Add chromaSubsampling and isProgressive to metadata #1186

docs/api-input.md

@@ -31,6 +31,8 @@ A Promises/A+ promise is returned when `callback` is not provided.
 -   `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
 -   `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...][2]
 -   `density`: Number of pixels per inch (DPI), if present
+-   `chromaSubsampling`: String containing JPEG chroma subsampling, `4:2:0` or `4:4:4` for RGB, `4:2:0:4` or `4:4:4:4` for CMYK
+-   `isProgressive`: Boolean indicating whether the image is interlaced using a progressive scan
 -   `hasProfile`: Boolean indicating the presence of an embedded ICC profile
 -   `hasAlpha`: Boolean indicating the presence of an alpha transparency channel
 -   `orientation`: Number value of the EXIF Orientation header, if present

docs/changelog.md

@@ -22,6 +22,9 @@ Requires libvips v8.7.0.
 * Switch from custom trim operation to `vips_find_trim`.
   [#914](https://github.com/lovell/sharp/issues/914)
 
+* Add `chromaSubsampling` and `isProgressive` properties to `metadata` response.
+  [#1186](https://github.com/lovell/sharp/issues/1186)
+
 * Drop Node 4 support.
   [#1212](https://github.com/lovell/sharp/issues/1212)
 

lib/input.js

@@ -183,6 +183,8 @@ function clone () {
  * - `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
  * - `depth`: Name of pixel depth format e.g. `uchar`, `char`, `ushort`, `float` [...](https://github.com/libvips/libvips/blob/master/libvips/iofuncs/enumtypes.c#L672)
  * - `density`: Number of pixels per inch (DPI), if present
+ * - `chromaSubsampling`: String containing JPEG chroma subsampling, `4:2:0` or `4:4:4` for RGB, `4:2:0:4` or `4:4:4:4` for CMYK
+ * - `isProgressive`: Boolean indicating whether the image is interlaced using a progressive scan
  * - `hasProfile`: Boolean indicating the presence of an embedded ICC profile
  * - `hasAlpha`: Boolean indicating the presence of an alpha transparency channel
  * - `orientation`: Number value of the EXIF Orientation header, if present

src/metadata.cc

@@ -62,6 +62,12 @@ class MetadataWorker : public Nan::AsyncWorker {
       if (sharp::HasDensity(image)) {
         baton->density = sharp::GetDensity(image);
       }
+      if (image.get_typeof("jpeg-chroma-subsample") == VIPS_TYPE_REF_STRING) {
+        baton->chromaSubsampling = image.get_string("jpeg-chroma-subsample");
+      }
+      if (image.get_typeof("interlaced") == G_TYPE_INT) {
+        baton->isProgressive = image.get_int("interlaced") == 1;
+      }
       baton->hasProfile = sharp::HasProfile(image);
       // Derived attributes
       baton->hasAlpha = sharp::HasAlpha(image);
@@ -125,6 +131,12 @@ class MetadataWorker : public Nan::AsyncWorker {
       if (baton->density > 0) {
         Set(info, New("density").ToLocalChecked(), New<v8::Uint32>(baton->density));
       }
+      if (!baton->chromaSubsampling.empty()) {
+        Set(info,
+          New("chromaSubsampling").ToLocalChecked(),
+          New<v8::String>(baton->chromaSubsampling).ToLocalChecked());
+      }
+      Set(info, New("isProgressive").ToLocalChecked(), New<v8::Boolean>(baton->isProgressive));
       Set(info, New("hasProfile").ToLocalChecked(), New<v8::Boolean>(baton->hasProfile));
       Set(info, New("hasAlpha").ToLocalChecked(), New<v8::Boolean>(baton->hasAlpha));
       if (baton->orientation > 0) {

src/metadata.h

@@ -31,6 +31,8 @@ struct MetadataBaton {
   int channels;
   std::string depth;
   int density;
+  std::string chromaSubsampling;
+  bool isProgressive;
   bool hasProfile;
   bool hasAlpha;
   int orientation;
@@ -50,6 +52,7 @@ struct MetadataBaton {
     height(0),
     channels(0),
     density(0),
+    isProgressive(false),
     hasProfile(false),
     hasAlpha(false),
     orientation(0),

test/unit/metadata.js

@@ -19,6 +19,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('4:2:0', metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -38,6 +40,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual(72, metadata.density);
+      assert.strictEqual('4:2:0', metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(true, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual(8, metadata.orientation);
@@ -85,6 +89,8 @@ describe('Image metadata', function () {
       assert.strictEqual(1, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual(300, metadata.density);
+      assert.strictEqual('undefined', typeof metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual(1, metadata.orientation);
@@ -104,6 +110,8 @@ describe('Image metadata', function () {
       assert.strictEqual(1, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual(300, metadata.density);
+      assert.strictEqual('undefined', typeof metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -123,6 +131,8 @@ describe('Image metadata', function () {
       assert.strictEqual(4, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual(72, metadata.density);
+      assert.strictEqual('undefined', typeof metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(true, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -142,6 +152,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('undefined', typeof metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -160,6 +172,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('undefined', typeof metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -177,6 +191,8 @@ describe('Image metadata', function () {
       assert.strictEqual(2, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('undefined', typeof metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(true, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -195,6 +211,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('4:2:0', metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -224,6 +242,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('4:2:0', metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -247,6 +267,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('4:2:0', metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -268,6 +290,8 @@ describe('Image metadata', function () {
       assert.strictEqual(3, metadata.channels);
       assert.strictEqual('uchar', metadata.depth);
       assert.strictEqual('undefined', typeof metadata.density);
+      assert.strictEqual('4:2:0', metadata.chromaSubsampling);
+      assert.strictEqual(false, metadata.isProgressive);
       assert.strictEqual(false, metadata.hasProfile);
       assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual('undefined', typeof metadata.orientation);
@@ -346,6 +370,56 @@ describe('Image metadata', function () {
       });
   });
 
+  it('chromaSubsampling 4:4:4:4 CMYK JPEG', function () {
+    return sharp(fixtures.inputJpgWithCmykProfile)
+      .metadata()
+      .then(function (metadata) {
+        assert.strictEqual('4:4:4:4', metadata.chromaSubsampling);
+      });
+  });
+
+  it('chromaSubsampling 4:4:4 RGB JPEG', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(10, 10)
+      .jpeg({ chromaSubsampling: '4:4:4' })
+      .toBuffer()
+      .then(function (data) {
+        return sharp(data)
+          .metadata()
+          .then(function (metadata) {
+            assert.strictEqual('4:4:4', metadata.chromaSubsampling);
+          });
+      });
+  });
+
+  it('isProgressive JPEG', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(10, 10)
+      .jpeg({ progressive: true })
+      .toBuffer()
+      .then(function (data) {
+        return sharp(data)
+          .metadata()
+          .then(function (metadata) {
+            assert.strictEqual(true, metadata.isProgressive);
+          });
+      });
+  });
+
+  it('isProgressive PNG', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(10, 10)
+      .png({ progressive: true })
+      .toBuffer()
+      .then(function (data) {
+        return sharp(data)
+          .metadata()
+          .then(function (metadata) {
+            assert.strictEqual(true, metadata.isProgressive);
+          });
+      });
+  });
+
   it('File input with corrupt header fails gracefully', function (done) {
     sharp(fixtures.inputJpgWithCorruptHeader)
       .metadata(function (err) {