fix(color): Add methods for Color to/from hex

We probably should have done this a while ago but better late than never.

ladybug/color.py

@@ -35,6 +35,18 @@ def __init__(self, r=0, g=0, b=0, a=255):
         self.b = b
         self.a = a
 
+    @classmethod
+    def from_hex(cls, hex_string):
+        """Create a color from a hex code.
+
+        Args:
+            hex_string: Text string of a hex code given as #rrggbb.
+        """
+        value = hex_string.lower().lstrip('#')
+        lv = len(value)
+        rgb = tuple(int(value[i:i + lv // 3], 16) for i in range(0, lv, lv // 3))
+        return cls(rgb[0], rgb[1], rgb[2])
+
     @classmethod
     def from_dict(cls, data):
         """Create a color from a dictionary.
@@ -102,6 +114,10 @@ def duplicate(self):
         """Return a copy of the current color."""
         return self.__copy__()
 
+    def to_hex(self):
+        """Get color as #rrggbb hex code."""
+        return '#%02x%02x%02x' % (self.r, self.g, self.b)
+
     def to_dict(self):
         """Get color as a dictionary."""
         return {

tests/color_test.py

@@ -28,6 +28,20 @@ def test_init_color():
         assert isinstance(c, int)
 
 
+def test_color_to_from_hex():
+    """Test the from_hex and to_hex methods."""
+    hex_code = '#ffffff'
+    color = Color.from_hex(hex_code)
+    assert color.r == 255
+    assert color.g == 255
+    assert color.b == 255
+    assert color.to_hex() == hex_code
+
+    color = Color(255, 0, 100)
+    hex_code = color.to_hex()
+    assert color.from_hex(hex_code) == color
+
+
 def test_init_color_invalid():
     """Test the initialization of invalid color objects."""
     with pytest.raises(Exception):