Oh gosh, we're starting to render foreground?

py/hexagram/cluster.py

@@ -111,3 +111,10 @@ class Cluster():
 
         for gauge in self.gauges:
             gauge.draw_bg(cr)
+
+    def draw_fg(self, cr: cairo.Context):
+        for gauge in self.gauges:
+            fn = getattr(gauge, 'draw_fg', None)
+
+            if fn is not None:
+                fn(cr)

py/hexagram/dial.py

@@ -15,6 +15,8 @@ class Dial(Gauge):
     )
 
     def __init__(self, x: float, y: float, radius: float, min_angle: float, max_angle: float, max_value: float):
+        super().__init__()
+
         self.x         = x
         self.y         = y
         self.radius    = radius
@@ -102,3 +104,6 @@ class Dial(Gauge):
         cr.set_line_width(self.BEZEL_WIDTH / 3)
         cr.arc(self.x, self.y, self.radius / 2, 0, 2.0 * math.pi)
         cr.stroke()
+
+    def draw_fg(self, cr: cairo.Context):
+        self.draw_needle(cr, 0.5, 0.89, self.value)

py/hexagram/fuel.py

@@ -73,3 +73,6 @@ class FuelGauge(Dial):
                 cr.set_source_rgb(1, 1, 1)
 
             self.draw_mark(cr, min_radius, 0.87, self.max_value - level)
+
+    def draw_fg(self, cr: cairo.Context):
+        pass

py/hexagram/gauge.py

@@ -1,5 +1,13 @@
 import cairo
 
 class Gauge():
+    __slots__ = 'value',
+
+    def __init__(self):
+        self.value = None
+
     def draw_bg(self, cr: cairo.Context):
         raise NotImplementedError
+
+    def set_value(self, value):
+        self.value = value

py/hexagram/speedo.py

@@ -19,6 +19,7 @@ class Speedo(Dial):
     def __init__(self, x: float, y: float, radius: float, max_value: float, units: SpeedUnits=SpeedUnits.KPH):
         super().__init__(x, y, radius, self.MIN_ANGLE, self.MAX_ANGLE, max_value)
 
+        self.value = 0
         self.units = units
 
     def draw_bg(self, cr: cairo.Context):

py/hexagram/tacho.py

@@ -4,8 +4,32 @@ import cairo
 
 from hexagram.dial import Dial
 
+class Gear(enum.Enum):
+    R       = -1
+    N       =  0
+    GEAR_1  =  1
+    GEAR_2  =  2
+    GEAR_3  =  3
+    GEAR_4  =  4
+    GEAR_5  =  5
+    GEAR_6  =  6
+    GEAR_7  =  7
+    GEAR_8  =  8
+    GEAR_9  =  9
+    GEAR_10 = 10
+
+    def __str__(self):
+        strs = {
+            -1: 'R', 0: 'N', 1:   '1',
+             2: '2', 3: '3', 4:   '4',
+             5: '5', 6: '6', 7:   '7',
+             8: '8', 9: '9', 10: '10'
+        }
+
+        return strs.get(self.value, '?')
+
 class Tacho(Dial):
-    __slots__ = 'units',
+    __slots__ = 'gear',
 
     MIN_ANGLE = 232.0 * (math.pi / 180.0)
     MAX_ANGLE = 488.0 * (math.pi / 180.0)
@@ -15,6 +39,9 @@ class Tacho(Dial):
     def __init__(self, x: float, y: float, radius: float, max_value: float):
         super().__init__(x, y, radius, self.MIN_ANGLE, self.MAX_ANGLE, max_value)
 
+        self.value = 0
+        self.gear: Gear = Gear.N
+
     def draw_number(self, cr: cairo.Context, radius: float, value: float, text: str):
         scale = value / self.max_value
         angle = self.min_angle + ((self.max_angle - self.min_angle) * scale) - Dial.ANGLE_OFFSET
@@ -51,3 +78,16 @@ class Tacho(Dial):
                 cr.set_source_rgb(1.0, 0.1, 0.1)
 
             self.draw_number(cr, 0.69, speed, "%d" % int(speed / 1000))
+
+    def draw_fg(self, cr: cairo.Context):
+        super().draw_fg(cr)
+
+        cr.select_font_face("HEX:gon Bold Italic")
+
+        cr.set_font_size(self.radius * 0.25)
+        cr.set_source_rgb(1, 0.4, 1)
+
+        cr.move_to(self.x - (self.radius * 0.25) / 2,
+                   self.y + (self.radius * 0.1))
+
+        cr.show_text(str(self.gear))

py/hexagram/thermo.py

@@ -70,3 +70,6 @@ class ThermoGauge(Dial):
                 cr.set_source_rgb(1, 1, 1)
 
             self.draw_mark(cr, 0.83, 0.87, self.max_value - level)
+
+    def draw_fg(self, cr: cairo.Context):
+        pass