From 1a800b67d74c409fd2e4b6c11e04548b5bf5d999 Mon Sep 17 00:00:00 2001
From: Kae <80987908+Novaenia@users.noreply.github.com>
Date: Fri, 6 Jun 2025 12:08:15 +1000
Subject: attempt at improving GCC ?saturation accuracy

[skip ci]
---
 source/core/StarColor.cpp           | 18 +++++++++---------
 source/core/StarColor.hpp           |  4 ++--
 source/core/StarImageProcessing.cpp | 27 ++++++++++++++++++++-------
 3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/source/core/StarColor.cpp b/source/core/StarColor.cpp
index cab4b4f..4238d1d 100644
--- a/source/core/StarColor.cpp
+++ b/source/core/StarColor.cpp
@@ -324,7 +324,7 @@ Vec3F Color::toRgbF() const {
 
 #ifdef __GNUC__
 #pragma GCC push_options
-#pragma GCC optimize("-fno-fast-math")
+#pragma GCC optimize("-fno-fast-math -fassociative-math -freciprocal-math")
 #endif
 Vec4F Color::toHsva() const {
   float h, s, v;
@@ -369,14 +369,6 @@ Vec4F Color::toHsva() const {
 
   return Vec4F(h, s, v, alphaF());
 }
-#ifdef __GNUC__
-#pragma GCC pop_options
-#endif
-
-String Color::toHex() const {
-  auto rgba = toRgba();
-  return hexEncode((char*)rgba.ptr(), rgba[3] == 255 ? 3 : 4);
-}
 
 float Color::hue() const {
   return toHsva()[0];
@@ -401,6 +393,9 @@ float Color::saturation() const {
 float Color::value() const {
   return max(max(m_data[0], m_data[1]), m_data[2]);
 }
+#ifdef __GNUC__
+#pragma GCC pop_options
+#endif
 
 void Color::setHue(float h) {
   auto hsva = toHsva();
@@ -453,6 +448,11 @@ float Color::fromLinear(float in) {
   return (1.0f + a) * powf(in, 1.0f / 2.4f) - a;
 }
 
+String Color::toHex() const {
+  auto rgba = toRgba();
+  return hexEncode((char*)rgba.ptr(), rgba[3] == 255 ? 3 : 4);
+}
+
 void Color::convertToLinear() {
   setRedF(toLinear(redF()));
   setGreenF(toLinear(greenF()));
diff --git a/source/core/StarColor.hpp b/source/core/StarColor.hpp
index 47e6896..e93629e 100644
--- a/source/core/StarColor.hpp
+++ b/source/core/StarColor.hpp
@@ -107,8 +107,6 @@ public:
 
   Vec4F toHsva() const;
 
-  String toHex() const;
-
   float hue() const;
   float saturation() const;
   float value() const;
@@ -123,6 +121,8 @@ public:
   // Reduce the color toward black by the given amount, from 0.0 to 1.0.
   void fade(float value);
 
+  String toHex() const;
+
   void convertToLinear();
   void convertToSRGB();
 
diff --git a/source/core/StarImageProcessing.cpp b/source/core/StarImageProcessing.cpp
index 1cfd847..b18fcf1 100644
--- a/source/core/StarImageProcessing.cpp
+++ b/source/core/StarImageProcessing.cpp
@@ -354,6 +354,25 @@ StringList imageOperationReferences(List<ImageOperation> const& operations) {
   return references;
 }
 
+#ifdef __GNUC__
+#pragma GCC push_options
+#pragma GCC optimize("-fno-fast-math -fassociative-math -freciprocal-math")
+#endif
+static void processSaturationShift(Image& image, SaturationShiftImageOperation const* op) {
+  image.forEachPixel([&op](unsigned, unsigned, Vec4B& pixel) {
+    if (pixel[3] != 0) {
+      Color color = Color::rgba(pixel);
+      color.setSaturation(clamp(color.saturation() + op->saturationShiftAmount, 0.0f, 1.0f));
+      pixel = color.toRgba();
+    }
+  });
+}
+#ifdef __GNUC__
+#pragma GCC pop_options
+#endif
+
+
+
 void processImageOperation(ImageOperation const& operation, Image& image, ImageReferenceCallback refCallback) {
   if (image.bytesPerPixel() == 3) {
     // Convert to an image format that has alpha so certain operations function properly
@@ -365,13 +384,7 @@ void processImageOperation(ImageOperation const& operation, Image& image, ImageR
         pixel = Color::hueShiftVec4B(pixel, op->hueShiftAmount);
     });
   } else if (auto op = operation.ptr<SaturationShiftImageOperation>()) {
-    image.forEachPixel([&op](unsigned, unsigned, Vec4B& pixel) {
-      if (pixel[3] != 0) {
-        Color color = Color::rgba(pixel);
-        color.setSaturation(clamp(color.saturation() + op->saturationShiftAmount, 0.0f, 1.0f));
-        pixel = color.toRgba();
-      }
-    });
+    processSaturationShift(image, op);
   } else if (auto op = operation.ptr<BrightnessMultiplyImageOperation>()) {
     image.forEachPixel([&op](unsigned, unsigned, Vec4B& pixel) {
       if (pixel[3] != 0) {
-- 
cgit v1.2.3