feat(decoder): add FFDC marker support (jpeg-js#79)

zed-0xff · Aug 24, 2020 · 05bb97a · 05bb97a
1 parent 422ae38
commit 05bb97a
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diff --git a/lib/decoder.js b/lib/decoder.js
@@ -782,6 +782,11 @@ var JpegImage = (function jpegImage() {
             resetInterval = readUint16();
             break;
 
+          case 0xFFDC: // Number of Lines marker
+            readUint16() // skip data length
+            readUint16() // Ignore this data since it represents the image height
+            break;
+
           case 0xFFDA: // SOS (Start of Scan)
             var scanLength = readUint16();
             var selectorsCount = data[offset++];

diff --git a/test/fixtures/marker-ffdc.jpg b/test/fixtures/marker-ffdc.jpg
diff --git a/test/index.js b/test/index.js
@@ -223,6 +223,14 @@ it('should be able to encode/decode image with exif data', function () {
   expect(loopImageData.exifBuffer).toEqual(imageData.exifBuffer);
 });
 
+it('should be to decode image with ffdc marker', function () {
+  var jpegData = fixture('marker-ffdc.jpg');
+  var imageData = jpeg.decode(new Uint8Array(jpegData));
+  expect(imageData.height).toEqual(200);
+  expect(imageData.width).toEqual(200);
+});
+
+
 it('should be able to decode large images within memory limits', () => {
   var jpegData = fixture('black-6000x6000.jpg');
   var rawImageData = jpeg.decode(jpegData);