implement Clock; include "sys.m";	sys: Sys; include "draw.m";	draw: Draw;	Point, Rect: import draw; include "math.m";	math: Math;	sqrt, atan2, hypot, Degree: import math; include "tk.m";	tk: Tk;	top: ref Tk->Toplevel; include "tkclient.m";	tkclient: Tkclient; Clock: module {	init:	fn(ctxt: ref Draw->Context, argl: list of string);}; cmds := array[] of {	"bind . <Configure> {send win resize}",	"canvas .face -height 200 -width 200 -bg yellow",	"bind .face <ButtonPress> {send ptr %x %y}",	"bind .face <ButtonRelease> {send ptr release}",	"pack .face -expand yes -fill both",	"button .reset -text Reset -command {send win reset}",	"pack .reset -after .Wm_t.title -side right -fill y",	"pack propagate . no",}; init(ctxt: ref Draw->Context, nil: list of string){	sys = load Sys Sys->PATH;	draw = load Draw Draw->PATH;	math = load Math Math->PATH;	tk = load Tk Tk->PATH;	tkclient = load Tkclient Tkclient->PATH;	tkclient->init(); 	sys->pctl(Sys->NEWPGRP, nil); 	clockface := sys->open("/chan/clockface", Sys->ORDWR);	if (clockface == nil) {		sys->print("open /chan/clockface failed: %r\n");		raise "fail:clockface";	}	tock := chan of string;	spawn readme(clockface, tock); 	titlech: chan of string;	(top, titlech) = tkclient->toplevel(ctxt, "hh:mm", "", Tkclient->Appl);	win := chan of string;	ptr := chan of string;	tk->namechan(top, win, "win");	tk->namechan(top, ptr, "ptr");	for(i:=0; i<len cmds; i++)		tk->cmd(top, cmds[i]);	tkclient->onscreen(top, nil);	tkclient->startinput(top, "ptr"::nil);	drawface();	spawn hands(ptr, clockface); 	for (;;) alt {	s := <-top.ctxt.kbd =>		tk->keyboard(top, s);	s := <-top.ctxt.ptr =>		tk->pointer(top, *s);	s := <-top.ctxt.ctl or	s = <-top.wreq or	s = <-titlech =>		tkclient->wmctl(top, s);	msg := <-win =>		case msg {		"resize" =>	drawface();		"reset" =>		sys->fprint(clockface, "reset");		}	nowis := <-tock =>		(n, toks) := sys->tokenize(nowis, ":");		if (n == 2) {			(hour, minute) = (int hd toks, int hd tl toks);			setclock();		}	}} readme(fd: ref Sys->FD, ch: chan of string){	buf := array[64] of byte;	while ((n := sys->read(fd, buf, len buf)) > 0) {		if (buf[n-1] == byte '\n')			n--;		ch <-= string buf[:n];	}	ch <-= "99:99";} hour, minute: int;center, focus: Point;major: int; Frim:	con .98;Fminute:	con .90;Fhour:	con .45;Fnub:	con .05; hands(ptr: chan of string, fd: ref Sys->FD){	for (;;) {		pos := <-ptr;		p := s2p(pos);		hand := "";		if (elinside(p, Fnub))			hand = nil;		else if (elinside(p, Fhour))			hand = "hour";		else if (elinside(p, Fminute))			hand = "minute"; 		do {			p = s2p(pos).sub(center);			angle := int (atan2(real -p.y, real p.x) / Degree);			if (hand != nil)				tkc(".face itemconfigure "+hand+" -start "+string angle+"; update");			case hand {			"hour" =>		hour = ((360+90-angle) / 30) % 12;			"minute" =>	minute = ((360+90-angle) / 6) % 60;			}		} while ((pos = <-ptr) != "release");		if (hand != nil)			sys->fprint(fd, "%d:%d\n", hour, minute);	}} drawface(){	elparms();	tkc(sys->sprint(".face configure -scrollregion {0 0 %d %d}", 2*center.x, 2*center.y));	tkc(".face delete all");	tkc(".face create oval "+elrect(Frim)+" -fill fuchsia -outline aqua -width 2");	for (a := 0; a < 360; a += 30)		tkc(".face create arc "+elrect(Frim)+" -fill aqua -outline aqua -width 2 -extent 1 -start "+string a);	tkc(".face create oval "+elrect(Fminute)+" -fill fuchsia -outline fuchsia");	tkc(".face create oval "+elrect(Fnub)+" -fill aqua -outline aqua");	tkc(".face create arc "+elrect(Fhour)+" -fill aqua -outline aqua -width 6 -extent 1 -tags hour");	tkc(".face create arc "+elrect(Fminute)+" -fill aqua -outline aqua -width 2 -extent 1 -tags minute");	setclock();} setclock(){	tkc(".face itemconfigure hour -start "+string (90 - 30*(hour%12) - minute/2));	tkc(".face itemconfigure minute -start "+string (90 - 6*minute));	tkc(sys->sprint(".Wm_t.title configure -text {%d:%.2d}", (hour+11)%12+1, minute));	tkc("update");} elparms(){	center = (int tkc(".face cget actwidth") / 2, int tkc(".face cget actheight") / 2);	dist := center.x*center.x - center.y*center.y;	if (dist > 0) {		major = 2 * center.x;		focus = (int sqrt(real dist), 0);	} else {		major = 2 * center.y;		focus = (0, int sqrt(real -dist));	}} elinside(p: Point, frac: real): int{	foc := mulf(focus, frac);	d := dist(p, center.add(foc)) + dist(p, center.sub(foc));	return (d < frac * real major);} elrect(frac: real): string{	inset := mulf(center, 1.-frac);	r := Rect(inset, center.mul(2).sub(inset));	return sys->sprint("%d %d %d %d", r.min.x, r.min.y, r.max.x, r.max.y);} mulf(p: Point, f: real): Point{	return (int (f * real p.x), int (f * real p.y));} dist(p, q: Point): real{	p = p.sub(q);	return hypot(real p.x, real p.y);} s2p(s: string): Point{	(nil, xy) := sys->tokenize(s, " ");	if (len xy != 2)		return (0, 0);	return (int hd xy, int hd tl xy);} tkc(msg: string): string{	ret := tk->cmd(top, msg);	if (ret != nil && ret[0] == '!')		sys->print("tk error? %s → %s\n", msg, ret);	return ret;}