115 lines
2.7 KiB
TypeScript
115 lines
2.7 KiB
TypeScript
/**
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* Identicon generator
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* https://en.wikipedia.org/wiki/Identicon
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*/
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import type { WriteStream } from "node:fs";
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import * as p from "pureimage";
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import gen from "random-seed";
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const size = 128; // px
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const n = 5; // resolution
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const margin = size / 4;
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const colors = [
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["#eb6f92", "#b4637a"],
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["#f6c177", "#ea9d34"],
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["#ebbcba", "#d7827e"],
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["#9ccfd8", "#56949f"],
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["#c4a7e7", "#907aa9"],
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["#eb6f92", "#f6c177"],
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["#eb6f92", "#ebbcba"],
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["#eb6f92", "#31748f"],
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["#eb6f92", "#9ccfd8"],
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["#eb6f92", "#c4a7e7"],
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["#f6c177", "#eb6f92"],
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["#f6c177", "#ebbcba"],
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["#f6c177", "#31748f"],
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["#f6c177", "#9ccfd8"],
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["#f6c177", "#c4a7e7"],
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["#ebbcba", "#eb6f92"],
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["#ebbcba", "#f6c177"],
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["#ebbcba", "#31748f"],
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["#ebbcba", "#9ccfd8"],
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["#ebbcba", "#c4a7e7"],
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["#31748f", "#eb6f92"],
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["#31748f", "#f6c177"],
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["#31748f", "#ebbcba"],
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["#31748f", "#9ccfd8"],
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["#31748f", "#c4a7e7"],
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["#9ccfd8", "#eb6f92"],
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["#9ccfd8", "#f6c177"],
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["#9ccfd8", "#ebbcba"],
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["#9ccfd8", "#31748f"],
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["#9ccfd8", "#c4a7e7"],
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["#c4a7e7", "#eb6f92"],
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["#c4a7e7", "#f6c177"],
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["#c4a7e7", "#ebbcba"],
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["#c4a7e7", "#31748f"],
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["#c4a7e7", "#9ccfd8"],
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];
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const actualSize = size - margin * 2;
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const cellSize = actualSize / n;
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const sideN = Math.floor(n / 2);
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/**
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* Generate buffer of an identicon by seed
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*/
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export function genIdenticon(seed: string, stream: WriteStream): Promise<void> {
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const rand = gen.create(seed);
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const canvas = p.make(size, size, undefined);
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const ctx = canvas.getContext("2d");
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const bgColors = colors[rand(colors.length)];
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const bg = ctx.createLinearGradient(0, 0, size, size);
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bg.addColorStop(0, bgColors[0]);
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bg.addColorStop(1, bgColors[1]);
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ctx.fillStyle = bg;
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ctx.beginPath();
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ctx.fillRect(0, 0, size, size);
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ctx.fillStyle = "#ffffff";
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// side bitmap (filled by false)
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const side: boolean[][] = new Array(sideN);
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for (let i = 0; i < side.length; i++) {
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side[i] = new Array(n).fill(false);
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}
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// 1*n (filled by false)
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const center: boolean[] = new Array(n).fill(false);
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for (let x = 0; x < side.length; x++) {
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for (let y = 0; y < side[x].length; y++) {
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side[x][y] = rand(3) === 0;
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}
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}
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for (let i = 0; i < center.length; i++) {
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center[i] = rand(3) === 0;
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}
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// Draw
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for (let x = 0; x < n; x++) {
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for (let y = 0; y < n; y++) {
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const isXCenter = x === (n - 1) / 2;
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if (isXCenter && !center[y]) continue;
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const isLeftSide = x < (n - 1) / 2;
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if (isLeftSide && !side[x][y]) continue;
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const isRightSide = x > (n - 1) / 2;
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if (isRightSide && !side[sideN - (x - sideN)][y]) continue;
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const actualX = margin + cellSize * x;
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const actualY = margin + cellSize * y;
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ctx.beginPath();
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ctx.fillRect(actualX, actualY, cellSize, cellSize);
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}
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}
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return p.encodePNGToStream(canvas, stream);
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}
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