Add RGB_to_YIQ and YIQ_to_RGB

colormath/color_conversions.py

@@ -32,6 +32,7 @@
     IPTColor,
     SpectralColor,
     BT2020Color,
+    YIQColor,
 )
 from colormath.chromatic_adaptation import apply_chromatic_adaptation
 from colormath.color_exceptions import InvalidIlluminantError, UndefinedConversionError
@@ -933,6 +934,22 @@ def IPT_to_XYZ(cobj, *args, **kwargs):
     return XYZColor(*xyz_values, observer="2", illuminant="d65")
 
 
+# noinspection PyPep8Naming,PyUnusedLocal
+@color_conversion_function(BaseRGBColor, YIQColor)
+def RGB_to_YIQ(cobj, *args, **kwargs):
+    rgb_values = numpy.array(cobj.get_value_tuple())
+    yiq_values = numpy.dot(YIQColor.conversion_matrices['rgb_to_yiq'], rgb_values)
+    return YIQColor(*yiq_values)
+
+
+# noinspection PyPep8Naming,PyUnusedLocal
+@color_conversion_function(YIQColor, BaseRGBColor)
+def YIQ_to_RGB(cobj, target_rgb, *args, **kwargs):
+    yiq_values = numpy.array(cobj.get_value_tuple())
+    rgb_values = numpy.dot(YIQColor.conversion_matrices['rgb_to_yiq'], yiq_values)
+    return target_rgb(*rgb_values)
+
+
 # We use this as a template conversion dict for each RGB color space. They
 # are all identical.
 _RGB_CONVERSION_DICT_TEMPLATE = {
@@ -947,6 +964,7 @@ def IPT_to_XYZ(cobj, *args, **kwargs):
     "LCHuvColor": [RGB_to_XYZ, XYZ_to_Luv, Luv_to_LCHuv],
     "LuvColor": [RGB_to_XYZ, XYZ_to_Luv],
     "IPTColor": [RGB_to_XYZ, XYZ_to_IPT],
+    "YIQColor": [RGB_to_YIQ],
 }
 
 

colormath/color_objects.py

@@ -977,3 +977,31 @@ def __init__(self, ipt_i, ipt_p, ipt_t):
     @property
     def hue_angle(self):
         return numpy.arctan2(self.ipt_t, self.ipt_p)
+
+
+class YIQColor(ColorBase):
+    """
+    Represents an YIQ color
+
+    Reference: https://en.wikipedia.org/wiki/YIQ
+    """
+    conversion_matrices = {
+        'rgb_to_yiq': numpy.array([[0.299, 0.587, 0.114],
+                             [0.59590059, -0.27455667, -0.32134392],
+                             [0.21153661, -0.52273617, 0.31119955]]),
+        'yiq_to_rgb': numpy.linalg.inv(numpy.array([[0.299, 0.587, 0.114],
+                             [0.59590059, -0.27455667, -0.32134392],
+                             [0.21153661, -0.52273617, 0.31119955]]))
+    }
+
+    def __init__(self, yiq_y, yiq_i, yiq_q):
+        """
+        :param yiq_y: Y coordinate.
+        :param yiq_i: I coordinate.
+        :param yiq_q: Q coordinate.
+        """
+        super(YIQColor, self).__init__()
+        self.yiq_y = yiq_y
+        self.yiq_i = yiq_i
+        self.yiq_q = yiq_q
+

doc_src/color_objects.rst

@@ -82,3 +82,8 @@ IPTColor
 ---------
 
 .. autoclass:: colormath.color_objects.IPTColor
+
+YIQColor
+---------
+
+.. autoclass:: colormath.color_objects.YIQColor