Square grid for Pi day with `matplotlib`

grid-no-fill.pdf

grid.pdf

grid.py

# $ FILL_BETWEEN=true python grid.py
# Saved grid.pdf
# $ python grid.py
# Saved grid-no-fill.pdf
import os

import matplotlib.pyplot as plt


FILL_BETWEEN = "FILL_BETWEEN" in os.environ


def main():
    figure = plt.figure(figsize=(8.5, 11.0))
    ax = figure.gca()
    ax.axis("off")
    ax.grid(False)

    column_width = 3
    max_column = 10
    row_width = 2
    max_row = 20
    digits = [0, 3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3, 2, 3, 0, 0]

    columns = list(range(max_column + 1))
    rows = list(range(max_row + 1))
    for column in columns:
        ax.plot(
            [column * column_width, column * column_width],
            [0.0, max_row * row_width],
            color="black",
        )
    for row in rows:
        ax.plot(
            [0.0, max_column * column_width],
            [row * row_width, row * row_width],
            color="black",
        )
        digit = digits[row]
        if digit == 0:
            continue

        if FILL_BETWEEN:
            ax.fill_between(
                [
                    (max_column - digit) * column_width,
                    max_column * column_width,
                ],
                row * row_width,
                (row + 1) * row_width,
                color="black",
                alpha=0.5,
            )
            continue

        x_start = (max_column - digit) * column_width
        x_end = max_column * column_width
        y_bottom = row * row_width
        y_top = (row + 1) * row_width
        ax.plot(
            [x_start, x_end], [y_top, y_top], color="black", linewidth=5,
        )
        ax.plot(
            [x_start, x_end], [y_bottom, y_bottom], color="black", linewidth=5,
        )
        for bar_position in range(0, digit + 1):
            x_position = (max_column - bar_position) * column_width
            ax.plot(
                [x_position, x_position],
                [y_bottom, y_top],
                color="black",
                linewidth=5,
            )

    buffer = 0.5 ** 7
    ax.set_xlim(
        -buffer * max_column * column_width,
        max_column * column_width * (1 + buffer),
    )
    ax.set_ylim(
        -buffer * max_row * row_width, max_row * row_width * (1 + buffer)
    )
    ax.set_aspect("equal")

    margin = 0.5 ** 6
    figure.subplots_adjust(
        left=margin,
        bottom=margin,
        right=1 - margin,
        top=1 - margin,
        wspace=0,
        hspace=0,
    )
    if FILL_BETWEEN:
        filename = "grid.pdf"
    else:
        filename = "grid-no-fill.pdf"
    figure.savefig(filename)
    print(f"Saved {filename}")


if __name__ == "__main__":
    main()