a knob can get into (un)focused state

knob.py

@@ -1,14 +1,18 @@
 import pygame
 import math
+from colors import *
 
 class Knob:
     
-    def __init__(self, screen, color, radius, position):
-        self.screen = screen
-        self.color = color
+    def __init__(self, gui, name, radius, position):
+        self.gui = gui
+        self.name = name
+        self.screen = gui.screen
+        self.color = color_primary
         self.radius = radius
         self.position = position
         self.value = 0
+        self.focused = False
 
     def set_value(self, value):
         self.value = value
@@ -16,9 +20,21 @@ class Knob:
     def set_color(self, color):
         self.color = color
 
+    def set_focused(self, focused):
+        if focused:
+            self.focused = True
+            self.color = color_primary_light
+            self.gui.deactivate_knobs_except(self)
+        else:
+            self.focused = False
+            self.color = color_primary
+
     def get_position(self):
         return self.position
 
+    def __eq__(self, other): 
+        return self.position == other.get_position()
+
     def get_pointer_position(self):
         angle = (self.value * 0.8 * 2 + 0.7) * math.pi
         x = (self.radius - 5) * math.cos(angle) + self.position[0]
@@ -26,6 +42,12 @@ class Knob:
         return(x, y)
 
     def display(self):
+        m1, m2, m3 = pygame.mouse.get_pressed(3)
+        if m1:
+            pos = pygame.mouse.get_pos()
+            if math.sqrt(math.pow(pos[0]-self.position[0],2) + math.pow(pos[1]-self.position[1],2)) < self.radius:
+                self.set_focused(True)
+
         pygame.draw.circle(self.screen, self.color, self.position, self.radius)
         pygame.draw.line(self.screen, "black", self.position, self.get_pointer_position(), 4)