multiplication_print.py

#!/usr/bin/env python3
"""Print a multiplication table on the S01 thermal printer.

A classic N x N times-table grid with highlighted headers -- handy for the wall
or the school bag.

Examples:
    python multiplication_print.py            # 12 x 12
    python multiplication_print.py --size 10
    python multiplication_print.py --no-print
"""
from __future__ import annotations

import argparse
from pathlib import Path

from PIL import Image, ImageDraw

from print_common import ROOT, Card, font


def draw_table(n: int, w: int) -> Image.Image:
    cells = n + 1
    cell = w // cells
    grid = cell * cells
    img = Image.new("L", (grid + 1, grid + 1), 255)
    d = ImageDraw.Draw(img)
    hf = font(True, round(cell * 0.45))
    nf = font(False, round(cell * 0.42))

    for r in range(cells):
        for c in range(cells):
            x0, y0 = c * cell, r * cell
            header = r == 0 or c == 0
            if header:
                d.rectangle((x0, y0, x0 + cell, y0 + cell), fill=0)
            if r == 0 and c == 0:
                txt, fill, fnt = "x", 255, hf
            elif r == 0:
                txt, fill, fnt = str(c), 255, hf
            elif c == 0:
                txt, fill, fnt = str(r), 255, hf
            else:
                txt, fill, fnt = str(r * c), 0, nf
            d.text((x0 + cell / 2, y0 + cell / 2), txt, fill=fill, font=fnt, anchor="mm")

    for i in range(cells + 1):
        wdt = 2 if i in (0, 1, cells) else 1
        d.line((i * cell, 0, i * cell, grid), fill=0, width=wdt)
        d.line((0, i * cell, grid, i * cell), fill=0, width=wdt)
    return img


def main() -> int:
    parser = argparse.ArgumentParser(description="Print a multiplication table on the S01 thermal printer.")
    parser.add_argument("--size", type=int, default=12, help="Table size N x N (default: 12).")
    parser.add_argument("--out", type=Path, default=None)
    parser.add_argument("--darkness", type=int, choices=range(1, 6), default=3)
    parser.add_argument("--bottom-feed", type=int, default=24)
    parser.add_argument("--no-print", action="store_true")
    args = parser.parse_args()

    if not 5 <= args.size <= 12:
        parser.error("--size must be 5-12")
    print(f"Generating {args.size}x{args.size} multiplication table ...")

    card = Card()
    card.title("TIMES TABLE")
    card.line(f"{args.size} x {args.size}", size=12, bold=False, center=True)
    card.gap(4).image(draw_table(args.size, card.inner_w), border=False)
    card.footer("multiplication", f"to {args.size}x{args.size}")
    out = args.out or ROOT / f"timestable_{args.size}.png"
    return card.finish(out, args.bottom_feed, args.darkness, do_print=not args.no_print)


if __name__ == "__main__":
    raise SystemExit(main())