# Tk_rgb_gradient.py

# Tk_rgb_gradient.py ZZZ left-click-scroll

from Tkinter import *
from PIL import Image, ImageTk
import random
import math
import time

wt = 1400
ht = 690
root = Tk()
root.title("Tk RGB")
root.geometry("%dx%d+0+0"%(wt,ht))
canvas = Canvas(root, width=wt, height=ht)
canvas.grid()

img = Image.new("RGB",(wt,ht), "white")

cc = {}
for x in range(wt):
    for y in range(ht):
        cc[x,y] = 0

xy = []
x2 = 256.0/wt
y2 = 256.0/ht
for y in range(ht):
    b = int(y*y2)
    for x in range(wt):
        a = int(x*x2)
        c = cc[a,b]
        xy += [(a,b,c)]
        cc[a,b] = c+1
0
if 1:
    img.putdata(xy)
    imgTk = ImageTk.PhotoImage(img)
    canvas.create_image(0, 0, anchor=NW, image=imgTk)
    root.update()