alpha_draw.py

import pygame

def draw_rect_alpha(surface, color, rect):
    shape_surf = pygame.Surface(pygame.Rect(rect).size, pygame.SRCALPHA)
    pygame.draw.rect(shape_surf, color, shape_surf.get_rect())
    surface.blit(shape_surf, rect)

def draw_circle_alpha(surface, color, center, radius):
    target_rect = pygame.Rect(center, (0, 0)).inflate((radius * 2, radius * 2))
    shape_surf = pygame.Surface(target_rect.size, pygame.SRCALPHA)
    pygame.draw.circle(shape_surf, color, (radius, radius), radius)
    surface.blit(shape_surf, target_rect)

def draw_polygon_alpha(surface, color, points):
    lx, ly = zip(*points)
    min_x, min_y, max_x, max_y = min(lx), min(ly), max(lx), max(ly)
    target_rect = pygame.Rect(min_x, min_y, max_x - min_x, max_y - min_y)
    shape_surf = pygame.Surface(target_rect.size, pygame.SRCALPHA)
    pygame.draw.polygon(shape_surf, color, [(x - min_x, y - min_y) for x, y in points])
    surface.blit(shape_surf, target_rect)