clock: import from plan 9

Fixes #250.

man/man1/date.1

@@ -1,6 +1,6 @@
 .TH DATE 1
 .SH NAME
-date \- date and time
+date, clock \- date and time
 .SH SYNOPSIS
 .B date
 [
@@ -8,8 +8,8 @@ date \- date and time
 ] [
 .I seconds
 ]
-.\" .br
+.br
-.\" .B clock
+.B clock
 .SH DESCRIPTION
 Print the date, in the format
 .PP
@@ -34,6 +34,9 @@ If the optional argument
 .I seconds
 is present, it is used as the time to convert rather than
 the real time.
+.PP
+.I Clock
+draws a simple analog clock in its window.
 .\" .SH FILES
 .\" .TF /adm/timezone/local
 .\" .TP
@@ -54,5 +57,5 @@ the real time.
 .\" draws a simple analog clock in its window.
 .SH SOURCE
 .B \*9/src/cmd/date.c
-.\" .br
+.br
-.\" .B \*9/src/cmd/draw/clock.c
+.B \*9/src/cmd/draw/clock.c

src/cmd/draw/clock.c

@@ -0,0 +1,104 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <event.h>
+
+Image *hrhand, *minhand;
+Image *dots, *back;
+
+Point
+circlept(Point c, int r, int degrees)
+{
+	double rad;
+	rad = (double) degrees * PI/180.0;
+	c.x += cos(rad)*r;
+	c.y -= sin(rad)*r;
+	return c;
+}
+
+void
+redraw(Image *screen)
+{
+	static int tm, ntm;
+	static Rectangle r;
+	static Point c;
+	static int rad;
+	int i;
+	int anghr, angmin;
+	static Tm tms;
+	static Tm ntms;
+
+	ntm = time(0);
+	if(ntm == tm && eqrect(screen->r, r))
+		return;
+
+	ntms = *localtime(ntm);
+	anghr = 90-(ntms.hour*5 + ntms.min/12)*6;
+	angmin = 90-ntms.min*6;
+	tm = ntm;
+	tms = ntms;
+	r = screen->r;
+	c = divpt(addpt(r.min, r.max), 2);
+	rad = Dx(r) < Dy(r) ? Dx(r) : Dy(r);
+	rad /= 2;
+	rad -= 8;
+
+	draw(screen, screen->r, back, nil, ZP);
+	for(i=0; i<12; i++)
+		fillellipse(screen, circlept(c, rad, i*(360/12)), 2, 2, dots, ZP);
+
+	line(screen, c, circlept(c, (rad*3)/4, angmin), 0, 0, 1, minhand, ZP);
+	line(screen, c, circlept(c, rad/2, anghr), 0, 0, 1, hrhand, ZP);
+
+	flushimage(display, 1);
+}
+
+void
+eresized(int new)
+{
+	if(new && getwindow(display, Refnone) < 0)
+		fprint(2,"can't reattach to window");
+	redraw(screen);
+}
+
+void
+main(int argc, char **argv)
+{
+	Event e;
+	Mouse m;
+	Menu menu;
+	char *mstr[] = {"exit", 0};
+	int key, timer;
+	int t;
+
+	USED(argc);
+	USED(argv);
+
+	if (initdraw(0, 0, "clock") < 0)
+		sysfatal("initdraw failed");
+	back = allocimagemix(display, DPalebluegreen, DWhite);
+
+	hrhand = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DDarkblue);
+	minhand = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DPaleblue);
+	dots = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DBlue);
+	redraw(screen);
+
+	einit(Emouse);
+	t = (30*1000);
+	timer = etimer(0, t);
+
+	menu.item = mstr;
+	menu.lasthit = 0;
+	for(;;) {
+		key = event(&e);
+		if(key == Emouse) {
+			m = e.mouse;
+			if(m.buttons & 4) {
+				if(emenuhit(3, &m, &menu) == 0)
+					exits(0);
+			}
+		} else if(key == timer) {
+			redraw(screen);
+		}
+	}
+}