Introduction to Python Turtle Graphics

Importing the Turtle Library

• To use turtle, you need to import it using the following code:
  • from turtle import *
  • import turtle

Creating a Turtle and Window

• You can create a window for drawing and a turtle using the following code:
  • wn = turtle.Screen()
  • wn.bgcolor("light green")
  • wn.title("Turtle")
  • skk = turtle.Turtle()

Moving the Turtle

• To move the turtle forward by a specified amount, use the following code:
  • skk.forward(100)
  • This will move the turtle 100 pixels forward in the direction it is facing.

Completing the Program

• After drawing, end the program with the done() function:
  • turtle.done()
  • This keeps the window open until you close it manually.

Example Shapes

• Square:

  • for i in range(4):
    • skk.forward(50)
    • skk.right(90)

• Star:

  • star.right(75)
  • star.forward(100)
  • for i in range(4):
    • star.right(144)
    • star.forward(100)

• Hexagon:

  • num_sides = 6
  • side_length = 70
  • angle = 360.0 / num_sides
    • for i in range(num_sides):
      • polygon.forward(side_length)
      • polygon.right(angle)

• Parallelogram:

  • for i in range(2):
    • t.forward(100)
    • t.left(60)
    • t.forward(50)
    • t.left(120)

• Circle:

  • pen.fillcolor("red")
  • pen.begin_fill()
  • pen.circle(100)
  • pen.end_fill()

Turtle Methods

• Turtle() : Creates a new turtle object.
• forward(): Moves the turtle forward by a specified amount.
• backward(): Moves the turtle backward by a specified amount.
• right(): Turns the turtle clockwise by a specified angle.
• left(): Turns the turtle counterclockwise by a specified angle.
• penup(): Lifts the turtle's pen, so it doesn't draw when moving.
• pendown(): Puts down the turtle's pen, so it draws when moving.
• up(): Lifts the turtle's pen.
• down(): Puts down the turtle's pen.
• color(): Changes the color of the turtle's pen.
• fillcolor(): Changes the fill color for drawing polygons.
• heading(): Returns the current heading (angle) of the turtle.
• position(): Returns the current position of the turtle (x, y coordinates).
• goto(): Moves the turtle to a specified position (x, y coordinates).
• begin_fill(): Marks the starting point of a filled polygon.
• end_fill(): Closes the polygon and fills it with the current fill color.
• dot(): Draws a dot at the current position.
• stamp(): Leaves a turtle shape impression at the current location.
• shape(): Changes the shape of the turtle. Options: 'arrow', 'classic', 'turtle', 'circle'.

Turtle Programming Roadmap

• 1. Import the turtle module: import turtle
• 2. Create a turtle to control: skk = turtle.Turtle()
• 3. Draw using turtle methods: Use methods like forward(), right(), left(), etc.
• 4. Run turtle.done(): turtle.done()

Turtle Programs

• Spiral Square Outside In and Inside Out:

  • The program draws squares with increasing size, creating a spiral effect.
  • for i in range(4):
    • skk.fd(size)
    • skk.left(90)
    • size = size + 5

• User Input Pattern:

  • The user enters the number of sides of a shape.
  • The program draws multiple shapes with random colors and positions.
  • It uses functions like input(), random.random(), and time.sleep().

• Spiral Helix Pattern:

  • This program draws a spiral helix.
  • It uses the turtle.circle() function to create circles with increasing size and turtle.left() for changing the angle.
  • for i in range(100):
    • turtle.circle(5*i)
    • turtle.circle(-5*i)
    • turtle.left(i)