Added clkinfogps

apps/clkinfogps/ChangeLog

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+0.01: First version

apps/clkinfogps/README.md

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+# GPS Clock Info
+
+## Screenshots
+
+Written by: [Hugh Barney](https://github.com/hughbarney)  For support and discussion please post in the [Bangle JS Forum](http://forum.espruino.com/microcosms/1424/)

apps/clkinfogps/clkinfo.js

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+(function () {
+  var timeout;
+  var last_fix;
+
+  var resetLastFix = function() {
+    last_fix = {
+      fix: 0,
+      alt: 0,
+      lat: 0,
+      lon: 0,
+      speed: 0,
+      time: 0,
+      course: 0,
+      satellites: 0
+    };
+  };
+  
+  var formatTime = function(now) {
+    try {
+      var fd = now.toUTCString().split(" ");
+      return fd[4];
+    } catch (e) {
+      return "00:00:00";
+    }
+  };
+
+  var onGPS = function(fix) {
+    console.log(fix);
+    last_fix.time = fix.time;
+
+    // we got a fix
+    if (fix.fix) {
+      last_fix = fix;
+      // cancel the timeout, if not already timed out
+      if (this.timeout) {
+	clearTimeout(timeout);
+	this.timeout = undefined;
+      }
+      // power off the GPS
+      Bangle.setGPSPower(0,"clkinfo");
+      // power on the GPS again in 3 minutes
+      timeout = setTimeout(function() {
+	timeout = undefined;
+	Bangle.setGPSPower(1,"clkinfo");
+      }, 180000);
+    }
+    info.items[0].emit("redraw"); 
+  };
+
+  var gpsText = function() {
+    if (last_fix === undefined)
+      return '----- , -----';
+
+    if (!last_fix.fix) 
+      return formatTime(last_fix.time);
+    
+    // use basic lat,lon for now
+    return last_fix.lat.toFixed(3) + ' , ' + last_fix.lon.toFixed(3);
+  };
+  
+  var info = {
+    name: "Gps",
+    items: [
+      {
+        name: "gridref",
+        get: function () { return ({
+          text: gpsText()
+        }); },
+	run : function() {
+          Bangle.setGPSPower(1,"clkinfo");
+          /* turn off after 5 minutes, sooner if we get a fix */
+          this.timeout = setTimeout(function() {
+            this.timeout = undefined;
+            Bangle.setGPSPower(0,"clkinfo");
+          }, 300000);
+	},
+        show: function () {
+          resetLastFix();
+	  Bangle.on("GPS",onGPS);
+	  this.run();
+        },
+        hide: function() {
+          Bangle.setGPSPower(0,"clkinfo");
+          Bangle.removeListener("GPS", onGPS);
+          if (this.timeout) {
+            clearTimeout(this.timeout);
+            this.timeout = undefined;
+          }
+          resetLastFix();
+        }
+      }
+    ]
+  };
+
+  return info;
+});

apps/clkinfogps/geotools.js

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+/**
+ * 
+ * A module of Geo functions for use with gps fixes
+ *
+ * let geo = require("geotools");
+ * let os = geo.gpsToOSGrid(fix);
+ * let ref = geo.gpsToOSMapRef(fix);
+ *
+ */
+
+Number.prototype.toRad = function() { return this*Math.PI/180; };
+/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
+/*  Ordnance Survey Grid Reference functions  (c) Chris Veness 2005-2014                          */
+/*   - www.movable-type.co.uk/scripts/gridref.js                                                  */
+/*   - www.movable-type.co.uk/scripts/latlon-gridref.html                                         */
+/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
+function OsGridRef(easting, northing) {
+  this.easting = 0|easting;
+  this.northing = 0|northing;
+}
+OsGridRef.latLongToOsGrid = function(point) {
+  var lat = point.lat.toRad();
+  var lon = point.lon.toRad();
+
+  var a = 6377563.396, b = 6356256.909;          // Airy 1830 major & minor semi-axes
+  var F0 = 0.9996012717;                         // NatGrid scale factor on central meridian
+  var lat0 = (49).toRad(), lon0 = (-2).toRad();  // NatGrid true origin is 49�N,2�W
+  var N0 = -100000, E0 = 400000;                 // northing & easting of true origin, metres
+  var e2 = 1 - (b*b)/(a*a);                      // eccentricity squared
+  var n = (a-b)/(a+b), n2 = n*n, n3 = n*n*n;
+
+  var cosLat = Math.cos(lat), sinLat = Math.sin(lat);
+  var nu = a*F0/Math.sqrt(1-e2*sinLat*sinLat);              // transverse radius of curvature
+  var rho = a*F0*(1-e2)/Math.pow(1-e2*sinLat*sinLat, 1.5);  // meridional radius of curvature
+  var eta2 = nu/rho-1;
+
+  var Ma = (1 + n + (5/4)*n2 + (5/4)*n3) * (lat-lat0);
+  var Mb = (3*n + 3*n*n + (21/8)*n3) * Math.sin(lat-lat0) * Math.cos(lat+lat0);
+  var Mc = ((15/8)*n2 + (15/8)*n3) * Math.sin(2*(lat-lat0)) * Math.cos(2*(lat+lat0));
+  var Md = (35/24)*n3 * Math.sin(3*(lat-lat0)) * Math.cos(3*(lat+lat0));
+  var M = b * F0 * (Ma - Mb + Mc - Md);              // meridional arc
+
+  var cos3lat = cosLat*cosLat*cosLat;
+  var cos5lat = cos3lat*cosLat*cosLat;
+  var tan2lat = Math.tan(lat)*Math.tan(lat);
+  var tan4lat = tan2lat*tan2lat;
+
+  var I = M + N0;
+  var II = (nu/2)*sinLat*cosLat;
+  var III = (nu/24)*sinLat*cos3lat*(5-tan2lat+9*eta2);
+  var IIIA = (nu/720)*sinLat*cos5lat*(61-58*tan2lat+tan4lat);
+  var IV = nu*cosLat;
+  var V = (nu/6)*cos3lat*(nu/rho-tan2lat);
+  var VI = (nu/120) * cos5lat * (5 - 18*tan2lat + tan4lat + 14*eta2 - 58*tan2lat*eta2);
+
+  var dLon = lon-lon0;
+  var dLon2 = dLon*dLon, dLon3 = dLon2*dLon, dLon4 = dLon3*dLon, dLon5 = dLon4*dLon, dLon6 = dLon5*dLon;
+
+  var N = I + II*dLon2 + III*dLon4 + IIIA*dLon6;
+  var E = E0 + IV*dLon + V*dLon3 + VI*dLon5;
+
+  return new OsGridRef(E, N);
+};
+
+/*
+ * converts northing, easting to standard OS grid reference.
+ *
+ * [digits=10] - precision (10 digits = metres)
+ *   to_map_ref(8, 651409, 313177); => 'TG 5140 1317'
+ *   to_map_ref(0, 651409, 313177); => '651409,313177'
+ *
+ */
+function to_map_ref(digits, easting, northing) {
+  if (![ 0,2,4,6,8,10,12,14,16 ].includes(Number(digits))) throw new RangeError(`invalid precision '${digits}'`); // eslint-disable-line comma-spacing
+
+  let e = easting;
+  let n = northing;
+
+  // use digits = 0 to return numeric format (in metres) - note northing may be >= 1e7
+  if (digits == 0) {
+    const format = { useGrouping: false,  minimumIntegerDigits: 6, maximumFractionDigits: 3 };
+    const ePad = e.toLocaleString('en', format);
+    const nPad = n.toLocaleString('en', format);
+    return `${ePad},${nPad}`;
+  }
+
+  // get the 100km-grid indices
+  const e100km = Math.floor(e / 100000), n100km = Math.floor(n / 100000);
+
+  // translate those into numeric equivalents of the grid letters
+  let l1 = (19 - n100km) - (19 - n100km) % 5 + Math.floor((e100km + 10) / 5);
+  let l2 = (19 - n100km) * 5 % 25 + e100km % 5;
+
+  // compensate for skipped 'I' and build grid letter-pairs
+  if (l1 > 7) l1++;
+  if (l2 > 7) l2++;
+  const letterPair = String.fromCharCode(l1 + 'A'.charCodeAt(0), l2 + 'A'.charCodeAt(0));
+
+  // strip 100km-grid indices from easting & northing, and reduce precision
+  e = Math.floor((e % 100000) / Math.pow(10, 5 - digits / 2));
+  n = Math.floor((n % 100000) / Math.pow(10, 5 - digits / 2));
+
+  // pad eastings & northings with leading zeros
+  e = e.toString().padStart(digits/2, '0');
+  n = n.toString().padStart(digits/2, '0');
+
+  return `${letterPair} ${e} ${n}`;
+}
+
+/**
+ * 
+ * Module exports section, example code below
+ *
+ * let geo = require("geotools");
+ * let os = geo.gpsToOSGrid(fix);
+ * let ref = geo.gpsToOSMapRef(fix);
+ */
+
+// get easting and northings
+exports.gpsToOSGrid = function(gps_fix) {
+  return OsGridRef.latLongToOsGrid(gps_fix);
+}
+
+// string with an OS Map grid reference
+exports.gpsToOSMapRef = function(gps_fix) {
+  let os = OsGridRef.latLongToOsGrid(last_fix);
+  return to_map_ref(6, os.easting, os.northing);
+}

apps/clkinfogps/metadata.json

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+{
+  "id": "clkinfogps",
+  "name": "GPS Grid Ref Clockinfo",
+  "version":"0.01",
+  "description": "Clockinfo that display the GPS OS Grid Refernce",
+  "icon": "app.png",
+  "type": "clkinfo",
+  "tags": "clkinfo,gps",
+  "supports" : ["BANGLEJS2"],
+  "readme":"README.md",
+  "storage": [
+    {"name":"geotools","url":"geotools.js"},
+    {"name":"gps.clkinfo.js","url":"clkinfo.js"}
+  ]
+}