Gradient ASCII

// Copyright (c) 2026 Bruno Delorence. MIT License.'use client';import {  useEffect,  useEffectEvent,  useMemo,  useRef,  useState,  type PointerEvent as ReactPointerEvent,  type RefObject,} from 'react';import { Panel } from './panel';import { DEFAULTS, presetOf, type GradientSettings, type Shape } from './presets';import { createRenderer, type Renderer } from './renderer';import { useAutoplay } from './use-autoplay';import styles from './gradient-ascii.module.css';export { CHARACTER_SETS, PRESETS, DEFAULTS } from './presets';export type { ClickEffect, GradientSettings, Shape } from './presets';/* * Gradient ASCII: a soft glow of light drawn in characters, as a background. Under it lies a

// Copyright (c) 2026 Bruno Delorence. MIT License.import type { GradientSettings, Shape } from './presets';/* * The renderer: one WebGL fragment shader draws the whole picture, the soft light and the * characters over it, at the canvas's device pixels. * * - The light is a field worked out per pixel: each shape gives how much light there is (L), how *   far into it a point lies (m: the edge colour gives way to the light's own), and where it sits *   across the light (u, which picks among the colours after the first). A slow noise warps the *   field so it wavers as it drifts. * - The characters live on a grid of cells, each 0.6 as wide as it is tall. A cell asks the same *   field at its middle how bright it is and picks a character from the ramp; a seeded noise *   leaves the dimmer cells empty first (density), and now and then a cell swaps with a *   neighbouring brightness (flicker). * - The glyphs come from an atlas drawn once on a 2D canvas, at the cell's exact size in device *   px, so they stay crisp; a blurred twin of it gives the glow and the out-of-focus characters. *   Blocks and dots are drawn as shapes, so they fill their cells whatever the font. * - Scrambling is an energy per cell, kept on the CPU (a few thousand bytes) and sent as a small *   texture: the pointer and a click's burst raise it, and it drains in about half a second. A *   click's ring is drawn by the shader itself, a thin band one cell wide travelling at about one *   height of the canvas a second. A cell with energy shows a random character from the ramp, *   changed sixteen times a second.

// Copyright (c) 2026 Bruno Delorence. MIT License.'use client';import {  useEffect,  useId,  useRef,  useState,  type CSSProperties,  type KeyboardEvent as ReactKeyboardEvent,  type PointerEvent as ReactPointerEvent,} from 'react';import {  CHARACTER_SETS,  PRESETS,  RANGES,  characterSetOf,  presetOf,  type CharacterSet,  type ClickEffect,  type GradientSettings,  type NumberSetting,  type Preset,

// Copyright (c) 2026 Bruno Delorence. MIT License./* * The settings a gradient takes, their defaults and ranges, and the named starting points: four * presets (a palette, a shape, a set of characters and a cell size each) and five sets of * characters. The panel and the renderer both read from here. */export type Shape = 'horizon' | 'pinch' | 'rise' | 'eclipse';export type ClickEffect = 'wave' | 'burst' | 'none';export type GradientSettings = {  /**   * Two to eight colours. The first is the edge of the shadow; the rest run across the light: on   * a horizon from the sun out to the far sky, on the other shapes from the outskirts in to the   * heart of the light.   */  colors: string[];  shape: Shape;  /** Characters from dimmest to brightest; a space leaves a cell empty. */  characters: string;  /** Height of a character cell in px; cells are 0.6 as wide. */  cellSize: number;  density: number;

// Copyright (c) 2026 Bruno Delorence. MIT License.'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(

/* Gradient ASCII (gradient-ascii.tsx): a framed stage with the light drawn in characters, and   under it the Customize card with its panel of rows in three columns (two under 600px, one   under 380px: a container query on the component's own width).   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). The light itself is drawn by the shader in   renderer.ts from its own colours; only the stage behind it comes from here.   Memory. The canvas is one layer, sized by its frame; the panel's fills, handles and knobs move   by width and transform on rows of fixed height, so a change never lays out the page around. */.root {  /* The stage behind the light, and its frame's edge. */  --stage: #f6f5f8;  --stage-edge: #e3e1e8;  /* The Customize card (the dark one is a white veil of 4% over the stage), the panel inside it     and its edge. */  --card: #efeef2;  --panel: #fff;  --panel-edge: rgb(0 0 0 / 0.07);  /* A row, a scrubber's fill, its ticks and its handle. */  --row: rgb(0 0 0 / 0.035);  --fill: rgb(0 0 0 / 0.05);