Add SparklePulse animation

adafruit_led_animation/animation.py

@@ -367,6 +367,59 @@ def draw(self):
         self.fill(color)
         self.show()
 
+class SparklePulse(Animation):
+    """
+    Combination of the Spark and Pulse animations.
+
+    :param pixel_object: The initialised LED object.
+    :param int speed: Animation refresh rate in seconds, e.g. ``0.1``.
+    :param color: Animation color in ``(r, g, b)`` tuple, or ``0x000000`` hex format.
+    :param period: Period to pulse the LEDs over.  Default 5.
+    :param max_intensity: The maximum intensity to pulse, between 0 and 1.0.  Default 1.
+    :param min_intensity: The minimum intensity to pulse, between 0 and 1.0.  Default 0.
+    """
+
+    # pylint: disable=too-many-arguments
+    def __init__(self, pixel_object, speed, color, period=5, max_intensity=1, min_intensity=0):
+        if len(pixel_object) < 2:
+            raise ValueError("Sparkle needs at least 2 pixels")
+        self.max_intensity = max_intensity
+        self.min_intensity = min_intensity
+        self._period = period
+        self._intensity_delta = max_intensity - min_intensity
+        self._half_period = period / 2
+        self._position_factor = 1 / self._half_period
+        self._bpp = len(pixel_object[0])
+        self._last_update = monotonic_ns()
+        self._cycle_position = 0
+        self._half_color = None
+        self._dim_color = None
+        super(SparklePulse, self).__init__(pixel_object, speed, color)
+
+    def _recompute_color(self, color):
+        half_color = tuple(color[rgb] // 4 for rgb in range(len(color)))
+        dim_color = tuple(color[rgb] // 10 for rgb in range(len(color)))
+        for pixel in range(len(self.pixel_object)):
+            if self.pixel_object[pixel] == self._half_color:
+                self.pixel_object[pixel] = half_color
+            elif self.pixel_object[pixel] == self._dim_color:
+                self.pixel_object[pixel] = dim_color
+        self._half_color = half_color
+        self._dim_color = dim_color
+
+    def draw(self):
+        pixel = random.randint(0, (len(self.pixel_object) - 2))
+
+        now = monotonic_ns()
+        time_since_last_draw = (now - self._last_update) / NANOS_PER_SECOND
+        self._last_update = now
+        pos = self._cycle_position = (self._cycle_position + time_since_last_draw) % self._period
+        if pos > self._half_period:
+            pos = self._period - pos
+        intensity = self.min_intensity + (pos * self._intensity_delta * self._position_factor)
+        color = [int(self.color[n] * intensity) for n in range(self._bpp)]
+        self.pixel_object[pixel] = color
+        self.show()
 
 class Chase(Animation):
     """