goocanvasmm Points class

[Ian Martin <ian_martin65 yahoo com au>]

Hi,
I'm playing with goocanvasmm and am finding it impossible to create any custom area.  Reading the docs, the logical method would be to use the Polyline; however, that in turn relies on the Points class, and I can't seem to create an instance of that at all.  I see Murray Cumming had a try in the demo example; uncommenting that makes the code noncompilable.

A RefPtr to the Points class causes the compiler to dummy spit; the error message I get is at the first call to the pointer (in the code below, at the "my_line1_points = ..." line.  The error is

Objects.cpp:131: error: no match for ‘operator=’ in ‘my_line1_points = Goocanvas::Points()’

Creating an instance without the pointer compiles, but then segfaults when it gets to the same line.

Glib::RefPtr<Goocanvas::Polyline> my_line1 ;
Glib::RefPtr<Goocanvas::Points> my_line1_points;
// or:  Goocanvas::Points my_line1_points;                 this will compile, but doesn't seem to accept points.
Glib::RefPtr<Goocanvas::Item> root = _canvas->get_root_item();

    my_line1_points = Goocanvas::Points();
  my_line1_points.set_coordinate(1, 200, 200);
  my_line1_points.set_coordinate(2, 200, 300);
   my_line1_points.set_coordinate(3, 250, 250);
   my_line1 = Goocanvas::Polyline::create(true, my_line1_points) ;
   root->add_child( my_line1);

the other possibility I looked at is the constructor which takes a series of doubles; however, I couldn't find a syntax documented anywhere for them.

Another compiler comment that makes it look like the Points class isn't working is
/usr/include/glibmm-2.4/glibmm/refptr.h:184: error: ‘class Goocanvas::Points’ has no member named ‘unreference’

So what am I doing wrong?  Or am I trying to use the library for something it isn't designed for?

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