Merge pull request #173 from k0nze/master

Added RGB to XY conversion example

examples/rgb_colors.py

@@ -0,0 +1,50 @@
+#!/usr/bin/python
+from phue import Bridge
+
+def rgb_to_xy(red, green, blue):
+    """ conversion of RGB colors to CIE1931 XY colors
+    Formulas implemented from: https://gist.github.com/popcorn245/30afa0f98eea1c2fd34d
+
+    Args: 
+        red (float): a number between 0.0 and 1.0 representing red in the RGB space
+        green (float): a number between 0.0 and 1.0 representing green in the RGB space
+        blue (float): a number between 0.0 and 1.0 representing blue in the RGB space
+
+    Returns:
+        xy (list): x and y
+    """
+
+    # gamma correction
+    red = pow((red + 0.055) / (1.0 + 0.055), 2.4) if red > 0.04045 else (red / 12.92)
+    green = pow((green + 0.055) / (1.0 + 0.055), 2.4) if green > 0.04045 else (green / 12.92)
+    blue =  pow((blue + 0.055) / (1.0 + 0.055), 2.4) if blue > 0.04045 else (blue / 12.92)
+
+    # convert rgb to xyz
+    x = red * 0.649926 + green * 0.103455 + blue * 0.197109
+    y = red * 0.234327 + green * 0.743075 + blue * 0.022598
+    z = green * 0.053077 + blue * 1.035763
+
+    # convert xyz to xy
+    x = x / (x + y + z)
+    y = y / (x + y + z)
+
+    # TODO check color gamut if known
+
+    return [x, y]
+
+
+b = Bridge() # Enter bridge IP here.
+
+#If running for the first time, press button on bridge and run with b.connect() uncommented
+#b.connect()
+
+# RGB colors to XY  
+xy = rgb_to_xy(1.0, 0.28627, 0.95686)
+
+lights = b.get_light_objects()
+
+for light in lights:
+    # y might be used as brightness value, however, dark colors will turn the lights off
+    #brightness = int(xy[1]*255)
+    brightness = 255 
+    light.xy = xy