Enhance color initialization with hex support (#1980)

* Enhance color initialization with hex support

* add tests for examples given by OCP

Author: akivab

cadquery/occ_impl/assembly.py

@@ -226,7 +226,9 @@ def __init__(self, *args, **kwargs):
             self.wrapped = Quantity_ColorRGBA()
         elif len(args) == 1:
             self.wrapped = Quantity_ColorRGBA()
-            exists = Quantity_ColorRGBA.ColorFromName_s(args[0], self.wrapped)
+            exists = Quantity_ColorRGBA.ColorFromName_s(
+                args[0], self.wrapped
+            ) or Quantity_ColorRGBA.ColorFromHex_s(args[0], self.wrapped)
             if not exists:
                 raise ValueError(f"Unknown color name: {args[0]}")
         elif len(args) == 3:

tests/test_assembly.py

@@ -644,6 +644,36 @@ def test_color():
     assert c4.wrapped.GetRGB().Green() == pytest.approx(0.2)
     assert c4.wrapped.Alpha() == 0.5
 
+    # test for hex string for short sRGB color
+    c5 = cq.Color("#FF0")
+    assert c5.wrapped.GetRGB().Red() == 1
+    assert c5.wrapped.GetRGB().Green() == 1
+    assert c5.wrapped.GetRGB().Blue() == 0
+    with pytest.raises(AttributeError):
+        c5.wrapped.GetRGB().Alpha()
+
+    # test for hex string for short sRGBA color
+    c6 = cq.Color("#FF0F")
+    assert c6.wrapped.GetRGB().Red() == 1
+    assert c6.wrapped.GetRGB().Green() == 1
+    assert c6.wrapped.GetRGB().Blue() == 0
+    assert c6.wrapped.Alpha() == 1.0
+
+    # test for hex string for RGB color
+    c7 = cq.Color("#FFFF00")
+    assert c7.wrapped.GetRGB().Red() == 1
+    assert c7.wrapped.GetRGB().Green() == 1
+    assert c7.wrapped.GetRGB().Blue() == 0
+    with pytest.raises(AttributeError):
+        c7.wrapped.GetRGB().Alpha()
+
+    # test for hex string for RGBA color
+    c8 = cq.Color("#FFFF00FF")
+    assert c8.wrapped.GetRGB().Red() == 1
+    assert c8.wrapped.GetRGB().Green() == 1
+    assert c8.wrapped.GetRGB().Blue() == 0
+    assert c8.wrapped.Alpha() == 1.0
+
     with pytest.raises(ValueError):
         cq.Color("?????")