Chapter 13: "Drawing with Code"

At the next meeting, Professor Bit met Alice with a mysterious smile.

— Today we'll be doing art, — he announced, pointing to a large monitor in the center of the room.

— Art? — Alice was surprised. — But aren't we studying programming?

— Programming and art are quite compatible, — the Professor replied. — Today we'll draw with code!

Byte joyfully jumped and displayed a colorful pattern of geometric shapes on his screen.

— For creating graphics with code, we'll use the Turtle library, — the Professor explained. — It's a simple but powerful drawing tool.

He paused for a moment and quietly read:

В рисунке — отпечатки эволюций,
В строке — звучанье древней глубины.
Витиеватость творческих конструкций
Приносит в код дыханье новизны.

И так плетёт фракталы мирозданье,
Ведя беззвучный, вечный диалог.
Творя, пока не кончится дыханье,
Мы в вечности проводим рода ток.

Любой куплет однажды спетой песни
Спет голосами тех, кто был до нас.
Их делая полней и интересней,
Мы сохраняем их для новых рас.

The Professor typed the first lines of code:

python
import turtle
Create canvas and brush

canvas = turtle.Screen()
canvas.bgcolor("white")  # White background
brush = turtle.Turtle()
brush.shape("turtle")   # Turtle shape
brush.color("blue")     # Blue color
brush.pensize(2)        # Line thickness
Draw a square

for _ in range(4):
    brush.forward(100)  # Move forward 100 steps
    brush.right(90)     # Turn right 90 degrees
canvas.exitonclick()     # Close window on click

A window with a white background appeared on the screen, on which a blue turtle drew a square.

— Wow! — Alice exclaimed. — The turtle really drew a square!

— The Turtle library works on the principle of "turtle graphics," — the Professor explained. — You control a "turtle" that leaves a trail when it moves. It's like if you were drawing with a pencil on paper.

— What does the underscore in for _ in range(4) mean? — Alice asked.

— Good question! — the Professor nodded. — The underscore (_) is used when we don't care about the loop variable. We just want to repeat the action 4 times, and we don't need to know the current iteration number.

— Let's draw something more complex! — Alice suggested.

— Of course! How about a colorful spiral? — The Professor wrote new code:

python
import turtle
import random
canvas = turtle.Screen()
canvas.bgcolor("black")  # Black background
brush = turtle.Turtle()
brush.speed(0)          # Maximum speed
List of colors for the spiral

colors = ["red", "orange", "yellow", "green", "blue", "purple"]
Draw spiral

for i in range(360):
    brush.color(random.choice(colors))  # Random color
    brush.forward(i * 0.01 + 1)          # Increase step
    brush.right(10)                      # Turn 10 degrees
canvas.exitonclick()

A colorful spiral shimmering with all the colors of the rainbow appeared on the black background.

— This is incredibly beautiful! — Alice admired. — What does brush.speed(0) mean?

— This sets the maximum movement speed of the turtle, — the Professor explained. — Values can be from 1 (slowest) to 10 (fast). A value of 0 means the movement animation is disabled, and the turtle draws instantly.

— Can we draw something that looks more like a real drawing? — Alice asked.

— Yes, you can create quite complex drawings, — the Professor nodded. — Let's draw a flower:

python
import turtle
import math
canvas = turtle.Screen()
canvas.bgcolor("skyblue")
brush = turtle.Turtle()
brush.speed(0)
Draw stem

brush.color("green")
brush.pensize(5)
brush.penup()
brush.goto(0, -200)
brush.pendown()
brush.left(90)
brush.forward(200)
Draw flower center

brush.color("brown")
brush.penup()
brush.goto(0, 0)
brush.pendown()
brush.begin_fill()
brush.circle(20)
brush.end_fill()
Draw petals

brush.color("pink")
for i in range(12):
    brush.penup()
    brush.goto(0, 0)
    brush.pendown()
    brush.setheading(i  30)  # Turn 30  i degrees
    # Draw petal
    brush.begin_fill()
    for j in range(60):
        brush.forward(2)
        brush.left(3)
    brush.end_fill()
Hide turtle and finish

brush.hideturtle()
canvas.exitonclick()

A flower with pink petals, a brown center, and a green stem appeared on the sky blue background.

— This is beautiful! — Alice exclaimed. — But the code became much more complex.

— Yes, here we used several new commands, — the Professor agreed. — For example:

goto(x, y) moves the turtle to the specified coordinates

penup() and pendown() allow lifting and lowering the "pen" to move without drawing

beginfill() and endfill() fill the area inside the drawn contour with color

setheading() sets the turtle's direction

hideturtle() hides the turtle so it doesn't spoil the drawing

Logic, observing the process, added:
— In programming graphics, we often use mathematics. Coordinates, angles, distances — all of these are mathematical concepts.

— Can we create animations? — Alice asked.

— Of course! — the Professor replied. — Let's create a simple animation of a moving sun:

python
import turtle
import time
canvas = turtle.Screen()
canvas.bgcolor("lightblue")
canvas.setup(600, 400)  # Window size
Create sun

sun = turtle.Turtle()
sun.shape("circle")
sun.color("yellow")
sun.penup()
sun.goto(-300, 0)  # Initial position on the left
Create ground

ground = turtle.Turtle()
ground.penup()
ground.goto(-300, -100)
ground.pendown()
ground.color("green")
ground.pensize(3)
ground.forward(600)  # Ground line
ground.hideturtle()
Sunrise and sunset animation

for x in range(-300, 301, 5):
    y = 100  (1 - ((x / 150) * 2))  # Parabola for trajectory
    sun.goto(x, y)
    time.sleep(0.05)  # Pause to create animation
canvas.exitonclick()

An animation appeared on the screen: a yellow sun slowly rose above the green horizon line, then set.

— This is already a real animation! — Alice admired. — We use a loop so the sun moves along a parabola from the left edge to the right.

— Another interesting application of programming in graphics is fractals, — said the Professor. — Fractals are geometric shapes that repeat their structure at different scales.

— Sounds complicated, — Alice frowned.

— Actually, they're quite simple to create using recursive functions, — the Professor smiled. — Look:

python
import turtle
canvas = turtle.Screen()
canvas.bgcolor("black")
brush = turtle.Turtle()
brush.color("green")
brush.speed(0)
Recursive function for drawing a branch

def draw_branch(turtle, length, level):
    if level == 0:
        return
    turtle.forward(length)
    turtle.right(30)
    draw_branch(turtle, length * 0.7, level - 1)
    turtle.left(60)
    draw_branch(turtle, length * 0.7, level - 1)
    turtle.right(30)
    turtle.backward(length)
Set initial position

brush.penup()
brush.goto(0, -200)
brush.left(90)
brush.pendown()
Draw fractal tree

draw_branch(brush, 100, 6)
brush.hideturtle()
canvas.exitonclick()

An elegant fractal tree with many branches appeared on the screen.

— This is amazing! — Alice exclaimed. — How does it work?

— The draw_branch function calls itself, creating smaller branches at the end of each branch, — the Professor explained. — The level parameter determines how many times this branching will occur. When level reaches zero, the recursion stops.

— Nature also has many fractals, — Logic noticed. — Trees, snowflakes, fern leaves, blood vessel systems — all have fractal structure.

— Computer graphics is a vast field, — the Professor summarized. — From simple geometric shapes to complex 3D models and animations. And all of this is created with code!

— Now I understand that programming isn't only solving problems and processing data, but also creativity, — said Alice. — It's like magic: write a few lines of code, and a beautiful drawing appears!