Maintain legacy comptibility with Unicorn HAT

Author: Gadgetoid

library/rpi_ws281x/rpi_ws281x.py

@@ -50,7 +50,7 @@ def __setitem__(self, pos, value):
 
 class PixelStrip(object):
     def __init__(self, num, pin, freq_hz=800000, dma=10, invert=False,
-            brightness=255, channel=0, strip_type=ws.WS2811_STRIP_RGB, gamma=None):
+            brightness=255, channel=0, strip_type=None, gamma=None):
         """Class to represent a SK6812/WS281x LED display.  Num should be the
         number of pixels in the display, and pin should be the GPIO pin connected
         to the display signal line (must be a PWM pin like 18!).  Optional
@@ -63,12 +63,14 @@ def __init__(self, num, pin, freq_hz=800000, dma=10, invert=False,
         if gamma is None:
             # Support gamma in place of strip_type for back-compat with
             # previous version of forked library
-            if type(strip_type) is list and len(strip_type) == 255:
+            if type(strip_type) is list and len(strip_type) == 256:
                 gamma = strip_type
+                strip_type = None
             else:
                 gamma = list(range(256))
 
-        self._gamma = gamma
+        if strip_type is None:
+            strip_type = ws.WS2811_STRIP_GRB
 
         # Create ws2811_t structure and fill in parameters.
         self._leds = ws.new_ws2811_t()
@@ -83,7 +85,7 @@ def __init__(self, num, pin, freq_hz=800000, dma=10, invert=False,
 
         # Initialize the channel in use
         self._channel = ws.ws2811_channel_get(self._leds, channel)
-        ws.ws2811_channel_t_gamma_set(self._channel, self._gamma)
+        ws.ws2811_channel_t_gamma_set(self._channel, gamma)
         ws.ws2811_channel_t_count_set(self._channel, num)
         ws.ws2811_channel_t_gpionum_set(self._channel, pin)
         ws.ws2811_channel_t_invert_set(self._channel, 0 if not invert else 1)
@@ -109,8 +111,7 @@ def _cleanup(self):
 
     def setGamma(self, gamma):
         if type(gamma) is list and len(gamma) == 256:
-            self._gamma = gamma
-            ws.ws2811_channel_t_gamma_set(self._channel, self._gamma)
+            ws.ws2811_channel_t_gamma_set(self._channel, gamma)
 
     def begin(self):
         """Initialize library, must be called once before other functions are