Update light color judgement by contrast ratio

Author: FangCunWuChang

src/ui/Utils.cpp

@@ -710,9 +710,30 @@ namespace utils {
 			+ juce::String{ num[6] } + juce::String{ num[7] };
 	}
 
-	bool isLightColor(const juce::Colour& color) {
-		float brightness = color.getRed() * 0.299 + color.getGreen() * 0.587 + color.getBlue() * 0.114;
-		return brightness > 140;
+	float colorLuminance(const juce::Colour& color) {
+		auto normalize = [](int c) {
+			float normalized = c / 255.0f;
+			return (normalized <= 0.03928) ? normalized / 12.92 : std::pow((normalized + 0.055) / 1.055, 2.4);
+			};
+		return 0.2126f * normalize(color.getRed()) + 0.7152f * normalize(color.getGreen()) + 0.0722f * normalize(color.getBlue());
+	}
+
+	float colorContrastRatio(float luminance1, float luminance2) {
+		float L1 = std::max(luminance1, luminance2);
+		float L2 = std::min(luminance1, luminance2);
+		return (L1 + 0.05f) / (L2 + 0.05f);
+	}
+
+	bool isLightColor(const juce::Colour& color,
+		const juce::Colour& textColorLight, const juce::Colour& textColorDark) {
+		float backgroundLuminance = colorLuminance(color);
+		float darkLuminance = colorLuminance(textColorDark);
+		float lightLuminance = colorLuminance(textColorLight);
+
+		float darkContrast = colorContrastRatio(backgroundLuminance, darkLuminance);
+		float lightContrast = colorContrastRatio(backgroundLuminance, lightLuminance);
+
+		return darkContrast < lightContrast;
 	}
 
 	const IntSectionList getUnionSections(const IntSectionList& source) {

src/ui/Utils.h

@@ -156,7 +156,11 @@ namespace utils {
 	const juce::String createTimeString(const TimeInSeconds& time);
 	const juce::String createBeatString(const TimeInBeats& time);
 
-	bool isLightColor(const juce::Colour& color);
+	float colorLuminance(const juce::Colour& color);
+	float colorContrastRatio(float luminance1, float luminance2);
+	bool isLightColor(const juce::Colour& color,
+		const juce::Colour& textColorLight = juce::Colours::black,
+		const juce::Colour& textColorDark = juce::Colours::white);
 	using IntSection = std::pair<int, int>;
 	using IntSectionList = juce::Array<IntSection>;
 	const IntSectionList getUnionSections(const IntSectionList& source);

src/ui/component/editor/MIDIContentViewer.cpp

@@ -36,7 +36,7 @@ void MIDIContentViewer::update(int index, uint64_t ref) {
 
 	if (index >= 0) {
 		this->trackColor = quickAPI::getSeqTrackColor(index);
-		this->trackColorIsLight = utils::isLightColor(this->trackColor);
+		//this->trackColorIsLight = utils::isLightColor(this->trackColor);
 
 		/** Note Color Gradient */
 		auto& laf = this->getLookAndFeel();

src/ui/component/editor/MIDIContentViewer.h

@@ -103,7 +103,7 @@ class MIDIContentViewer final
 	std::unique_ptr<juce::Image> noteTemp = nullptr;
 
 	juce::Colour trackColor;
-	bool trackColorIsLight = false;
+	//bool trackColorIsLight = false;
 	juce::Array<juce::Colour> noteColorGradient;
 
 	void updateKeyImageTemp();

src/ui/component/mixer/MixerTrackComponent.cpp

@@ -289,14 +289,12 @@ void MixerTrackComponent::update(int index) {
 		this->trackColor = quickAPI::getMixerTrackColor(index);
 
 		auto& laf = this->getLookAndFeel();
-		if (utils::isLightColor(this->trackColor)) {
-			this->nameColor = laf.findColour(
-				juce::Label::ColourIds::textWhenEditingColourId);
-		}
-		else {
-			this->nameColor = laf.findColour(
-				juce::Label::ColourIds::textColourId);
-		}
+		auto textColorLight = laf.findColour(
+			juce::Label::ColourIds::textWhenEditingColourId);
+		auto textColorDark = laf.findColour(
+			juce::Label::ColourIds::textColourId);
+		this->nameColor = utils::isLightColor(this->trackColor, textColorLight, textColorDark)
+			? textColorLight : textColorDark;
 
 		this->sideChain->update(index);
 

src/ui/component/sequencer/SeqTrackComponent.cpp

@@ -130,14 +130,12 @@ void SeqTrackComponent::update(int index) {
 		this->trackColor = quickAPI::getSeqTrackColor(index);
 
 		auto& laf = this->getLookAndFeel();
-		if (utils::isLightColor(this->trackColor)) {
-			this->idColor = laf.findColour(
-				juce::Label::ColourIds::textWhenEditingColourId);
-		}
-		else {
-			this->idColor = laf.findColour(
-				juce::Label::ColourIds::textColourId);
-		}
+		auto textColorLight = laf.findColour(
+			juce::Label::ColourIds::textWhenEditingColourId);
+		auto textColorDark = laf.findColour(
+			juce::Label::ColourIds::textColourId);
+		this->idColor = utils::isLightColor(this->trackColor, textColorLight, textColorDark)
+			? textColorLight : textColorDark;
 
 		auto name = quickAPI::getSeqTrackName(index);
 		if (name.isEmpty()) {

src/ui/component/sequencer/SeqTrackContentViewer.cpp

@@ -71,14 +71,12 @@ void SeqTrackContentViewer::update(int index) {
 		this->trackColor = quickAPI::getSeqTrackColor(index);
 
 		auto& laf = this->getLookAndFeel();
-		if (utils::isLightColor(this->trackColor)) {
-			this->nameColor = laf.findColour(
-				juce::Label::ColourIds::textWhenEditingColourId);
-		}
-		else {
-			this->nameColor = laf.findColour(
-				juce::Label::ColourIds::textColourId);
-		}
+		auto textColorLight = laf.findColour(
+			juce::Label::ColourIds::textWhenEditingColourId);
+		auto textColorDark = laf.findColour(
+			juce::Label::ColourIds::textColourId);
+		this->nameColor = utils::isLightColor(this->trackColor, textColorLight, textColorDark)
+			? textColorLight : textColorDark;
 
 		if (changeData) {
 			this->updateDataRef();