Saturation & Brightness/Value Gain using Oklab color space (#1477)

* Imported Oklab reference implementation

* Add Okhsv conversions

* Fixed formatting error

* Add saturation and value gain to schemas

* Add english translation for saturation, value gain

* Created OkhsvTransform

* Make OkhsvTransform configurable

* Apply OkhvsTransform

* Clamped values during transform

* Precalculate isIdentity in OkhsvTransform

* Skip OkhsvTransform if it is the identity function

* Added changelog message

* Allow for full desaturation

* Imported recommended changes by LordGrey

* Fixed typo in constant

* Fixed anti-pattern in ok_color.h

* Correct indentions

* Correct remote-control

* Limited maximum gain settings to practical range

* Renane valueGain to brightnessGain for clarity and understanding

Co-authored-by: LordGrey <lordgrey.emmel@gmail.com>

libsrc/utils/OkhsvTransform.cpp

@@ -0,0 +1,69 @@
+#include <algorithm>
+
+#include <utils/OkhsvTransform.h>
+#include <utils/ColorSys.h>
+
+/// Clamps between 0.f and 1.f. Should generally be branchless
+double clamp(double value)
+{
+	return std::max(0.0, std::min(value, 1.0));
+}
+
+OkhsvTransform::OkhsvTransform()
+{
+	_saturationGain = 1.0;
+	_brightnessGain = 1.0;
+	_isIdentity = true;
+}
+
+OkhsvTransform::OkhsvTransform(double saturationGain, double brightnessGain)
+{
+	_saturationGain = saturationGain;
+	_brightnessGain = brightnessGain;
+	updateIsIdentity();
+}
+
+double OkhsvTransform::getSaturationGain() const
+{
+	return _saturationGain;
+}
+
+void OkhsvTransform::setSaturationGain(double saturationGain)
+{
+	_saturationGain = saturationGain;
+	updateIsIdentity();
+}
+
+double OkhsvTransform::getBrightnessGain() const
+{
+	return _brightnessGain;
+}
+
+void OkhsvTransform::setBrightnessGain(double brightnessGain)
+{
+	_brightnessGain= brightnessGain;
+	updateIsIdentity();
+}
+
+bool OkhsvTransform::isIdentity() const
+{
+	return _isIdentity;
+}
+
+void OkhsvTransform::transform(uint8_t & red, uint8_t & green, uint8_t & blue) const
+{
+	double hue;
+	double saturation;
+	double brightness;
+	ColorSys::rgb2okhsv(red, green, blue, hue, saturation, brightness);
+
+	saturation = clamp(saturation * _saturationGain);
+	brightness = clamp(brightness * _brightnessGain);
+
+	ColorSys::okhsv2rgb(hue, saturation, brightness, red, green, blue);
+}
+
+void OkhsvTransform::updateIsIdentity()
+{
+	_isIdentity = _saturationGain == 1.0 && _brightnessGain == 1.0;
+}