I'm using Python PIL module to draw some lines and I use for loop to change the width of the line. But now I would like to do, when line width is to 0, I want to go and add value of lw. Basicly when width value go to zero, then I want it to go back to the 120.

This is my code...

from PIL import Image, ImageDraw

img = Image.new('RGB', (2000, 2000), (0, 0, 0))
draw = ImageDraw.Draw(img)

lw = 0
for y in range(-100, 2100, 100):
    lw = lw   10
    draw.line((2000, y, 0, y), (255,0,0), 120-lw)   
img 

This is an image from this code...

I was thinking to use if statement but I don't know where to incorporate it. Any ideas?

Thanks in advance!

CodePudding user response：

for y in range(-100, 2100, 100):
    lw = lw   10
    draw.line((2000, y, 0, y), (255,0,0), 120-lw)   

Nice attempt.

I was thinking to use if statement but I don't know where to incorporate it. Any ideas?

In this case I would suggest to do this:

for y in range(-100, 2100, 100):
    lw = lw   10
    if (lw >= 120): # When lw reaches 120...
        lw = 0 # ...you set it to 0
    draw.line((2000, y, 0, y), (255,0,0), 120-lw)

Anyway a more elegant solution (which doesn't involve if statements) would be this:

for y in range(-100, 2100, 100):
    lw = lw   10
    draw.line((2000, y, 0, y), (255,0,0), 120-(lw0))

The % operator gets the remainder of lw/120, so that when lw>=120 you won't have a value greater than 120 anyway.

EDIT

I want to go from 120 to 0, and from 0 to 120. In this way it goes like this (120, 110,..., 20, 10, 0, 120, 110,...), but I would like to go like this (120, 110,..., 20, 10, 0, 10, 20,...,

In this case you have to use an if statement:

incrementing = True
lw = 0
for y in range(-100, 2100, 100):
    if (lw == 120):
        incrementing = False
    elif (lw == 0):
        incrementing = True
    if (incrementing):
        lw = lw   10
    else:
        lw = lw - 10
    draw.line((2000, y, 0, y), (255,0,0), 120-lw)   

My suggestion is to use a boolean variable to make the incrementing/decrementing easier.