Add resolutionUnit to metadata and as tiff option #3023

Co-authored-by: Lovell Fuller <github@lovell.info>

lib/constructor.js

@@ -262,6 +262,7 @@ const Sharp = function (input, options) {
     tiffTileWidth: 256,
     tiffXres: 1.0,
     tiffYres: 1.0,
+    tiffResolutionUnit: 'inch',
     heifQuality: 50,
     heifLossless: false,
     heifCompression: 'av1',

lib/output.js

@@ -704,6 +704,7 @@ function trySetAnimationOptions (source, target) {
  * @param {number} [options.tileHeight=256] - vertical tile size
  * @param {number} [options.xres=1.0] - horizontal resolution in pixels/mm
  * @param {number} [options.yres=1.0] - vertical resolution in pixels/mm
+ * @param {string} [options.resolutionUnit='inch'] - resolution unit options: inch, cm
  * @param {number} [options.bitdepth=8] - reduce bitdepth to 1, 2 or 4 bit
  * @returns {Sharp}
  * @throws {Error} Invalid options
@@ -777,6 +778,14 @@ function tiff (options) {
         throw is.invalidParameterError('predictor', 'one of: none, horizontal, float', options.predictor);
       }
     }
+    // resolutionUnit
+    if (is.defined(options.resolutionUnit)) {
+      if (is.string(options.resolutionUnit) && is.inArray(options.resolutionUnit, ['inch', 'cm'])) {
+        this.options.tiffResolutionUnit = options.resolutionUnit;
+      } else {
+        throw is.invalidParameterError('resolutionUnit', 'one of: inch, cm', options.resolutionUnit);
+      }
+    }
   }
   return this._updateFormatOut('tiff', options);
 }

package.json

@@ -80,7 +80,8 @@
     "Brad Parham <baparham@gmail.com>",
     "Taneli Vatanen <taneli.vatanen@gmail.com>",
     "Joris Dugué <zaruike10@gmail.com>",
-    "Chris Banks <christopher.bradley.banks@gmail.com>"
+    "Chris Banks <christopher.bradley.banks@gmail.com>",
+    "Ompal Singh <ompal.hitm09@gmail.com>"
   ],
   "scripts": {
     "install": "(node install/libvips && node install/dll-copy && prebuild-install) || (node install/can-compile && node-gyp rebuild && node install/dll-copy)",

src/metadata.cc

@@ -77,6 +77,9 @@ class MetadataWorker : public Napi::AsyncWorker {
       if (image.get_typeof("heif-compression") == VIPS_TYPE_REF_STRING) {
         baton->compression = image.get_string("heif-compression");
       }
+      if (image.get_typeof(VIPS_META_RESOLUTION_UNIT) == VIPS_TYPE_REF_STRING) {
+        baton->resolutionUnit = image.get_string(VIPS_META_RESOLUTION_UNIT);
+      }
       if (image.get_typeof("openslide.level-count") == VIPS_TYPE_REF_STRING) {
         int const levels = std::stoi(image.get_string("openslide.level-count"));
         for (int l = 0; l < levels; l++) {
@@ -198,6 +201,9 @@ class MetadataWorker : public Napi::AsyncWorker {
       if (!baton->compression.empty()) {
         info.Set("compression", baton->compression);
       }
+      if (!baton->resolutionUnit.empty()) {
+        info.Set("resolutionUnit", baton->resolutionUnit == "in" ? "inch" : baton->resolutionUnit);
+      }
       if (!baton->levels.empty()) {
         int i = 0;
         Napi::Array levels = Napi::Array::New(env, static_cast<size_t>(baton->levels.size()));

src/metadata.h

@@ -40,6 +40,7 @@ struct MetadataBaton {
   std::vector<int> delay;
   int pagePrimary;
   std::string compression;
+  std::string resolutionUnit;
   std::vector<std::pair<int, int>> levels;
   int subifds;
   std::vector<double> background;

src/pipeline.cc

@@ -913,7 +913,8 @@ class PipelineWorker : public Napi::AsyncWorker {
             ->set("tile_height", baton->tiffTileHeight)
             ->set("tile_width", baton->tiffTileWidth)
             ->set("xres", baton->tiffXres)
-            ->set("yres", baton->tiffYres)));
+            ->set("yres", baton->tiffYres)
+            ->set("resunit", baton->tiffResolutionUnit)));
           baton->bufferOut = static_cast<char*>(area->data);
           baton->bufferOutLength = area->length;
           area->free_fn = nullptr;
@@ -1071,7 +1072,8 @@ class PipelineWorker : public Napi::AsyncWorker {
             ->set("tile_height", baton->tiffTileHeight)
             ->set("tile_width", baton->tiffTileWidth)
             ->set("xres", baton->tiffXres)
-            ->set("yres", baton->tiffYres));
+            ->set("yres", baton->tiffYres)
+            ->set("resunit", baton->tiffResolutionUnit));
           baton->formatOut = "tiff";
         } else if (baton->formatOut == "heif" || (mightMatchInput && isHeif) ||
           (willMatchInput && inputImageType == sharp::ImageType::HEIF)) {
@@ -1542,6 +1544,10 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   baton->tiffPredictor = static_cast<VipsForeignTiffPredictor>(
   vips_enum_from_nick(nullptr, VIPS_TYPE_FOREIGN_TIFF_PREDICTOR,
     sharp::AttrAsStr(options, "tiffPredictor").data()));
+  baton->tiffResolutionUnit = static_cast<VipsForeignTiffResunit>(
+  vips_enum_from_nick(nullptr, VIPS_TYPE_FOREIGN_TIFF_RESUNIT,
+    sharp::AttrAsStr(options, "tiffResolutionUnit").data()));
+
   baton->heifQuality = sharp::AttrAsUint32(options, "heifQuality");
   baton->heifLossless = sharp::AttrAsBool(options, "heifLossless");
   baton->heifCompression = static_cast<VipsForeignHeifCompression>(
@@ -1550,6 +1556,7 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   baton->heifEffort = sharp::AttrAsUint32(options, "heifEffort");
   baton->heifChromaSubsampling = sharp::AttrAsStr(options, "heifChromaSubsampling");
 
+
   // Raw output
   baton->rawDepth = static_cast<VipsBandFormat>(
     vips_enum_from_nick(nullptr, VIPS_TYPE_BAND_FORMAT,

src/pipeline.h

@@ -167,6 +167,7 @@ struct PipelineBaton {
   int tiffTileWidth;
   double tiffXres;
   double tiffYres;
+  VipsForeignTiffResunit tiffResolutionUnit;
   int heifQuality;
   VipsForeignHeifCompression heifCompression;
   int heifEffort;
@@ -305,6 +306,7 @@ struct PipelineBaton {
     tiffTileWidth(256),
     tiffXres(1.0),
     tiffYres(1.0),
+    tiffResolutionUnit(VIPS_FOREIGN_TIFF_RESUNIT_INCH),
     heifQuality(50),
     heifCompression(VIPS_FOREIGN_HEIF_COMPRESSION_AV1),
     heifEffort(4),

test/unit/metadata.js

@@ -99,6 +99,7 @@ describe('Image metadata', function () {
       assert.strictEqual(1, metadata.orientation);
       assert.strictEqual('undefined', typeof metadata.exif);
       assert.strictEqual('undefined', typeof metadata.icc);
+      assert.strictEqual('inch', metadata.resolutionUnit);
       done();
     });
   });

test/unit/tiff.js

@@ -288,6 +288,30 @@ describe('TIFF', function () {
       });
   });
 
+  it('TIFF resolutionUnit of inch (default)', async () => {
+    const data = await sharp({ create: { width: 8, height: 8, channels: 3, background: 'red' } })
+      .tiff()
+      .toBuffer();
+    const { resolutionUnit } = await sharp(data).metadata();
+    assert.strictEqual(resolutionUnit, 'inch');
+  });
+
+  it('TIFF resolutionUnit of inch', async () => {
+    const data = await sharp({ create: { width: 8, height: 8, channels: 3, background: 'red' } })
+      .tiff({ resolutionUnit: 'inch' })
+      .toBuffer();
+    const { resolutionUnit } = await sharp(data).metadata();
+    assert.strictEqual(resolutionUnit, 'inch');
+  });
+
+  it('TIFF resolutionUnit of cm', async () => {
+    const data = await sharp({ create: { width: 8, height: 8, channels: 3, background: 'red' } })
+      .tiff({ resolutionUnit: 'cm' })
+      .toBuffer();
+    const { resolutionUnit } = await sharp(data).metadata();
+    assert.strictEqual(resolutionUnit, 'cm');
+  });
+
   it('TIFF deflate compression with horizontal predictor shrinks test file', function (done) {
     const startSize = fs.statSync(fixtures.inputTiffUncompressed).size;
     sharp(fixtures.inputTiffUncompressed)
@@ -383,6 +407,12 @@ describe('TIFF', function () {
     });
   });
 
+  it('TIFF invalid resolutionUnit option throws', function () {
+    assert.throws(function () {
+      sharp().tiff({ resolutionUnit: 'none' });
+    });
+  });
+
   it('TIFF horizontal predictor does not throw error', function () {
     assert.doesNotThrow(function () {
       sharp().tiff({ predictor: 'horizontal' });