Two-color linear gradient positioning with PIL Python

Question

Perhaps it is something easy for many. I am trying to create a background from 2 colors. The intention is that it starts on the left with one color and ends with another color on its right side (horizontally.)

the question is that I have from corner to corner. and what I'm looking for is that it is side by side.

My code:

from PIL import Image, ImageDraw

def interpolate(f_co, t_co, interval):
    det_co =[(t - f) / interval for f , t in zip(f_co, t_co)]
    for i in range(interval):
        yield [round(f + det * i) for f, det in zip(f_co, det_co)]


imgsize=(1920,1080)
gradient = Image.new('RGBA', imgsize, color=0)
draw = ImageDraw.Draw(gradient)

f_co = (253, 46, 216)
t_co = (23, 214, 255)
for i, color in enumerate(interpolate(f_co, t_co, gradient.width * 2)):
    draw.line([(i, 0), (0, i)], tuple(color), width=1)
gradient.show()

result: https://i.imgur.com/p5slKTg.png

AKX_51685 · Answer

For left to right, the easiest fix is to just modify the draw.line coordinates from

draw.line([(i, 0), (0, i)], tuple(color), width=1)

to

draw.line([(i, 0), (i, gradient.height)], tuple(color), width=1)

and adjust gradient.width * 2 in the interpolate() call to just gradient.width. The result is

For top to bottom, you'll need to adjust the argument to interpolate() to use gradient.height and do

draw.line([(0, i), (gradient.width, i)], tuple(color), width=1)

and the result is

user_2836621 · Answer

I think I would take a different approach rather than drawing 3,840 lines:

#!/usr/bin/env python3

import numpy as np
from PIL import Image

# Define start and end colours and image height and width
colourA=[255, 0, 255]
colourB=[0, 255, 255]
h, w = 1080, 1920

# Make output image
gradient = np.zeros((h,w,3), np.uint8)

# Fill R, G and B channels with linear gradient between two end colours
gradient[:,:,0] = np.linspace(colourA[0], colourB[0], w, dtype=np.uint8)
gradient[:,:,1] = np.linspace(colourA[1], colourB[1], w, dtype=np.uint8)
gradient[:,:,2] = np.linspace(colourA[2], colourB[2], w, dtype=np.uint8)

# Save result
Image.fromarray(gradient).save('result.png')

Two-color linear gradient positioning with PIL Python

2 Answers