// These functions are called by our public methods before and after each
// call to DoGetTextExtent(). Derived classes may override them to prepare
// for -- possibly several -- subsequent calls to DoGetTextExtent().
//
// As these calls must be always paired, they're never called directly but
// only by our friend MeasuringGuard class.
// These functions are called by our public methods before and after each
// call to DoGetTextExtent(). Derived classes may override them to prepare
// for -- possibly several -- subsequent calls to DoGetTextExtent().
//
// As these calls must be always paired, they're never called directly but
// only by our friend MeasuringGuard class.