92 lines
2.0 KiB
TypeScript
92 lines
2.0 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 * as p from 'pureimage';
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import * as gen from 'random-seed';
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import { WriteStream } from 'fs';
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const size = 256; // px
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const n = 5; // resolution
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const margin = (size / n);
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const colors = [
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'#e57373',
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'#F06292',
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'#BA68C8',
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'#9575CD',
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'#7986CB',
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'#64B5F6',
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'#4FC3F7',
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'#4DD0E1',
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'#4DB6AC',
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'#81C784',
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'#8BC34A',
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'#AFB42B',
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'#F57F17',
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'#FF5722',
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'#795548',
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'#455A64',
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];
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const bg = '#e9e9e9';
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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);
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const ctx = canvas.getContext('2d');
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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 = colors[rand(colors.length)];
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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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// eslint:disable-next-line:prefer-for-of
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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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