Loading state

// Copyright (c) 2026 Bruno Delorence. MIT License.'use client';import { useEffect, useId, useRef, useState, type CSSProperties, type KeyboardEvent } from 'react';import { RunnerClip } from './runner-clip';import { useAutoplay } from './use-autoplay';import styles from './loading-state.module.css';/* * Loading state: what an assistant shows while it works. A tiny 3 × 3 grid of pixels pulses, a * status word shimmers, and a monospaced timer counts the seconds since the work began. Four * styles of loader, picked from a segmented switch under it: * * - Drive: square pixels light up in a chevron wave, left to right, 650 ms a lap. * - Dots: the same wave in round dots. * - Orbit: a light runs clockwise round the eight outer pixels, 950 ms a lap, its tail fading *   behind it; the middle pixel stays dim. * - Surfer: the Drive grid with a different word, and under it a small clip of an endless runner *   that pops in (drawn on a canvas, runner-clip.tsx). * * How it moves * - Each pixel plays the same CSS keyframes (dim → lit for a quarter of the lap → dim), started *   at its own delay; the delays draw the pattern. Only opacity changes, so the compositor plays

// Copyright (c) 2026 Bruno Delorence. MIT License.'use client';import { useEffect, useRef } from 'react';/* * The Surfer loader's little clip: an endless runner, drawn on a canvas instead of played from a * video file. A runner dashes down three tracks between two arched viaduct walls, hops from lane * to lane, jumps now and then, picks up coins, and lets the trains pass in the other lanes. * * - One camera, one projection: a point X across, Y up and z ahead of the camera is drawn at *   (CX + K·X / z, HORIZON + K·(1 − Y) / z). Everything is a polygon of projected points, painted *   far to near. * - It is all a function of one clock: the tracks, arches and bushes repeat along z; the runner, *   coins and trains follow a 9.6 s script of six 1.6 s beats. So a frame never depends on the *   one before it, and a paused clip resumes exactly where it stopped. * - It draws only while `playing`; otherwise it holds its last frame (or, the first time, draws *   a still one). *//** The clip's own size in CSS px (it is drawn at the device's pixel ratio, up to 2). */const W = 224;const H = 126;

/* Loading state (loading-state.tsx): a quiet grey stage with the loader in its middle and the   switch between loaders at its foot. At night it is near-black, the pixels and the shimmer's   highlight almost white; by day it is a pale grey, and they turn near-black.   Colours are the tokens below, light-dark(light, dark) where the two differ: the component takes   the color-scheme it inherits from the page (light unless the page says otherwise), or the one   its colorScheme prop sets (data-color-scheme).   Memory. Everything that moves is opacity, a transform or a background position on a few small   boxes; the clip is one 224 × 126 canvas, drawn only while it plays. */.root {  /* The words and the lit pixels; a step down; the muted grey of the timer and the idle words. */  --ink: oklch(24.7% 0.006 258.361);  --ink-2: oklch(50.6% 0.01 264.477);  --ink-3: oklch(69.5% 0.009 264.505);  /* The stage, its edge, the switch's track and its picked button. */  --canvas: oklch(96.1% 0.002 247.84);  --line: oklch(94.6% 0.003 264.542);  --field: oklch(96.1% 0.001 286.375);  --surface: oklch(100% 0 0);  /* The picked button's edge and lift: a ring and a soft glow by day, a faint light ring and a     drop shadow at night (the layer one scheme doesn't use is transparent). */  --button-ring: oklch(91.2% 0.005 258.326);

'use client';import { useCallback, useEffect, useRef, useState } from 'react';/* * When a demo may play on its own: while part of it is on screen and the tab is visible, never * under reduced motion, and not while the reader is using it. `take()` hands it to the reader; it * takes back over `idle` ms after their last input. */export function useAutoplay<T extends HTMLElement>(idle = 6000) {  const ref = useRef<T>(null);  const [visible, setVisible] = useState(false);  const [reduced, setReduced] = useState(true);  const [taken, setTaken] = useState(false);  const timer = useRef(0);  useEffect(() => {    const element = ref.current;    if (!element) return;    let onScreen = false;    const update = () => setVisible(onScreen && !document.hidden);    const observer = new IntersectionObserver(      ([entry]) => {        onScreen = entry.isIntersecting;