Clyune Component GalleryTypewriter · How it works & code
"Show one more word every fixed time on the axis." It looks like someone's typing; it's all done. Stop 1 Authorities, one word at a time and one word at a time.
Runtime logic
Visiting `/gsap/type`, DemoHost lazy-loads `demos/kits/kit-gsap.js` (registry `mod: 'kit-gsap'`) and calls `mount(host, { variant: 'type' })`. mount resolves the variant to family `type`; `withControls` builds the control panel (6 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; fmt — Number formatting (fixed decimals); F — Formula block HTML; getLang — Current UI language (zh/en); S.clear — Clears with the background colour (translucent = trails); S.onFrame — Registers a per-frame callback; its return value feeds the info panel; ctx.fillText() — Draws filled text; ctx.measureText() — Measures text width; ctx.fillRect() — Fills a rectangle; ctx.beginPath() — Starts a new path; ctx.moveTo() — Moves the pen without drawing; ctx.arcTo() — Adds an arc using tangent lines; ctx.closePath() — Closes the current sub-path; ctx.fill() — Fills the current path; ctx.stroke() — Strokes the current path; ctx.save() — Saves the drawing state (transform, styles, clip); ctx.rect() — Adds a rectangle to the path; ctx.clip() — Turns the current path into the clipping region; ctx.translate() — Translates the coordinate system; ctx.restore() — Restores the saved drawing state
Source code
frontend/src/demos/kits/kit-gsap.js: FAM.type (L389-L403)
Code walkthrough
L389-403: Calls the factory `gFam()` to produce the full definition (spec + doc + build) from the options below. L389-389: Title shown in the info and control panels: “Typewriter”. L389-389: Range/default of the count slider. L389-389: Extra demo-specific slider/toggle: Per character duration. L389-389: Range/default of the size slider. L389-389: Default main colour. L390-390: Help text of the count parameter. L390-390: Help text of the extra parameter. L390-390: Help text of the size parameter. L391-391: Preset buttons: name → parameter overrides (5). L392-392: Body of the “Notes” section. L393-393: Main formula of the “Formula” section. L393-393: Second formula line. L394-403: Per-frame draw function: draws with Canvas 2D `fillText`, `measureText`, `fillRect`; math via `Math.floor`, `Math.max`, `Math.min`, `Math.abs`, `Math.round`; returns readouts `mode`, `cell` to the info panel.
Principles
86 = field (time) / Time per word) gsap.to(state, { n: Total number of words, duration: Total number of words · 0.08, ease: "none", onUpdate: () => el.textContent = text.slice(0, state.n) }) 打字机：时间轴上每隔固定时间「多显示一个字」，看起来就像有人在打字；全部打完停 1 秒，再用一半的时间一个字一个字删掉。闪烁的竖线是光标。用 GSAP When achieved, a number can be supplemented (from 0 To the total number of words) each frame intercepts the text to this length. There's no load here GSAP 库，而是用几十行代码复刻了它最核心的几个概念：补间（tween，从 A Smooth transition of value B Value, slow motion ease，Control the slow pace of transition, the time axis timeline，Sort multi-part patches in order) and staggered ( stagger，让一组元素依次出发）。每一帧都直接根据「当前时间」算出画面，所以拖动右侧滑条会立即看到变化。公式区给出了对应的 GSAP In writing, you can move directly to the real project.