Files
portal/gesture.js
T
Bendik Aagaard LynghaugandClaude Fable 5 72674afe05
Test / test (push) Successful in 25s
Gesture widget: stop drawing the decoded ghost path
decode_key's reconstruction is too rough to have value on screen;
the ack's key is kept, its path ignored. Revisit only once the
reconstruction is fixed at the core in redoal.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-08-30 11:21:20 +02:00

306 lines
11 KiB
JavaScript
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
// The `type: gesture` requirement widget: draw one stroke on a canvas,
// and the stroke becomes the field's value. Mirrors the two house
// patterns at once:
//
// - prosekit-editor.js's hidden-input bridge: the widget writes JSON
// into a paired hidden <input> and fires a real bubbling `input`
// event, so the Rust side reuses the exact same RwSignal/on:input
// wiring every other field kind uses - no bespoke value channel.
// - yes.js's lifecycle: mountGesture returns a handle whose stop()
// tears everything down (socket, listeners, rAF), because SPA
// navigation never unloads the document.
//
// When a relay URL is given, the widget also speaks the redoal-relay
// protocol (ADR-0013 in the redoal repo): announce the stroke, receive
// an ack carrying the stroke's gesture key (the decoded path it also
// carries is ignored: decode_key's sketch is too rough to show), and
// receive echoes of similar strokes other visitors drew, shown as
// thumbnails.
// Everything network is best-effort: no relay, refused connection, or
// a dropped socket all degrade to a plain offline drawing input.
//
// Canvas colors can't come from CSS custom properties (same
// constraint yes.js documents), so the widget carries its own copy of
// the palette for both themes - any palette change must land here AND
// in style/main.css.
const THEMES = {
dark: {
stroke: '#8ec2c0',
echo: '#8ec2c0',
},
light: {
stroke: '#47807e',
echo: '#47807e',
},
};
const MIN_POINT_DISTANCE = 3; // css px between recorded points
const MAX_ECHOES = 8;
const RECONNECT_BASE_MS = 1000;
const RECONNECT_MAX_MS = 30000;
class GestureWidget {
constructor(container, hidden, relayUrl) {
this.container = container;
this.hidden = hidden || null;
this.relayUrl = relayUrl || '';
this.points = [];
this.drawing = false;
this.stopped = false;
this.ws = null;
this.reconnectDelay = RECONNECT_BASE_MS;
this.reconnectTimer = null;
this.pendingAnnounce = null;
this.canvas = document.createElement('canvas');
this.canvas.className = 'gesture-canvas';
container.appendChild(this.canvas);
this.echoes = document.createElement('div');
this.echoes.className = 'gesture-echoes';
container.appendChild(this.echoes);
if (this.relayUrl) {
this.status = document.createElement('span');
this.status.className = 'gesture-status offline';
this.status.setAttribute('aria-label', 'relay connection');
container.appendChild(this.status);
}
this._themeQuery = window.matchMedia('(prefers-color-scheme: light)');
this._onTheme = () => this.render();
this._themeQuery.addEventListener('change', this._onTheme);
this._onResize = () => { this.sizeCanvas(); this.render(); };
window.addEventListener('resize', this._onResize);
this.sizeCanvas();
this._onDown = (e) => this.beginStroke(e);
this._onMove = (e) => this.extendStroke(e);
this._onUp = (e) => this.endStroke(e);
this.canvas.addEventListener('pointerdown', this._onDown);
this.canvas.addEventListener('pointermove', this._onMove);
this.canvas.addEventListener('pointerup', this._onUp);
this.canvas.addEventListener('pointercancel', this._onUp);
if (this.relayUrl) this.connect();
}
theme() {
return this._themeQuery.matches ? THEMES.light : THEMES.dark;
}
sizeCanvas() {
const rect = this.canvas.getBoundingClientRect();
const dpr = window.devicePixelRatio || 1;
this.canvas.width = Math.max(1, Math.round(rect.width * dpr));
this.canvas.height = Math.max(1, Math.round(rect.height * dpr));
this.ctx = this.canvas.getContext('2d');
this.ctx.scale(dpr, dpr);
this.cssWidth = rect.width;
this.cssHeight = rect.height;
}
pos(e) {
const rect = this.canvas.getBoundingClientRect();
return { x: e.clientX - rect.left, y: e.clientY - rect.top };
}
beginStroke(e) {
e.preventDefault();
this.canvas.setPointerCapture(e.pointerId);
// One stroke only - a new pointerdown replaces the old drawing
// (and any ambient trails from the previous round).
this.drawing = true;
this.points = [this.pos(e)];
this.render();
}
extendStroke(e) {
if (!this.drawing) return;
const p = this.pos(e);
const last = this.points[this.points.length - 1];
const dx = p.x - last.x, dy = p.y - last.y;
if (Math.sqrt(dx * dx + dy * dy) < MIN_POINT_DISTANCE) return;
this.points.push(p);
this.render();
}
endStroke() {
if (!this.drawing) return;
this.drawing = false;
if (this.points.length < 2) return;
const normalized = this.normalized();
this.setValue({ points: normalized, key: null });
this.announce(normalized);
}
// Canvas-frame normalization into the -1..1 square (the relay
// re-normalizes around the stroke itself before keying - this
// just bounds the payload and keeps the stored value
// resolution-independent).
normalized() {
const half = Math.max(this.cssWidth, this.cssHeight) / 2;
const cx = this.cssWidth / 2, cy = this.cssHeight / 2;
return this.points.map((p) => [
Math.round(((p.x - cx) / half) * 10000) / 10000,
Math.round(((p.y - cy) / half) * 10000) / 10000,
]);
}
setValue(value) {
if (!this.hidden) return;
this.hidden.value = JSON.stringify(value);
this.hidden.dispatchEvent(new Event('input', { bubbles: true }));
}
// ── Relay ──────────────────────────────────────────────────────
connect() {
if (this.stopped) return;
let ws;
try {
ws = new WebSocket(this.relayUrl);
} catch {
this.scheduleReconnect();
return;
}
this.ws = ws;
ws.addEventListener('open', () => {
if (this.stopped) return;
this.reconnectDelay = RECONNECT_BASE_MS;
this.status?.classList.replace('offline', 'live');
if (this.pendingAnnounce) {
ws.send(JSON.stringify({ type: 'announce', points: this.pendingAnnounce }));
this.pendingAnnounce = null;
}
});
ws.addEventListener('message', (e) => this.onMessage(e));
ws.addEventListener('close', () => {
this.status?.classList.replace('live', 'offline');
this.ws = null;
this.scheduleReconnect();
});
// 'error' is always followed by 'close'; nothing to do here.
}
scheduleReconnect() {
if (this.stopped || this.reconnectTimer) return;
this.reconnectTimer = setTimeout(() => {
this.reconnectTimer = null;
this.connect();
}, this.reconnectDelay);
this.reconnectDelay = Math.min(this.reconnectDelay * 2, RECONNECT_MAX_MS);
}
announce(points) {
if (!this.relayUrl) return;
if (this.ws && this.ws.readyState === WebSocket.OPEN) {
this.ws.send(JSON.stringify({ type: 'announce', points }));
} else {
this.pendingAnnounce = points;
}
}
onMessage(e) {
let msg;
try {
msg = JSON.parse(e.data);
} catch {
return;
}
if (msg.type === 'ack') {
if (this.points.length >= 2) {
this.setValue({ points: this.normalized(), key: msg.key });
}
} else if (msg.type === 'echo') {
this.addEchoThumbnail(msg);
}
// 'error' frames are intentionally silent: the widget is a
// form field first, and a rate-limited announce shouldn't
// alarm anyone mid-form.
}
addEchoThumbnail(msg) {
const thumb = document.createElement('canvas');
thumb.className = 'gesture-echo';
// Closer strokes render stronger; 500 is comfortably past the
// relay's default threshold, so everything stays visible.
const strength = Math.max(0.35, Math.min(1, 1 - msg.distance / 500));
thumb.style.setProperty('--echo-strength', String(strength));
this.echoes.prepend(thumb);
while (this.echoes.children.length > MAX_ECHOES) {
this.echoes.lastChild.remove();
}
const dpr = window.devicePixelRatio || 1;
const rect = thumb.getBoundingClientRect();
thumb.width = Math.max(1, Math.round(rect.width * dpr));
thumb.height = Math.max(1, Math.round(rect.height * dpr));
const ctx = thumb.getContext('2d');
ctx.scale(dpr, dpr);
this.drawPath(ctx, msg.path, rect.width, rect.height, this.theme().echo, 1.5, 0.15);
// A timeout, not requestAnimationFrame: the class must land on
// a later tick for the opacity transition to run, and rAF
// doesn't tick at all in headless engines.
setTimeout(() => thumb.classList.add('shown'), 30);
}
// ── Rendering ──────────────────────────────────────────────────
// Draw a normalized (-1..1) path fitted into w×h with padding.
drawPath(ctx, path, w, h, color, width, pad) {
if (!path || path.length < 2) return;
const scale = (Math.min(w, h) / 2) * (1 - pad);
const cx = w / 2, cy = h / 2;
ctx.strokeStyle = color;
ctx.lineWidth = width;
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
ctx.beginPath();
path.forEach(([x, y], i) => {
const px = cx + x * scale, py = cy + y * scale;
if (i === 0) ctx.moveTo(px, py);
else ctx.lineTo(px, py);
});
ctx.stroke();
}
render() {
if (!this.ctx) return;
const t = this.theme();
this.ctx.clearRect(0, 0, this.cssWidth, this.cssHeight);
if (this.points.length >= 1) {
this.ctx.strokeStyle = t.stroke;
this.ctx.lineWidth = 2;
this.ctx.lineCap = 'round';
this.ctx.lineJoin = 'round';
this.ctx.beginPath();
this.points.forEach((p, i) => {
if (i === 0) this.ctx.moveTo(p.x, p.y);
else this.ctx.lineTo(p.x, p.y);
});
this.ctx.stroke();
}
}
stop() {
this.stopped = true;
if (this.reconnectTimer) clearTimeout(this.reconnectTimer);
if (this.ws) {
// The close event still fires, but scheduleReconnect
// no-ops once stopped is set.
try { this.ws.close(); } catch { /* already dead */ }
this.ws = null;
}
window.removeEventListener('resize', this._onResize);
this._themeQuery.removeEventListener('change', this._onTheme);
this.canvas.removeEventListener('pointerdown', this._onDown);
this.canvas.removeEventListener('pointermove', this._onMove);
this.canvas.removeEventListener('pointerup', this._onUp);
this.canvas.removeEventListener('pointercancel', this._onUp);
}
}
export function mountGesture(container, hidden, relayUrl) {
return new GestureWidget(container, hidden, relayUrl);
}