Add face.listNames() and face.getName()

Author: khaledhosny

build.sh

@@ -18,7 +18,7 @@ em++ \
 	-s MODULARIZE \
 	-s EXPORT_NAME=createHarfBuzz \
 	-s [email protected] \
-	-s EXPORTED_RUNTIME_METHODS='["addFunction", "removeFunction", "stackAlloc", "wasmMemory", "wasmExports", "HEAP8", "HEAPU8", "HEAP32", "HEAPU32", "HEAPF32"]' \
+	-s EXPORTED_RUNTIME_METHODS='["addFunction", "removeFunction", "stackAlloc", "wasmMemory", "wasmExports", "HEAP8", "HEAPU8", "HEAPU16", "HEAP32", "HEAPU32", "HEAPF32"]' \
 	-s INITIAL_MEMORY=256KB \
 	-s ALLOW_MEMORY_GROWTH \
 	-s ALLOW_TABLE_GROWTH \

config-override.h

@@ -9,4 +9,5 @@
 #undef HB_NO_AVAR2
 #undef HB_NO_CUBIC_GLYF
 #undef HB_NO_VAR_COMPOSITES
+#undef HB_NO_NAME
 #define HB_BUFFER_MESSAGE_MORE 1

hb.symbols

@@ -70,9 +70,13 @@ _hb_ot_layout_table_get_script_tags
 _hb_ot_layout_table_get_feature_tags
 _hb_ot_layout_script_get_language_tags
 _hb_ot_layout_language_get_feature_tags
+_hb_ot_name_list_names
+_hb_ot_name_get_utf16
 _hb_ot_var_get_axis_infos
 _hb_script_from_string
 _hb_feature_from_string
+_hb_language_from_string
+_hb_language_to_string
 _hb_set_create
 _hb_set_destroy
 _hb_set_get_population

hbjs.js

@@ -49,6 +49,19 @@ function hbjs(Module) {
     return 0x0;
   }
 
+  function _language_to_string(language) {
+    var ptr = exports.hb_language_to_string(language);
+    var str = utf8Decoder.decode(Module.HEAPU8.subarray(ptr, Module.HEAPU8.indexOf(0, ptr)));
+    return str;
+  }
+
+  function _language_from_string(str) {
+    var languageStr = createAsciiString(str);
+    var languagePtr = exports.hb_language_from_string(languageStr.ptr, -1);
+    languageStr.free();
+    return languagePtr;
+  }
+
   /**
   * Create an object representing a Harfbuzz blob.
   * @param {string} blob A blob of binary data (usually the contents of a font file).
@@ -234,6 +247,41 @@ function hbjs(Module) {
         }
         return tags;
       },
+      /**
+       * Return all names in the specified face's name table.
+       **/
+      listNames: function () {
+        var numEntriesPtr = Module.stackAlloc(4);
+        var entriesPtr = exports.hb_ot_name_list_names(ptr, numEntriesPtr);
+        var numEntries = Module.HEAPU32[numEntriesPtr / 4];
+        var entries = [];
+        for (var i = 0; i < numEntries; i++) {
+          // FIXME: this depends on the struct memory layout.
+          // A more robust way would involve ading helper C functions to access
+          // the struct and use them here.
+          entries.push({
+            nameId: Module.HEAPU32[(entriesPtr / 4) + (i * 3)],
+            language: _language_to_string(Module.HEAPU32[(entriesPtr / 4) + (i * 3) + 2])
+          });
+        }
+        return entries;
+      },
+      /**
+       * Get the name of the specified face.
+       * @param {number} nameId The ID of the name to get.
+       * @param {string} language The language of the name to get.
+       **/
+      getName: function (nameId, language) {
+        var languagePtr = _language_from_string(language);
+        var nameLen = exports.hb_ot_name_get_utf16(ptr, nameId, languagePtr, 0, 0) + 1;
+        var textSizePtr = Module.stackAlloc(4);
+        var textPtr = exports.malloc(nameLen * 2);
+        Module.HEAPU32[textSizePtr / 4] = nameLen;
+        exports.hb_ot_name_get_utf16(ptr, nameId, languagePtr, textSizePtr, textPtr);
+        var name = String.fromCharCode.apply(null, Module.HEAPU16.subarray(textPtr / 2, textPtr / 2 + nameLen - 1));
+        exports.free(textPtr);
+        return name;
+      },
       /**
        * Free the object.
        */

test/index.js

@@ -110,6 +110,22 @@ describe('Face', function () {
       }
     });
   });
+
+  it('listNames fetches all names', function () {
+    blob = hb.createBlob(fs.readFileSync(path.join(__dirname, 'fonts/noto/NotoSans-Regular.ttf')));
+    face = hb.createFace(blob);
+    let names = face.listNames();
+    expect(names.length).to.equal(38);
+    expect(names[0]).to.deep.equal({ nameId: 0, language: 'en' });
+    expect(names[37]).to.deep.equal({ nameId: 278, language: 'en' });
+  })
+
+  it('getName fetches a name', function () {
+    blob = hb.createBlob(fs.readFileSync(path.join(__dirname, 'fonts/noto/NotoSans-Regular.ttf')));
+    face = hb.createFace(blob);
+    expect(face.getName(1, 'en')).to.equal('Noto Sans');
+    expect(face.getName(256, 'en')).to.equal('florin symbol');
+  })
 });
 
 describe('Font', function () {