49 lines
1.4 KiB
JavaScript
49 lines
1.4 KiB
JavaScript
// @ts-check
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const stream = require("stream")
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const {PNG} = require("pngjs")
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const SIZE = 160 // Discord's display size on 1x displays is 160
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/**
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* @typedef RlottieWasm
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* @prop {(string) => boolean} load load lottie data from string of json
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* @prop {() => number} frames get number of frames
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* @prop {(frameCount: number, width: number, height: number) => Uint8Array} render render lottie data to bitmap
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*/
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const Rlottie = (async () => {
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const Rlottie = require("./rlottie-wasm.js")
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await new Promise(resolve => Rlottie.onRuntimeInitialized = resolve)
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return Rlottie
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})()
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/**
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* @param {string} text
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* @returns {Promise<import("stream").Readable>}
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*/
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async function convert(text) {
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const r = await Rlottie
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/** @type RlottieWasm */
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const rh = new r.RlottieWasm()
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const status = rh.load(text)
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if (!status) throw new Error(`Rlottie unable to load ${text.length} byte data file.`)
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const rendered = rh.render(0, SIZE, SIZE)
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let png = new PNG({
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width: SIZE,
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height: SIZE,
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bitDepth: 8, // 8 red + 8 green + 8 blue + 8 alpha
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colorType: 6, // RGBA
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inputColorType: 6, // RGBA
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inputHasAlpha: true,
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})
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png.data = Buffer.from(rendered)
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// The transform stream is necessary because PNG requires me to pipe it somewhere before this event loop ends
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const resultStream = png.pack()
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const p = new stream.PassThrough()
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resultStream.pipe(p)
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return p
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}
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module.exports.convert = convert
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module.exports.SIZE = SIZE
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