GypsyPosition

GypsyPosition — Object for obtaining positions from gypsy-daemon

Synopsis




                    GypsyPosition;
#define             GYPSY_POSITION_DBUS_INTERFACE
#define             GYPSY_POSITION_DBUS_SERVICE
enum                GypsyPositionFields;
GypsyPosition*      gypsy_position_new                  (const char *object_path);
GypsyPositionFields gypsy_position_get_position         (GypsyPosition *position,
                                                         int *timestamp,
                                                         double *latitude,
                                                         double *longitude,
                                                         double *altitude,
                                                         GError **error);

Object Hierarchy


  GObject
   +----GypsyPosition

Properties


  "object-path"              gchararray            : Write / Construct Only

Signals


  "position-changed"                               : Run First / No Recursion

Description

GypsyPosition is used whenever the client program wishes to know about GPS position changes. It can report the current position, and has a signal to notify listeners of changes.

A GypsyPosition object is created using gypsy_position_new() using the D-Bus path of the GPS device. This path is returned from the gypsy_control_create() function. The client can then find out about the position with gypsy_position_get_position().

As the position information changes GypsyPosition will emit the position-changed signal. This signal contains the fix position if gypsy-daemon knows it. It has a fields paramater which is a bitmask of GypsyPositionFields which indicates which of the latitude, longitude or altitude contains valid information. The timestamp will always be valid if it is greater than 0. 

GypsyPosition *position;
GError *error = NULL;

. . .

/ * path comes from the gypsy_control_create() function * /
position = gypsy_position_new (path);
g_signal_connect (position, "position-changed", G_CALLBACK (position_changed), NULL);

. . .

static void position_changed (GypsyPosition *position, 
GypsyPositionFields fields,
int timestamp,
double latitude,
double longitude,
double altitude,
gpointer userdata)
{
  g_print ("latitude, longitude (%f, %f)\n", (fields & GYPSY_POSITION_FIELDS_LATITUDE) ? latitude : -1.0, (fields & GYPSY_POSITION_FIELDS_LONGITUDE) ? longitude : -1.0);
}

Details

GypsyPosition

typedef struct _GypsyPosition GypsyPosition;

There are no public fields in GypsyPosition.

GYPSY_POSITION_DBUS_INTERFACE

#define GYPSY_POSITION_DBUS_INTERFACE "org.freedesktop.Gypsy.Position"

A define containing the name of the Position interface

GYPSY_POSITION_DBUS_SERVICE

#define GYPSY_POSITION_DBUS_SERVICE "org.freedesktop.Gypsy"

A define containing the address of the Position service

enum GypsyPositionFields

typedef enum {
	GYPSY_POSITION_FIELDS_NONE = 1 << 0,
	GYPSY_POSITION_FIELDS_LATITUDE = 1 << 1,
	GYPSY_POSITION_FIELDS_LONGITUDE = 1 << 2,
	GYPSY_POSITION_FIELDS_ALTITUDE = 1 << 3
} GypsyPositionFields;

A bitmask telling which fields in the position_changed callback are valid

GYPSY_POSITION_FIELDS_NONE None of the fields are valid
GYPSY_POSITION_FIELDS_LATITUDE The latitude field is valid
GYPSY_POSITION_FIELDS_LONGITUDE The longitude field is valid
GYPSY_POSITION_FIELDS_ALTITUDE The altitude field is valid

gypsy_position_new ()

GypsyPosition*      gypsy_position_new                  (const char *object_path);

Creates a new GypsyPosition object that listens for position changes from the GPS found at object_path.

object_path : Object path to the GPS device
Returns : A GypsyPosition object

gypsy_position_get_position ()

GypsyPositionFields gypsy_position_get_position         (GypsyPosition *position,
                                                         int *timestamp,
                                                         double *latitude,
                                                         double *longitude,
                                                         double *altitude,
                                                         GError **error);

Obtains the current position, if known, from the GPS device. timestamp, latitude, longitude and altitude can be NULL if the result is not required.

position : A GypsyPosition
timestamp : Pointer to store the timestamp
latitude : Pointer to store the latitude
longitude : Pointer to store the longitude
altitude : Pointer to store the altitude
error : Pointer to store a GError
Returns : Bitmask of GypsyPositionFields indicating what field was set

Property Details

The "object-path" property

  "object-path"              gchararray            : Write / Construct Only

The path of the Gypsy GPS object

Default value: ""

Signal Details

The "position-changed" signal

void                user_function                      (GypsyPosition *fields,
                                                        gint           timestamp,
                                                        gint           latitude,
                                                        gdouble        longitude,
                                                        gdouble        altitude,
                                                        gdouble        arg5,
                                                        gpointer       user_data)      : Run First / No Recursion

The ::position-changed signal is emitted when the GPS device indicates that one or more of the position fields has changed. The fields which have changed will be indicated in the fields bitmask.

fields : A bitmask of GypsyPositionFields indicating which of the following fields are valid
timestamp : The timestamp when this change occurred
latitude : The new latitude
longitude : The new longitude
altitude : The new altitude
user_data : user data set when the signal handler was connected.