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32 lines
1.2 KiB
32 lines
1.2 KiB
3 years ago
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import { inflate } from 'pako';
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import Lerc from 'lerc';
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import BaseDecoder from './basedecoder.js';
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import { LercParameters, LercAddCompression } from '../globals.js';
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export default class LercDecoder extends BaseDecoder {
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constructor(fileDirectory) {
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super();
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this.planarConfiguration = typeof fileDirectory.PlanarConfiguration !== 'undefined' ? fileDirectory.PlanarConfiguration : 1;
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this.samplesPerPixel = typeof fileDirectory.SamplesPerPixel !== 'undefined' ? fileDirectory.SamplesPerPixel : 1;
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this.addCompression = fileDirectory.LercParameters[LercParameters.AddCompression];
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}
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decodeBlock(buffer) {
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switch (this.addCompression) {
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case LercAddCompression.None:
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break;
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case LercAddCompression.Deflate:
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buffer = inflate(new Uint8Array(buffer)).buffer; // eslint-disable-line no-param-reassign, prefer-destructuring
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break;
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default:
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throw new Error(`Unsupported LERC additional compression method identifier: ${this.addCompression}`);
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}
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const lercResult = Lerc.decode(buffer, { returnPixelInterleavedDims: this.planarConfiguration === 1 });
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const lercData = lercResult.pixels[0];
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return lercData.buffer;
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}
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}
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