Tweaks to speed up track rendering

apps/openstmap/ChangeLog

@@ -33,4 +33,5 @@
 0.26: Ensure that when redrawing, we always cancel any in-progress track draw
 0.27: Display message if no map is installed
 0.28: Fix rounding errors
-0.29: move exit to bottom of menu
+0.29: Keep exit at bottom of menu
+      Speed up latLonToXY for track rendering

apps/openstmap/openstmap.js

@@ -38,17 +38,17 @@ if (m.map) {
   m.lat = m.map.lat; // position of middle of screen
   m.lon = m.map.lon;  // position of middle of screen
 }
+var CX = g.getWidth()/2;
+var CY = g.getHeight()/2;
 
 // return number of tiles drawn
 exports.draw = function() {
-  var cx = g.getWidth()/2;
-  var cy = g.getHeight()/2;
   var p = Bangle.project({lat:m.lat,lon:m.lon});
   let count = 0;
   m.maps.forEach((map,idx) => {
     var d = map.scale/m.scale;
-    var ix = (p.x-map.center.x)/m.scale + (map.imgx*d/2) - cx;
-    var iy = (map.center.y-p.y)/m.scale + (map.imgy*d/2) - cy;
+    var ix = (p.x-map.center.x)/m.scale + (map.imgx*d/2) - CX;
+    var iy = (map.center.y-p.y)/m.scale + (map.imgy*d/2) - CY;
     var o = {};
     var s = map.tilesize;
     if (d!=1) { // if the two are different, add scaling
@@ -85,14 +85,12 @@ exports.draw = function() {
 };
 
 /// Convert lat/lon to pixels on the screen
-exports.latLonToXY = function(lat, lon) {
-  var p = Bangle.project({lat:m.lat,lon:m.lon});
-  var q = Bangle.project({lat:lat, lon:lon});
-  var cx = g.getWidth()/2;
-  var cy = g.getHeight()/2;
+exports.latLonToXY = function(lat, lon) { "ram"
+  var p = Bangle.project({lat:m.lat,lon:m.lon}),
+      q = Bangle.project({lat:lat, lon:lon});
   return {
-    x : Math.round((q.x-p.x)/m.scale + cx),
-    y : Math.round(cy - (q.y-p.y)/m.scale)
+    x : Math.round((q.x-p.x)/m.scale + CX),
+    y : Math.round(CY - (q.y-p.y)/m.scale)
   };
 };
 

apps/recorder/ChangeLog

@@ -45,3 +45,4 @@
 0.36: When recording with 1 second periods, log time with one decimal.
 0.37: 1 second periods + gps log => log when gps event is received, not with
 	setInterval.
+0.38: Tweaks to speed up track rendering

apps/recorder/app.js

@@ -213,8 +213,10 @@ function viewTrack(filename, info) {
     });
   };
   menu['< Back'] = () => { viewTracks(); };
+  return E.showMenu(menu);
+}
 
-  function plotTrack(info) { "ram"
+function plotTrack(info) { "ram"
   function distance(lat1,long1,lat2,long2) { "ram"
     var x = (long1-long2) * Math.cos((lat1+lat2)*Math.PI/360);
     var y = lat2 - lat1;
@@ -222,7 +224,7 @@ function viewTrack(filename, info) {
   }
 
   // Function to convert lat/lon to XY
-    var getMapXY;
+  var XY;
   if (info.qOSTM) {
     // scale map to view full track
     const max = Bangle.project({lat: info.maxLat, lon: info.maxLong});
@@ -230,9 +232,9 @@ function viewTrack(filename, info) {
     const scaleX = (max.x-min.x)/Bangle.appRect.w;
     const scaleY = (max.y-min.y)/Bangle.appRect.h;
     osm.scale = Math.ceil((scaleX > scaleY ? scaleX : scaleY)*1.1); // add 10% margin
-      getMapXY = osm.latLonToXY.bind(osm);
+    XY = osm.latLonToXY.bind(osm);
   } else {
-      getMapXY = function(lat, lon) { "ram"
+    XY = function(lat, lon) { "ram"
       return {x:cx + Math.round((long - info.lon)*info.lfactor*info.scale),
               y:cy + Math.round((info.lat - lat)*info.scale)};
     };
@@ -243,6 +245,7 @@ function viewTrack(filename, info) {
   g.flip(); // on buffered screens, draw a not saying we're busy
   g.clear(1);
   var s = require("Storage");
+  var G = g;
   var W = g.getWidth();
   var H = g.getHeight();
   var cx = W/2;
@@ -275,7 +278,7 @@ function viewTrack(filename, info) {
   // now start plotting
   var lat = +c[latIdx];
   var long = +c[lonIdx];
-    var mp = getMapXY(lat, long);
+  var mp = XY(lat, long);
   g.moveTo(mp.x,mp.y);
   g.setColor("#0f0");
   g.fillCircle(mp.x,mp.y,5);
@@ -288,16 +291,16 @@ function viewTrack(filename, info) {
     if (c[latIdx]=="")continue;
     lat = +c[latIdx];
     long = +c[lonIdx];
-      mp = getMapXY(lat, long);
-      g.lineTo(mp.x,mp.y);
-      if (info.qOSTM) g.fillCircle(mp.x,mp.y,2); // make the track more visible
+    mp = XY(lat, long);
+    G.lineTo(mp.x,mp.y);
+    if (info.qOSTM) G.fillCircle(mp.x,mp.y,2); // make the track more visible
     var d = distance(olat,olong,lat,long);
     if (!isNaN(d)) dist+=d;
     olat = lat;
     olong = long;
     ox = mp.x;
     oy = mp.y;
-      if (++i > 100) { g.flip();i=0; }
+    if (++i > 100) { G.flip();i=0; }
   }
   g.setColor("#f00");
   g.fillCircle(ox,oy,5);
@@ -313,9 +316,9 @@ function viewTrack(filename, info) {
   }, isBTN3?BTN3:BTN1);
   Bangle.drawWidgets();
   g.flip();
-  }
+}
 
-  function plotGraph(info, style) { "ram"
+function plotGraph(info, style) { "ram"
   E.showMenu(); // remove menu
   E.showMessage(/*LANG*/"Calculating...",/*LANG*/"Track "+info.fn);
   var filename = info.filename;
@@ -433,9 +436,6 @@ function viewTrack(filename, info) {
     viewTrack(info.filename, info);
   }, isBTN3?BTN3:BTN1);
   g.flip();
-  }
-
-  return E.showMenu(menu);
 }
 
 

apps/recorder/metadata.json

@@ -2,7 +2,7 @@
   "id": "recorder",
   "name": "Recorder",
   "shortName": "Recorder",
-  "version": "0.37",
+  "version": "0.38",
   "description": "Record GPS position, heart rate and more in the background, then download to your PC.",
   "icon": "app.png",
   "tags": "tool,outdoors,gps,widget,clkinfo",