THotPDF GSUB Script and Language Methods

THotPDF API reference

選取並探索所有 GSUB lookup queries 使用的 OpenType GSUB ScriptList、LangSys 與 FeatureList entries

Delphi 語法

SetGSUBScript 很嚴格：未知 script tag 會讓後續 queries 傳回 no-op results。SetGSUBLanguage 會在要求的 language tag 不可用時 fallback 到 script default LangSys，符合常見 OpenType behaviour

procedure SetGSUBLanguage(const LangTag: AnsiString);

function GetGSUBScripts: TGSUBStringArray;

function GetGSUBLanguages(const ScriptTag: AnsiString): TGSUBStringArray;

function GetGSUBFeatures(const ScriptTag, LangTag: AnsiString): TGSUBStringArray;

Covered APIs

API	使用注意事項
`SetGSUBScript`	Selects the OpenType script tag used by later GSUB feature and lookup queries
`SetGSUBLanguage`	Selects the OpenType language-system tag and falls back to the script default when unavailable
`GetGSUBScripts`	Returns the script tags advertised by the registered Unicode font's GSUB ScriptList
`GetGSUBLanguages`	Returns the language-system tags available for a script tag
`GetGSUBFeatures`	Returns the feature tags reachable for a script and language-system pair

使用注意事項

SetGSUBScript 採嚴格處理：unknown script tag 會讓後續 queries 傳回 no-op results。當 requested language tag 不可用時，SetGSUBLanguage 會退回 script default LangSys，符合常見 OpenType behaviour

請參閱： OpenType GSUB Engine GSUB lookup methods ShapingFeatures