Ensure id attr can be set for IIIF tile output #2612

Author: lovell

docs/changelog.md

@@ -16,6 +16,10 @@ Requires libvips v8.10.6
 
 * Reduce concurrency on glibc-based Linux when using the default memory allocator to help prevent fragmentation.
 
+* Ensure `@id` attribute can be set for IIIF tile-based output.
+  [#2612](https://github.com/lovell/sharp/issues/2612)
+  [@edsilv](https://github.com/edsilv)
+
 ## v0.27 - *avif*
 
 Requires libvips v8.10.5

lib/constructor.js

@@ -279,6 +279,7 @@ const Sharp = function (input, options) {
     tileSkipBlanks: -1,
     tileBackground: [255, 255, 255, 255],
     tileCentre: false,
+    tileId: 'https://example.com/iiif',
     linearA: 1,
     linearB: 0,
     // Function to notify of libvips warnings

lib/output.js

@@ -727,6 +727,7 @@ function raw () {
  * @param {string} [options.layout='dz'] filesystem layout, possible values are `dz`, `iiif`, `zoomify` or `google`.
  * @param {boolean} [options.centre=false] centre image in tile.
  * @param {boolean} [options.center=false] alternative spelling of centre.
+ * @param {string} [options.id='https://example.com/iiif'] when `layout` is `iiif`, sets the `@id` attribute of `info.json`
  * @returns {Sharp}
  * @throws {Error} Invalid parameters
  */
@@ -800,6 +801,14 @@ function tile (options) {
     if (is.defined(centre)) {
       this._setBooleanOption('tileCentre', centre);
     }
+    // @id attribute for IIIF layout
+    if (is.defined(options.id)) {
+      if (is.string(options.id)) {
+        this.options.tileId = options.id;
+      } else {
+        throw is.invalidParameterError('id', 'string', options.id);
+      }
+    }
   }
   // Format
   if (is.inArray(this.options.formatOut, ['jpeg', 'png', 'webp'])) {

src/pipeline.cc

@@ -1038,6 +1038,7 @@ class PipelineWorker : public Napi::AsyncWorker {
             ->set("angle", CalculateAngleRotation(baton->tileAngle))
             ->set("background", baton->tileBackground)
             ->set("centre", baton->tileCentre)
+            ->set("id", const_cast<char*>(baton->tileId.data()))
             ->set("skip_blanks", baton->tileSkipBlanks);
           // libvips chooses a default depth based on layout. Instead of replicating that logic here by
           // not passing anything - libvips will handle choice
@@ -1438,6 +1439,7 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
     vips_enum_from_nick(nullptr, VIPS_TYPE_FOREIGN_DZ_DEPTH,
     sharp::AttrAsStr(options, "tileDepth").data()));
   baton->tileCentre = sharp::AttrAsBool(options, "tileCentre");
+  baton->tileId = sharp::AttrAsStr(options, "tileId");
 
   // Force random access for certain operations
   if (baton->input->access == VIPS_ACCESS_SEQUENTIAL) {

src/pipeline.h

@@ -192,6 +192,7 @@ struct PipelineBaton {
   std::vector<double> tileBackground;
   int tileSkipBlanks;
   VipsForeignDzDepth tileDepth;
+  std::string tileId;
   std::unique_ptr<double[]> recombMatrix;
 
   PipelineBaton():

test/unit/tile.js

@@ -297,6 +297,22 @@ describe('Tile', function () {
     });
   });
 
+  it('Valid id parameter value passes', function () {
+    assert.doesNotThrow(function () {
+      sharp().tile({
+        id: 'test'
+      });
+    });
+  });
+
+  it('Invalid id parameter value fails', function () {
+    assert.throws(function () {
+      sharp().tile({
+        id: true
+      });
+    });
+  });
+
   it('Deep Zoom layout', function (done) {
     const directory = fixtures.path('output.dzi_files');
     rimraf(directory, function () {
@@ -815,11 +831,14 @@ describe('Tile', function () {
   });
 
   it('IIIF layout', function (done) {
-    const directory = fixtures.path('output.iiif.info');
+    const name = 'output.iiif.info';
+    const directory = fixtures.path(name);
     rimraf(directory, function () {
+      const id = 'https://sharp.test.com/iiif';
       sharp(fixtures.inputJpg)
         .tile({
-          layout: 'iiif'
+          layout: 'iiif',
+          id
         })
         .toFile(directory, function (err, info) {
           if (err) throw err;
@@ -828,6 +847,8 @@ describe('Tile', function () {
           assert.strictEqual(2225, info.height);
           assert.strictEqual(3, info.channels);
           assert.strictEqual('number', typeof info.size);
+          const infoJson = require(path.join(directory, 'info.json'));
+          assert.strictEqual(`${id}/${name}`, infoJson['@id']);
           fs.stat(path.join(directory, '0,0,256,256', '256,', '0', 'default.jpg'), function (err, stat) {
             if (err) throw err;
             assert.strictEqual(true, stat.isFile());