape('turtle')
for i in range(m): 
  for i in range(n):
    t.pencolor("black")
    t.forward(30)
    t.right(360.0/(n))
  t.right(360.0/n)

turtle.done()

Great work!

Links of all demos

Rangoli

Code Link

Variations of  outer pattern

Code Link

Variations of the inner pattern

Code Link

Happy Hacking:

Hey, now it's your turn to make your own Rangoli. Share your designs on Link. I would love to see your creations. Keep enjoying and keep hacking!