/// <summary>
/// Gets a collection of all language systems supported by a single script the typeface. List of all known lang sys tags can be found here: http://www.microsoft.com/typography/developers/opentype/languagetags.aspx .
/// </summary>
/// <param name="typeface">The typeface.</param>
/// <param name="script">The script tag.</param>
/// <returns>
/// Collection of tags.
/// </returns>
public IEnumerable <Tag> GetLangSysTags(GlyphTypeface typeface, Tag script)
{
dynamic fontTableHeader = this.GetFontTableHeader();
dynamic fontTable = this.GetFontTable(typeface);
if (!fontTable.IsPresent)
{
yield break;
}
dynamic scriptList = new AccessPrivateWrapper(fontTableHeader.GetScriptList(fontTable.Wrapped));
dynamic scriptTable = new AccessPrivateWrapper(scriptList.FindScript(fontTable.Wrapped, TagConverter.UintFromTag(script)));
if (scriptTable.IsNull)
{
throw new ArgumentOutOfRangeException("script");
}
if (scriptTable.IsDefaultLangSysExists(fontTable.Wrapped))
{
yield return(new Tag("dflt"));
}
var uintTags = this.GetEnumerableFromInternalList(
() => scriptTable.GetLangSysCount(fontTable.Wrapped),
p => (uint)scriptTable.GetLangSysTag(fontTable.Wrapped, p));
foreach (var uintTag in uintTags)
{
yield return(TagConverter.TagFromUint(uintTag));
}
}