James Cameron's --unit patch.

3 files changed, 37 insertions, 15 deletions

diff --git a/gps.h b/gps.h
index f892badb..777b8a1f 100644
--- a/gps.h
+++ b/gps.h
@@ -108,7 +108,7 @@ void gps_set_raw_hook(struct gps_data_t *gpsdata, void (*hook)(char *buf));
 #define METERS_TO_FEET	3.2808399	/* Imperial (U.S./British) feet */
 #define METERS_TO_MILES	0.00062137119	/* International miles */
 #define KNOTS_TO_MPH	1.1507794	/* International miles and knots */
-#define KNOTS_TO_KMPH	1.852		/* Kilometers and knots */
+#define KNOTS_TO_KPH	1.852		/* International knots */
 #define PI 3.14159265358979323846	/* for radians-to-degrees and vv. */
 
 /* gps_open() error return values */
diff --git a/gpsd.xml b/gpsd.xml
index 8f730da9..5bd538d0 100644
--- a/gpsd.xml
+++ b/gpsd.xml
@@ -33,7 +33,6 @@ and speedometer</refpurpose>
 <cmdsynopsis>
   <command>xgps</command>  
       <arg choice='opt'><replaceable>X-options</replaceable></arg>
-      <arg choice='opt'>-k </arg>
       <arg choice='opt'>-h </arg>
       <arg choice='opt'>-v </arg>
       <arg choice='opt'><replaceable>server</replaceable></arg>
@@ -44,6 +43,7 @@ and speedometer</refpurpose>
       <arg choice='opt'>-nc <replaceable>X-color</replaceable></arg>
       <arg choice='opt'>-h </arg>
       <arg choice='opt'>-v </arg>
+      <arg choice='opt'>--units <replaceable>kph</replaceable></arg>
       <arg choice='opt'><replaceable>server</replaceable></arg>
 </cmdsynopsis>
 
@@ -306,11 +306,6 @@ confused state but can be soft-reset by pulling down DTR.</para>
 current GPS animation and (for GPSes that support the feature) the
 locations of accessible satellites.</para>
 
-<para><application>xgps</application> accepts a -k option to change
-speed reporting to use km/h as a unit, rather than mp/h.  This option
-is experimental and may be dropped or replaced by an X resource
-un a future release.</para>
-
 <para><application>xgps</application> accepts an -h option as for
 <application>gpsd</application>, or a -v option to dump the package
 version and exit. An optional argument may specify an
@@ -325,9 +320,11 @@ direct-connect to the serial device has been removed.</para>
 position information from the GPS. It accepts an -h option and
 optional argument as for <application>gps</application>, or a -v
 option to dump the package version and exit.  Additionally, it accepts
--rv (reverse video) and -nc (needle color) options. The misfeature of
-previous versions that allowed it to direct-connect to the serial
-device has been removed.</para>
+-rv (reverse video) and -nc (needle color) options.</para>
+
+<para>The --units option can be used to set the units for display;
+follow the keyword with either kph for kilometres per hour, or mph for
+miles per hour.  The default is miles per hour.</para>
 
 </refsect2>
 </refsect1>
diff --git a/xgpsspeed.c b/xgpsspeed.c
index 2031d68b..532748ed 100644
--- a/xgpsspeed.c
+++ b/xgpsspeed.c
@@ -9,6 +9,7 @@
 #include <X11/Shell.h>
 #include <X11/Xaw/Label.h>
 #include <X11/Xaw/Paned.h>
+#include <Xm/XmStrDefs.h>
 #include <Tachometer.h>
 
 #include "xgpsspeed.icon"
@@ -19,12 +20,14 @@ static XrmOptionDescRec options[] = {
 {"-rv",		"*reverseVideo",	XrmoptionNoArg,		"TRUE"},
 {"-nc",         "*needleColor",         XrmoptionSepArg,        NULL},
 {"-needlecolor","*needleColor",         XrmoptionSepArg,        NULL},
+{"--units",     "*units",               XrmoptionSepArg,        NULL},
 };
 String fallback_resources[] = {NULL};
 
 static struct gps_data_t *gpsdata;
 static Widget tacho;
-static double speedfactor = KNOTS_TO_MPH;
+static double speedfactor;
+static Widget toplevel;
 
 static void update_display(char *buf UNUSED)
 {
@@ -37,27 +40,49 @@ static void handle_input(XtPointer client_data UNUSED,
     gps_poll(gpsdata);
 }
 
+static char *get_resource(char *name, char *default_value)
+{
+  XtResource xtr;
+  char *value = NULL;
+
+  xtr.resource_name = name;
+  xtr.resource_class = "AnyClass";
+  xtr.resource_type = XmRString;
+  xtr.resource_size = sizeof(String);
+  xtr.resource_offset = 0;
+  xtr.default_type = XmRImmediate;
+  xtr.default_addr = default_value;
+  XtGetApplicationResources(toplevel, &value, &xtr, 1, NULL, 0);
+  if (value) return value;
+  return default_value;
+}
+
 int main(int argc, char **argv)
 {
     Arg             args[10];
     XtAppContext app;
     int option;
-    char *colon, *server = NULL, *port = DEFAULT_GPSD_PORT;
-    Widget toplevel, base;
+    char *colon, *server = NULL, *port = DEFAULT_GPSD_PORT, *units;
+    Widget base;
 
     toplevel = XtVaAppInitialize(&app, "xpsspeed.ad", 
 				 options, XtNumber(options),
 				 &argc, argv, fallback_resources, NULL);
+
+    speedfactor = KNOTS_TO_MPH;
+    units = get_resource("units", "mph");
+    if (!strcmp(units, "kph")) speedfactor = KNOTS_TO_KPH;
+
     while ((option = getopt(argc, argv, "?hkv")) != -1) {
 	switch (option) {
 	case 'k':
-	    speedfactor = KNOTS_TO_KMPH;
+	    speedfactor = KNOTS_TO_KPH;
 	    break;
 	case 'v':
 	    printf("xgpsspeed %s\n", VERSION);
 	    exit(0);
 	case 'h': case '?': default:
-	    fputs("usage: gps [-?] [-h] [-v] [-rv] [-nc] [-needlecolor] [server[:port]]\n", stderr);
+	    fputs("usage: gps [-?] [-h] [-v] [-rv] [-nc] [-needlecolor] [--units {kph,mph}] [server[:port]]\n", stderr);
 	    exit(1);
 	}
     }