rocky linux

[github]

the mountain in a green circle, scanned now and then

distros 56×28 30 fps in colour or one ink 7.3 kB

use it

html

<script type="module" src="https://ascii.rest/ascii.js"></script>

<ascii-art piece="rocky-linux" options='{"scan":5}'></ascii-art>

No install and no build step. ascii.js defines the <ascii-art> tag, loads the piece from ascii.rest, plays it while it is on screen, and holds the first frame for anyone who prefers reduced motion. Add mono, <ascii-art piece="rocky-linux" mono>, for one ink.

react

// npm install github:bas3line/ascii
import { Ascii } from "ascii.rest/react";
import { rockyLinux } from "ascii.rest/pieces";

<Ascii piece={rockyLinux} options={{"scan":5}} />

A client component, so it works in the Next.js app router as it is. Pass the name instead, piece="rocky-linux", to fetch the piece only when it mounts. Add mono for one ink.

astro

---
// npm install github:bas3line/ascii
import Ascii from "ascii.rest/astro";
---

<Ascii piece="rocky-linux" options={{"scan":5}} />

Renders the first frame on the server, so the page is whole before any script runs, then plays the piece once it loads. Add mono for one ink.

typescript

// npm install github:bas3line/ascii
import { mount } from "ascii.rest";
import { rockyLinux } from "ascii.rest/pieces";

const el = document.querySelector<HTMLCanvasElement>("canvas")!;
const stop = mount(el, rockyLinux, {"scan":5});

mount plays a piece in a <pre>, or on a <canvas> for the coloured ones, and returns a function that stops it. Every piece, option and frame is typed. Mount it in a <pre> for one ink.

rocky-linux.ts

[js] [github] 
/*
 * rocky linux: the Rocky Linux logo, a mountain cut from a green circle, with
 * a scan line running down it every few seconds that scrambles what it passes.
 *
 * Drawn from devicon's rockylinux-original.svg (MIT): each cell holds the
 * character whose shape best matches the logo's edge through it, and 8 where
 * the logo is solid. On a canvas it takes the logo's colours, lifted on a dark
 * page where they would sink into it; in a <pre> it is one ink, from the same
 * drawing. The logo is a trademark of its owner, shown here to name the
 * distribution.
 */
import type { Frame, Meta } from "../types.ts";

export interface RockyLinuxOptions {
  [key: string]: unknown;
  /** Seconds between scans; 0 keeps the logo still. */
  scan: number;
}

export const meta = {
  name: "rocky linux",
  category: "distros",
  note: "the mountain in a green circle, scanned now and then",
  cols: 56,
  rows: 28,
  fps: 30,
  options: { scan: 5 },
  // The logo's colour for a light page, then for a dark one; each as drawn, then twice lighter for the scan.
  palette: [
    "#10bd85", "#64d4b0", "#b7ebda", "#10bd85", "#64d4b0", "#b7ebda",
  ],
} satisfies Meta<RockyLinuxOptions>;

// In a <pre>, in the page's own colour.
const MONO = String.raw`

                  __pppq88888888qqqq__
              __p8888888888888888888888q_,
           _pp8888888888888888888888888888qq,
         _p8888888888888888888888888888888888q,
       _p88888888888888888888888888888888888888q,
      _888888888888888888888888888888888888888888_
     q88888888888888888888888888888888888888888888p
    q8888888888888888888888888888888888888888888888p
   q888888888888888888888888888888888888888888888888p
  .8888888888888888888888888888888P'"8888888888888888,
  q88888888888888888888888888888P'    "88888888888888p
  8888888888888888888888888888P'        "8888888888888
  88888888888888888888888888P'            "88888888888
  888888888888888888888888P'                "888888888
  8888888888888888888888P'                    "8888888
  d8888888888888888888P'           __           "8888P
  '88888888888888888P'           _888q_           "88'
   )88888888888888P'           _8888888q_           '
    Y88888888888P'           _88888888888q_
     Y88888888P'           _888888888888888q_
      "88888P'           _8888888888888888888q_
       'Y8P'           _88888888888888888888888P
                     _88888888888888888888888P'
                   _88888888888888888888888"'
                 \888888888888888888888P"'
                  '""Y888888888888P""'

`;

// On a canvas, and the colour of each cell: an index into the logo's colours.
const ART = String.raw`

                  __pppq88888888qqqq__
              __p8888888888888888888888q_,
           _pp8888888888888888888888888888qq,
         _p8888888888888888888888888888888888q,
       _p88888888888888888888888888888888888888q,
      _888888888888888888888888888888888888888888_
     q88888888888888888888888888888888888888888888p
    q8888888888888888888888888888888888888888888888p
   q888888888888888888888888888888888888888888888888p
  .8888888888888888888888888888888P'"8888888888888888,
  q88888888888888888888888888888P'    "88888888888888p
  8888888888888888888888888888P'        "8888888888888
  88888888888888888888888888P'            "88888888888
  888888888888888888888888P'                "888888888
  8888888888888888888888P'                    "8888888
  d8888888888888888888P'           __           "8888P
  '88888888888888888P'           _888q_           "88'
   )88888888888888P'           _8888888q_           '
    Y88888888888P'           _88888888888q_
     Y88888888P'           _888888888888888q_
      "88888P'           _8888888888888888888q_
       'Y8P'           _88888888888888888888888P
                     _88888888888888888888888P'
                   _88888888888888888888888"'
                 \888888888888888888888P"'
                  '""Y888888888888P""'

`;
const INK = String.raw`

                  00000000000000000000
              0000000000000000000000000000
           0000000000000000000000000000000000
         00000000000000000000000000000000000000
       000000000000000000000000000000000000000000
      00000000000000000000000000000000000000000000
     0000000000000000000000000000000000000000000000
    000000000000000000000000000000000000000000000000
   00000000000000000000000000000000000000000000000000
  0000000000000000000000000000000000000000000000000000
  00000000000000000000000000000000    0000000000000000
  000000000000000000000000000000        00000000000000
  0000000000000000000000000000            000000000000
  00000000000000000000000000                0000000000
  000000000000000000000000                    00000000
  0000000000000000000000           00           000000
  00000000000000000000           000000           0000
   00000000000000000           0000000000           0
    00000000000000           00000000000000
     00000000000           000000000000000000
      00000000           0000000000000000000000
       00000           0000000000000000000000000
                     00000000000000000000000000
                   00000000000000000000000000
                 0000000000000000000000000
                  00000000000000000000

`;

const START = 0.5; // seconds before the first scan
const PASS = 2; // seconds a scan takes, top to bottom
const HEAD = 2; // rows the line scrambles
const TRAIL = 5; // rows of afterglow behind it
const NOISE = "#$%&*+<=>?@[]{}"; // what the line scrambles the logo into

const lines = (art: string) => art.slice(1, -1).split("\n").map((line) => line.padEnd(meta.cols));

function hash(x: number, y: number, k: number) {
  let h = Math.imul(x, 73856093) ^ Math.imul(y, 19349663) ^ Math.imul(k, 83492791);
  h = Math.imul(h ^ (h >>> 13), 1274126177);
  return (h ^ (h >>> 16)) >>> 0;
}

export default function rockyLinux({ scan = meta.options.scan }: Partial<RockyLinuxOptions> = {}): Frame {
  const { cols, rows, fps } = meta;
  const mono = lines(MONO), art = lines(ART), ink = lines(INK);
  const n = meta.palette.length / 6;
  const every = scan > 0 ? Math.max(scan, PASS + 0.5) : 0;
  // The line runs from the logo's first row to past its last, rather than the whole frame.
  let first = rows, last = -1;
  for (const pic of [mono, art])
    pic.forEach((line, y) => {
      if (line.trim()) (first = Math.min(first, y)), (last = Math.max(last, y));
    });
  const span = last - first + 1 + HEAD + TRAIL;

  return (t, { paper = false, color } = {}) => {
    const pic = color ? art : mono;
    const since = t - START;
    const at = every && since >= 0 ? first + (span * (since % every)) / PASS : -Infinity;
    const tick = Math.floor((t * fps) / 2); // the noise changes every other frame
    const out: string[] = [];
    for (let y = 0; y < rows; y++) {
      const d = at - y; // rows since the line reached this one
      const level = d >= 0 && d < HEAD ? 2 : d >= HEAD && d < HEAD + TRAIL ? 1 : 0;
      let line = "";
      for (let x = 0; x < cols; x++) {
        let ch = pic[y][x];
        if (ch !== " ") {
          if (level === 2) {
            const h = hash(x, y, tick);
            if (h % 4) ch = NOISE[(h >>> 2) % NOISE.length];
          }
          if (color) color[y * cols + x] = (paper ? 0 : 3 * n) + level * n + parseInt(ink[y][x], 36);
        }
        line += ch;
      }
      out.push(line);
    }
    return out.join("\n");
  };
}