add rainbow

src/blinki.py

@@ -53,15 +53,37 @@ def morph_grb(grb, steps, mode='single'):
         raise Exception(f'Mode "{mode}" is not supported.')
 
     return grb
+def rainbow(device, min_value=1, max_value=255):
+    """
+    Takes an int between 0-255 and either increments or decreases it by the specified steps.
+    """
+    direction = [
+        choice([-1, 1]),
+        choice([-1, 1]),
+        choice([-1, 1])
+    ]
 
+    grb = [
+        randint(min_value, max_value),
+        randint(min_value, max_value),
+        randint(min_value, max_value)
+    ]
+
+    channel = randint(0, 2)
+    while True:
+        #channel = (channel + 1) % 3
+        channel = randint(0, 2)
+        for i in range(30):
+            candidate = grb[channel] + 1 * direction[channel]
+
+            # if we go out of bounds reverse the direction
+            if candidate < min_value or candidate > max_value:
+                direction[channel] = direction[channel] * -1
+            else:
+                grb[channel] = candidate
+                set_all_leds(device, grb)
 
 
 device = blinkstick.find_first()
 
-# get a random initial color
+rainbow(device)
-grb = random_grb()
-
-while True:
-    set_all_leds(device, grb)
-
-    grb = morph_grb(grb, 2)