t_canvas is now just a t_glist. a t_glist is a list of objects that
represents a patch, here's what I wrote about it a while back:
http://wiki.puredata.info/en/glist
I am pretty sure that t_pd is a generic class pointer, like a pointer
to Object in Java.
.hc
On Feb 6, 2011, at 2:15 AM, Rich E wrote:
Update to this: it seems that I can just use t_pd pointers to open
and close the patches, although I still need to return the t_pd *x
pointer from glob_evalfile(). I don't know which method is best for
opening/closing, with t_canvas or t_pd..
The new methods look like this:
t_pd *glob_evalfile(t_pd *ignore, t_symbol *name, t_symbol *dir)
{
t_pd *x = 0;
t_pd *x_loaded = 0;
/* even though binbuf_evalfile appears to take care of dspstate,
we have to do it again here, because canvas_startdsp() assumes
that all toplevel canvases are visible. LATER check if this
is still necessary -- probably not. */
int dspstate = canvas_suspend_dsp();
binbuf_evalfile(name, dir);
while ((x != s__X.s_thing) && (x = s__X.s_thing))
{
vmess(x, gensym("pop"), "i", 1);
x_loaded = x;
}
pd_doloadbang();
canvas_resume_dsp(dspstate);
return x_loaded;
}
t_pd *libpd_openfile(const char *basename, const char *dirname) {
t_pd *x = glob_evalfile(0, gensym(basename), gensym(dirname));
pd_pushsym(x);
int dzero = canvas_getdollarzero();
pd_popsym(x);
return x;
}
void libpd_closefile(t_pd *x) {
pd_free(x);
}
I would appreciate any feedback/suggestions from you guys who know
the pd API much, much more thoroughly that myself.
Cheers,
Rich
On Sun, Feb 6, 2011 at 4:49 PM, Rich E <[email protected]> wrote:
I can't remember, are questions related to pd's C API appropriate
for pd-list, or are they better asked here? It seems that everyone
who responds to those questions is on this list just as much, anyway.
I have been mucking around with opening and closing pd patches using
API calls instead of pd's messaging system. The reason for this is
that I would like to be able to manage (open/close) multiple
instances of a patch, and be able to send each copy of the patch a
unique message via its $0 argument (see http://www.mail-archive.com/[email protected]/msg41648.html)
. So far, the method has been to hack glob_evalfile to look like:
t_canvas *glob_evalfile(t_pd *ignore, t_symbol *name, t_symbol *dir)
{
t_pd *x = 0;
/* even though binbuf_evalfile appears to take care of dspstate,
we have to do it again here, because canvas_startdsp() assumes
that all toplevel canvases are visible. LATER check if this
is still necessary -- probably not. */
t_canvas *x_canvas = 0;
int dspstate = canvas_suspend_dsp();
binbuf_evalfile(name, dir);
while ((x != s__X.s_thing) && (x = s__X.s_thing))
{
x_canvas = canvas_getcurrent();
vmess(x, gensym("pop"), "i", 1);
}
pd_doloadbang();
canvas_resume_dsp(dspstate);
return x_canvas;
}
The only addition is that x_canvas is retrieved before x is 'popped'
off of pd's global stack, and is then returned, giving me a handle
to close that particular patch with something like:
canvas_menuclose(x_canvas, 0);
But I realize that in global_evalfile, t_pd and x_canvas point to
the same address space. This leads me to ask, what is the
difference between these two pointers? Is t_canvas a t_pd along
with variables for its graphical nature?
Mathieu also pointed to me (as I was using the first set of these)
that canvas_setcurrent() and canvas_unsetcurrent() are aliases of
pd_pushsym() and pd_popsym(). Is there a good reason to use one
over the other?
Last question: Does anyone see a way that I could get the value of
x in glob_evalfile above without changing the function? I don't
think it is a dangerous change (and it looks like I could just hand
x.gl_pd to canvas_menuclose, thereby not really needing a t_canvas
pointer), but I would of course prefer to not change the API if
possible.
Cheers,
Rich
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