ColorW type for extended sRGB

include/brisk/graphics/Color.hpp

@@ -85,6 +85,22 @@ using ColorF = ColorOf<float, ColorGamma::Default>;
 /** @brief A standard 8-bit sRGB color type. */
 using Color  = ColorOf<uint8_t, ColorGamma::sRGB>;
 
+/** @brief An extended-range 16-bit sRGB color type with 13-bit precision. */
+using ColorW = ColorOf<int16_t, ColorGamma::sRGB>;
+
+namespace Internal {
+
+template <typename T>
+constexpr int colorScale() {
+    if constexpr (std::is_floating_point_v<T>)
+        return 1;
+    else if constexpr (std::is_unsigned_v<T>)
+        return std::numeric_limits<T>::max();
+    else if constexpr (std::is_same_v<T, int16_t>)
+        return 8192; // 16-bit Extended range sRGB
+}
+} // namespace Internal
+
 /**
  * @brief Converts a 32-bit RGBA color to a `Color` instance.
  *
@@ -103,11 +119,8 @@ struct ColorOf {
 
     /**
      * @brief Maximum value for color components, based on the type `T`.
-     *
-     * If `T` is a floating-point type, the maximum is 1.0. If `T` is an integer type, the maximum is
-     * determined by the limits of that type (e.g., 255 for `uint8_t`).
      */
-    constexpr static inline int maximum = std::is_floating_point_v<T> ? 1 : std::numeric_limits<T>::max();
+    constexpr static inline int maximum = Internal::colorScale<T>();
 
     /**
      * @brief Returns the color space of the current color based on the gamma setting.

src/graphics/Color_test.cpp

@@ -24,6 +24,36 @@
 #include <brisk/core/Reflection.hpp>
 
 namespace Brisk {
+
+TEST_CASE("colorGamma") {
+    CHECK_THAT(Internal::srgbGammaToLinear(0.f), Catch::Matchers::WithinAbs(0.f, 0.001f));
+    CHECK_THAT(Internal::srgbGammaToLinear(0.5f), Catch::Matchers::WithinAbs(0.21404f, 0.001f));
+    CHECK_THAT(Internal::srgbGammaToLinear(1.f), Catch::Matchers::WithinAbs(1.f, 0.001f));
+    CHECK_THAT(Internal::srgbGammaToLinear(2.f), Catch::Matchers::WithinAbs(4.9538f, 0.001f));
+    CHECK_THAT(Internal::srgbGammaToLinear(-0.5f), Catch::Matchers::WithinAbs(-0.21404f, 0.001f));
+    CHECK_THAT(Internal::srgbGammaToLinear(-1.f), Catch::Matchers::WithinAbs(-1.f, 0.001f));
+    CHECK_THAT(Internal::srgbGammaToLinear(-2.f), Catch::Matchers::WithinAbs(-4.9538f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(0.f), Catch::Matchers::WithinAbs(0.f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(0.5f), Catch::Matchers::WithinAbs(0.73536f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(1.f), Catch::Matchers::WithinAbs(1.f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(2.f), Catch::Matchers::WithinAbs(1.3532f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(-0.5f), Catch::Matchers::WithinAbs(-0.73536f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(-1.f), Catch::Matchers::WithinAbs(-1.f, 0.001f));
+    CHECK_THAT(Internal::srgbLinearToGamma(-2.f), Catch::Matchers::WithinAbs(-1.3532f, 0.001f));
+}
+
+TEST_CASE("ColorW") {
+    bool linearColor = true;
+    std::swap(linearColor, Brisk::linearColor);
+    SCOPE_EXIT {
+        std::swap(linearColor, Brisk::linearColor);
+    };
+
+    CHECK(ColorW(Color(255, 128, 0)).v == ColorW(8192, 4112, 0, 8192).v);
+    CHECK_THAT(ColorF(ColorW(32767, -32767, 32767, 8192)).v,
+               Catch::Matchers::SIMDWithinMatcher(ColorF(25.312836, -25.312836, 25.312836, 1.f).v, 0.001));
+}
+
 TEST_CASE("rgbToColor") {
     CHECK(rgbToColor(0xAABBCC) == Color{ 0xAA, 0xBB, 0xCC, 0xFF });