geotiff.js/src/compression/index.js

GeoTIFF image decoding in JavaScript

import RawDecoder from './raw';
import LZWDecoder from './lzw';
import JpegDecoder from './jpeg';
import DeflateDecoder from './deflate';
import PackbitsDecoder from './packbits';

export function getDecoder(fileDirectory) {
  switch (fileDirectory.Compression) {
    case undefined:
    case 1: // no compression
      return new RawDecoder();
    case 5: // LZW
      return new LZWDecoder();
    case 6: // JPEG
      throw new Error('old style JPEG compression is not supported.');
    case 7: // JPEG
      return new JpegDecoder(fileDirectory);
    case 8: // Deflate as recognized by Adobe
    case 32946: // Deflate GDAL default
      return new DeflateDecoder();
    case 32773: // packbits
      return new PackbitsDecoder();
    default:
      throw new Error(`Unknown compression method identifier: ${fileDirectory.Compression}`);
  }
}