Now "TButton" is descendant of "TView" so it could use both TButton and TView methods because of @ISA - is the same possible in "magic" approach?

Multiple inheritance is an interesting situation! I think it should work... Your magic would be for type 'TObject*' (or a record with a TObject* field, since extra fields are almost always needed) and then you could use dynamic_cast to find out whether the method was being called on the correct type.

TVision.xs

struct tvision_info {
  TObject *tobj;
};

struct tvision_info*
tvision_info_from_magic(SV *objref, int flags) {
  ...
}
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typemap

TYPEMAP
TObject*    O_TObject
TView*      O_TView
TButton*    O_TButton

INPUT
O_TObject
  $var= tvision_info_from_magic($arg, OR_DIE)->tobj;

O_TView
  $var= dynamic_cast<TView*>(tvision_info_from_magic($arg, OR_DIE)->to
+bj);
  if (!$var) croak("Not an instance of TView");

O_TButton
  $var= dynamic_cast<TButton*>(tvision_info_from_magic($arg, OR_DIE)->
+tobj);
  if (!$var) croak("Not an instance of TButton");
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later in TVision.xs

bool
focus(view)
  TView* view
  CODE:
    RETVAL= view->focus();
  OUTPUT:
    RETVAL
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You might even be able to use a C++ template function to fetch the magic, but I've never tried that. (my C++ is rusty, don't expect this to work as-is)

template <T> void tvision_obj_from_magic(T *dest, SV *objref, int flag
+s) {
  struct tvision_info* tinfo= tvision_info_from_magic(objref, flags);
  T typed= tinfo->tobj? dynamic_cast<T>(tinfo->tobj) : NULL;
  if ((flags & OR_DIE) && !typed) croak("Wrong type of object");
  *dest= typed;
}
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O_TButton
  tvision_obj_from_magic(&$var, $arg, OR_DIE);
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Update

There's no need for a C++ template here because Perl XS provides you a variable '$type'.

TYPEMAP
TObject*    O_TObject
TView*      O_TObject
TButton*    O_TObject

INPUT
O_TObject
  $var= dynamic_cast<$type>(tvision_info_from_magic($arg, OR_DIE)->tob
+j);
  if (!$var) croak("Object is not a $type");
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