shithub: monome

ref: ce0c4507d6c7e6460ed098e8a364194ea69b0e72
dir: /volume.c/

#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>
#include <thread.h>

#define RATE 44100

int rate;
double vol;
Point c;

void
volume(unsigned char *buf, int len)
{
	short l, r;
	int i;

	for(i = 0; i < len; i += 4){
		l = buf[i+0] | (buf[i+1] << 8);
		r = buf[i+2] | (buf[i+3] << 8);

		l *= vol;
		r *= vol;

		buf[i+0] = l & 0xFF;
		buf[i+1] = (l >> 8) & 0xFF;
		buf[i+2] = r & 0xFF;
		buf[i+3] = (r >> 8) & 0xFF;
	}
}

void
doproc(void *unused)
{
	unsigned char *buf = malloc(rate * 4);
	int r;

	while((r = read(0, buf, rate * 4)) > 0){
		volume(buf, r);
		write(1, buf, r);
	}
}

void
redraw(Image *screen)
{
	int x = c.x * vol;

	draw(screen, screen->r, display->white, nil, ZP);

	draw(screen, Rect(screen->r.min.x + x - 1, screen->r.min.y,
					screen->r.min.x + x + 1, screen->r.max.y),
				display->black, nil, ZP);
}

void
eresized(int new)
{
	if(new && getwindow(display, Refnone) < 0)
		fprint(2,"can't reattach to window");
	c = divpt(subpt(screen->r.max, screen->r.min), 2);
	redraw(screen);
}

void
threadmain(int argc, char **argv)
{
	Mouse m;
	Point xy;
	rate = RATE;
	vol = 1.0;

	if (argc > 1)
		rate = atoi(argv[1]);

	if(initdraw(0, 0, "volume") < 0)
		sysfatal("initdraw: %r");
	einit(Emouse);

	eresized(0);
	proccreate(doproc, nil, mainstacksize);

	for(;;m = emouse()){
		if(m.buttons & 1){
			xy = subpt(m.xy, screen->r.min);

			vol = xy.x / (double)c.x;
			
			redraw(screen);
		}
	}
}