Function parseGposTable

libraries/p5.js:4863–4883

(data, start, font)

// Parse the `GPOS` table which contains, among other things, kerning pairs.
// https://www.microsoft.com/typography/OTSPEC/gpos.htm
function parseGposTable(data, start, font) {
    var p = new parse.Parser(data, start);
    var tableVersion = p.parseFixed();
    check.argument(tableVersion === 1, 'Unsupported GPOS table version.');

    // ScriptList and FeatureList - ignored for now
    parseTaggedListTable(data, start + p.parseUShort());
    // 'kern' is the feature we are looking for.
    parseTaggedListTable(data, start + p.parseUShort());

    // LookupList
    var lookupListOffset = p.parseUShort();
    p.relativeOffset = lookupListOffset;
    var lookupCount = p.parseUShort();
    var lookupTableOffsets = p.parseOffset16List(lookupCount);
    var lookupListAbsoluteOffset = start + lookupListOffset;
    for (var i = 0; i < lookupCount; i++) {
        var table = parseLookupTable(data, lookupListAbsoluteOffset + lookupTableOffsets[i]);
        if (table.lookupType === 2 && !font.getGposKerningValue) font.getGposKerningValue = table.getKerningValue;
    }
}

exports.parse = parseGposTable;