ENH: Make default-constructors of RGBPixel and RGBAPixel constexpr

Tested by means of `CheckConstexprBeginAndEndOfContainer()`. Note that these default-constructors were already `constexpr` _implicitly_, as implied by `= default`, when `ITK_FUTURE_LEGACY_REMOVE` would be enabled.
N-Dekker · Dec 17, 2024 · 6464b88 · 6464b88
1 parent d786f75
commit 6464b88
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Showing 4 changed files with 16 additions and 2 deletions.
diff --git a/Modules/Core/Common/include/itkRGBAPixel.h b/Modules/Core/Common/include/itkRGBAPixel.h
@@ -81,7 +81,9 @@ class ITK_TEMPLATE_EXPORT RGBAPixel : public FixedArray<TComponent, 4>
 #ifdef ITK_FUTURE_LEGACY_REMOVE
   RGBAPixel() = default;
 #else
-  RGBAPixel() { this->Fill(0); }
+  constexpr RGBAPixel()
+    : Superclass()
+  {}
 #endif
 
   /** Pass-through constructor for the Array base class. */

diff --git a/Modules/Core/Common/include/itkRGBPixel.h b/Modules/Core/Common/include/itkRGBPixel.h
@@ -80,7 +80,9 @@ class ITK_TEMPLATE_EXPORT RGBPixel : public FixedArray<TComponent, 3>
 #ifdef ITK_FUTURE_LEGACY_REMOVE
   RGBPixel() = default;
 #else
-  RGBPixel() { this->Fill(0); }
+  constexpr RGBPixel()
+    : Superclass()
+  {}
 #endif
 
 #if defined(ITK_LEGACY_REMOVE)

diff --git a/Modules/Core/Common/test/itkRGBAPixelGTest.cxx b/Modules/Core/Common/test/itkRGBAPixelGTest.cxx
@@ -22,6 +22,11 @@
 #include <gtest/gtest.h>
 
 
+static_assert(itk::RangeGTestUtilities::CheckConstexprBeginAndEndOfContainer<itk::RGBAPixel<>>() &&
+              itk::RangeGTestUtilities::CheckConstexprBeginAndEndOfContainer<itk::RGBAPixel<std::uint8_t>>() &&
+              itk::RangeGTestUtilities::CheckConstexprBeginAndEndOfContainer<itk::RGBAPixel<float>>());
+
+
 // Tests that a RGBAPixel that is "value-initialized" (by empty braces, `{}`) is zero-filled.
 TEST(RGBAPixel, ValueInitializedIsZeroFilled)
 {

diff --git a/Modules/Core/Common/test/itkRGBPixelGTest.cxx b/Modules/Core/Common/test/itkRGBPixelGTest.cxx
@@ -22,6 +22,11 @@
 #include <gtest/gtest.h>
 
 
+static_assert(itk::RangeGTestUtilities::CheckConstexprBeginAndEndOfContainer<itk::RGBPixel<>>() &&
+              itk::RangeGTestUtilities::CheckConstexprBeginAndEndOfContainer<itk::RGBPixel<std::uint8_t>>() &&
+              itk::RangeGTestUtilities::CheckConstexprBeginAndEndOfContainer<itk::RGBPixel<float>>());
+
+
 // Tests that a RGBPixel that is "value-initialized" (by empty braces, `{}`) is zero-filled.
 TEST(RGBPixel, ValueInitializedIsZeroFilled)
 {