getFeatureTable method

dynamic getFeatureTable(dynamic script, dynamic language, dynamic feature, bool create,)

Get a specific feature table. @instance @param {string} script='DFLT' @param {string} language='dlft' @param {string} feature - One of the codes listed at https://www.microsoft.com/typography/OTSPEC/featurelist.htm @param {boolean} create - forces the creation of the feature table if it doesn't exist. @return {Object}

Implementation

getFeatureTable(script, language, feature, bool create) {
    var langSysTable = this.getLangSysTable(script, language, create);
    if (langSysTable != null) {
        var featureRecord;
        var featIndexes = langSysTable["featureIndexes"];
        var allFeatures = this.font.tables[this.tableName]["features"];
        // The FeatureIndex array of indices is in arbitrary order,
        // even if allFeatures is sorted alphabetically by feature tag.
        for (var i = 0; i < featIndexes.length; i++) {
            featureRecord = allFeatures[featIndexes[i]];
            if (featureRecord["tag"] == feature) {
                return featureRecord["feature"];
            }
        }
        if (create) {
            var index = allFeatures.length;
            // Automatic ordering of features would require to shift feature indexes in the script list.
            assertfn(index == 0 || feature >= allFeatures[index - 1]["tag"], 'Features must be added in alphabetical order.');
            featureRecord = {
                "tag": feature,
                "feature": { "params": 0, "lookupListIndexes": [] }
            };
            allFeatures.add(featureRecord);
            featIndexes.add(index);
            return featureRecord["feature"];
        }
    }
}