Clyune Component GallerySpiral Sampling · How it works & code
Archimedean / Logarithmic / Fermat Spiral
Runtime logic
Visiting `/canvas/spiral`, DemoHost lazy-loads `demos/kits/kit-canvas.js` (registry `mod: 'kit-canvas'`) and calls `mount(host, { variant: 'spiral' })`. mount resolves the variant to family `spiral`; `withControls` builds the control panel (4 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; hexRgb — Colour string → [r, g, b]; rgba — Builds an rgba() colour string; 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.get — Reads current control values; S.onFrame — Registers a per-frame callback; its return value feeds the info panel; ctx.beginPath() — Starts a new path; ctx.moveTo() — Moves the pen without drawing; ctx.lineTo() — Adds a straight line to a point; ctx.stroke() — Strokes the current path; ctx.setLineDash() — Sets the dash pattern for strokes; ctx.arc() — Adds a circular arc (center, radius, start/end angle); ctx.fill() — Fills the current path
Source code
frontend/src/demos/kits/kit-canvas.js: FAM.spiral (L993-L1030)
Code walkthrough
L994-994: Control definitions (colour/speed/size/count/extras): Spiral Color, Pitch b, Polar Grid, Type 1 Akimid 2 logarithm 3 Ferma, Rainbow Gradient, Number of Turns. L995-995: Preset buttons: name → parameter overrides (4). L996-1004: Info-panel content: live rows(v), formula, notes, params, steps. L1005-1029: Init function: sets up state and returns the per-frame callback: draws with Canvas 2D `beginPath`, `moveTo`, `lineTo`, `stroke`, `setLineDash`, `arc` …; math via `Math.round`, `Math.min`, `Math.max`, `Math.exp`, `Math.sqrt`, `Math.cos` …; returns readouts `type`, `arms`, `b`, `turns`, `th`, `rp` to the info panel.
Principles
Akimid: r = b·θ (Circle distance constant 2πb) Logarithm: r = a·e^(bθ) (Zoom in every circle e^(2πb) Double, Nautilus) Fermat: r = b·√θ (Equities, sunflower seeds) The screw is in Polar Coordinates Best described: angle θ Keep growing. Radius r 随 θ By a certain pattern. The lengths of the Akimid spiral are the same as those of the record; the logarithmic spirals are magnified at a fixed rate, and the nautilus, typhoons, and spiral arms of the galaxies in nature are approaching it; and the pema screws are more and more dense and form the basis for the sorting of sunflower seeds. Multiple arms are the whole curve 360°/Polar Grid Draw again. Pointer angle indicates the radius corresponding to that angle.