<pixel-canvas> Web Component

index.html

<main>
  <div class="card">
    <pixel-canvas></pixel-canvas>
    <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentcolor" viewBox="0 0 256 256">
      <path d="M216,42H40A14,14,0,0,0,26,56V200a14,14,0,0,0,14,14H216a14,14,0,0,0,14-14V56A14,14,0,0,0,216,42ZM40,54H216a2,2,0,0,1,2,2V98H38V56A2,2,0,0,1,40,54ZM38,200V110H98v92H40A2,2,0,0,1,38,200Zm178,2H110V110H218v90A2,2,0,0,1,216,202Z"></path>
    </svg>
    <button>Layout</buton>
  </div>

  <div class="card" style="--active-color: #e0f2fe">
    <pixel-canvas data-gap="10" data-speed="25" data-colors="#e0f2fe, #7dd3fc, #0ea5e9"></pixel-canvas>
    <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentcolor" viewBox="0 0 256 256">
      <path d="M67.84,92.61,25.37,128l42.47,35.39a6,6,0,1,1-7.68,9.22l-48-40a6,6,0,0,1,0-9.22l48-40a6,6,0,0,1,7.68,9.22Zm176,30.78-48-40a6,6,0,1,0-7.68,9.22L230.63,128l-42.47,35.39a6,6,0,1,0,7.68,9.22l48-40a6,6,0,0,0,0-9.22Zm-81.79-89A6,6,0,0,0,154.36,38l-64,176A6,6,0,0,0,94,221.64a6.15,6.15,0,0,0,2,.36,6,6,0,0,0,5.64-3.95l64-176A6,6,0,0,0,162.05,34.36Z"></path>
    </svg>
    <button>Code</buton>
  </div>

  <div class="card" style="--active-color: #fef08a">
    <pixel-canvas data-gap="3" data-speed="20" data-colors="#fef08a, #fde047, #eab308"></pixel-canvas>
    <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentcolor" viewBox="0 0 256 256">
      <path d="M180,146H158V110h22a34,34,0,1,0-34-34V98H110V76a34,34,0,1,0-34,34H98v36H76a34,34,0,1,0,34,34V158h36v22a34,34,0,1,0,34-34ZM158,76a22,22,0,1,1,22,22H158ZM54,76a22,22,0,0,1,44,0V98H76A22,22,0,0,1,54,76ZM98,180a22,22,0,1,1-22-22H98Zm12-70h36v36H110Zm70,92a22,22,0,0,1-22-22V158h22a22,22,0,0,1,0,44Z"></path>
    </svg>
    <button>Command</buton>
  </div>

  <div class="card" style="--active-color: #fecdd3">
    <pixel-canvas data-gap="6" data-speed="80" data-colors="#fecdd3, #fda4af, #e11d48" data-no-focus></pixel-canvas>
    <svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" fill="currentcolor" viewBox="0 0 256 256">
      <path d="M222,67.34a33.81,33.81,0,0,0-10.64-24.25C198.12,30.56,176.68,31,163.54,44.18L142.82,65l-.63-.63a22,22,0,0,0-31.11,0l-9,9a14,14,0,0,0,0,19.81l3.47,3.47L53.14,149.1a37.81,37.81,0,0,0-9.84,36.73l-8.31,19a11.68,11.68,0,0,0,2.46,13A13.91,13.91,0,0,0,47.32,222,14.15,14.15,0,0,0,53,220.82L71,212.92a37.92,37.92,0,0,0,35.84-10.07l52.44-52.46,3.47,3.48a14,14,0,0,0,19.8,0l9-9a22.06,22.06,0,0,0,0-31.13l-.66-.65L212,91.85A33.76,33.76,0,0,0,222,67.34Zm-123.61,127a26,26,0,0,1-26,6.47,6,6,0,0,0-4.17.24l-20,8.75a2,2,0,0,1-2.09-.31l9.12-20.9a5.94,5.94,0,0,0,.19-4.31A25.91,25.91,0,0,1,56,166h70.78ZM138.78,154H65.24l48.83-48.84,36.76,36.78Zm64.77-70.59L178.17,108.9a6,6,0,0,0,0,8.47l4.88,4.89a10,10,0,0,1,0,14.15l-9,9a2,2,0,0,1-2.82,0l-60.69-60.7a2,2,0,0,1,0-2.83l9-9a10,10,0,0,1,14.14,0l4.89,4.89a6,6,0,0,0,4.24,1.75h0a6,6,0,0,0,4.25-1.77L172,52.66c8.57-8.58,22.51-9,31.07-.85a22,22,0,0,1,.44,31.57Z"></path>
    </svg>
    <button>Dropper</buton>
  </div>
</main>

pixel-canvas-web-component.markdown

Web Component

Web Component that applies a shimmering pixel background on element hover.

Read the blog post

A Pen by Ryan Mulligan on CodePen.

License.

script.js

class Pixel {
  constructor(canvas, context, x, y, color, speed, delay) {
    this.width = canvas.width;
    this.height = canvas.height;
    this.ctx = context;
    this.x = x;
    this.y = y;
    this.color = color;
    this.speed = this.getRandomValue(0.1, 0.9) * speed;
    this.size = 0;
    this.sizeStep = Math.random() * 0.4;
    this.minSize = 0.5;
    this.maxSizeInteger = 2;
    this.maxSize = this.getRandomValue(this.minSize, this.maxSizeInteger);
    this.delay = delay;
    this.counter = 0;
    this.counterStep = Math.random() * 4 + (this.width + this.height) * 0.01;
    this.isIdle = false;
    this.isReverse = false;
    this.isShimmer = false;
  }

  getRandomValue(min, max) {
    return Math.random() * (max - min) + min;
  }

  draw() {
    const centerOffset = this.maxSizeInteger * 0.5 - this.size * 0.5;

    this.ctx.fillStyle = this.color;
    this.ctx.fillRect(
      this.x + centerOffset,
      this.y + centerOffset,
      this.size,
      this.size
    );
  }

  appear() {
    this.isIdle = false;

    if (this.counter <= this.delay) {
      this.counter += this.counterStep;
      return;
    }

    if (this.size >= this.maxSize) {
      this.isShimmer = true;
    }

    if (this.isShimmer) {
      this.shimmer();
    } else {
      this.size += this.sizeStep;
    }

    this.draw();
  }

  disappear() {
    this.isShimmer = false;
    this.counter = 0;

    if (this.size <= 0) {
      this.isIdle = true;
      return;
    } else {
      this.size -= 0.1;
    }

    this.draw();
  }

  shimmer() {
    if (this.size >= this.maxSize) {
      this.isReverse = true;
    } else if (this.size <= this.minSize) {
      this.isReverse = false;
    }

    if (this.isReverse) {
      this.size -= this.speed;
    } else {
      this.size += this.speed;
    }
  }
}

class PixelCanvas extends HTMLElement {
  static register(tag = "pixel-canvas") {
    if ("customElements" in window) {
      customElements.define(tag, this);
    }
  }

  static css = `
    :host {
      display: grid;
      inline-size: 100%;
      block-size: 100%;
      overflow: hidden;
    }
  `;

  get colors() {
    return this.dataset.colors?.split(",") || ["#f8fafc", "#f1f5f9", "#cbd5e1"];
  }

  get gap() {
    const value = this.dataset.gap || 5;
    const min = 4;
    const max = 50;

    if (value <= min) {
      return min;
    } else if (value >= max) {
      return max;
    } else {
      return parseInt(value);
    }
  }

  get speed() {
    const value = this.dataset.speed || 35;
    const min = 0;
    const max = 100;
    const throttle = 0.001;

    if (value <= min || this.reducedMotion) {
      return min;
    } else if (value >= max) {
      return max * throttle;
    } else {
      return parseInt(value) * throttle;
    }
  }

  get noFocus() {
    return this.hasAttribute("data-no-focus");
  }

  connectedCallback() {
    const canvas = document.createElement("canvas");
    const sheet = new CSSStyleSheet();

    this._parent = this.parentNode;
    this.shadowroot = this.attachShadow({ mode: "open" });

    sheet.replaceSync(PixelCanvas.css);

    this.shadowroot.adoptedStyleSheets = [sheet];
    this.shadowroot.append(canvas);
    this.canvas = this.shadowroot.querySelector("canvas");
    this.ctx = this.canvas.getContext("2d");
    this.timeInterval = 1000 / 60;
    this.timePrevious = performance.now();
    this.reducedMotion = window.matchMedia(
      "(prefers-reduced-motion: reduce)"
    ).matches;

    this.init();
    this.resizeObserver = new ResizeObserver(() => this.init());
    this.resizeObserver.observe(this);

    this._parent.addEventListener("mouseenter", this);
    this._parent.addEventListener("mouseleave", this);

    if (!this.noFocus) {
      this._parent.addEventListener("focusin", this);
      this._parent.addEventListener("focusout", this);
    }
  }

  disconnectedCallback() {
    this.resizeObserver.disconnect();
    this._parent.removeEventListener("mouseenter", this);
    this._parent.removeEventListener("mouseleave", this);

    if (!this.noFocus) {
      this._parent.removeEventListener("focusin", this);
      this._parent.removeEventListener("focusout", this);
    }

    delete this._parent;
  }

  handleEvent(event) {
    this[`on${event.type}`](event);
  }

  onmouseenter() {
    this.handleAnimation("appear");
  }

  onmouseleave() {
    this.handleAnimation("disappear");
  }

  onfocusin(e) {
    if (e.currentTarget.contains(e.relatedTarget)) return;
    this.handleAnimation("appear");
  }

  onfocusout(e) {
    if (e.currentTarget.contains(e.relatedTarget)) return;
    this.handleAnimation("disappear");
  }

  handleAnimation(name) {
    cancelAnimationFrame(this.animation);
    this.animation = this.animate(name);
  }

  init() {
    const rect = this.getBoundingClientRect();
    const width = Math.floor(rect.width);
    const height = Math.floor(rect.height);

    this.pixels = [];
    this.canvas.width = width;
    this.canvas.height = height;
    this.canvas.style.width = `${width}px`;
    this.canvas.style.height = `${height}px`;
    this.createPixels();
  }

  getDistanceToCanvasCenter(x, y) {
    const dx = x - this.canvas.width / 2;
    const dy = y - this.canvas.height / 2;
    const distance = Math.sqrt(dx * dx + dy * dy);

    return distance;
  }

  createPixels() {
    for (let x = 0; x < this.canvas.width; x += this.gap) {
      for (let y = 0; y < this.canvas.height; y += this.gap) {
        const color = this.colors[
          Math.floor(Math.random() * this.colors.length)
        ];
        const delay = this.reducedMotion
          ? 0
          : this.getDistanceToCanvasCenter(x, y);

        this.pixels.push(
          new Pixel(this.canvas, this.ctx, x, y, color, this.speed, delay)
        );
      }
    }
  }

  animate(fnName) {
    this.animation = requestAnimationFrame(() => this.animate(fnName));

    const timeNow = performance.now();
    const timePassed = timeNow - this.timePrevious;

    if (timePassed < this.timeInterval) return;

    this.timePrevious = timeNow - (timePassed % this.timeInterval);

    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);

    for (let i = 0; i < this.pixels.length; i++) {
      this.pixels[i][fnName]();
    }

    if (this.pixels.every((pixel) => pixel.isIdle)) {
      cancelAnimationFrame(this.animation);
    }
  }
}

PixelCanvas.register();

style.css

:root {
  --space: 1rem;
  --bg: #09090b;
  --fg: #e3e3e3;
  --surface-1: #101012;
  --surface-2: #27272a;
  --surface-3: #52525b;
  --ease-out: cubic-bezier(0.5, 1, 0.89, 1);
  --ease-in-out: cubic-bezier(0.45, 0, 0.55, 1);
}

* {
  box-sizing: border-box;
}

height,
body {
  height: 100%;
}

body {
  display: grid;
  color: var(--fg);
  background: var(--bg);
  padding: var(--space);
  min-height: 100vh;
}

main {
  display: grid;
  grid-template-columns: repeat(var(--count, 1), 1fr);
  gap: var(--space);
  margin: auto;
  inline-size: min(var(--max, 15rem), 100%);

  @media (min-width: 25rem) {
    --count: 2;
    --max: 30rem;
  }

  @media (min-width: 45rem) {
    --count: 4;
    --max: 60rem;
  }
}

.card {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-areas: "card";
  place-items: center;
  aspect-ratio: 4/5;
  border: 1px solid var(--surface-2);
  isolation: isolate;
  transition: border-color 200ms var(--ease-out);
  user-select: none;

  &::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(
      circle at bottom left,
      transparent 55%,
      var(--surface-1)
    );
    pointer-events: none;
    box-shadow: var(--bg) -0.5cqi 0.5cqi 2.5cqi inset;
    transition: opacity 900ms var(--ease-out);
  }

  &::after {
    content: "";
    position: absolute;
    inset: 0;
    margin: auto;
    aspect-ratio: 1;
    background: radial-gradient(circle, var(--bg), transparent 65%);
    opacity: 0;
    transition: opacity 800ms var(--ease-out);
  }

  > * {
    grid-area: card;
  }

  svg {
    position: relative;
    z-index: 1;
    width: 30%;
    height: auto;
    color: var(--surface-3);
    transition: 300ms var(--ease-out);
    transition-property: color, scale;
  }

  button {
    opacity: 0;
  }

  &:focus-within {
    outline: 5px auto Highlight;
    outline: 5px auto -webkit-focus-ring-color;
  }

  &:where(:hover, :focus-within) {
    border-color: var(--active-color, var(--fg));
    transition: border-color 800ms var(--ease-in-out);
  }

  &:where(:hover, :focus-within) svg {
    color: var(--active-color, var(--fg));
    scale: 1.1;
    transition: 300ms var(--ease-in-out);
  }

  &:where(:hover, :focus-within)::before {
    opacity: 0;
  }

  &:where(:hover, :focus-within)::after {
    opacity: 1;
  }
}