Hi Dan,
On 5/30/19 8:16 PM, Dan Murphy wrote:
[...]
+Multicolor Class Brightness Control
+-----------------------------------
+The multicolor class will redirect the device drivers call back
+function for brightness control to the multicolor class brightness
+control function.
+
+The brightness level for each LED is calculated based on the color LED
+brightness setting divided by the color LED max brightness setting multiplied by
+the requested value.
+
+led_brightness = requested_value*(led_color_brightness/led_color_max_brightness)
+
+Example:
+Three LEDs are present in the group as defined in "Directory Layout Example"
+within this document.
+
+A user first writes the color LED brightness file with the brightness level that
+is neccesary to achieve a blueish violet output from the RGB LED group.
+
+echo 138 > /sys/class/leds/rgb:grouped_leds/red/brightness
+echo 43 > /sys/class/leds/rgb:grouped_leds/green/brightness
+echo 226 > /sys/class/leds/rgb:grouped_leds/blue/brightness
+
+red -
+ brightness = 138
+ max_brightness = 255
+green -
+ brightness = 43
+ max_brightness = 255
+blue -
+ brightness = 226
+ max_brightness = 255
+
+The user can control the brightness of that RGB group by writing the parent
+'brightness' control. Assuming a parent max_brightness of 255 the user may want
+to dim the LED color group to half. The user would write a value of 128 to the
+parent brightness file then the values written to each LED will be adjusted
+base on this value
+
+cat /sys/class/leds/rgb:grouped_leds/max_brightness
+255
+echo 128 > /sys/class/leds/rgb:grouped_leds/brightness
+
+adjusted_red_value = 128 * (138/255) = 69
+adjusted_green_value = 128 * (43/255) = 21
+adjusted_blue_value = 128 * (226/255) = 113
+
+Reading the parent brightness file will return the current brightness value of
+the color LED group.
I've tested this algorithm with python script and at least on my LED
monitor it works as expected. Attached is the script I've come up with.
+cat /sys/class/leds/rgb:grouped_leds/max_brightness
+255
+
+echo 128 > /sys/class/leds/rgb:grouped_leds/brightness
+
+cat /sys/class/leds/rgb:grouped_leds/max_brightness
+128
+
+
--
Best regards,
Jacek Anaszewski
#!/usr/bin/python3.5
from PIL import Image
import sys
import time
WIDTH = 500
HEIGHT = 500
def print_usage():
print ('Usage: led_color.py RED GREEN BLUE TOP_BRIGHTNESS')
sys.exit(0)
def main():
if len(sys.argv) != 5:
print_usage()
MAX_R = int(sys.argv[4])
MAX_G = int(sys.argv[4])
MAX_B = int(sys.argv[4])
R = int(sys.argv[1])
G = int(sys.argv[2])
B = int(sys.argv[3])
TB = int(sys.argv[4])
for BR in range(1,TB+1):
OUT_R = int(BR * R / MAX_R)
OUT_G = int(BR * G / MAX_G)
OUT_B = int(BR * B / MAX_B)
print("red: {}, green: {}, blue: {}".format(OUT_R, OUT_G, OUT_B))
img = Image.new("RGB", (WIDTH,HEIGHT), (OUT_R,OUT_G,OUT_B))
img.show()
time.sleep(0.1)
if __name__ == "__main__":
main()
