web/web_company_color/utils.py

# Copyright 2019 Alexandre Díaz <dev@redneboa.es>
# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
import base64
import math
from PIL import Image
from io import BytesIO


def n_rgb_to_hex(_r, _g, _b):
    return '#%02x%02x%02x' % (int(255*_r), int(255*_g), int(255*_b))


def convert_to_image(field_binary):
    return Image.open(BytesIO(base64.b64decode(field_binary)))


def image_to_rgb(img):
    def normalize_vec3(vec3):
        _l = 1.0 / math.sqrt(vec3[0]*vec3[0]
                             + vec3[1]*vec3[1]
                             + vec3[2]*vec3[2])
        return (vec3[0]*_l, vec3[1]*_l, vec3[2]*_l)

    # Force Alpha Channel
    if img.mode != 'RGBA':
        img = img.convert('RGBA')
    width, height = img.size
    # Reduce pixels
    width, height = (max(1, int(width/4)), max(1, int(height/4)))
    img = img.resize((width, height))
    rgb_sum = [0, 0, 0]
    # Mix. image colors using addition method
    RGBA_WHITE = (255, 255, 255, 255)
    for i in range(0, height*width):
        rgba = img.getpixel((i % width, i / width))
        if rgba[3] > 128 and rgba != RGBA_WHITE:
            rgb_sum[0] += rgba[0]
            rgb_sum[1] += rgba[1]
            rgb_sum[2] += rgba[2]
    _r, _g, _b = normalize_vec3(rgb_sum)
    return (_r, _g, _b)