From c2c627ed4dd3cb13301e044b8dc5d114b9d19de4 Mon Sep 17 00:00:00 2001
From: Hans-Christian Ebke <ebke@cs.rwth-aachen.de>
Date: Mon, 9 Nov 2015 18:51:00 +0100
Subject: [PATCH] C++11: Added _htmlColor literal operator.

Allows inline specification of colors in HTML syntax.
---
 src/OpenMesh/Core/Geometry/VectorT.hh  | 20 ++++++++++++++++++++
 src/Unittests/unittests_vector_type.cc | 12 ++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/OpenMesh/Core/Geometry/VectorT.hh b/src/OpenMesh/Core/Geometry/VectorT.hh
index 9c3db706..9dad0795 100644
--- a/src/OpenMesh/Core/Geometry/VectorT.hh
+++ b/src/OpenMesh/Core/Geometry/VectorT.hh
@@ -412,6 +412,26 @@ typedef VectorT<double,6> Vec6d;
 //=============================================================================
 } // namespace OpenMesh
 //=============================================================================
+
+
+#ifdef CPP11_ENABLED
+/**
+ * Literal operator for inline specification of colors in HTML syntax.
+ *
+ * Example:
+ * \code{.cpp}
+ * OpenMesh::Vec4f light_blue = 0x1FCFFFFF_htmlColor;
+ * \endcode
+ */
+constexpr OpenMesh::Vec4f operator"" _htmlColor(unsigned long long raw_color) {
+    return OpenMesh::Vec4f(
+            ((raw_color >> 24) & 0xFF) / 255.0f,
+            ((raw_color >> 16) & 0xFF) / 255.0f,
+            ((raw_color >>  8) & 0xFF) / 255.0f,
+            ((raw_color >>  0) & 0xFF) / 255.0f);
+}
+#endif
+
 #endif // OPENMESH_VECTOR_HH defined
 //=============================================================================
 #endif // DOXYGEN
diff --git a/src/Unittests/unittests_vector_type.cc b/src/Unittests/unittests_vector_type.cc
index 0d157766..58172537 100644
--- a/src/Unittests/unittests_vector_type.cc
+++ b/src/Unittests/unittests_vector_type.cc
@@ -111,6 +111,18 @@ TEST_F(OpenMeshVectorTest, cpp11_constructors) {
     EXPECT_EQ(1.23, vec4d[2]);
     EXPECT_EQ(1.23, vec4d[3]);
 }
+
+TEST_F(OpenMeshVectorTest, cpp11_htmlColorLiteral) {
+    const OpenMesh::Vec4f light_blue = 0x1FCFFFFF_htmlColor;
+    EXPECT_LE((OpenMesh::Vec4f(0.1215686274f, 0.8117647058f, 1.0f, 1.0f)
+        - light_blue).sqrnorm(), 1e-10);
+
+    const auto light_blue_2 = 0x1FCFFFFF_htmlColor;
+    // Check whether auto type deduction works as expected.
+    static_assert(std::is_same<decltype(light_blue_2), decltype(light_blue)>
+        ::value, "Bad type deduced from _htmlColor literal.");
+    EXPECT_EQ(light_blue, light_blue_2);
+}
 #endif
 
 }