Grid Maker

grid_maker.py

"""
Create a custom grid-paper design as a minified vector image.

This uses a unique adaptation of "stroke-dasharray" to create the grid
pattern in a very small svg.

Usage:
    python grid_maker.py > grid.svg
    python grid_mater.py --help

Functionalized to adjust minor and major grid size, color, and grid line
thickness.
"""
import argparse

base = '''
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 {width} {height}">
  <g stroke-width="{height}" fill="none" stroke="{color}">
    <path stroke-dasharray="{i}" d="M0,{hh:.1f}h{width}"/>
    <path stroke-dasharray="{a}" d="M0,{hh:.1f}h{width}"/>
  </g>
  <g stroke-width="{width}" fill="none" stroke="{color}">
    <path stroke-dasharray="{i}" d="M{hw:.1f},0v{height}"/>
    <path stroke-dasharray="{a}" d="M{hw:.1f},0v{height}"/>
  </g>
</svg>
'''.strip('\n')


def get_dasharray(spacing, stroke):
    """Get stroke-dasharray string from input arguments."""
    on = stroke / 100
    off = spacing - 2 * on
    return '{:.2f},{:.2f},{:.2f},0'.format(on, off, on)


parser = argparse.ArgumentParser(description="Create a custom grid-paper "
                                 "design as a minified vector image.")
parser.add_argument('--width', type=int, default=100, help="Width of "
                    "the vector image.")
parser.add_argument('--height', type=int, default=100, help="Height of "
                    "the vector image.")
parser.add_argument('--color', type=str, default="#444", help="Grid "
                    "color, as RGB hex.")
parser.add_argument('--minor', type=int, default=1, help="Minor grid size, "
                    "relative to vector image dimensions.")
parser.add_argument('--major', type=int, default=10, help="Major grid size, "
                    "relative to vector image dimensions.")
parser.add_argument('--minor-stroke', type=int, default=2, help="Minor stroke "
                    "width.")
parser.add_argument('--major-stroke', type=int, default=5, help="Major stroke "
                    "width.")
args = parser.parse_args()

if not 1 <= args.width <= 1000:
    raise ValueError("Only accepting widths 1-1000")
if not 1 <= args.height <= 1000:
    raise ValueError("Only accepting heights 1-1000")

svg = base.format(
    width=args.width,
    height=args.height,
    color=args.color,
    hw=args.width / 2,
    hh=args.height / 2,
    i=get_dasharray(args.minor, args.minor_stroke),
    a=get_dasharray(args.major, args.major_stroke),
)
print(svg)

Example usage:

python grid_maker.py

python grid_maker.py --width=41 --height=70 --color=blue