BangleApps/apps/aclock/clock-analog.js

const p = Math.PI/2;
const PRad = Math.PI/180;

let intervalRefMin = null;
let intervalRefSec = null;

let minuteDate = new Date();
let secondDate = new Date();

function seconds(angle, r) {
  const a = angle*PRad;
  const x = 120+Math.sin(a)*r;
  const y = 120-Math.cos(a)*r;
  g.fillRect(x-1,y-1,x+1,y+1);
}
function hand(angle, r1,r2) {
  const a = angle*PRad;
  const r3 = 3;
  g.fillPoly([
    120+Math.sin(a)*r1,
    120-Math.cos(a)*r1,
    120+Math.sin(a+p)*r3,
    120-Math.cos(a+p)*r3,
    120+Math.sin(a)*r2,
    120-Math.cos(a)*r2,
    120+Math.sin(a-p)*r3,
    120-Math.cos(a-p)*r3]);
}

function drawAll() {
  g.clear();
  secondDate = minuteDate = new Date();
  // draw hands first
  onMinute();
  // draw seconds
  g.setColor(0,0,0.6);
  for (let i=0;i<60;i++)
    seconds(360*i/60, 90);
  onSecond();
}

function onSecond() {
  g.setColor(0,0,0.6);
  seconds(360*secondDate.getSeconds()/60, 90);
  g.setColor(1,0,0);
  secondDate = new Date();
  seconds(360*secondDate.getSeconds()/60, 90);
  g.setColor(1,1,1);

}

function onMinute() {
  g.setColor(0,0,0);
  hand(360*(minuteDate.getHours() + (minuteDate.getMinutes()/60))/12, -10, 50);
  hand(360*minuteDate.getMinutes()/60, -10, 82);
  minuteDate = new Date();
  g.setColor(1,1,1);
  hand(360*(minuteDate.getHours() + (minuteDate.getMinutes()/60))/12, -10, 50);
  hand(360*minuteDate.getMinutes()/60, -10, 82);
  if(minuteDate.getHours() >= 0 && minuteDate.getMinutes() === 0) {
    Bangle.buzz();
  }
}

function clearTimers() {
  if(intervalRefMin) {clearInterval(intervalRefMin);}
  if(intervalRefSec) {clearInterval(intervalRefSec);}
}

function startTimers() {
  minuteDate = new Date();
  secondDate = new Date();
  intervalRefSec = setInterval(onSecond,1000);
  intervalRefMin = setInterval(onMinute,60*1000);
  drawAll();
}

Bangle.on('lcdPower',function(on) {
  if (on) {
    g.clear();
    Bangle.drawWidgets();
    startTimers();
  }else {
    clearTimers();
  }
});

g.clear();
Bangle.loadWidgets();
Bangle.drawWidgets();
drawAll();
startTimers();
// Show launcher when middle button pressed
setWatch(Bangle.showLauncher, BTN2, {repeat:false,edge:"falling"});