Hey I used Python and Pillow to make grids for my drawing. Read on to watch my brain while I figured it out. Apologies for the minimal editing and the ridiculous number of images.
I draw. See? Many of my sketches have repeated elements, like zentangle or celtic inspired patterns. Okay, I don’t have many examples on the site. Sure there’s plenty of repetition based on symmetry tools in the drawing apps I use, and a little bit taking advantage of perspective grids. Not much in the way of simple grid-based repetition though.
Templates exist, but I want custom templates to fit the size of my workspace. I started exploring the Pillow library recently, so let’s use that to make custom grids for my drawings.
from PIL import Image
if __name__ == '__main__': height = 600 width = 600 image = Image.new(mode='L', size=(height, width), color=255)
image.show()I use a modest 600 by 600 pixel grayscale image while working out the details.
No point saving anything until I know what’s going on, so just show() the
image.
Most of what I want is in the ImageDraw module.
Simple Grid
from PIL import Image, ImageDraw
if __name__ == '__main__': height = 600 width = 600 image = Image.new(mode='L', size=(height, width), color=255)
# Draw a line draw = ImageDraw.Draw(image) x = image.width / 2 y_start = 0 y_end = image.height line = ((x, y_start), (x, y_end)) draw.line(line, fill=128) del draw
image.show()
Nice. Okay, how about repeating some lines across?
from PIL import Image, ImageDraw
if __name__ == '__main__': height = 600 width = 600 image = Image.new(mode='L', size=(height, width), color=255)
# Draw some lines draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / 10)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
del draw
image.show()
Lovely. How about an actual grid?
from PIL import Image, ImageDraw
if __name__ == '__main__': height = 600 width = 600 image = Image.new(mode='L', size=(height, width), color=255)
# Draw some lines draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / 10)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
x_start = 0 x_end = image.width
for y in range(0, image.height, step_size): line = ((x_start, y), (x_end, y)) draw.line(line, fill=128)
del draw
image.show()
Okay cool but I often need a specific number of squares in my grid.
from PIL import Image, ImageDraw
if __name__ == '__main__': step_count = 25 height = 600 width = 600 image = Image.new(mode='L', size=(height, width), color=255)
# Draw some lines draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / step_count)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
x_start = 0 x_end = image.width
for y in range(0, image.height, step_size): line = ((x_start, y), (x_end, y)) draw.line(line, fill=128)
del draw
image.show()
Right but I don’t want to edit the code every time.
import sys
from PIL import Image, ImageDraw
if __name__ == '__main__': step_count = 10
if len(sys.argv) == 2: step_count = int(sys.argv[1])
height = 600 width = 600 image = Image.new(mode='L', size=(height, width), color=255)
# Draw some lines draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / step_count)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
x_start = 0 x_end = image.width
for y in range(0, image.height, step_size): line = ((x_start, y), (x_end, y)) draw.line(line, fill=128)
del draw
image.show()Run it.
$ python grid.py 12
I can specify step count from the command line. Cool. Uh hey about height and width?
import sys
from PIL import Image, ImageDraw
if __name__ == '__main__': step_count = 10 height = 600 width = 600
if len(sys.argv) == 2: step_count = int(sys.argv[1]) elif len(sys.argv) == 3: width = int(sys.argv[1]) height = int(sys.argv[2]) elif len(sys.argv) == 4: width = int(sys.argv[1]) height = int(sys.argv[2]) step_count = int(sys.argv[3])
image = Image.new(mode='L', size=(height, width), color=255)
# Draw some lines draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / step_count)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
x_start = 0 x_end = image.width
for y in range(0, image.height, step_size): line = ((x_start, y), (x_end, y)) draw.line(line, fill=128)
del draw
image.show()Oh come on. Stop it with sys.argv. Get some real command line handling in
there.
import argparse
from PIL import Image, ImageDraw
if __name__ == '__main__': parser = argparse.ArgumentParser() parser.add_argument("width", help="width of image in pixels", type=int) parser.add_argument("height", help="height of image in pixels", type=int) parser.add_argument("step_count", help="how many steps across the grid", type=int) args = parser.parse_args()
step_count = args.step_count height = args.height width = args.width
image = Image.new(mode='L', size=(height, width), color=255)
# Draw some lines draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / step_count)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
x_start = 0 x_end = image.width
for y in range(0, image.height, step_size): line = ((x_start, y), (x_end, y)) draw.line(line, fill=128)
del draw
image.show()Much better. Run it.
$ python grid.pyusage: grid.py [-h] width height step_count
positional arguments: width width of image in pixels height height of image in pixels step_count how many steps across the grid
optional arguments: -h, --help show this help message and exit
$ python grid.py 500 500 20I like Argparse.
Anyways - what if I ask for a rectangle instead of a square?
$ python grid.py 400 600 24 \{\{< /console >}}
Hold on. I was handing height and width to Image in the
wrong order this whole time.
if __name__ == '__main__': # ...
image = Image.new(mode='L', size=(width, height), color=255)
# ...Run it.
$ python grid.py 400 600 24
This works. I have half a dozen ideas left, but I want to use it for a sketch now.
import argparse
from PIL import Image, ImageDraw
if __name__ == '__main__': parser = argparse.ArgumentParser() parser.add_argument("width", help="width of image in pixels", type=int) parser.add_argument("height", help="height of image in pixels", type=int) parser.add_argument("step_count", help="how many steps across the grid", type=int) args = parser.parse_args()
step_count = args.step_count height = args.height width = args.width image = Image.new(mode='L', size=(width, height), color=255)
# Draw a grid draw = ImageDraw.Draw(image) y_start = 0 y_end = image.height step_size = int(image.width / step_count)
for x in range(0, image.width, step_size): line = ((x, y_start), (x, y_end)) draw.line(line, fill=128)
x_start = 0 x_end = image.width
for y in range(0, image.height, step_size): line = ((x_start, y), (x_end, y)) draw.line(line, fill=128)
del draw
filename = "grid-{}-{}-{}.png".format(width, height, step_count) print("Saving {}".format(filename)) image.save(filename)$ python grid.py 1800 2400 50Saving grid-1800-2400-50.png$ lsgrid-1800-2400-50.png grid.py*Let’s skim over the part where I get the grid onto the iPad and import it as a new layer in my current sketch. That part includes no code — for now.
Anyways, back to the sketch.