added pixel_order

README.rst

@@ -69,6 +69,19 @@ method is called.
  pixels[9] = (0, 10, 0)
  pixels.show()
 
+This example demonstrates using a single NeoPixel tied to a GPIO pin and with
+a ``pixel_order`` to specify the color channel order. Note that ``bpp`` does not
+need to be specified as it is computed from the supplied ``pixel_order``.
+
+.. code-block:: python
+
+ import board
+ import neopixel
+
+ pixel = neopixel.NeoPixel(board.D0, 1, pixel_order=neopixel.RGBW)
+ pixel[0] = (30, 0, 20, 10)
+
+
 Contributing
 ============
 

examples/pixel.py

@@ -0,0 +1,24 @@
+# This example shows how to create a single pixel with a specific color channel
+# order and blink it.
+# Most NeoPixels = neopixel.GRB or neopixel.GRBW
+# The 8mm Diffused NeoPixel (PID 1734) = neopixel.RGB
+import time
+import board
+import neopixel
+
+# Configure the setup
+PIXEL_PIN = board.D1 # pin that the NeoPixel is connected to
+ORDER = neopixel.RGB # pixel color channel order
+COLOR = (100, 50, 150) # color to blink
+CLEAR = (0, 0, 0) # clear (or second color)
+DELAY = 0.25 # blink rate in seconds
+
+# Create the NeoPixel object
+pixel = neopixel.NeoPixel(PIXEL_PIN, 1, pixel_order=ORDER)
+
+# Loop forever and blink the color
+while True:
+ pixel[0] = COLOR
+ time.sleep(DELAY)
+ pixel[0] = CLEAR
+ time.sleep(DELAY)

neopixel.py

@@ -36,6 +36,16 @@
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_NeoPixel.git"
 
+# Pixel color order constants
+RGB = (0, 1, 2)
+"""Red Green Blue"""
+GRB = (1, 0, 2)
+"""Green Red Blue"""
+RGBW = (0, 1, 2, 3)
+"""Red Green Blue White"""
+GRBW = (1, 0, 2, 3)
+"""Green Red Blue White"""
+
 class NeoPixel:
  """
  A sequence of neopixels.
@@ -47,6 +57,7 @@ class NeoPixel:
  brightness
  :param bool auto_write: True if the neopixels should immediately change when set. If False,
  `show` must be called explicitly.
+ :param tuple pixel_order: Set the pixel color channel order. GRBW is set by default.
 
  Example for Circuit Playground Express:
 
@@ -76,13 +87,17 @@ class NeoPixel:
  pixels[::2] = [RED] * (len(pixels) // 2)
  time.sleep(2)
  """
- ORDER = (1, 0, 2, 3)
- def __init__(self, pin, n, *, bpp=3, brightness=1.0, auto_write=True):
+ def __init__(self, pin, n, *, bpp=3, brightness=1.0, auto_write=True, pixel_order=None):
  self.pin = digitalio.DigitalInOut(pin)
  self.pin.direction = digitalio.Direction.OUTPUT
  self.n = n
- self.bpp = bpp
- self.buf = bytearray(n * bpp)
+ if pixel_order is None:
+ self.order = GRBW
+ self.bpp = bpp
+ else:
+ self.order = pixel_order
+ self.bpp = len(self.order)
+ self.buf = bytearray(self.n * self.bpp)
  # Set auto_write to False temporarily so brightness setter does _not_
  # call show() while in __init__.
  self.auto_write = False
@@ -132,11 +147,11 @@ def _set_item(self, index, value):
  r, g, b = value
  else:
  r, g, b, w = value
- self.buf[offset + self.ORDER[0]] = r
- self.buf[offset + self.ORDER[1]] = g
- self.buf[offset + self.ORDER[2]] = b
+ self.buf[offset + self.order[0]] = r
+ self.buf[offset + self.order[1]] = g
+ self.buf[offset + self.order[2]] = b
  if self.bpp == 4:
- self.buf[offset + self.ORDER[3]] = w
+ self.buf[offset + self.order[3]] = w
 
  def __setitem__(self, index, val):
  if isinstance(index, slice):
@@ -158,15 +173,15 @@ def __getitem__(self, index):
  if isinstance(index, slice):
  out = []
  for in_i in range(*index.indices(len(self.buf) // self.bpp)):
- out.append(tuple(self.buf[in_i * self.bpp + self.ORDER[i]]
+ out.append(tuple(self.buf[in_i * self.bpp + self.order[i]]
  for i in range(self.bpp)))
  return out
  if index < 0:
  index += len(self)
  if index >= self.n or index < 0:
  raise IndexError
  offset = index * self.bpp
- return tuple(self.buf[offset + self.ORDER[i]]
+ return tuple(self.buf[offset + self.order[i]]
  for i in range(self.bpp))
 
  def __len__(self):