addSingle top-level property

Null Function(dynamic feature, dynamic substitution, dynamic script, dynamic language) addSingle

Implementation

Substitution.prototype.addSingle = function(feature, substitution, script, language) {
    const lookupTable = this.getLookupTables(script, language, feature, 1, true)[0];
    const subtable = getSubstFormat(lookupTable, 2, {                // lookup type 1 subtable, format 2, coverage format 1
        substFormat: 2,
        coverage: {format: 1, glyphs: []},
        substitute: []
    });
    check.assert(subtable.coverage.format === 1, 'Single: unable to modify coverage table format ' + subtable.coverage.format);
    const coverageGlyph = substitution.sub;
    let pos = this.binSearch(subtable.coverage.glyphs, coverageGlyph);
    if (pos < 0) {
        pos = -1 - pos;
        subtable.coverage.glyphs.splice(pos, 0, coverageGlyph);
        subtable.substitute.splice(pos, 0, 0);
    }
    subtable.substitute[pos] = substitution.by;
};