pygame draw transparent rectangle

You can draw a transparent rectangle in pygame by using the set_alpha() method of the Surface class. Here's an example:

import pygame

# Initialize pygame
pygame.init()

# Set the width and height of the screen
width, height = 800, 600
screen = pygame.display.set_mode((width, height))

# Set the transparency value
alpha = 128

# Create a surface with the desired dimensions and transparency
rect_surface = pygame.Surface((200, 100), pygame.SRCALPHA)

# Set the transparency value for the surface
rect_surface.set_alpha(alpha)

# Draw a rectangle on the surface
rect_color = (255, 0, 0)  # Red color
rect_position = (300, 200)  # Position of the rectangle
rect_size = (200, 100)  # Size of the rectangle
pygame.draw.rect(rect_surface, rect_color, (0, 0, *rect_size))

# Blit the surface onto the screen
screen.blit(rect_surface, rect_position)

# Update the screen
pygame.display.flip()

# Event loop
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

# Quit pygame
pygame.quit()

This code will create a transparent rectangle with a red color and blit it onto the screen using the blit() function. The transparency value is set using the set_alpha() method of the Surface class. The pygame.SRCALPHA flag is passed to the Surface constructor to enable per-pixel alpha blending.