Source code for adafruit_apds9960.colorutility

# SPDX-FileCopyrightText: 2017 Michael McWethy for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
`colorutility`
====================================================

Helper functions for color calculations

* Author(s): Michael McWethy
"""

__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_APDS9960.git"


[docs]def calculate_color_temperature(r, g, b): """Converts the raw R/G/B values to color temperature in degrees Kelvin""" # 1. Map RGB values to their XYZ counterparts. # Based on 6500K fluorescent, 3000K fluorescent # and 60W incandescent values for a wide range. # Note: Y = Illuminance or lux x = (-0.14282 * r) + (1.54924 * g) + (-0.95641 * b) y = (-0.32466 * r) + (1.57837 * g) + (-0.73191 * b) z = (-0.68202 * r) + (0.77073 * g) + (0.56332 * b) # 2. Calculate the chromaticity co-ordinates xchrome = x / (x + y + z) ychrome = y / (x + y + z) # 3. Use to determine the CCT n = (xchrome - 0.3320) / (0.1858 - ychrome) # 4. Calculate the final CCT cct = (449.0 * pow(n, 3)) + (3525.0 * pow(n, 2)) + (6823.3 * n) + 5520.33 # Return the results in degrees Kelvin return cct
[docs]def calculate_lux(r, g, b): """Calculate ambient light values""" # This only uses RGB ... how can we integrate clear or calculate lux # based exclusively on clear since this might be more reliable? illuminance = (-0.32466 * r) + (1.57837 * g) + (-0.73191 * b) return illuminance