Adds skyview rotation support to xgps and xgpsspeed.

This adds an optional argument to rotate the skyview display, making
it possible to orient it correctly based on the direction one is
actually facing.  The specified heading is positioned at the top.

This edit does not update contrib/webgps.py, which is somewhat
more complicated to fix due to the Javascript involvement.

TESTED:
Ran both programs with and without the -r or --rotate option.

Signed-off-by: Gary E. Miller <gem@rellim.com>

1 files changed, 23 insertions, 14 deletions

diff --git a/xgps b/xgps
index 066401f2..44ea0628 100755
--- a/xgps
+++ b/xgps
@@ -3,7 +3,7 @@
 '''
 xgps -- test client for gpsd
 
-usage: xgps [-D level] [-hV?] [-l degmfmt] [-u units] [server[:port[:device]]]
+usage: xgps [-D level] [-hV?] [-l degmfmt] [-u units] [-r rotation] [server[:port[:device]]]
 '''
 
 # This code runs compatibly under Python 2 and 3.x for x >= 2.
@@ -95,7 +95,7 @@ class SkyView(Gtk.DrawingArea):
     HORIZON_PAD = 40    # How much whitespace to leave around horizon
     SAT_RADIUS = 5      # Diameter of satellite circle
 
-    def __init__(self):
+    def __init__(self, rotate=0.0):
         GObject.GObject.__init__(self)
         self.set_size_request(400, 400)
         self.cr = None   # New cairo context for each expose event
@@ -104,6 +104,7 @@ class SkyView(Gtk.DrawingArea):
         self.connect('draw', self.on_draw)
         self.satellites = []
         self.center_x = self.center_y = self.radius = None
+        self.rotate = rotate
 
     def on_size_allocate(self, _unused, allocation):
         width = allocation.width
@@ -181,6 +182,7 @@ class SkyView(Gtk.DrawingArea):
 
     def pol2cart(self, az, el):
         "Polar to Cartesian coordinates within the horizon circle."
+        az = (az - self.rotate) % 360.0
         az *= (math.pi / 180)  # Degrees to radians
         # Exact spherical projection would be like this:
         # el = sin((90.0 - el) * DEG_2_RAD);
@@ -223,14 +225,14 @@ class SkyView(Gtk.DrawingArea):
         self.draw_line(x1, y1, x2, y2)
 
         # The compass-point letters
-        (x, y) = self.pol2cart(0, 0)
-        self.draw_string(x, y - 10, "N")
-        (x, y) = self.pol2cart(90, 0)
-        self.draw_string(x + 10, y, "E")
-        (x, y) = self.pol2cart(180, 0)
-        self.draw_string(x, y + 10, "S")
-        (x, y) = self.pol2cart(270, 0)
-        self.draw_string(x - 10, y, "W")
+        (x, y) = self.pol2cart(0, -5)
+        self.draw_string(x, y, "N")
+        (x, y) = self.pol2cart(90, -5)
+        self.draw_string(x, y, "E")
+        (x, y) = self.pol2cart(180, -5)
+        self.draw_string(x, y, "S")
+        (x, y) = self.pol2cart(270, -5)
+        self.draw_string(x, y, "W")
 
         # The satellites
         self.cr.set_line_width(2)
@@ -460,8 +462,9 @@ class Base(object):
         ("EPD", lambda s, r: s.update_err_degrees(r, "epd")),
     )
 
-    def __init__(self, deg_type):
+    def __init__(self, deg_type, rotate=0.0):
         self.deg_type = deg_type
+        self.rotate = rotate
         self.conversions = unit_adjustments()
         self.saved_mode = -1
         self.ais_latch = False
@@ -579,7 +582,7 @@ class Base(object):
 
         viewframe = Gtk.Frame(label="Skyview")
         self.satbox.add(viewframe)
-        self.skyview = SkyView()
+        self.skyview = SkyView(self.rotate)
         viewframe.add(self.skyview)
 
         self.rawdisplay = Gtk.Entry()
@@ -869,11 +872,12 @@ class Base(object):
 if __name__ == "__main__":
     try:
         import getopt
-        (options, arguments) = getopt.getopt(sys.argv[1:], "D:hl:u:V?",
+        (options, arguments) = getopt.getopt(sys.argv[1:], "D:hl:u:r:V?",
                                              ['verbose'])
         debug = 0
         degreefmt = 'd'
         unit_system = None
+        rotate = 0.0
         for (opt, val) in options:
             if opt in '-D':
                 debug = int(val)
@@ -881,6 +885,11 @@ if __name__ == "__main__":
                 degreeformat = val
             elif opt == '-u':
                 unit_system = val
+            elif opt == '-r':
+                try:
+                    rotate = float(val)
+                except ValueError:
+                    rotate = 0.0
             elif opt in ('-?', '-h', '--help'):
                 print(__doc__)
                 sys.exit(0)
@@ -902,7 +911,7 @@ if __name__ == "__main__":
             if len(args) >= 3:
                 device = args[2]
 
-        base = Base(deg_type=degreefmt)
+        base = Base(deg_type=degreefmt, rotate=rotate)
         base.set_units(unit_system)
         try:
             daemon = gps.gps(host=host,