fix: support images that do not define samplesPerPixel

Closes: #21
image-js · Aug 7, 2020 · 2c2587b · 2c2587b
1 parent c5a0fce
commit 2c2587b
Show file tree

Hide file tree

Showing 4 changed files with 85 additions and 33 deletions.
diff --git a/img/cells.tif b/img/cells.tif
diff --git a/src/__tests__/decode.test.ts b/src/__tests__/decode.test.ts
@@ -7,34 +7,95 @@ function readImage(file: string): Buffer {
   return readFileSync(join(__dirname, '../../img', file));
 }
 
-const files = [
+interface TiffFile {
+  name: string;
+  width: number;
+  height: number;
+  bitsPerSample: number;
+  components: number;
+}
+
+const files: TiffFile[] = [
   // TODO: Unsupported LZW compression?
   // 'color-1px.tif',
-  'color8.tif',
-  'color8-lzw.tif',
-  'color16.tif',
-  'color16-lzw.tif',
-  'grey8.tif',
-  'grey8-lzw.tif',
-  'grey16.tif',
-  'whiteIsZero.tif',
+  {
+    name: 'color8.tif',
+    width: 160,
+    height: 120,
+    bitsPerSample: 8,
+    components: 3,
+  },
+  {
+    name: 'color8-lzw.tif',
+    width: 160,
+    height: 120,
+    bitsPerSample: 8,
+    components: 3,
+  },
+  {
+    name: 'color16.tif',
+    width: 160,
+    height: 120,
+    bitsPerSample: 16,
+    components: 3,
+  },
+  {
+    name: 'color16-lzw.tif',
+    width: 160,
+    height: 120,
+    bitsPerSample: 16,
+    components: 3,
+  },
+  { name: 'grey8.tif', width: 30, height: 90, bitsPerSample: 8, components: 1 },
+  {
+    name: 'grey8-lzw.tif',
+    width: 30,
+    height: 90,
+    bitsPerSample: 8,
+    components: 1,
+  },
+  {
+    name: 'grey16.tif',
+    width: 30,
+    height: 90,
+    bitsPerSample: 16,
+    components: 1,
+  },
+  {
+    name: 'whiteIsZero.tif',
+    width: 1248,
+    height: 1248,
+    bitsPerSample: 16,
+    components: 1,
+  },
+  {
+    name: 'cells.tif',
+    width: 2048,
+    height: 2048,
+    bitsPerSample: 16,
+    components: 1,
+  },
 ];
-const cases = files.map((name) => [name, readImage(name)] as const);
+const cases = files.map((file) => [file, readImage(file.name)] as const);
 
 const stack = readImage('stack.tif');
 
-test.each(cases)('should decode %s', (_, image) => {
+test.each(cases)('should decode %s', (file, image) => {
   const result = decode(image);
   expect(result).toHaveLength(1);
-  const { data, samplesPerPixel, width, height } = result[0];
-  expect(data).toHaveLength(width * height * samplesPerPixel);
+  const { data, bitsPerSample, width, height, components } = result[0];
+  expect(width).toBe(file.width);
+  expect(height).toBe(file.height);
+  expect(components).toBe(file.components);
+  expect(bitsPerSample).toBe(file.bitsPerSample);
+  expect(data).toHaveLength(file.width * file.height * file.components);
 });
 
-test('should decode RGB', () => {
+test('should decode RGB 8bit', () => {
   const [result] = decode(readImage('color-5x5.tif'));
   expect(result.width).toBe(5);
   expect(result.height).toBe(5);
-  expect(result.bitsPerSample).toStrictEqual(Uint16Array.from([8, 8, 8]));
+  expect(result.bitsPerSample).toBe(8);
   expect(result.components).toBe(3);
   expect(result.data).toStrictEqual(
     // prettier-ignore

diff --git a/src/tiffDecoder.ts b/src/tiffDecoder.ts
@@ -180,7 +180,7 @@ export default class TIFFDecoder extends IOBuffer {
     this.applyPredictor(ifd);
     if (ifd.type === 0) {
       // WhiteIsZero: we invert the values
-      const bitDepth = validateBitDepth(ifd.bitsPerSample);
+      const bitDepth = ifd.bitsPerSample;
       const maxValue = Math.pow(2, bitDepth) - 1;
       for (let i = 0; i < ifd.data.length; i++) {
         ifd.data[i] = maxValue - ifd.data[i];
@@ -192,7 +192,7 @@ export default class TIFFDecoder extends IOBuffer {
     const width = ifd.width;
     const height = ifd.height;
 
-    const bitDepth = validateBitDepth(ifd.bitsPerSample);
+    const bitDepth = ifd.bitsPerSample;
     const sampleFormat = ifd.sampleFormat;
     const size = width * height * ifd.samplesPerPixel;
     const data = getDataArray(size, bitDepth, sampleFormat);
@@ -268,7 +268,7 @@ export default class TIFFDecoder extends IOBuffer {
   }
 
   private applyPredictor(ifd: TiffIfd): void {
-    const bitDepth = validateBitDepth(ifd.bitsPerSample);
+    const bitDepth = ifd.bitsPerSample;
     switch (ifd.predictor) {
       case 1: {
         // No prediction scheme, nothing to do
@@ -358,16 +358,3 @@ function fillFloat32(
 function unsupported(type: string, value: any): Error {
   return new Error(`Unsupported ${type}: ${value}`);
 }
-
-function validateBitDepth(bitDepth: number[] | number): number {
-  if (typeof bitDepth !== 'number') {
-    const bitDepthArray = bitDepth;
-    bitDepth = bitDepthArray[0];
-    for (let i = 0; i < bitDepthArray.length; i++) {
-      if (bitDepthArray[i] !== bitDepth) {
-        throw unsupported('bit depth', bitDepthArray);
-      }
-    }
-  }
-  return bitDepth;
-}
diff --git a/src/tiffIfd.ts b/src/tiffIfd.ts
@@ -47,7 +47,11 @@ export default class TiffIfd extends Ifd {
     return this.get(257);
   }
   public get bitsPerSample(): number {
-    return this.get(258);
+    const data = this.get(258);
+    if (data && typeof data !== 'number') {
+      return data[0];
+    }
+    return data;
   }
   public get compression(): number {
     return this.get(259) || 1;
@@ -71,7 +75,7 @@ export default class TiffIfd extends Ifd {
     return this.get(274);
   }
   public get samplesPerPixel(): number {
-    return this.get(277);
+    return this.get(277) || 1;
   }
   public get rowsPerStrip(): number {
     return this.get(278);