Add circle loading pattern

src/patterns.py

@@ -23,6 +23,7 @@ class Patterns(PatternBase): # Inherit from PatternBase
             "o": self.off,
             "on": self.on,
             "bl": self.blink,
+            "cl": self.circle_loading,
         }    
         self.step = 0
         self.run = True
@@ -64,6 +65,79 @@ class Patterns(PatternBase): # Inherit from PatternBase
         self.run = False
         self.running = False
 
+    def circle_loading(self):
+        """Circle loading pattern - grows to n2, then tail moves forward at n3 until min length n4"""
+        self.run = True
+        head = 0
+        tail = 0
+        
+        # Calculate timing
+        head_rate = max(1, int(self.n1))  # n1 = head moves per second
+        tail_rate = max(1, int(self.n3))  # n3 = tail moves per second
+        max_length = max(1, int(self.n2))  # n2 = max length
+        min_length = max(0, int(self.n4))  # n4 = min length
+        
+        head_delay = 1000 // head_rate  # ms between head movements
+        tail_delay = 1000 // tail_rate  # ms between tail movements
+        
+        last_head_move = utime.ticks_ms()
+        last_tail_move = utime.ticks_ms()
+        
+        phase = "growing"  # "growing", "shrinking", or "off"
+        
+        while self.run:
+            self.wdt.feed()
+            current_time = utime.ticks_ms()
+            
+            # Clear all LEDs
+            self.n.fill((0, 0, 0))
+            
+            # Calculate segment length
+            segment_length = (head - tail) % self.num_leds
+            if segment_length == 0 and head != tail:
+                segment_length = self.num_leds
+            
+            # Draw segment from tail to head
+            color = self.apply_brightness(self.colors[0])
+            for i in range(segment_length + 1):
+                led_pos = (tail + i) % self.num_leds
+                self.n[led_pos] = color
+            
+            # Move head continuously at n1 LEDs per second
+            if utime.ticks_diff(current_time, last_head_move) >= head_delay:
+                head = (head + 1) % self.num_leds
+                last_head_move = current_time
+            
+            # Tail behavior based on phase
+            if phase == "growing":
+                # Growing phase: tail stays at 0 until max length reached
+                if segment_length >= max_length:
+                    phase = "shrinking"
+            elif phase == "shrinking":
+                # Shrinking phase: move tail forward at n3 LEDs per second
+                if utime.ticks_diff(current_time, last_tail_move) >= tail_delay:
+                    tail = (tail + 1) % self.num_leds
+                    last_tail_move = current_time
+                    
+                    # Check if we've reached min length
+                    current_length = (head - tail) % self.num_leds
+                    if current_length == 0 and head != tail:
+                        current_length = self.num_leds
+                    
+                    # For min_length = 0, we need at least 1 LED (the head)
+                    if min_length == 0 and current_length <= 1:
+                        phase = "off"  # All LEDs off for 1 step
+                    elif min_length > 0 and current_length <= min_length:
+                        phase = "growing"  # Cycle repeats
+            else:  # phase == "off"
+                # Off phase: all LEDs off for 1 step, then restart
+                phase = "growing"
+            
+            self.n.write()
+             
+        self.run = False
+        self.running = False
+
 #     def flicker(self):
 #         current_time = utime.ticks_ms()
 #         base_color = self.colors[0]