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[browser][WebCrypto] Identicon generator with WebCrypto API
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| <!doctype html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8" /> | |
| <title>Simple Identicon Generator</title> | |
| <script src="script.js"></script> | |
| </head> | |
| <body> | |
| Type Your ID: <input id="id" /> | |
| <div> | |
| <canvas id="icon" width="420" height="420" | |
| style="background-color: #f0f0f0;"/> | |
| </div> | |
| </body> | |
| </html> |
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| "use strict"; | |
| window.addEventListener("load", ev => { | |
| const id = document.getElementById("id"); | |
| const icon = document.getElementById("icon"); | |
| const c2d = icon.getContext("2d"); | |
| function drawIcon(ev) { | |
| const buf = new TextEncoder("utf-8").encode(id.value.trim()); | |
| crypto.subtle.digest({name: "SHA-1"}, buf).then(hashToIcon).then(draw); | |
| } | |
| function hashToIcon(hash) { | |
| const dv = new DataView(hash); | |
| const hue = dv.getUint16(0, true) % 360; | |
| const sat = dv.getUint8(2) % 50 + 25; | |
| const lum = dv.getUint8(3) % 50 + 25; | |
| const buf = Array.from(new Uint8Array(hash, 4, 15)); | |
| const col5x3 = split(buf.map(v => v % 2 === 1), 5); | |
| const cols = col5x3.concat([col5x3[1], col5x3[0]]); | |
| return {hue, sat, lum, cols}; | |
| } | |
| function split(a, n) { | |
| return Array.from(Array(Math.ceil(a.length / n)), | |
| (_, i) => a.slice(i * n, i * n + n)); | |
| } | |
| function draw(icon) { | |
| const {width, height} = c2d.canvas; | |
| const block = {w: width / 6, h: height / 6}; | |
| const pad = {w: block.w / 2, h: block.h / 2}; | |
| c2d.fillStyle = c2d.canvas.style.backgroundColor; | |
| c2d.fillRect(0, 0, width, height); | |
| c2d.fillStyle = `hsl(${icon.hue}, ${icon.sat}%, ${icon.lum}%)`; | |
| icon.cols.forEach((col, x) => col.forEach((cell, y) => { | |
| if (cell) c2d.fillRect( | |
| pad.w + x * block.w, pad.h + y * block.h, block.w, block.h); | |
| })); | |
| } | |
| id.addEventListener("input", drawIcon, false); | |
| }, false); |
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demo: https://rawgit.com/bellbind/b528e26a63c8db919e0d/raw/index.html