app.py

import pygame
import sys
import random

pygame.init()

width, height = 800, 600
screen = pygame.display.set_mode((width, height))
pygame.display.set_caption("Cloth Trail")
clock = pygame.time.Clock()

trail = []
max_length = 50
color = (100, 149, 237)  # Cornflower Blue
fade_speed = 5  # Decrease in alpha per frame

def draw_trail():
    for i, point in enumerate(trail):
        x, y, alpha = point
        current_alpha = max(0, alpha - i * fade_speed // max_length)
        current_color = (color[0], color[1], color[2], current_alpha) # RGBA
        size = max(1, 10 * (1 - i / max_length))
        pygame.draw.circle(screen, current_color, (int(x), int(y)), int(size // 2))

alpha_surface = pygame.Surface((width, height), pygame.SRCALPHA)

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    mouse_x, mouse_y = pygame.mouse.get_pos()
    trail.append([mouse_x, mouse_y, 255]) # Initial alpha is fully opaque
    if len(trail) > max_length:
        trail.pop(0)

    screen.fill((0, 0, 0)) # Black background

    # Draw the trail onto the alpha surface
    alpha_surface.fill((0, 0, 0, 0)) # Clear the alpha surface
    for i, point in enumerate(trail):
        x, y, alpha = point
        current_alpha = max(0, 255 - i * fade_speed)
        current_color = (color[0], color[1], color[2], current_alpha)
        size = max(1, 10 * (1 - i / max_length))
        pygame.draw.circle(alpha_surface, current_color, (int(x), int(y)), int(size // 2))

    # Blit the alpha surface onto the main screen
    screen.blit(alpha_surface, (0, 0))

    pygame.display.flip()
    clock.tick(60)