drivers/led/neopixel: Optimize for speed on non-FP builds.

Signed-off-by: Tom Mount <tmountjr@gmail.com>

micropython/drivers/led/neopixel/neopixel.py

@@ -8,11 +8,13 @@ class NeoPixel:
     # G R B W
     ORDER = (1, 0, 2, 3)
 
-    def __init__(self, pin, n, bpp=3, timing=1, brightness: float = 1.0):
+    def __init__(self, pin, n, bpp=3, timing=1, brightness: float = None):
         self.pin = pin
         self.n = n
         self.bpp = bpp
-        self.brightness = min(max(brightness, 0.0), 1.0)
+        self.brightness = (
+            min(max(brightness, 0.0), 1.0) if brightness is not None else None
+        )
         self.buf = bytearray(n * bpp)
         self.pin.init(pin.OUT)
         # Timing arg can either be 1 for 800kHz or 0 for 400kHz,
@@ -23,28 +25,40 @@ class NeoPixel:
             else timing
         )
 
-    def _calculate_brightness(self, v):
-        return round(v * self.brightness)
+    def _apply_brightness(self, v):
+        if self.brightness is not None:
+            return tuple(round(c * self.brightness) for c in v)
+        return v
 
     def __len__(self):
         return self.n
 
     def __setitem__(self, i, v):
         offset = i * self.bpp
-        adjusted_v = tuple(self._calculate_brightness(c) for c in v)
+        v = self._apply_brightness(v)
         for i in range(self.bpp):
-            self.buf[offset + self.ORDER[i]] = adjusted_v[i]
+            self.buf[offset + self.ORDER[i]] = v[i]
 
     def __getitem__(self, i):
         offset = i * self.bpp
         return tuple(self.buf[offset + self.ORDER[i]] for i in range(self.bpp))
 
     def fill(self, v):
-        for i in range(self.n):
-            self[i] = v
+        v = self._apply_brightness(v)
+        b = self.buf
+        l = len(self.buf)
+        bpp = self.bpp
+        for i in range(bpp):
+            c = v[i]
+            j = self.ORDER[i]
+            while j < l:
+                b[j] = c
+                j += bpp
 
     def set_brightness(self, b: float):
         self.brightness = min(max(b, 0.0), 1.0)
+        # This may look odd but because __getitem__ and __setitem__ handle all the
+        # brightness logic already, we can offload the work to those methods.
         for i in range(self.n):
             self[i] = self[i]