Make 'Color' a 'constexpr' class

include/SFML/Graphics/Color.hpp

@@ -37,7 +37,7 @@ namespace sf
 /// \brief Utility class for manipulating RGBA colors
 ///
 ////////////////////////////////////////////////////////////
-class SFML_GRAPHICS_API Color
+class Color
 {
 public:
 
@@ -48,7 +48,7 @@ public:
     /// sf::Color(0, 0, 0, 255).
     ///
     ////////////////////////////////////////////////////////////
-    Color();
+    constexpr Color();
 
     ////////////////////////////////////////////////////////////
     /// \brief Construct the color from its 4 RGBA components
@@ -59,7 +59,7 @@ public:
     /// \param alpha Alpha (opacity) component (in the range [0, 255])
     ///
     ////////////////////////////////////////////////////////////
-    Color(Uint8 red, Uint8 green, Uint8 blue, Uint8 alpha = 255);
+    constexpr Color(Uint8 red, Uint8 green, Uint8 blue, Uint8 alpha = 255);
 
     ////////////////////////////////////////////////////////////
     /// \brief Construct the color from 32-bit unsigned integer
@@ -67,7 +67,7 @@ public:
     /// \param color Number containing the RGBA components (in that order)
     ///
     ////////////////////////////////////////////////////////////
-    explicit Color(Uint32 color);
+    constexpr explicit Color(Uint32 color);
 
     ////////////////////////////////////////////////////////////
     /// \brief Retrieve the color as a 32-bit unsigned integer
@@ -75,20 +75,20 @@ public:
     /// \return Color represented as a 32-bit unsigned integer
     ///
     ////////////////////////////////////////////////////////////
-    Uint32 toInteger() const;
+    constexpr Uint32 toInteger() const;
 
     ////////////////////////////////////////////////////////////
     // Static member data
     ////////////////////////////////////////////////////////////
-    static const Color Black;       //!< Black predefined color
+    SFML_GRAPHICS_API static const Color Black;       //!< Black predefined color
-    static const Color White;       //!< White predefined color
+    SFML_GRAPHICS_API static const Color White;       //!< White predefined color
-    static const Color Red;         //!< Red predefined color
+    SFML_GRAPHICS_API static const Color Red;         //!< Red predefined color
-    static const Color Green;       //!< Green predefined color
+    SFML_GRAPHICS_API static const Color Green;       //!< Green predefined color
-    static const Color Blue;        //!< Blue predefined color
+    SFML_GRAPHICS_API static const Color Blue;        //!< Blue predefined color
-    static const Color Yellow;      //!< Yellow predefined color
+    SFML_GRAPHICS_API static const Color Yellow;      //!< Yellow predefined color
-    static const Color Magenta;     //!< Magenta predefined color
+    SFML_GRAPHICS_API static const Color Magenta;     //!< Magenta predefined color
-    static const Color Cyan;        //!< Cyan predefined color
+    SFML_GRAPHICS_API static const Color Cyan;        //!< Cyan predefined color
-    static const Color Transparent; //!< Transparent (black) predefined color
+    SFML_GRAPHICS_API static const Color Transparent; //!< Transparent (black) predefined color
 
     ////////////////////////////////////////////////////////////
     // Member data
@@ -111,7 +111,7 @@ public:
 /// \return True if colors are equal, false if they are different
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API bool operator ==(const Color& left, const Color& right);
+[[nodiscard]] constexpr bool operator ==(const Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -125,7 +125,7 @@ SFML_GRAPHICS_API bool operator ==(const Color& left, const Color& right);
 /// \return True if colors are different, false if they are equal
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API bool operator !=(const Color& left, const Color& right);
+[[nodiscard]] constexpr bool operator !=(const Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -140,7 +140,7 @@ SFML_GRAPHICS_API bool operator !=(const Color& left, const Color& right);
 /// \return Result of \a left + \a right
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API Color operator +(const Color& left, const Color& right);
+[[nodiscard]] constexpr Color operator +(const Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -155,7 +155,7 @@ SFML_GRAPHICS_API Color operator +(const Color& left, const Color& right);
 /// \return Result of \a left - \a right
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API Color operator -(const Color& left, const Color& right);
+[[nodiscard]] constexpr Color operator -(const Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -172,7 +172,7 @@ SFML_GRAPHICS_API Color operator -(const Color& left, const Color& right);
 /// \return Result of \a left * \a right
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API Color operator *(const Color& left, const Color& right);
+[[nodiscard]] constexpr Color operator *(const Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -188,7 +188,7 @@ SFML_GRAPHICS_API Color operator *(const Color& left, const Color& right);
 /// \return Reference to \a left
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API Color& operator +=(Color& left, const Color& right);
+constexpr Color& operator +=(Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -204,7 +204,7 @@ SFML_GRAPHICS_API Color& operator +=(Color& left, const Color& right);
 /// \return Reference to \a left
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API Color& operator -=(Color& left, const Color& right);
+constexpr Color& operator -=(Color& left, const Color& right);
 
 ////////////////////////////////////////////////////////////
 /// \relates Color
@@ -222,7 +222,9 @@ SFML_GRAPHICS_API Color& operator -=(Color& left, const Color& right);
 /// \return Reference to \a left
 ///
 ////////////////////////////////////////////////////////////
-SFML_GRAPHICS_API Color& operator *=(Color& left, const Color& right);
+constexpr Color& operator *=(Color& left, const Color& right);
+
+#include <SFML/Graphics/Color.inl>
 
 } // namespace sf
 

include/SFML/Graphics/Color.inl

@@ -0,0 +1,149 @@
+////////////////////////////////////////////////////////////
+//
+// SFML - Simple and Fast Multimedia Library
+// Copyright (C) 2007-2021 Laurent Gomila (laurent@sfml-dev.org)
+//
+// This software is provided 'as-is', without any express or implied warranty.
+// In no event will the authors be held liable for any damages arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it freely,
+// subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented;
+//    you must not claim that you wrote the original software.
+//    If you use this software in a product, an acknowledgment
+//    in the product documentation would be appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such,
+//    and must not be misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source distribution.
+//
+////////////////////////////////////////////////////////////
+
+
+////////////////////////////////////////////////////////////
+constexpr Color::Color() :
+r(0),
+g(0),
+b(0),
+a(255)
+{
+
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color::Color(Uint8 red, Uint8 green, Uint8 blue, Uint8 alpha) :
+r(red),
+g(green),
+b(blue),
+a(alpha)
+{
+
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color::Color(Uint32 color) :
+r(static_cast<Uint8>((color & 0xff000000) >> 24)),
+g(static_cast<Uint8>((color & 0x00ff0000) >> 16)),
+b(static_cast<Uint8>((color & 0x0000ff00) >> 8)),
+a(static_cast<Uint8>(color & 0x000000ff))
+{
+
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Uint32 Color::toInteger() const
+{
+    return static_cast<Uint32>((r << 24) | (g << 16) | (b << 8) | a);
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr bool operator ==(const Color& left, const Color& right)
+{
+    return (left.r == right.r) &&
+           (left.g == right.g) &&
+           (left.b == right.b) &&
+           (left.a == right.a);
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr bool operator !=(const Color& left, const Color& right)
+{
+    return !(left == right);
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color operator +(const Color& left, const Color& right)
+{
+    const auto clampedAdd = [](Uint8 lhs, Uint8 rhs) -> Uint8
+    {
+        const int intResult = static_cast<int>(lhs) + static_cast<int>(rhs);
+        return static_cast<Uint8>(intResult < 255 ? intResult : 255);
+    };
+
+    return Color(clampedAdd(left.r, right.r),
+                 clampedAdd(left.g, right.g),
+                 clampedAdd(left.b, right.b),
+                 clampedAdd(left.a, right.a));
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color operator -(const Color& left, const Color& right)
+{
+    const auto clampedSub = [](Uint8 lhs, Uint8 rhs) -> Uint8
+    {
+        const int intResult = static_cast<int>(lhs) - static_cast<int>(rhs);
+        return static_cast<Uint8>(intResult > 0 ? intResult : 0);
+    };
+
+    return Color(clampedSub(left.r, right.r),
+                 clampedSub(left.g, right.g),
+                 clampedSub(left.b, right.b),
+                 clampedSub(left.a, right.a));
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color operator *(const Color& left, const Color& right)
+{
+    const auto scaledMul = [](Uint8 lhs, Uint8 rhs) -> Uint8
+    {
+        const auto uint16Result = static_cast<Uint16>(static_cast<Uint16>(lhs) * static_cast<Uint16>(rhs));
+        return static_cast<Uint8>(uint16Result / 255u);
+    };
+
+    return Color(scaledMul(left.r, right.r),
+                 scaledMul(left.g, right.g),
+                 scaledMul(left.b, right.b),
+                 scaledMul(left.a, right.a));
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color& operator +=(Color& left, const Color& right)
+{
+    return left = left + right;
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color& operator -=(Color& left, const Color& right)
+{
+    return left = left - right;
+}
+
+
+////////////////////////////////////////////////////////////
+constexpr Color& operator *=(Color& left, const Color& right)
+{
+    return left = left * right;
+}

src/SFML/Graphics/CMakeLists.txt

@@ -8,6 +8,7 @@ set(SRC
     ${INCROOT}/BlendMode.hpp
     ${SRCROOT}/Color.cpp
     ${INCROOT}/Color.hpp
+    ${INCROOT}/Color.inl
     ${INCROOT}/Export.hpp
     ${SRCROOT}/Font.cpp
     ${INCROOT}/Font.hpp

src/SFML/Graphics/Color.cpp

@@ -26,7 +26,6 @@
 // Headers
 ////////////////////////////////////////////////////////////
 #include <SFML/Graphics/Color.hpp>
-#include <algorithm>
 
 
 namespace sf
@@ -44,112 +43,4 @@ const Color Color::Magenta(255, 0, 255);
 const Color Color::Cyan(0, 255, 255);
 const Color Color::Transparent(0, 0, 0, 0);
 
-
-////////////////////////////////////////////////////////////
-Color::Color() :
-r(0),
-g(0),
-b(0),
-a(255)
-{
-
-}
-
-
-////////////////////////////////////////////////////////////
-Color::Color(Uint8 red, Uint8 green, Uint8 blue, Uint8 alpha) :
-r(red),
-g(green),
-b(blue),
-a(alpha)
-{
-
-}
-
-
-////////////////////////////////////////////////////////////
-Color::Color(Uint32 color) :
-r(static_cast<Uint8>((color & 0xff000000) >> 24)),
-g(static_cast<Uint8>((color & 0x00ff0000) >> 16)),
-b((color & 0x0000ff00) >> 8 ),
-a((color & 0x000000ff) >> 0 )
-{
-
-}
-
-
-////////////////////////////////////////////////////////////
-Uint32 Color::toInteger() const
-{
-    return static_cast<Uint32>((r << 24) | (g << 16) | (b << 8) | a);
-}
-
-
-////////////////////////////////////////////////////////////
-bool operator ==(const Color& left, const Color& right)
-{
-    return (left.r == right.r) &&
-           (left.g == right.g) &&
-           (left.b == right.b) &&
-           (left.a == right.a);
-}
-
-
-////////////////////////////////////////////////////////////
-bool operator !=(const Color& left, const Color& right)
-{
-    return !(left == right);
-}
-
-
-////////////////////////////////////////////////////////////
-Color operator +(const Color& left, const Color& right)
-{
-    return Color(Uint8(std::min(int(left.r) + right.r, 255)),
-                 Uint8(std::min(int(left.g) + right.g, 255)),
-                 Uint8(std::min(int(left.b) + right.b, 255)),
-                 Uint8(std::min(int(left.a) + right.a, 255)));
-}
-
-
-////////////////////////////////////////////////////////////
-Color operator -(const Color& left, const Color& right)
-{
-    return Color(Uint8(std::max(int(left.r) - right.r, 0)),
-                 Uint8(std::max(int(left.g) - right.g, 0)),
-                 Uint8(std::max(int(left.b) - right.b, 0)),
-                 Uint8(std::max(int(left.a) - right.a, 0)));
-}
-
-
-////////////////////////////////////////////////////////////
-Color operator *(const Color& left, const Color& right)
-{
-    return Color(Uint8(int(left.r) * right.r / 255),
-                 Uint8(int(left.g) * right.g / 255),
-                 Uint8(int(left.b) * right.b / 255),
-                 Uint8(int(left.a) * right.a / 255));
-}
-
-
-////////////////////////////////////////////////////////////
-Color& operator +=(Color& left, const Color& right)
-{
-    return left = left + right;
-}
-
-
-////////////////////////////////////////////////////////////
-Color& operator -=(Color& left, const Color& right)
-{
-    return left = left - right;
-}
-
-
-////////////////////////////////////////////////////////////
-Color& operator *=(Color& left, const Color& right)
-{
-    return left = left * right;
-}
-
 } // namespace sf