Transforms video from webcam into a real-time ascii art

cam_to_ascii.py

import math
import cv2 as cv
import numpy as np
import sys
import pygame


gscale1 = "$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"`'. "[::-1]
thresholds = [x * 5 for x in range(70)]


def get_ascii_from_frame(frame):
    img = frame
    height, width = img.shape
    max_height = 100
    h = height
    if height >= max_height:
        h = max_height
        ratio = height // max_height
        w = width // ratio
    else:
        w = width // (width // height)
    img = cv.resize(img, (int(w), int(h)), interpolation=cv.INTER_CUBIC)

    thresh_img = np.zeros(img.shape)
    for i, threshold in enumerate(thresholds):
        thresh_img[img > threshold] = i
    thresh_img = thresh_img.astype(int)

    art = []
    for row in thresh_img:
        art_row = []
        for i in row:
            art_row.append(gscale1[i % len(gscale1)])
        art.append(art_row)
    return art


pygame.init()
screen = pygame.display.set_mode((1280, 720))
clock = pygame.time.Clock()


def map_to_range(val, lmin, lmax, rmin, rmax):
    return rmin + ((rmax - rmin) / (lmax - lmin)) * (val - lmin)


def get_color():
    time = pygame.time.get_ticks()
    booster = 0.001
    r = map_to_range(math.sin(time * booster), -1, 1, 0, 255)
    g = map_to_range(math.sin(time * booster + 4), -1, 1, 0, 255)
    b = map_to_range(math.sin(time * booster + 8), -1, 1, 0, 255)
    return (r, g, b)


def render_ascii(frame=None):
    frame = get_ascii_from_frame(frame)
    img = list(zip(*frame[::-1]))

    size = 6
    for i, row in enumerate(img):
        for j, col in enumerate(row[::-1]):
            char = font.render(col, True, (255, 255, 255))
            screen.blit(char, (i * size, j * size))


font = pygame.font.Font(None, 20)

cap = cv.VideoCapture(0)
if not cap.isOpened():
    print("Can't open cam")
    exit()


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

    screen.fill((20, 20, 30))

    ret, frame = cap.read()
    if not ret:
        print("Can't read frame")
        break

    frame = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
    render_ascii(frame)

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