THPDFHeadlessDocument.SetPushButtonAppearance

procedure SetPushButtonAppearance(FieldIndex: Integer; const Caption: UnicodeString;
  const TrueTypeFont: SysUtils.TBytes;
  const Options: THPDFHeadlessTextAppearanceOptions);

Generates centered Unicode captions and rectangular normal appearance borders for writable push-button Btn fields

The existing field value is retained, including its original PDF object type; caption generation does not install or execute an action

The shared appearance pipeline applies widget rotation, font permissions, object budgets, cancellation, and transactional publication of graph changes