Fixed gasp support bugs per #738 (#739)

* Fixed gasp support bugs per #738

* Added test for gasp table writing

* Minor update to test

Author: Balearica

src/opentype.mjs

@@ -310,8 +310,13 @@ function parseBuffer(buffer, opt={}) {
                 metaTableEntry = tableEntry;
                 break;
             case 'gasp':
-                table = uncompressTable(data, tableEntry);
-                font.tables.gasp = gasp.parse(table.data, table.offset);
+                try {
+                    table = uncompressTable(data, tableEntry);
+                    font.tables.gasp = gasp.parse(table.data, table.offset);
+                } catch (e) {
+                    console.warn('Failed to parse gasp table, skipping.');
+                    console.warn(e);
+                }
                 break;
             case 'SVG ':
                 table = uncompressTable(data, tableEntry);

src/tables/gasp.mjs

@@ -34,9 +34,9 @@ function makeGaspTable(gasp) {
         {name: 'numRanges', type: 'USHORT', value: gasp.numRanges},
     ]);
 
-    for (let i in gasp.numRanges) {
-        result.fields.push({name: 'rangeMaxPPEM', type: 'USHORT', value: gasp.numRanges[i].rangeMaxPPEM});
-        result.fields.push({name: 'rangeGaspBehavior', type: 'USHORT', value: gasp.numRanges[i].rangeGaspBehavior});
+    for (let i in gasp.gaspRanges) {
+        result.fields.push({name: 'rangeMaxPPEM', type: 'USHORT', value: gasp.gaspRanges[i].rangeMaxPPEM});
+        result.fields.push({name: 'rangeGaspBehavior', type: 'USHORT', value: gasp.gaspRanges[i].rangeGaspBehavior});
     }
 
     return result;

test/tables/gasp.spec.mjs

@@ -29,4 +29,9 @@ describe('tables/gasp.mjs', function () {
         assert.equal(font.tables.gasp.gaspRanges[1].rangeGaspBehavior, 0x0001 + 0x0002 + 0x0004 + 0x0008); // all flags set = 15
     });
 
+    it('can write tables that are read as identical to the original', function() {
+        const font2 = parse(font.toArrayBuffer());
+        assert.deepStrictEqual(font.tables.gasp, font2.tables.gasp);
+    });
+
 });