pygame Drawing on the screen Drawing with the draw module

Example

Pygame has a module, pygame.draw, that contains functions which can draw shapes directly to a Surface.

Function	Description
pygame.draw.rect	draw a rectangle shape
pygame.draw.polygon	draw a shape with any number of sides
pygame.draw.circle	draw a circle around a point
pygame.draw.ellipse	draw a round shape inside a rectangle
pygame.draw.arc	draw a partial section of an ellipse
pygame.draw.line	draw a straight line segment
pygame.draw.lines	draw multiple contiguous line segments
pygame.draw.aaline	draw fine antialiased lines
pygame.draw.aalines	draw a connected sequence of antialiased lines

How to use the module

To use the module you first need to import and initialize pygame correctly and set a mode for the display. It's convenient to define color constants in advance, making your code more readable and more beautiful. All functions takes a Surface to draw on, a color and a position argument that's either a pygame Rect or a 2-element integer/float sequence (the pygame.draw.circle will only take integers because of undefined reasons).

Example

The code below will showcase all the different functions, how they are used and how they look. We'll initialize pygame and define some constants before the examples.

import pygame
from math import pi
pygame.init()

screen = pygame.display.set_mode((100, 100))
WHITE = pygame.Color(255, 255, 255)
RED = pygame.Color(255, 0, 0) 

The black color is the Surface default color and represents the part of the Surface that hasn't been drawn onto. The parameters of each function is explained down below at Parameters .

Rect

size = (50, 50)

rect_border = pygame.Surface(size)  # Create a Surface to draw on.
pygame.draw.rect(rect_border, RED, rect_border.get_rect(), 10)  # Draw on it.

rect_filled = pygame.Surface(size)
pygame.draw.rect(rect_filled, RED, rect_filled.get_rect())   

Polygon

size = (50, 50)
points = [(25, 0), (50, 25), (25, 50), (0, 25)]  # The corner points of the polygon.

polygon = pygame.Surface(size)
pygame.draw.polygon(polygon, RED, points, 10)

polygon_filled = pygame.Surface(size)
pygame.draw.polygon(polygon_filled, RED, points)

Circle

size = (50, 50)
radius = 25

circle = pygame.Surface(size)
pygame.draw.circle(circle, RED, (radius, radius), radius, 10)  # Position is the center of the circle.

circle_filled = pygame.Surface(size)
pygame.draw.circle(circle_filled, RED, (radius, radius), radius)

The holes is a unfortunate consequence of pygame's drawing algorithm.

Ellipse

size = (50, 25)  # Minimize it's height so it doesn't look like a circle.

ellipse = pygame.Surface(size)  
pygame.draw.ellipse(ellipse, RED, ellipse.get_rect(), 5)

ellipse_filled = pygame.Surface(size)
pygame.draw.ellipse(ellipse_filled, RED, ellipse.get_rect())

The holes is a unfortunate consequence of pygame's drawing algorithm.

Arc

size = (50, 50)

arc = pygame.Surface(size)
pygame.draw.arc(arc, RED, arc.get_rect(), 0, pi)  # 0 to pi is 180° creating a half circle.

Line

size = (50, 50)

line = pygame.Surface(size)
pygame.draw.line(line, RED, (0, 0), (50, 50))  # Start at topleft and ends at bottomright.

Lines

size = (50, 50)
points = [(25, 0), (50, 25), (25, 50), (0, 25)]

lines = pygame.Surface(size)
pygame.draw.lines(lines, RED, False, points)

lines_closed = pygame.Surface(size)
pygame.draw.lines(lines_closed, RED, True, points)

Antialiased line

size = (50, 50)

antialiased_line = pygame.Surface(size)
pygame.draw.aaline(antialiased_line, RED, (0, 0), (50, 50))

Antialiased lines

size = (50, 50)
points = [(25, 0), (50, 25), (25, 50), (0, 25)]

antialiased_lines = pygame.Surface(size)
pygame.draw.aalines(antialiased_lines, RED, False, points)

antialiased_lines_closed = pygame.Surface(size)
pygame.draw.aalines(antialiased_lines_closed, RED, True, points)

Try it out

To try it out for yourself: copy one of the code snippets above and the code below in an empty file, change the name image to the name of the Surface you want to blit and experiment.

import pygame
from math import pi
pygame.init()

screen = pygame.display.set_mode((100, 100))
WHITE = pygame.Color(255, 255, 255)
RED = pygame.Color(255, 0, 0) 

# But code snippet here

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            quit()
    
    screen.blit(image, (25, 25))
    pygame.display.update()