Re: MPS: scroll-bars

[Helmut Eller <eller.helmut@gmail.com>]

On Sat, May 04 2024, Po Lu wrote:

> Helmut Eller <eller.helmut@gmail.com> writes:
>
>> The function xterm.c:xg_finish_scroll_bar_creation hands a pointer to a
>> struct scroll_bar to GTK.  GTK simply passes this along to the
>> callback.  How could we trace this or how could we pin scroll bars?
>
> Connect a callback that unpins the object's scroll bars to the "destroy"
> signal of the object, as xg_gtk_scroll_destroy is immediately above.

xg_gtk_scroll_destroy uses id_to_widget. That's a global variable.  I'd
rather avoid that.

I could allocate a single cell as ambiguous root to the scroll_bar.  That
would pin it.  Then pass that cell to a "destroy" callback to free the
cell.  Hmm.. a lot of work.

Could we perhaps use the mark-and-sweep pool for the widget-like
objects, like scroll_bar and window?  That would perhaps be easier,
because then widgets wouldn't move and tracing would be very similar to
what the old GC does.  And the widgets are hardly performance critical.