shr: transplant RGBColor

mavwolverine · Steve Canny · commit 3c839ee4963a · 2015-02-19T21:39:35.000-08:00
diff --git a/docx/shared.py b/docx/shared.py
@@ -124,6 +124,37 @@ def __new__(cls, twips):
         return Length.__new__(cls, emu)
 
 
+class RGBColor(tuple):
+    """
+    Immutable value object defining a particular RGB color.
+    """
+    def __new__(cls, r, g, b):
+        msg = 'RGBColor() takes three integer values 0-255'
+        for val in (r, g, b):
+            if not isinstance(val, int) or val < 0 or val > 255:
+                raise ValueError(msg)
+        return super(RGBColor, cls).__new__(cls, (r, g, b))
+
+    def __repr__(self):
+        return 'RGBColor(0x%02x, 0x%02x, 0x%02x)' % self
+
+    def __str__(self):
+        """
+        Return a hex string rgb value, like '3C2F80'
+        """
+        return '%02X%02X%02X' % self
+
+    @classmethod
+    def from_string(cls, rgb_hex_str):
+        """
+        Return a new instance from an RGB color hex string like ``'3C2F80'``.
+        """
+        r = int(rgb_hex_str[:2], 16)
+        g = int(rgb_hex_str[2:4], 16)
+        b = int(rgb_hex_str[4:], 16)
+        return cls(r, g, b)
+
+
 def lazyproperty(f):
     """
     @lazyprop decorator. Decorated method will be called only on first access
diff --git a/tests/test_shared.py b/tests/test_shared.py
@@ -11,7 +11,9 @@
 import pytest
 
 from docx.opc.part import XmlPart
-from docx.shared import ElementProxy, Length, Cm, Emu, Inches, Mm, Pt, Twips
+from docx.shared import (
+    ElementProxy, Length, Cm, Emu, Inches, Mm, Pt, RGBColor, Twips
+)
 
 from .unitutil.cxml import element
 from .unitutil.mock import instance_mock
@@ -113,3 +115,26 @@ def construct_fixture(self, request):
     def units_fixture(self, request):
         emu, units_prop_name, expected_length_in_units, type_ = request.param
         return emu, units_prop_name, expected_length_in_units, type_
+
+
+class DescribeRGBColor(object):
+
+    def it_is_natively_constructed_using_three_ints_0_to_255(self):
+        RGBColor(0x12, 0x34, 0x56)
+        with pytest.raises(ValueError):
+            RGBColor('12', '34', '56')
+        with pytest.raises(ValueError):
+            RGBColor(-1, 34, 56)
+        with pytest.raises(ValueError):
+            RGBColor(12, 256, 56)
+
+    def it_can_construct_from_a_hex_string_rgb_value(self):
+        rgb = RGBColor.from_string('123456')
+        assert rgb == RGBColor(0x12, 0x34, 0x56)
+
+    def it_can_provide_a_hex_string_rgb_value(self):
+        assert str(RGBColor(0x12, 0x34, 0x56)) == '123456'
+
+    def it_has_a_custom_repr(self):
+        rgb_color = RGBColor(0x42, 0xF0, 0xBA)
+        assert repr(rgb_color) == 'RGBColor(0x42, 0xf0, 0xba)'
