iceshrimp-161sh/packages/backend/src/misc/gen-identicon.ts
ThatOneCalculator ac64087a1e no more eslint
2023-01-12 20:54:33 -08:00

100 lines
2.4 KiB
TypeScript

/**
* Identicon generator
* https://en.wikipedia.org/wiki/Identicon
*/
import type { WriteStream } from "node:fs";
import * as p from "pureimage";
import gen from "random-seed";
const size = 128; // px
const n = 5; // resolution
const margin = size / 4;
const colors = [
["#FF512F", "#DD2476"],
["#FF61D2", "#FE9090"],
["#72FFB6", "#10D164"],
["#FD8451", "#FFBD6F"],
["#305170", "#6DFC6B"],
["#00C0FF", "#4218B8"],
["#009245", "#FCEE21"],
["#0100EC", "#FB36F4"],
["#FDABDD", "#374A5A"],
["#38A2D7", "#561139"],
["#121C84", "#8278DA"],
["#5761B2", "#1FC5A8"],
["#FFDB01", "#0E197D"],
["#FF3E9D", "#0E1F40"],
["#766eff", "#00d4ff"],
["#9bff6e", "#00d4ff"],
["#ff6e94", "#00d4ff"],
["#ffa96e", "#00d4ff"],
["#ffa96e", "#ff009d"],
["#ffdd6e", "#ff009d"],
];
const actualSize = size - margin * 2;
const cellSize = actualSize / n;
const sideN = Math.floor(n / 2);
/**
* Generate buffer of an identicon by seed
*/
export function genIdenticon(seed: string, stream: WriteStream): Promise<void> {
const rand = gen.create(seed);
const canvas = p.make(size, size, undefined);
const ctx = canvas.getContext("2d");
const bgColors = colors[rand(colors.length)];
const bg = ctx.createLinearGradient(0, 0, size, size);
bg.addColorStop(0, bgColors[0]);
bg.addColorStop(1, bgColors[1]);
ctx.fillStyle = bg;
ctx.beginPath();
ctx.fillRect(0, 0, size, size);
ctx.fillStyle = "#ffffff";
// side bitmap (filled by false)
const side: boolean[][] = new Array(sideN);
for (let i = 0; i < side.length; i++) {
side[i] = new Array(n).fill(false);
}
// 1*n (filled by false)
const center: boolean[] = new Array(n).fill(false);
for (let x = 0; x < side.length; x++) {
for (let y = 0; y < side[x].length; y++) {
side[x][y] = rand(3) === 0;
}
}
for (let i = 0; i < center.length; i++) {
center[i] = rand(3) === 0;
}
// Draw
for (let x = 0; x < n; x++) {
for (let y = 0; y < n; y++) {
const isXCenter = x === (n - 1) / 2;
if (isXCenter && !center[y]) continue;
const isLeftSide = x < (n - 1) / 2;
if (isLeftSide && !side[x][y]) continue;
const isRightSide = x > (n - 1) / 2;
if (isRightSide && !side[sideN - (x - sideN)][y]) continue;
const actualX = margin + cellSize * x;
const actualY = margin + cellSize * y;
ctx.beginPath();
ctx.fillRect(actualX, actualY, cellSize, cellSize);
}
}
return p.encodePNGToStream(canvas, stream);
}