Simplify code around drawing bottom gauges

py/hexagram/cluster.py

@@ -82,9 +82,10 @@ class Odometer(Gauge):
     __slots__ = 'x', 'y',
 
     def __init__(self, x: float, y: float):
-        self.value = 0
+        super().__init__(0, 999999999)
-        self.x     = x
+
-        self.y     = y
+        self.x = x
+        self.y = y
 
     def draw_bg(self, cr: cairo.Context):
         pass
@@ -104,9 +105,10 @@ class AmbientTemp(Gauge):
     __slots__ = 'x', 'y',
 
     def __init__(self, x: float, y: float):
-        self.value = 0
+        super().__init__(-100, 100)
-        self.x     = x
+
-        self.y     = y
+        self.x = x
+        self.y = y
 
     def draw_bg(self, cr: cairo.Context):
         pass
@@ -126,9 +128,10 @@ class Clock(Gauge):
     __slots__ = 'x', 'y',
 
     def __init__(self, x: float, y: float):
-        self.value = 0
+        super().__init__(0, 9999)
-        self.x     = x
+
-        self.y     = y
+        self.x = x
+        self.y = y
 
     def draw_bg(self, cr: cairo.Context):
         pass

py/hexagram/dial.py

@@ -4,7 +4,7 @@ import cairo
 from hexagram.gauge import Gauge
 
 class Dial(Gauge):
-    __slots = 'x', 'y', 'radius', 'min_angle', 'max_angle', 'max_value',
+    __slots = 'x', 'y', 'radius', 'min_angle', 'max_angle',
 
     ANGLE_OFFSET = math.pi / 2
 
@@ -14,15 +14,14 @@ class Dial(Gauge):
         (1, 0.4, 0.0, 0.4, 0.0)
     )
 
-    def __init__(self, x: float, y: float, radius: float, min_angle: float, max_angle: float, max_value: float):
+    def __init__(self, x: float, y: float, radius: float, min_angle: float, max_angle: float, min_value: float, max_value: float):
-        super().__init__()
+        super().__init__(min_value, max_value)
 
         self.x         = x
         self.y         = y
         self.radius    = radius
         self.min_angle = min_angle
         self.max_angle = max_angle
-        self.max_value = max_value
 
     def _gradient(self):
         gradient = cairo.LinearGradient(self.x - self.radius,
@@ -46,8 +45,11 @@ class Dial(Gauge):
         cr.stroke()
 
     def draw_mark(self, cr: cairo.Context, min_radius: float, max_radius: float, value: float):
+        adj     = value - self.min_value
+        adj_max = self.max_value - self.min_value
+
         angle = self.min_angle + \
-            ((self.max_angle - self.min_angle) * (value / self.max_value)) - self.ANGLE_OFFSET
+            ((self.max_angle - self.min_angle) * (adj / adj_max)) - self.ANGLE_OFFSET
 
         cr.move_to(self.x + (min_radius * self.radius) * math.cos(angle),
                    self.y + (min_radius * self.radius) * math.sin(angle))
@@ -58,8 +60,11 @@ class Dial(Gauge):
         cr.stroke()
 
     def draw_needle(self, cr: cairo.Context, min_radius: float, max_radius: float, value: float):
+        adj     = value - self.min_value
+        adj_max = self.max_value - self.min_value
+
         angle = self.min_angle + \
-            ((self.max_angle - self.min_angle) * (value / self.max_value)) \
+            ((self.max_angle - self.min_angle) * (adj / adj_max)) \
             - self.ANGLE_OFFSET
 
         cr.set_source_rgba(1, 0.4, 1, 0.75)
@@ -101,8 +106,26 @@ class Dial(Gauge):
         self.draw_needle(cr, 0.5, 0.89, self.value)
 
 class BottomDial(Dial):
+    def draw_mark(self, cr: cairo.Context, min_radius: float, max_radius: float, value: float):
+        adj     = value - self.min_value
+        adj_max = self.max_value - self.min_value
+
+        angle = self.min_angle + \
+            ((self.max_angle - self.min_angle) * (adj / adj_max)) - self.ANGLE_OFFSET
+
+        cr.move_to(self.x + (min_radius * self.radius) * math.cos(angle),
+                   self.y + (min_radius * self.radius) * math.sin(angle))
+
+        cr.line_to(self.x + (max_radius * self.radius) * math.cos(angle),
+                   self.y + (max_radius * self.radius) * math.sin(angle))
+
+        cr.stroke()
+
     def draw_fg(self, cr: cairo.Context):
         min_radius = 0.8
         max_radius = 0.9
 
-        self.draw_needle(cr, min_radius, max_radius, self.MAX_VALUE - self.value)
+        adj     = self.value - self.min_value
+        adj_max = self.max_value - self.min_value
+
+        self.draw_needle(cr, min_radius, max_radius, adj_max - adj)

py/hexagram/fuel.py

@@ -8,12 +8,17 @@ class FuelGauge(BottomDial):
     MIN_ANGLE = 144.0 * (math.pi / 180.0)
     MAX_ANGLE = 216.0 * (math.pi / 180.0)
 
+    MIN_VALUE =  0
     MAX_VALUE = 15
 
     FONT_FACE = "Muli"
 
     def __init__(self, x: float, y: float, radius: float):
-        super().__init__(x, y, radius, self.MIN_ANGLE, self.MAX_ANGLE, self.MAX_VALUE)
+        super().__init__(x, y, radius,
+                         self.MIN_ANGLE,
+                         self.MAX_ANGLE,
+                         self.MIN_VALUE,
+                         self.MAX_VALUE)
 
         self.value = 0
 
@@ -27,18 +32,6 @@ class FuelGauge(BottomDial):
         cr.show_text(text)
         cr.stroke()
 
-    def draw_mark(self, cr: cairo.Context, min_radius: float, max_radius: float, value: float):
-        angle = self.min_angle + \
-            ((self.max_angle - self.min_angle) * (value / self.max_value)) - self.ANGLE_OFFSET
-
-        cr.move_to(self.x + (min_radius * self.radius) * math.cos(angle),
-                   self.y + (min_radius * self.radius) * math.sin(angle))
-
-        cr.line_to(self.x + (max_radius * self.radius) * math.cos(angle),
-                   self.y + (max_radius * self.radius) * math.sin(angle))
-
-        cr.stroke()
-
     def draw_bg(self, cr: cairo.Context):
         cr.set_line_width(24)
         cr.set_source_rgb(0.2, 0.2, 0.2)

py/hexagram/gauge.py

@@ -1,10 +1,12 @@
 import cairo
 
 class Gauge():
-    __slots__ = 'value',
+    __slots__ = 'min_value', 'max_value', 'value',
 
-    def __init__(self):
+    def __init__(self, min_value: float, max_value: float):
-        self.value = None
+        self.min_value: float = min_value
+        self.max_value: float = max_value
+        self.value: float     = min_value
 
     def set_value(self, value):
         self.value = value

py/hexagram/speedo.py

@@ -17,7 +17,7 @@ class Speedo(Dial):
     FONT_FACE = "Muli"
 
     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)
+        super().__init__(x, y, radius, self.MIN_ANGLE, self.MAX_ANGLE, 0, max_value)
 
         self.value = 0
         self.units = units

py/hexagram/tacho.py

@@ -37,7 +37,7 @@ class Tacho(Dial):
     FONT_FACE = "Muli"
 
     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)
+        super().__init__(x, y, radius, self.MIN_ANGLE, self.MAX_ANGLE, 0, max_value)
 
         self.value = 0
         self.gear: Gear = Gear.N

py/hexagram/thermo.py

@@ -15,12 +15,20 @@ class ThermoGauge(BottomDial):
     FONT_FACE = "Muli"
 
     def __init__(self, x: float, y: float, radius: float):
-        super().__init__(x, y, radius, self.MIN_ANGLE, self.MAX_ANGLE, self.MAX_VALUE - self.MIN_VALUE)
+        super().__init__(x, y, radius,
+                         self.MIN_ANGLE,
+                         self.MAX_ANGLE,
+                         self.MIN_VALUE,
+                         self.MAX_VALUE)
 
-        self.value = self.MIN_VALUE
+    def draw_needle(self, cr: cairo.Context, min_radius: float, max_radius: float, value: float):
+        super().draw_needle(cr, min_radius, max_radius, self.max_value - value)
 
     def draw_value(self, cr: cairo.Context, radius: float, value: float, text: str, x_offset: float, y_offset: float):
-        scale = (self.max_value - value) / self.max_value
+        adj     = value - self.min_value
+        adj_max = self.max_value - self.min_value
+
+        scale = adj / adj_max
         angle = self.min_angle + ((self.max_angle - self.min_angle) * scale) - self.ANGLE_OFFSET
 
         cr.move_to(self.x + radius * self.radius * math.cos(angle) + x_offset,
@@ -29,18 +37,6 @@ class ThermoGauge(BottomDial):
         cr.show_text(text)
         cr.stroke()
 
-    def draw_mark(self, cr: cairo.Context, min_radius: float, max_radius: float, value: float):
-        angle = self.min_angle + \
-            ((self.max_angle - self.min_angle) * (value / self.max_value)) - self.ANGLE_OFFSET
-
-        cr.move_to(self.x + (min_radius * self.radius) * math.cos(angle),
-                   self.y + (min_radius * self.radius) * math.sin(angle))
-
-        cr.line_to(self.x + (max_radius * self.radius) * math.cos(angle),
-                   self.y + (max_radius * self.radius) * math.sin(angle))
-
-        cr.stroke()
-
     def draw_bg(self, cr: cairo.Context):
         cr.set_line_width(24)
         cr.set_source_rgb(0.2, 0.2, 0.2)
@@ -58,10 +54,10 @@ class ThermoGauge(BottomDial):
         cr.set_font_size(self.radius * 0.1)
 
         cr.set_source_rgb(1, 1, 1)
-        self.draw_value(cr, 0.78,  0, "C", 0, 5)
+        self.draw_value(cr, 0.78, self.min_value, "C", 0, 5)
 
         cr.set_source_rgb(1, 0, 0)
-        self.draw_value(cr, 0.75, self.MAX_VALUE - self.MIN_VALUE, "H", -25, 15)
+        self.draw_value(cr, 0.75, self.max_value, "H", -25, 15)
 
         cr.set_line_width(6.0)