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Avoid using float when dealing with GPS location

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Float values have insufficient precision compared to the udeg we usually
store - so we create a special callback function to use from osm-gps-map
and everywhere else use integers.

This patch also increases the decimal places displayed in the GPS text
entry box - this way we can cut and paste the text without loss of
precision.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
This commit is contained in:
Dirk Hohndel 2013-02-08 19:27:54 -08:00
parent b12b2f1c85
commit 51f97a97ce
1 changed files with 21 additions and 15 deletions
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36
info.c
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@ -639,31 +639,32 @@ struct location_update {
void (*callback)(float, float); void (*callback)(float, float);
} location_update; } location_update;
static void print_gps_coordinates(char *buffer, int len, float lat, float lon) /* take latitude and longitude in udeg and print them in a human readable
* form, without losing precision */
static void print_gps_coordinates(char *buffer, int len, int lat, int lon)
{ {
unsigned int latdeg, londeg; unsigned int latdeg, londeg;
float latmin, lonmin; double latmin, lonmin;
char *lath, *lonh; char *lath, *lonh;
if (!lat && !lon) { if (!lat && !lon) {
*buffer = 0; *buffer = 0;
return; return;
} }
lath = lat >= 0 ? _("N") : _("S");
lath = lat >= 0.0 ? _("N") : _("S"); lonh = lon >= 0 ? _("E") : _("W");
lonh = lon >= 0.0 ? _("E") : _("W"); lat = abs(lat);
lat = fabs(lat); lon = abs(lon);
lon = fabs(lon); latdeg = lat / 1000000;
latdeg = lat; londeg = lon / 1000000;
londeg = lon; latmin = (lat % 1000000) * 60.0 / 1000000.0;
latmin = (lat - latdeg) * 60.0; lonmin = (lon % 1000000) * 60.0 / 1000000.0;
lonmin = (lon - londeg) * 60.0;
snprintf(buffer, len, "%s%u%s %8.5f\' , %s%u%s %8.5f\'", snprintf(buffer, len, "%s%u%s %8.5f\' , %s%u%s %8.5f\'",
lath, latdeg, UTF8_DEGREE, latmin, lath, latdeg, UTF8_DEGREE, latmin,
lonh, londeg, UTF8_DEGREE, lonmin); lonh, londeg, UTF8_DEGREE, lonmin);
} }
static void update_gps_entry(float lat, float lon) static void update_gps_entry(int lat, int lon)
{ {
if (location_update.entry) { if (location_update.entry) {
print_gps_coordinates(location_update.text, 45, lat, lon); print_gps_coordinates(location_update.text, 45, lat, lon);
@ -671,6 +672,11 @@ static void update_gps_entry(float lat, float lon)
} }
} }
static void update_gps_entry_callback(float lat, float lon)
{
update_gps_entry(lat * 1000000, lon * 1000000);
}
#if HAVE_OSM_GPS_MAP #if HAVE_OSM_GPS_MAP
static gboolean gps_map_callback(GtkWidget *w, gpointer data) static gboolean gps_map_callback(GtkWidget *w, gpointer data)
{ {
@ -680,7 +686,7 @@ static gboolean gps_map_callback(GtkWidget *w, gpointer data)
gps_text = gtk_entry_get_text(location_update.entry); gps_text = gtk_entry_get_text(location_update.entry);
(void)gps_changed(dive, NULL, gps_text); (void)gps_changed(dive, NULL, gps_text);
} }
show_gps_location(dive, update_gps_entry); show_gps_location(dive, update_gps_entry_callback);
location_update.set_by_hand = 1; location_update.set_by_hand = 1;
return TRUE; return TRUE;
} }
@ -740,7 +746,7 @@ static void location_entry_change_cb(GtkComboBox *location, gpointer *userdata)
continue; continue;
if (!dive->location || strcasecmp(dive->location, name)) if (!dive->location || strcasecmp(dive->location, name))
continue; continue;
update_gps_entry(dive->latitude.udeg / 1000000.0, dive->longitude.udeg / 1000000.0); update_gps_entry(dive->latitude.udeg, dive->longitude.udeg);
return; return;
} }
update_gps_entry(0, 0); update_gps_entry(0, 0);
@ -770,7 +776,7 @@ static void dive_info_widget(GtkWidget *box, struct dive *dive, struct dive_info
location_update.entry = info->gps; location_update.entry = info->gps;
location_update.dive = dive; location_update.dive = dive;
update_gps_entry(dive->latitude.udeg / 1000000.0, dive->longitude.udeg / 1000000.0); update_gps_entry(dive->latitude.udeg, dive->longitude.udeg);
location_update.set_by_hand = !!location_update.text[0]; location_update.set_by_hand = !!location_update.text[0];
gtk_widget_add_events(GTK_WIDGET(info->gps), GDK_FOCUS_CHANGE_MASK); gtk_widget_add_events(GTK_WIDGET(info->gps), GDK_FOCUS_CHANGE_MASK);