BangleApps/apps/doztime/app-bangle2.js

// Positioning values for graphics buffers
const g_height = 80; // total graphics height
const g_x_off = 0; // position from left
const g_y_off = (180 - g_height)/2; // vertical center for graphics region
const g_width = 240 - 2 * g_x_off; // total graphics width
const g_height_d = 28; // height of date region
const g_y_off_d = 0; // y position of date region within graphics region
const spacing = 6; // space between date and time in graphics region
const g_y_off_t = g_y_off_d + g_height_d + spacing; // y position of time within graphics region
const g_height_t = 44; // height of time region

// Other vars
const A1 = [30,30,30,30,31,31,31,31,31,31,30,30];
const B1 = [30,30,30,30,30,31,31,31,31,31,30,30];
const B2 = [30,30,30,30,31,31,31,31,31,30,30,30];
const timeColour = "#ffffff";
const dateColours = ["#ff0000","#ff8000","#ffff00","#00ff00","#0080ff","#ff00ff","#ffffff"];
const calen10 = {"size":26,"pt0":[18-g_x_off,16],"step":[16,0],"dx":-4.5,"dy":-4.5}; // positioning for usual calendar line
const calen7 = {"size":26,"pt0":[48-g_x_off,16],"step":[16,0],"dx":-4.5,"dy":-4.5}; // positioning for S-day calendar line
const time5 = {"size":42,"pt0":[39-g_x_off,24],"step":[26,0],"dx":-6.5,"dy":-6.5}; // positioning for lull time line
const time6 = {"size":42,"pt0":[26-g_x_off,24],"step":[26,0],"dx":-6.5,"dy":-6.5}; // positioning for twinkling time line ft w 48, 48-g, step 30
const baseYear = 11584;
const baseDate = Date(2020,11,21); // month values run from 0 to 11
let accum = new Date(baseDate.getTime());
let sequence = [];
let timeActiveUntil;
let addTimeDigit = false;
let dateFormat = false;
let lastX = 999999999;
let res = {};
//var last_time_log = 0;

var drawtime_timeout;

// Date and time graphics buffers
var dateColour = "#ffffff"; // override later
var timeColour2 = timeColour;
var g_d = Graphics.createArrayBuffer(g_width,g_height_d,1,{'msb':true});
var g_t = Graphics.createArrayBuffer(g_width,g_height_t,1,{'msb':true});
// Set screen mode and function to write graphics buffers
//Bangle.setLCDMode();
g.clear(); // start with blank screen
g.flip = function()
{
  g.setBgColor(0,0,0);
  g.setColor(dateColour);
  g.drawImage(
  {
    width:g_width,
    height:g_height_d,
    buffer:g_d.buffer
  }, g_x_off, g_y_off + g_y_off_d);
  g.setColor(timeColour2);
  g.drawImage(
  {
    width:g_width,
    height:g_height_t,
    buffer:g_t.buffer
  }, g_x_off, g_y_off + g_y_off_t);
};

setWatch(function(){ modeTime(); }, BTN, {repeat:true} );
setWatch(function(){ Bangle.showLauncher(); }, BTN, { repeat: false, edge: "falling" });

Bangle.on('touch', function(button, xy) { //from Gordon Williams
  if (button==1) toggleTimeDigits();
  if (button==2) toggleDateFormat();
});

function buildSequence(targ){
  for(let i=0;i<targ.length;++i){
    sequence.push(new Date(accum.getTime()));
    accum.setDate(accum.getDate()+targ[i]);
  }
}
buildSequence(B2);
buildSequence(B2);
buildSequence(A1);
buildSequence(B1);
buildSequence(B2);
buildSequence(B2);
buildSequence(A1);
buildSequence(B1);
buildSequence(B2);
buildSequence(B2);
buildSequence(A1);
buildSequence(B1);
buildSequence(B2);

function getDate(dt){
  let index = sequence.findIndex(n => n > dt)-1;
  let year = baseYear+parseInt(index/12);
  let month = index % 12;
  let day = parseInt((dt-sequence[index])/86400000);
  let colour = dateColours[day % 6];
  if(day==30){ colour=dateColours[6]; }
  return({"year":year,"month":month,"day":day,"colour":colour});
}
function toggleTimeDigits(){
  addTimeDigit = !addTimeDigit;
  modeTime();
}
function toggleDateFormat(){
  dateFormat = !dateFormat;
  modeTime();
}
function formatDate(res,dateFormat){
  let yyyy = res.year.toString(12);
  calenDef = calen10;
  if(!dateFormat){ //ordinal format
    let mm = ("0"+(res.month+1).toString(12)).substr(-2);
    let dd = ("0"+(res.day+1).toString(12)).substr(-2);
    if(res.day==30){
      calenDef = calen7;
      let m = ((res.month+1).toString(12)).substr(-2);
      return(yyyy+"-"+"S"+m); // ordinal format
    }
    return(yyyy+"-"+mm+"-"+dd);
  }
  let m = res.month.toString(12); // cardinal format
  let w = parseInt(res.day/6);
  let d = res.day%6;
  //return(yyyy+"-"+res.month+"-"+w+"-"+d);
  return(yyyy+"-"+m+"-"+w+"-"+d);
}

function writeDozTime(text,def){
  let pts = def.pts;
  let x=def.pt0[0];
  let y=def.pt0[1];
  g_t.clear();
  g_t.setFont("Vector",def.size);
  for(let i in text){
    if(text[i]=="a"){ g_t.setFontAlign(0,0,2); g_t.drawString("2",x+2+def.dx,y+1+def.dy); }
    else if(text[i]=="b"){ g_t.setFontAlign(0,0,2); g_t.drawString("3",x+2+def.dx,y+1+def.dy); }
    else{ g_t.setFontAlign(0,0,0); g_t.drawString(text[i],x,y); }
    x = x+def.step[0];
    y = y+def.step[1];
  }
}
function writeDozDate(text,def,colour){
  
  dateColour = colour;
  let pts = def.pts;
  let x=def.pt0[0];
  let y=def.pt0[1];
  g_d.clear();
  g_d.setFont("Vector",def.size);
  for(let i in text){
    if(text[i]=="a"){ g_d.setFontAlign(0,0,2); g_d.drawString("2",x+2+def.dx,y+1+def.dy); }
    else if(text[i]=="b"){ g_d.setFontAlign(0,0,2); g_d.drawString("3",x+2+def.dx,y+1+def.dy); }
    else{ g_d.setFontAlign(0,0,0); g_d.drawString(text[i],x,y); }
    x = x+def.step[0];
    y = y+def.step[1];
  }
}

Bangle.loadWidgets();
//for malaire's Adjust Clock widget, if used
function adjustedNow() {
  return WIDGETS.adjust ? new Date(WIDGETS.adjust.now()) : new Date();
}
Bangle.drawWidgets();

// Functions for time mode
function drawTime()
{
  let dt = adjustedNow();
  let date = "";
  let timeDef;
  let x = 0;
  dt.setDate(dt.getDate());
  if(addTimeDigit){
    x =
    10368*dt.getHours()+172.8*dt.getMinutes()+2.88*dt.getSeconds()+0.00288*dt.getMilliseconds();
    let msg = "00000"+Math.floor(x).toString(12);
    let time = msg.substr(-5,3)+"."+msg.substr(-2);
    let wait = 347*(1-(x%1));
    timeDef = time6;
  } else {
    x =
    864*dt.getHours()+14.4*dt.getMinutes()+0.24*dt.getSeconds()+0.00024*dt.getMilliseconds();
    let msg = "0000"+Math.floor(x).toString(12);
    let time = msg.substr(-4,3)+"."+msg.substr(-1);
    let wait = 4167*(1-(x%1));
    timeDef = time5;
  }
  if(lastX > x){ res = getDate(dt); } // calculate date once at start-up and once when turning over to a new day
  date = formatDate(res,dateFormat);
  if(dt<timeActiveUntil)
  {
    // Write to background buffers, then display on screen
    writeDozDate(date,calenDef,res.colour);
    writeDozTime(time,timeDef);
    g.flip();
    // Ready next interval
    drawtime_timeout = setTimeout(drawTime,wait);
  }
  else
  {
    // Clear screen
    g_d.clear();
    g_t.clear();
    g.flip();

  }
  lastX = x;
}
function modeTime()
{
  timeActiveUntil = adjustedNow();
  timeActiveUntil.setDate(timeActiveUntil.getDate());
  timeActiveUntil.setSeconds(timeActiveUntil.getSeconds()+604800);
  if (typeof drawtime_timeout !== 'undefined')
  {
    clearTimeout(drawtime_timeout);
  }
  drawTime();
}

// Start time on twist
Bangle.on('twist',function() {
  modeTime();
});