kanvas 0.1.6

A minimalist creative-coding toolkit for Python (homage to Processing/p5).

kanvas

A minimalist creative-coding toolkit for Python, inspired by Processing and p5.js.

Key Features:

• Simple setup/draw loop similar to Processing
• Built on pygame for cross-platform support
• Lightweight and hackable codebase
• Basic shape primitives (line, rect, circle)
• Educational focus with readable code

Installation

pip install kanvas

Requirements

• Python 3.9 or higher
• pygame 2.0+
• numpy 1.23+

Quick Start

from kanvas import run

def setup(model):
    model.clear(30)  # gray background

def draw(model, frame, dt):
    # Moving white line
    x = (frame // 2) % model.w
    for y in range(model.h):
        model.pixel(x, y, 255, 255, 255)

run(setup, draw, size=(800, 600), title="My First Sketch")

Press ESC to quit or S to save frame as PNG.

Examples

Basic Shapes

from kanvas import run

def draw(model, frame, dt):
    model.clear(0)
    model.line(10, 10, model.w - 10, model.h - 10, 255, 255, 255)  # line
    model.rect(20, 20, 100, 60, 255, 0, 0)  # rectangle
    model.circle(model.w // 2, model.h // 2, 50, 0, 255, 0)  # circle

run(lambda m: None, draw, size=(400, 300))

Animated Examples

Check the examples/ folder for:

• Fractal Tree: Recursive tree with swaying motion
• Orbiting Circle: Circular motion animation
• Sierpinski Triangle: Chaos game fractal generation

from kanvas.core import run
import random

def setup(model):
    model.clear(20)

def draw(model, frame, dt):
    # Define triangle vertices
    a = {'x': int(model.w/2), 'y': 0}
    b = {'x': 0, 'y': model.h - 1}
    c = {'x': model.w - 1, 'y': model.h - 1}
    targets = [a, b, c]
    
    # Starting point
    p = {'x': int(model.w/2), 'y': int(model.h/2)}
    
    # Generate 1000 points
    for i in range(1000):
        target = random.choice(targets)
        p['x'] = (p['x'] + target['x']) // 2
        p['y'] = (p['y'] + target['y']) // 2
        model.pixel(p['x'], p['y'], 255, 255, 255)

run(setup, draw, size=(800, 800), title="Sierpinski Triangle")

Ulam Spiral

Visualize prime numbers in a spiral pattern:

from kanvas.core import run

def is_prime(n):
    if n <= 1:
        return False
    if n % 2 == 0:
        return n == 2
    r = int(n**0.5)
    f = 3
    while f <= r:
        if n % f == 0:
            return False
        f += 2
    return True

def setup(model):
    model.clear(20)
    
    # Spiral generation logic
    directions = [(1,0), (0,-1), (-1,0), (0,1)]  # right, up, left, down
    x, y = model.w // 2, model.h // 2
    
    n = 1
    dir_idx = 0
    steps_in_leg = 1
    steps_taken = 0
    legs_done_at_length = 0
    
    while 0 <= x < model.w and 0 <= y < model.h:
        if is_prime(n):
            model.pixel(x, y, 255, 255, 255)
        
        # Move in spiral
        dx, dy = directions[dir_idx]
        x += dx * 4  # Step size
        y += dy * 4
        
        n += 1
        steps_taken += 1
        
        # Turn logic for spiral pattern
        if steps_taken == steps_in_leg:
            dir_idx = (dir_idx + 1) % 4
            steps_taken = 0
            legs_done_at_length += 1
            if legs_done_at_length == 2:
                steps_in_leg += 1
                legs_done_at_length = 0

def draw(model, frame, dt):
    pass

run(setup, draw, size=(800, 800), title="Ulam Spiral")

API Reference

Core Functions

run(setup_func, draw_func, **kwargs)

Main entry point to start a kanvas sketch.

Parameters:

• setup_func: Function called once at startup, receives model parameter
• draw_func: Function called every frame, receives model, frame, and dt parameters
• size: Tuple of (width, height) for window size (default: (640, 360))
• title: Window title string (default: "kanvas")
• target_fps: Target frames per second (default: 60)

Drawing API

model.pixel(x, y, r, g, b)           # Set pixel color
model.clear(gray)                    # Clear to grayscale 
model.clear(r, g, b)                 # Clear to RGB color
model.line(x0, y0, x1, y1, r, g, b)  # Draw line
model.rect(x, y, w, h, r, g, b, fill=False)      # Draw rectangle
model.circle(cx, cy, radius, r, g, b, fill=False) # Draw circle

Properties: model.w (width), model.h (height)

Loop Control

• noLoop() / loop() - Stop/start animation
• isLooping() - Check if animating

Controls

• ESC: Quit
• S: Save frame as PNG

Philosophy

kanvas is designed for learning by doing. The codebase is simple and readable, perfect for understanding how creative coding frameworks work. Ideal for education, prototyping, and creative exploration.

Source Code

Visit the project on GitHub: https://github.com/robinoscarsson/kanvas

License

MIT License - see the GitHub repository for full details.

Acknowledgments

• Inspired by Processing and p5.js
• Built with pygame
• Created for educational purposes and creative exploration