make_icon.py

"""Generates icon.icns for the app: a heat signature in the inferno palette."""
import os
import subprocess
import sys

import numpy as np
from matplotlib import cm
from PIL import Image, ImageDraw, ImageFilter

S = 1024
OUT = os.path.dirname(os.path.abspath(__file__))


def gauss(cx, cy, sx, sy, amp, yy, xx):
    return amp * np.exp(-(((xx - cx) ** 2) / (2 * sx**2) + ((yy - cy) ** 2) / (2 * sy**2)))


def build():
    y, x = np.mgrid[0:S, 0:S].astype(np.float32)

    # The heat field: one large warm blob plus a couple of secondary sources.
    f = np.zeros((S, S), np.float32)
    f += gauss(0.60 * S, 0.56 * S, 0.20 * S, 0.22 * S, 1.00, y, x)
    f += gauss(0.36 * S, 0.40 * S, 0.13 * S, 0.14 * S, 0.55, y, x)
    f += gauss(0.72 * S, 0.30 * S, 0.09 * S, 0.10 * S, 0.35, y, x)
    f += gauss(0.30 * S, 0.74 * S, 0.16 * S, 0.11 * S, 0.28, y, x)

    # A slight background gradient, so the corners are not flatly black.
    f += 0.10 * (1.0 - y / S) * 0.5
    f = np.clip(f / f.max(), 0, 1)
    f = f**0.85

    rgba = (cm.inferno(f) * 255).astype(np.uint8)
    img = Image.fromarray(rgba, "RGBA")
    img = img.filter(ImageFilter.GaussianBlur(radius=S * 0.006))

    # Crosshair on the hottest point.
    d = ImageDraw.Draw(img, "RGBA")
    hy, hx = np.unravel_index(np.argmax(f), f.shape)
    r = int(S * 0.085)
    w = max(2, int(S * 0.011))
    d.ellipse([hx - r, hy - r, hx + r, hy + r], outline=(255, 255, 255, 230), width=w)
    arm, gap = int(S * 0.155), int(S * 0.052)
    for dx, dy in ((1, 0), (-1, 0), (0, 1), (0, -1)):
        d.line(
            [hx + dx * gap, hy + dy * gap, hx + dx * arm, hy + dy * arm],
            fill=(255, 255, 255, 230),
            width=w,
        )

    # A macOS-style rounded mask plus a thin inner stroke.
    pad = int(S * 0.085)
    mask = Image.new("L", (S, S), 0)
    ImageDraw.Draw(mask).rounded_rectangle(
        [pad, pad, S - pad, S - pad], radius=int(S * 0.225), fill=255
    )
    img.putalpha(mask)

    ring = Image.new("RGBA", (S, S), (0, 0, 0, 0))
    ImageDraw.Draw(ring).rounded_rectangle(
        [pad, pad, S - pad, S - pad],
        radius=int(S * 0.225),
        outline=(255, 255, 255, 46),
        width=max(2, int(S * 0.004)),
    )
    return Image.alpha_composite(img, ring)


def main():
    base = build()
    iconset = os.path.join(OUT, "icon.iconset")
    os.makedirs(iconset, exist_ok=True)
    for px in (16, 32, 128, 256, 512):
        base.resize((px, px), Image.LANCZOS).save(f"{iconset}/icon_{px}x{px}.png")
        base.resize((px * 2, px * 2), Image.LANCZOS).save(f"{iconset}/icon_{px}x{px}@2x.png")
    base.resize((512, 512), Image.LANCZOS).save(os.path.join(OUT, "icon-preview.png"))

    icns = os.path.join(OUT, "icon.icns")
    subprocess.run(["iconutil", "-c", "icns", iconset, "-o", icns], check=True)
    print(f"Done: {icns}")


if __name__ == "__main__":
    sys.exit(main())