Making tileable images with Python

Here's an interesting bit of Python code I hacked together – it's a script that takes an image and warps it so that it is tileable (making it suitable for a repeating backgound or a texture in a game).

$A fractal$

A Mandlebrot fractal

If you use it on a photograph, it will come out looking like a fair-ground mirror. But it works well when applied to a pattern, or something more abstract, such as the fractal image on the left.

The code is public domain – use it for whatever the heck you want!

Example Output

Update: Here's another, more interesting example, The original is here.

The Code

import Image
from math import *

def maketilable(src_path, dst_path):
    src = Image.open(src_path)
    src = src.convert('RGB')
    src_w, src_h = src.size

    dst = Image.new('RGB', (src_w, src_h))
    w, h = dst.size

    def warp(p, l, dl):
        i = float(p) / l
        i = sin(i*pi*2 + pi)
        i = i / 2.0 + .5
        return abs(i * dl)

    warpx = [warp(x, w-1, src_w-1) for x in range(w)]
    warpy = [warp(y, h-1, src_h-1) for y in range(h)]

    get = src.load()
    put = dst.load()

    def getpixel(x, y):

        frac_x = x - floor(x)
        frac_y = y - floor(y)

        x1 = (x+1)%src_w
        y1 = (y+1)%src_h

        a = get[x, y]
        b = get[x1, y]
        c = get[x, y1]
        d = get[x1, y1]

        area_d = frac_x * frac_y
        area_c = (1.-frac_x) * frac_y
        area_b = frac_x * (1. - frac_y)
        area_a = (1.-frac_x) * (1. - frac_y)

        a = [n*area_a for n in a]
        b = [n*area_b for n in b]
        c = [n*area_c for n in c]
        d = [n*area_d for n in d]

        return tuple(int(sum(s)) for s in zip(a,b,c,d))


    old_status_msg = None
    status_msg = ''
    for y in xrange(h):

        status_msg = '%2d%% complete' % ((float(y) / h)*100.0)
        if status_msg != old_status_msg:
            print status_msg
        old_status_msg = status_msg

        for x in xrange(w):
            put[x, y] = getpixel(warpx[x], warpy[y])

    dst.save(dst_path)


if __name__ == "__main__":

    import sys
    try:
        src_path = sys.argv[1]
        dst_path = sys.argv[2]
    except IndexError:
        print "<source image path>, <destination image path>"
    else:
        maketilable(src_path, dst_path)

This blog post was posted to It's All Geek to Me on Saturday July 18th, 2009 at 6:06PM

3 Responses to "Making tileable images with Python"

Pauli Virtanen

July 18th, 2009, 9:37 p.m.

Smells like a job for Numpy (http://www.scipy.org [scipy.org]):

import Image
import numpy as np

def maketilable(src_path, dst_path, w=None, h=None):
    src_img = Image.open(src_path)
    src_img = src_img.convert('RGB')
    src = np.asarray(src_img)

    src_w, src_h, ncolors = src.shape

    if w is None:
        w = src_w
    if h is None:
        h = src_h

    def warp(p, l, dl):
        i = p * 1.0 / l
        i = np.sin(i*np.pi*2 + np.pi)
        i = i / 2.0 + .5
        return abs(i * dl)

    xp = warp(np.arange(w), w-1, src_w-1)[:,np.newaxis]
    yp = warp(np.arange(h), h-1, src_h-1)[np.newaxis,:]

    x = xp.astype(int)
    y = yp.astype(int)

    x1 = (x + 1) % src_w
    y1 = (y + 1) % src_h

    a = src[x, y]
    b = src[x1, y]
    c = src[x, y1]
    d = src[x1, y1]

    frac_x = (xp - np.floor(xp))[...,np.newaxis]
    frac_y = (yp - np.floor(yp))[...,np.newaxis]
    
    d *= frac_x * frac_y
    c *= (1.-frac_x) * frac_y
    b *= frac_x * (1. - frac_y)
    a *= (1.-frac_x) * (1. - frac_y)

    dst = a + b + c + d
    dst_img = Image.fromarray(dst, 'RGB')
    dst_img.save(dst_path)

if __name__ == "__main__":
    import sys
    try:
        src_path = sys.argv[1]
        dst_path = sys.argv[2]
    except IndexError:
        print "<source image path>, <destination image path>"
    else:
        maketilable(src_path, dst_path)

Will McGugan

July 18th, 2009, 9:49 p.m.

Pauli, Nice! I think it is a job for Numpy.

Pauli Virtanen

July 18th, 2009, 10:11 p.m.

Once more, this time demonstrating the use of scipy.ndimage for the interpolation:

import Image
import numpy as np
import scipy.ndimage

def maketilable(src_path, dst_path, w=None, h=None):
    src_img = Image.open(src_path)
    src_img = src_img.convert('RGB')
    src = np.asarray(src_img)

    src_w, src_h, ncolors = src.shape

    if w is None:
        w = src_w
    if h is None:
        h = src_h

    def warp(p, l, dl):
        i = p * 1.0 / l
        i = np.sin(i*np.pi*2 + np.pi)
        i = i / 2.0 + .5
        return abs(i * dl)

    x = warp(np.arange(w), w-1, src_w-1)
    y = warp(np.arange(h), h-1, src_h-1)

    coords = np.broadcast_arrays(*np.ix_(x, y))

    dst = np.empty((w, h, 3), src.dtype)
    for j in xrange(3):
        dst[:,:,j] = \
            scipy.ndimage.map_coordinates(src[:,:,j], 
                                          coords,
                                          mode='wrap',
                                          order=3)

    dst_img = Image.fromarray(dst, 'RGB')
    dst_img.save(dst_path)

if __name__ == "__main__":
    import sys
    try:
        src_path = sys.argv[1]
        dst_path = sys.argv[2]
    except IndexError:
        print "<source image path>, <destination image path>"
    else:
        maketilable(src_path, dst_path)

Previewing comment, please wait a moment...

My name is Will McGugan. I am an unabashed geek, an author, a hacker and a Python expert – amongst other things!

You are reading my tech blog. See the homepage for my other blogs.

Search for Posts

Possibly related posts

A 3D Texture-Mapped Globe Rendered with Javascript and HTML

Recent Comments

http://www.iclshoes.com/alexander-mcqueen-c-13.html [iclshoes.com] http://www.iclshoes.com/jimmy-choo-shoes-c-2.html [iclshoes.com] http://www.iclshoes.com/ [iclshoes.com] http://www.zentai-mart.com/Play-Costumes-c-5.html [zentai-mart.com] http://www.zentai-mart.com/Latex-Catsuits-Clothes-c-3.html [zentai-mart.com] http://www.zentai-mart.com/PVC-Catsuits-Clothes-c-6.html [zentai-mart.com] http://www.zentai-mart.com/ [zentai-mart.com] http://www.hereshoes.com/miu-miu-shoes-c-31.html [hereshoes.com] http://www.hereshoes.com/giuseppe-zanotti-c-43.html [hereshoes.com] http://www.hereshoes.com/lanvin-shoes-c-50.html [hereshoes.com] ...

- Christian Louboutin on Turning website favicons in to 3D

What are the charmings of?a href="http://www.iclshoes.com [iclshoes.com]cl shoes/a?They are quality,comfort and style.The a href=http://www.iclshoes.com/jimmy-choo-shoes-c-2.html [iclshoes.com]Jimmy Choo shoes/a are made from ...

- Christian Louboutin on Turning website favicons in to 3D

Thanks a lot for that: I had first tried sudo aptitude purge adobe-flashplugin then sudo aptitude install flashplugin-nonfree but that ...

- Jérôme on No audio in Flash on Ubuntu 10.04

Andre, the name is derived from the class name (camel case converted to lower case with underscores). But, you can ...

- Will McGugan on Announcing Sore Thumb, a thumbnail and image processing module for Django

is this using some kind of name mangling to map sorethumb:rounded_corners_edged to the RoundedCornersEdged class? that seems a little unnecessary ...

- Andre LeBlanc on Announcing Sore Thumb, a thumbnail and image processing module for Django

Making tileable images with Python

Example Output

The Code

3 Responses to "Making tileable images with Python"

Leave a Comment