72 lines
2.0 KiB
Python
72 lines
2.0 KiB
Python
import jarray
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import math
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import itertools
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_byte_lookup = {}
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brightness_max = 0.5
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# Bit values which represent the zero and one bit pulses.
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_ZERO = bytearray([0b00000000])
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_ONE = bytearray([0b11111111])
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def _build_byte_lookup():
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"""Return lookup table to map from every byte value 0-255 and the associated raw SPI data."""
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lookup = {}
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for i in range(256):
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value = bytearray()
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for j in range(7, -1, -1):
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if ((i >> j) & 1) == 0:
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value += _ZERO
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else:
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value += _ONE
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lookup[i] = value
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return lookup
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def color_to_rgb(c):
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"""Convert a 24 bit color to RGB triplets."""
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return ((c >> 16) & 0xFF, (c >> 8) & 0xFF, c & 0xFF)
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def _encode_color_grb(c):
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"""Encode an RGB tuple into NeoPixel GRB 24 byte SPI bit stream."""
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return _byte_lookup[int(c[1] * brightness)] + _byte_lookup[int(c[0] * brightness)] + _byte_lookup[int(c[2] * brightness)]
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def _encode_pixel(c):
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"""Encode an RGB tuple into NeoPixel GRB 24 byte SPI bit stream."""
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rgb = color_to_rgb(c)
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encoded = _encode_color_grb(rgb)
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return encoded
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def prepare_data(dimension, b):
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global brightness
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global _byte_lookup
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if b > brightness_max:
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brightness = brightness_max
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else:
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brightness = b
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_byte_lookup = _build_byte_lookup()
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data = jarray.zeros(dimension * 24 + 1, "b")
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return data
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def image2data(data, long_line):
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offset = 0
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pixel_nb = 0
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loadPixels()
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for x in range(0, height):
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pixel_line = pixels[pixel_nb:pixel_nb+width]
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if long_line and pixel_nb/width%2 == 1:
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pixel_line = reversed(pixel_line)
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for px in pixel_line:
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py_bytes = _encode_pixel(px)
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for b in py_bytes:
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if b > 127:
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# Convert to signed bytes (expected by jarray)
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b -= 256
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data[offset] = b
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else:
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data[offset] = b
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offset += 1
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pixel_nb +=1
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# New line
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data[-1] = 10
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return data
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