Adding a diagonal gradient to a PIL image - implemented in a hack day

add_gradient_to_image.py

from PIL import Image
import math

def gradient_fill(im, from_color, to_color):
    start_x = 0
    start_y = 0

    pixel_data = im.load()
    for x in range(im.size[0]):
        for y in range(im.size[1]):
            dist = math.fabs(start_x - x) + math.fabs(start_y - y)
            start_rgb = (184, 108, 0)
            end_rgb = (255, 180, 0)
            # reduce distance travelled to a percentage of the total image size
            dist = dist / (im.size[0] + im.size[1])
            # run through the rgb object and calculate relative distances between start+end
            r, g, b = map(lambda start, end: start+end,
                          map(lambda start: start*(1-dist), from_color),
                          map(lambda end: end*dist, to_color))
            pixel_data[x, y] = int(r), int(g), int(b)
    return im