feat: add support for Zlib/deflate compression

README.md

@@ -14,17 +14,15 @@ npm i tiff
 
 ## Compatibility
 
-### Platform
-
-This package is written using ES2015 features. It is natively compatible with
-recent web browsers and Node.js. You can transpile it with a tool like
-[babel](https://babeljs.io/) if you need to support more JavaScript engines.
-
 ### [TIFF standard](./TIFF6.pdf)
 
 The library can currently decode greyscale and RGB images (8, 16 or 32 bits).
 It supports LZW compression and images with an additional alpha channel.
 
+### Extensions
+
+Images compressed with Zlib/deflate algorithm are also supported.
+
 ## API
 
 ### tiff.decode(data[, options])

package.json

@@ -37,11 +37,13 @@
     "testEnvironment": "node"
   },
   "dependencies": {
-    "iobuffer": "^5.0.2"
+    "iobuffer": "^5.0.2",
+    "pako": "^2.0.2"
   },
   "devDependencies": {
     "@types/jest": "^26.0.16",
     "@types/node": "^14.14.10",
+    "@types/pako": "^1.0.1",
     "eslint": "^7.14.0",
     "eslint-config-cheminfo-typescript": "^8.0.5",
     "jest": "^26.6.3",

src/__tests__/decode.test.ts

@@ -98,6 +98,13 @@ const files: TiffFile[] = [
     bitsPerSample: 8,
     components: 3,
   },
+  {
+    name: 'color-5x5-deflate.tif',
+    width: 5,
+    height: 5,
+    bitsPerSample: 8,
+    components: 3,
+  },
   {
     name: 'color-alpha-2x2.tif',
     width: 2,
@@ -229,3 +236,16 @@ test('should decode palette', () => {
   // @ts-ignore
   expect(palette[0]).toStrictEqual([65535, 0, 0]);
 });
+
+test('should decode image compressed with deflate algorithm', () => {
+  const decoded = decode(readImage('tile_rgb_deflate.tif'));
+  expect(decoded).toHaveLength(1);
+  expect(decoded[0]).toMatchObject({
+    alpha: false,
+    bitsPerSample: 16,
+    components: 3,
+    compression: 8,
+    width: 128,
+    height: 128,
+  });
+});

src/tiffDecoder.ts

@@ -9,6 +9,7 @@ import { getByteLength, readData } from './ifdValue';
 import { decompressLzw } from './lzw';
 import TiffIfd from './tiffIfd';
 import { BufferType, IDecodeOptions, IFDKind, DataArray } from './types';
+import { decompressZlib } from './zlib';
 
 const defaultOptions: IDecodeOptions = {
   ignoreImageData: false,
@@ -228,12 +229,17 @@ export default class TIFFDecoder extends IOBuffer {
           dataToFill = decompressLzw(stripData);
           break;
         }
+        case 8: {
+          // Zlib compression
+          dataToFill = decompressZlib(stripData);
+          break;
+        }
         case 2: // CCITT Group 3 1-Dimensional Modified Huffman run length encoding
           throw unsupported('Compression', 'CCITT Group 3');
         case 32773: // PackBits compression
           throw unsupported('Compression', 'PackBits');
         default:
-          throw new Error(`invalid compression: ${ifd.compression}`);
+          throw unsupported('Compression', ifd.compression);
       }
 
       pixel = this.fillUncompressed(

src/zlib.ts

@@ -0,0 +1,15 @@
+import { inflate } from 'pako';
+
+export function decompressZlib(stripData: DataView): DataView {
+  const stripUint8 = new Uint8Array(
+    stripData.buffer,
+    stripData.byteOffset,
+    stripData.byteLength,
+  );
+  const inflated = inflate(stripUint8);
+  return new DataView(
+    inflated.buffer,
+    inflated.byteOffset,
+    inflated.byteLength,
+  );
+}