Max 5 API Reference

pictmeter~.c

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/**
    @file
    pictmeter~ - audio meter that works by resizing an image

    @ingroup    examples
*/

#include "ext.h"                            // standard Max include, always required
#include "ext_obex.h"                       // required for new style Max object
#include "jpatcher_api.h"
#include "jgraphics.h"
#include "z_dsp.h"                          // should be after jpatcher_api.h
#include "ext_drag.h"

typedef struct _pictmeter 
{
    t_pxjbox    p_obj;
    t_jsurface *p_surface;
    void *p_clock;
    double p_value;
    double p_max;
    char p_startclock;
} t_pictmeter;

void *pictmeter_new(t_symbol *s, long argc, t_atom *argv);
void pictmeter_free(t_pictmeter *x);
void pictmeter_assist(t_pictmeter *x, void *b, long m, long a, char *s);
void pictmeter_paint(t_pictmeter *x, t_object *patcherview);
void pictmeter_read(t_pictmeter *x, t_symbol *s);
void pictmeter_doread(t_pictmeter *x, t_symbol *s, long argc, t_atom *argv);
long pictmeter_acceptsdrag_unlocked(t_pictmeter *x, t_object *drag, t_object *view);
void pictmeter_dsp(t_pictmeter *x, t_signal **sp, short *count);
t_int *pictmeter_perform(t_int *w);
void pictmeter_tick(t_pictmeter *x);
void pictmeter_free(t_pictmeter *x);
void *pictmeter_new(t_symbol *s, long argc, t_atom *argv);

static t_class *s_pictmeter_class;

int main(void)
{   
    t_class *c;
        
    c = class_new("pictmeter~", (method)pictmeter_new, (method)pictmeter_free, sizeof(t_pictmeter), 0L, A_GIMME, 0);

    c->c_flags |= CLASS_FLAG_NEWDICTIONARY;
    jbox_initclass(c, 0);
    class_dspinitjbox(c);

    class_addmethod(c, (method)pictmeter_dsp, "dsp", A_CANT, 0);
    class_addmethod(c, (method)pictmeter_paint, "paint",    A_CANT, 0);
    class_addmethod(c, (method)pictmeter_assist,            "assist",       A_CANT, 0);  
    class_addmethod(c, (method)pictmeter_acceptsdrag_unlocked, "acceptsdrag_unlocked", A_CANT, 0);
    class_addmethod(c, (method)pictmeter_acceptsdrag_unlocked, "acceptsdrag_locked", A_CANT, 0);
    class_addmethod(c, (method)pictmeter_read, "read", A_DEFSYM, 0);
    
    CLASS_ATTR_DEFAULT(c,"patching_rect",0, "0. 0. 128. 128.");
    
    class_register(CLASS_BOX, c);
    s_pictmeter_class = c;
    return 0;
}

void pictmeter_assist(t_pictmeter *x, void *b, long m, long a, char *s)
{
    if (m == ASSIST_INLET)  //inlet
        sprintf(s, "(signal) Audio Input");
}

void pictmeter_paint(t_pictmeter *x, t_object *patcherview)
{
    t_rect src, dst, rect;
    t_jgraphics *g = (t_jgraphics*) patcherview_get_jgraphics(patcherview);     // obtain graphics context
    jbox_get_rect_for_view((t_object *)x, patcherview, &rect);
    
    if (!x->p_surface)
        return;

    // draw if the value is non zero
    if (x->p_value) {
        src.width = jgraphics_image_surface_get_width(x->p_surface);
        src.height = jgraphics_image_surface_get_height(x->p_surface);
        src.x = 0;
        src.y = 0;
        dst.width = rect.width * x->p_value;
        dst.height = rect.height * x->p_value;
        if (dst.width < 1 || dst.height < 1)
            return;
        dst.x = 0 + ((rect.width * 0.5) - (dst.width * 0.5));
        dst.y = 0 + ((rect.height * 0.5) - (dst.height * 0.5));
        
        jgraphics_image_surface_draw(g, x->p_surface, src, dst);
    }
}

void pictmeter_read(t_pictmeter *x, t_symbol *s)
{
    defer((t_object *)x, (method)pictmeter_doread, s, 0, NULL);
}

void pictmeter_doread(t_pictmeter *x, t_symbol *s, long argc, t_atom *argv)
{
    char filename[MAX_PATH_CHARS];
    long *type,ntype,outtype;
    t_max_err err;
    char alloc;
    short path;
    t_jsurface *surface;
    
    jgraphics_getfiletypes(x, &ntype, &type, &alloc);
    if (s == gensym("")) {
        err = open_dialog(filename, &path,(void *)&outtype, (void *)type, ntype);
        if (err)
            return;
    } else {        
        strcpy(filename,s->s_name);
        err = locatefile_extended(filename, &path, &outtype, type, ntype);
        if (err)
            return;
    }
    surface = jgraphics_image_surface_create_referenced(filename, path); 
    if (surface)
        x->p_surface = surface;
    if (alloc)
        sysmem_freeptr((char *)type);
}

long pictmeter_acceptsdrag_unlocked(t_pictmeter *x, t_object *drag, t_object *view)
{
    if (jdrag_matchdragrole(drag, gensym("imagefile"), 0)) {
        jdrag_box_add(drag, (t_object *)x, gensym("read"));
        return true;
    }
    return false;
}

void pictmeter_dsp(t_pictmeter *x, t_signal **sp, short *count)
{
    x->p_value = 0.;
    x->p_max = 0.;
    // only put perf func on dsp chain if sig is connected
    if (count[0]) {
        dsp_add(pictmeter_perform, 3, x, sp[0]->s_vec, sp[0]->s_n);
        x->p_startclock = true;
    }
}

t_int *pictmeter_perform(t_int *w)
{
    t_pictmeter *x = (t_pictmeter *)(w[1]);
    t_float *in = (t_float *)(w[2]);
    int n = (int)(w[3]);
    double xn, max;
        
    if (x->p_obj.z_disabled)
        goto out;
        
    max = x->p_max;
    
    while (n--) {
        xn = *in++;
        if (xn < 0)
            xn = -xn;
        if (xn > max)
            max = xn;
    }
    x->p_max = max;
        
    if (x->p_startclock) {
        x->p_startclock = 0;
        clock_delay(x->p_clock,0);
    }
out:
    return w + 4;
}

void pictmeter_tick(t_pictmeter *x)
{
    // for the astute student of the Max SDK:
    //
    // this method is called by the scheduler thread
    // x->p_max is also accessed by the perform method in the audio thread
    // we could use a mutex or critical region to protect the following block of code from having the value of x->p_max modified during its execution.
    // however, mutexes and critical regions carry a performance penalty.
    //
    // in this case, due to the nature of what we are doing (drawing something every tenth of second showing the history of the previous samples),
    // the mutex or critical region will not add anything to the object, or protect us from crashes, and it carries a performance penalty.
    // so we have made a conscious decision to not use the aforementioned thread locking mechanisms.
    
    if (x->p_value != x->p_max) {
        x->p_value = x->p_max;
        if (x->p_value > 1.)
            x->p_value = 1.;
        x->p_max = 0;
        jbox_redraw((t_jbox *)x);
    }
    
    if (sys_getdspstate())  // if the dsp is still on, schedule a next pictmeter_tick() call
        clock_fdelay(x->p_clock, 100);
}

void pictmeter_free(t_pictmeter *x)
{
    dsp_freejbox((t_pxjbox *)x);
    freeobject((t_object *)x->p_clock);
    jbox_free((t_jbox *)x);
}

void *pictmeter_new(t_symbol *s, long argc, t_atom *argv)
{
    t_pictmeter *x = NULL;
    t_dictionary *d=NULL;
    long boxflags;
    
    if (!(d=object_dictionaryarg(argc,argv)))
        return NULL;
   
    x = (t_pictmeter *)object_alloc(s_pictmeter_class);
    boxflags = 0 
            | JBOX_DRAWFIRSTIN 
            | JBOX_NODRAWBOX
            | JBOX_DRAWINLAST
            | JBOX_TRANSPARENT  
    //      | JBOX_NOGROW
    //      | JBOX_GROWY
            | JBOX_GROWBOTH
    //      | JBOX_HILITE
    //      | JBOX_BACKGROUND
    //      | JBOX_DRAWBACKGROUND
    //      | JBOX_NOFLOATINSPECTOR
    //      | JBOX_TEXTFIELD
    //      | JBOX_MOUSEDRAGDELTA
    //      | JBOX_TEXTFIELD
            ;

    jbox_new((t_jbox *)x, boxflags, argc, argv);
    x->p_obj.z_box.b_firstin = (void *)x;
    dsp_setupjbox((t_pxjbox *)x,1);
    x->p_clock = clock_new(x,(method)pictmeter_tick);
    x->p_value = x->p_max = 0;
    x->p_startclock = false;
    jbox_ready((t_jbox *)x);
    return x;
}

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