Clyune Component GalleryClip-path · How it works & code
clip-path Reveal/Transform
Runtime logic
Visiting `/css-fx/clip`, DemoHost lazy-loads `demos/kits/kit-css.js` (registry `mod: 'kit-css'`) and calls `mount(host, { variant: 'clip' })`. mount resolves the variant to family `clip`; `withControls` builds the control panel (10 presets + sliders). `createCanvasStage` creates the `<canvas>` (HiDPI ≤ 2×, ResizeObserver) and the info panel. The family’s `build(S)` initialises state and returns the per-frame callback. Every `requestAnimationFrame`: read controls, advance a speed-scaled clock (dt ≤ 50 ms), run the frame callback; returned readouts go to the info panel. Changing parameters: colour/speed/size apply live; structural ones remount; leaving the page cancels rAF, removes listeners and frees resources.
Environment
Canvas 2D: 2D canvas drawing; requestAnimationFrame: Display-synced animation loop; ResizeObserver: Canvas follows container size; Pointer Events: Unified mouse/touch/pen events; devicePixelRatio: Crisp HiDPI rendering (capped at 2×) · react 18.3.1, react-router-dom 6.30.6, vite 5.4.21
Dependencies
react 18.3.1
Imported APIs
withControls — Wraps the demo in the shared control panel (presets, sliders, reset); hot-updates or remounts on change; paramsFromSpec — Turns the spec (colour/speed/size/count/extras) into control-panel parameter definitions; createCanvasStage — Shared Canvas 2D stage: canvas + info panel, HiDPI, one rAF loop, pointer state, idle auto-pointer; hueOf — Hue of a colour (0–360°); clamp — Clamps a value to a range; TAU — Constant 2π; fmt — Number formatting (fixed decimals); F — Formula block HTML; S.clear — Clears with the background colour (translucent = trails); S.onFrame — Registers a per-frame callback; its return value feeds the info panel; ctx.createLinearGradient() — Creates a linear gradient; ctx.save() — Saves the drawing state (transform, styles, clip); ctx.beginPath() — Starts a new path; ctx.arc() — Adds a circular arc (center, radius, start/end angle); ctx.moveTo() — Moves the pen without drawing; ctx.lineTo() — Adds a straight line to a point; ctx.closePath() — Closes the current sub-path; ctx.rect() — Adds a rectangle to the path; ctx.clip() — Turns the current path into the clipping region; ctx.fillRect() — Fills a rectangle; ctx.restore() — Restores the saved drawing state; ctx.fillText() — Draws filled text; ctx.arcTo() — Adds an arc using tangent lines; ctx.fill() — Fills the current path
Source code
frontend/src/demos/kits/kit-css.js: FAM.clip (L374-L412)
Code walkthrough
L375-378: Control definitions (colour/speed/size/count/extras): Primary Color, Scale, Shape, Reveal Amount. L379-379: Preset buttons: name → parameter overrides (5). L380-380: Info-panel content: live rows(v), formula, notes, params, steps. L381-411: Init function: sets up state and returns the per-frame callback: draws with Canvas 2D `createLinearGradient`, `save`, `beginPath`, `arc`, `moveTo`, `lineTo` …; math via `Math.round`, `Math.min`, `Math.sin`, `Math.cos`; returns readouts `mode`, `ph`, `cell`, `colorHex` to the info panel.
Principles
progress = fract(t × speed) clip-path Cut out the shape. Discovery from 0→1 It's like closing the curtains, showing a gradient.