summaryrefslogtreecommitdiffstats
path: root/dom/system/gonk/GeolocationUtil.cpp
diff options
context:
space:
mode:
authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /dom/system/gonk/GeolocationUtil.cpp
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
downloadUXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.gz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.lz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.xz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.zip
Add m-esr52 at 52.6.0
Diffstat (limited to 'dom/system/gonk/GeolocationUtil.cpp')
-rw-r--r--dom/system/gonk/GeolocationUtil.cpp28
1 files changed, 28 insertions, 0 deletions
diff --git a/dom/system/gonk/GeolocationUtil.cpp b/dom/system/gonk/GeolocationUtil.cpp
new file mode 100644
index 000000000..99d484a19
--- /dev/null
+++ b/dom/system/gonk/GeolocationUtil.cpp
@@ -0,0 +1,28 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GeolocationUtil.h"
+
+double CalculateDeltaInMeter(double aLat, double aLon, double aLastLat, double aLastLon)
+{
+ // Use spherical law of cosines to calculate difference
+ // Not quite as correct as the Haversine but simpler and cheaper
+ const double radsInDeg = M_PI / 180.0;
+ const double rNewLat = aLat * radsInDeg;
+ const double rNewLon = aLon * radsInDeg;
+ const double rOldLat = aLastLat * radsInDeg;
+ const double rOldLon = aLastLon * radsInDeg;
+ // WGS84 equatorial radius of earth = 6378137m
+ double cosDelta = (sin(rNewLat) * sin(rOldLat)) +
+ (cos(rNewLat) * cos(rOldLat) * cos(rOldLon - rNewLon));
+ if (cosDelta > 1.0) {
+ cosDelta = 1.0;
+ } else if (cosDelta < -1.0) {
+ cosDelta = -1.0;
+ }
+ return acos(cosDelta) * 6378137;
+}
+