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>

include/hyperion/ColorAdjustment.h

@@ -1,4 +1,5 @@
-#pragma once
+#ifndef COLORADJUSTMENT_H
+#define COLORADJUSTMENT_H
 
 // STL includes
 #include <QString>
@@ -6,6 +7,7 @@
 // Utils includes
 #include <utils/RgbChannelAdjustment.h>
 #include <utils/RgbTransform.h>
+#include <utils/OkhsvTransform.h>
 
 class ColorAdjustment
 {
@@ -31,4 +33,7 @@ public:
 	RgbChannelAdjustment _rgbYellowAdjustment;
 
 	RgbTransform _rgbTransform;
+	OkhsvTransform _okhsvTransform;
 };
+
+#endif // COLORADJUSTMENT_H

include/utils/ColorSys.h

@@ -1,4 +1,5 @@
-#pragma once
+#ifndef COLORSYS_H
+#define COLORSYS_H
 
 // STL includes
 #include <cstdint>
@@ -76,4 +77,34 @@ public:
 	/// @param[out] green The green RGB-component
 	/// @param[out] blue The blue RGB-component
 	static void yuv2rgb(uint8_t y, uint8_t u, uint8_t v, uint8_t & r, uint8_t & g, uint8_t & b);
+
+	///
+	/// Translates an RGB (red, green, blue) color to an Okhsv (hue, saturation, value) color
+	///
+	/// @param[in] red The red RGB-component
+	/// @param[in] green The green RGB-component
+	/// @param[in] blue The blue RGB-component
+	/// @param[out] hue The hue Okhsv-component
+	/// @param[out] saturation The saturation Okhsv-component
+	/// @param[out] value The value Okhsv-component
+	///
+	/// @note See https://bottosson.github.io/posts/colorpicker/#okhsv
+	///
+	static void rgb2okhsv(uint8_t red, uint8_t green, uint8_t blue, double & hue, double & saturation, double & value);
+
+	///
+	/// Translates an Okhsv (hue, saturation, value) color to an RGB (red, green, blue) color
+	///
+	/// @param[in] hue The hue Okhsv-component
+	/// @param[in] saturation The saturation Okhsv-component
+	/// @param[in] value The value Okhsv-component
+	/// @param[out] red The red RGB-component
+	/// @param[out] green The green RGB-component
+	/// @param[out] blue The blue RGB-component
+	///
+	/// @note See https://bottosson.github.io/posts/colorpicker/#okhsv
+	///
+	static void okhsv2rgb(double hue, double saturation, double value, uint8_t & red, uint8_t & green, uint8_t & blue);
 };
+
+#endif // COLORSYS_H

include/utils/OkhsvTransform.h

@@ -0,0 +1,63 @@
+#ifndef OKHSVTRANSFORM_H
+#define OKHSVTRANSFORM_H
+
+#include <cstdint>
+
+///
+/// Color transformation to adjust the saturation and value of Okhsv colors
+///
+class OkhsvTransform
+{
+public:
+	///
+	/// Default constructor
+	///
+	OkhsvTransform();
+
+	///
+	/// Constructor
+	///
+	/// @param saturationGain gain factor to apply to saturation
+	/// @param brightnessGain gain factor to apply to value/brightness
+	///
+	OkhsvTransform(double saturationGain, double brightnessGain);
+
+	/// @return The current saturation gain value
+	double getSaturationGain() const;
+
+	/// @param saturationGain new saturation gain
+	void setSaturationGain(double saturationGain);
+
+	/// @return The current brightness gain value
+	double getBrightnessGain() const;
+
+	/// @param brightnessGain new value/brightness gain
+	void setBrightnessGain(double brightnessGain);
+
+	/// @return true if the current gain settings result in an identity transformation
+	bool isIdentity() const;
+
+	///
+	/// Apply the transform the the given RGB values.
+	///
+	/// @param red The red color component
+	/// @param green The green color component
+	/// @param blue The blue color component
+	///
+	/// @note The values are updated in place.
+	///
+	void transform(uint8_t & red, uint8_t & green, uint8_t & blue) const;
+
+private:
+	/// Sets _isIdentity to true if both gain values are at their neutral setting
+	void updateIsIdentity();
+
+	/// Gain settings
+	double _saturationGain;
+	double _brightnessGain;
+
+	/// Is true if the gain settings result in an identity transformation
+	bool _isIdentity;
+};
+
+#endif // OKHSVTRANSFORM_H

include/utils/hyperion.h

@@ -81,6 +81,14 @@ namespace hyperion {
 		return RgbTransform(gammaR, gammaG, gammaB, backlightThreshold, backlightColored, static_cast<uint8_t>(brightness), static_cast<uint8_t>(brightnessComp));
 	}
 
+	OkhsvTransform createOkhsvTransform(const QJsonObject& colorConfig)
+	{
+		const double saturationGain = colorConfig["saturationGain"].toDouble(1.0);
+		const double brightnessGain = colorConfig["brightnessGain"].toDouble(1.0);
+
+		return OkhsvTransform(saturationGain, brightnessGain);
+	}
+
 	RgbChannelAdjustment createRgbChannelAdjustment(const QJsonObject& colorConfig, const QString& channelName, int defaultR, int defaultG, int defaultB)
 	{
 		const QJsonArray& channelConfig  = colorConfig[channelName].toArray();
@@ -107,6 +115,7 @@ namespace hyperion {
 		adjustment->_rgbMagentaAdjustment = createRgbChannelAdjustment(adjustmentConfig, "magenta", 255,  0,255);
 		adjustment->_rgbYellowAdjustment  = createRgbChannelAdjustment(adjustmentConfig, "yellow" , 255,255,  0);
 		adjustment->_rgbTransform         = createRgbTransform(adjustmentConfig);
+		adjustment->_okhsvTransform       = createOkhsvTransform(adjustmentConfig);
 
 		return adjustment;
 	}