planning

node_modules/geotiff/dist-module/compression/lerc.js

@@ -0,0 +1,31 @@
+import { inflate } from 'pako';
+import Lerc from 'lerc';
+import BaseDecoder from './basedecoder.js';
+import { LercParameters, LercAddCompression } from '../globals.js';
+
+export default class LercDecoder extends BaseDecoder {
+  constructor(fileDirectory) {
+    super();
+
+    this.planarConfiguration = typeof fileDirectory.PlanarConfiguration !== 'undefined' ? fileDirectory.PlanarConfiguration : 1;
+    this.samplesPerPixel = typeof fileDirectory.SamplesPerPixel !== 'undefined' ? fileDirectory.SamplesPerPixel : 1;
+
+    this.addCompression = fileDirectory.LercParameters[LercParameters.AddCompression];
+  }
+
+  decodeBlock(buffer) {
+    switch (this.addCompression) {
+      case LercAddCompression.None:
+        break;
+      case LercAddCompression.Deflate:
+        buffer = inflate(new Uint8Array(buffer)).buffer; // eslint-disable-line no-param-reassign, prefer-destructuring
+        break;
+      default:
+        throw new Error(`Unsupported LERC additional compression method identifier: ${this.addCompression}`);
+    }
+
+    const lercResult = Lerc.decode(buffer, { returnPixelInterleavedDims: this.planarConfiguration === 1 });
+    const lercData = lercResult.pixels[0];
+    return lercData.buffer;
+  }
+}