Fallback to KERN table if GPOS table is empty in `Font.getKerningValue`

[miere43]

Expected Behavior

Font.getKerningValue returns kerning value from KERN table if GPOS table is empty.

Current Behavior

Font.getKerningValue returns 0 if GPOS table is empty, even if there are values in KERN table.

Possible Solution

1. Maybe GPOS parsing is broken and doesn't work for Arial font (not sure).
2. Fallback to KERN table if font.position.defaultKerningTables.length === 0 is zero in Font.getKerningValue. See: https://github.com/miere43/opentype.js/commit/6acfd4e41b7aa2901f84cfd49433a6e63bf60cbe

Steps to Reproduce (for bugs)

const arial = opentype.loadSync('C:\\Windows\\Fonts\\arial.ttf');
const kerning = arial.getKerningValue(arial.charToGlyph('T'), arial.charToGlyph('e'));
console.log('kerning is', kerning);

Output:

kerning is 0

Expected:

kerning is -227

Context

Drawing text.

Your Environment

• Version used: 1.3.4
• Font used: Arial
• Browser Name and version: ---
• Operating System and version (desktop or mobile): Windows 10
• Link to your project: ---

[rafallyczkowskiadylic]

@ILOVEPIE this is fixed within https://github.com/opentypejs/opentype.js/pull/557 I tested this using test code snippet

describe('Arial fonts test', () => {
        it('should have a correct kerning value', () => {
            const font = loadSync('./fonts/arial.ttf');
            const kerning = font.getKerningValue(font.charToGlyph('T'), font.charToGlyph('e'));
            assert.strictEqual(kerning, -227);
        });
    });

unfortunately I cannot commit this because of arial font's License.