Max 5 API Reference

windowwatcher.c

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/**
    @file
    windowwatcher - Demonstrate how to get notifications about the window for a patcher in which an object exists.
                    Scrolling or sizing can be obtained by attaching to the patcherview to get notifications.
                    Getting the actual window position requires the "boxscreenrectchanged" method to be added.
 
    @ingroup        examples

    Copyright 2009 - Cycling '74
    Timothy Place, tim@cycling74.com    
*/

#include "ext.h"
#include "ext_obex.h"
#include "jpatcher_api.h"


// Data Structures
typedef struct _ww {
    t_object    w_obj;
    t_object    *w_patcher;
    t_object    *w_patcherview;
    void        *w_outlet;
} t_ww;


// Prototypes
t_ww*       ww_new(t_symbol *s, short argc, t_atom *argv);
void        ww_free(t_ww *x);
void        ww_attach(t_ww *x);
t_max_err   ww_notify(t_ww *x, t_symbol *s, t_symbol *msg, void *sender, void *data);
void        ww_boxscreenrectchanged(t_jbox *box, t_object *patcherview);

// Globals and Statics
static t_class  *s_ww_class = NULL;


/**********************************************************************/
// Class Definition and Life Cycle

int main(void)
{
    t_class *c; 
    
    common_symbols_init();
    c = class_new("windowwatcher", (method)ww_new, (method)ww_free, sizeof(t_ww), (method)NULL, A_GIMME, 0L);
    
    class_addmethod(c, (method)ww_notify,               "notify",               A_CANT, 0);

    // If your object were a UI external, then you could simple add the method to the class as below.
    // However, this example object is not a UI extern.
    
    // At somepoint in the future instance-methods may be supported.  
    // If/when they are we cound add a method to our instance in the 'new' method instead.
    
    //class_addmethod(c, (method)ww_boxscreenrectchanged,   "boxscreenrectchanged", A_CANT, 0);
    
    class_register(_sym_box, c);
    s_ww_class = c;
    return 0;
}


t_ww* ww_new(t_symbol *s, short argc, t_atom *argv)
{
    t_ww        *x = NULL;
    t_object    *box = NULL;
        
    x = (t_ww*)object_alloc(s_ww_class);
    if (x) {
        x->w_outlet = outlet_new(x, 0L);
        attr_args_process(x, argc, argv);

        object_obex_lookup(x, _sym_pound_P, &x->w_patcher);
        object_obex_lookup(x, _sym_pound_B, &box);
        
        // If/when instance methods are supported, we can use object_addmethod() to add the method
        // (as opposed to a class method) to our box.
        // Then we can be called when our box is moved.
        object_addmethod(box, (method)ww_boxscreenrectchanged, "boxscreenrectchanged",  A_CANT, 0);
        
        // The patcherview is not available when the object is created as a patcher is being read from disk,
        // so we have to defer to wait for it before getting it and attaching for notifications.
        // if we were in a ui object then we would instead add a 'patcherview_vis' method 
        // (and possibly a 'patcherview_invis' method) and attach to our patcherview at that time.
        defer_low(x, (method)ww_attach, NULL, 0, NULL);
        
    }
    return x;
}


void ww_free(t_ww *x)
{
    if(x->w_patcherview)
        object_detach_byptr((t_object *)x, x->w_patcherview);
}


/**********************************************************************/
// Methods

void ww_attach(t_ww *x)
{   
    x->w_patcherview = object_attr_getobj(x->w_patcher, _sym_firstview);
    object_attach_byptr_register(x, x->w_patcherview, _sym_nobox);
}


t_max_err ww_notify(t_ww *x, t_symbol *s, t_symbol *msg, void *sender, void *data)
{
    t_symbol    *name = NULL;
    t_rect      r;
    t_atom      a[4];
    
    if(sender == x->w_patcherview){
        if(msg == _sym_attr_modified){
            name = (t_symbol *)object_method((t_object *)data, _sym_getname);

            // the patcherview is notified when its rect changes size
            if(name == _sym_rect){
                object_attr_get_rect(x->w_patcherview, _sym_rect, &r);
                atom_setfloat(a+0, r.x);
                atom_setfloat(a+1, r.y);
                atom_setfloat(a+2, r.width);
                atom_setfloat(a+3, r.height);
                outlet_anything(x->w_outlet, _sym_patcherview, 4, a);
            }
            // the patcherview is notified when its visible rect has changed (i.e. scrollbars have been moved)
            if(name == _sym_visiblecanvasrect){
                object_attr_get_rect(x->w_patcherview, _sym_visiblecanvasrect, &r);
                atom_setfloat(a+0, r.x);
                atom_setfloat(a+1, r.y);
                atom_setfloat(a+2, r.width);
                atom_setfloat(a+3, r.height);
                outlet_anything(x->w_outlet, _sym_visiblecanvasrect, 4, a);
            }
        }
        else if(msg == _sym_free){
            object_detach_byptr((t_object *)x, x->w_patcherview);
            x->w_patcherview = NULL;
        }
    }
    return MAX_ERR_NONE;
}


void ww_boxscreenrectchanged(t_jbox *box, t_object *patcherview)
{
    t_rect      r;
    t_atom      a[4];
    t_ww        *x = (t_ww *)box->b_firstin;
    
    // This method is an instance method of our box object (newobj)
    // So ...
    
    object_attr_get_rect(x->w_patcherview, _sym_rect, &r);
    atom_setfloat(a+0, r.x);
    atom_setfloat(a+1, r.y);
    atom_setfloat(a+2, r.width);
    atom_setfloat(a+3, r.height);
    outlet_anything(x->w_outlet, _sym_boxscreenrectchanged, 4, a);
}

Copyright © 2008, Cycling '74