render.py

from io import BytesIO
from PIL import Image, ImageEnhance

from colors import color


def render(image_data, width=70, height_scale=0.48, colorize=True):
    img = Image.open(image_data)

    org_width, orig_height = img.size
    aspect_ratio = orig_height / org_width
    new_height = aspect_ratio * width * height_scale
    img = img.resize((width, int(new_height)))
    img = img.convert('RGBA')
    img = ImageEnhance.Sharpness(img).enhance(2.0)
    pixels = img.getdata()

    def mapto(r, g, b, alpha):
        if alpha == 0.:
            return ' '
        chars = ["B", "S", "#", "&", "@", "$", "%", "*", "!", ".", " "]
        pixel = (r * 19595 + g * 38470 + b * 7471 + 0x8000) >> 16
        if colorize:
            return color(chars[pixel // 25], (r, g, b))
        else:
            return chars[pixel // 25]

    new_pixels = [mapto(r, g, b, alpha) for r, g, b, alpha in pixels]
    new_pixels_count = len(new_pixels)
    ascii_image = [''.join(new_pixels[index:index + width]) for index in range(0, new_pixels_count, width)]
    ascii_image = "\n".join(ascii_image)
    return ascii_image