Detect dark mode in iOS

Author: JoelOtter

src/core/include/growl/core/api/api_internal.h

@@ -26,6 +26,7 @@ class SystemAPIInternal : public SystemAPI, public APIInternal {
 	virtual ~SystemAPIInternal() {}
 	// Used in push-style touch input e.g. on iOS.
 	virtual void onTouch(InputTouchEvent touch) {}
+	virtual void setDarkMode(bool dark_mode) {}
 };
 
 class GraphicsAPIInternal : public GraphicsAPI, public APIInternal {

src/core/include/growl/core/api/system_api.h

@@ -45,6 +45,10 @@ class SystemAPI {
 
 	virtual void setLogLevel(LogLevel log_level) = 0;
 
+	virtual bool isDarkMode() {
+		return false;
+	}
+
 	virtual Result<std::unique_ptr<File>>
 	openFile(std::string path, size_t start = 0, size_t end = 0) = 0;
 

src/platforms/ios/src/view_controller.mm

@@ -47,6 +47,10 @@ - (void)viewDidLoad {
 				  << std::endl;
 		exit(1);
 	}
+
+	systemInternal.setDarkMode(
+		self.traitCollection.userInterfaceStyle == UIUserInterfaceStyleDark);
+
 	if (auto err = graphicsInternal.init()) {
 		api->system().log(
 			Growl::LogLevel::Fatal, "ViewController",
@@ -159,4 +163,13 @@ - (void)viewWillAppear:(BOOL)animated {
 	game->resize(w, h);
 }
 
+- (void)willTransitionToTraitCollection:(UITraitCollection*)newCollection
+			  withTransitionCoordinator:
+				  (id<UIViewControllerTransitionCoordinator>)coordinator {
+	auto& systemInternal =
+		static_cast<Growl::SystemAPIInternal&>(api->system());
+	systemInternal.setDarkMode(
+		newCollection.userInterfaceStyle == UIUserInterfaceStyleDark);
+}
+
 @end

src/plugins/ios/src/ios_system.h

@@ -17,6 +17,10 @@ class IOSSystemAPI : public SystemAPIInternal {
 	bool isRunning() override {
 		return running;
 	}
+
+	void setDarkMode(bool dark_mode) override;
+	bool isDarkMode() override;
+
 	virtual Result<std::unique_ptr<Window>>
 	createWindow(const Config& config) override;
 	void setLogLevel(LogLevel log_level) override;
@@ -36,6 +40,7 @@ class IOSSystemAPI : public SystemAPIInternal {
 
 	API& api;
 	bool running;
+	bool dark_mode;
 	GCController* controller = nullptr;
 	id game_controller_connect_observer;
 	id game_controller_disconnect_observer;

src/plugins/ios/src/ios_system.mm

@@ -93,6 +93,14 @@
 		OS_LOG_DEFAULT, OS_LOG_TYPE_DEBUG, "[%s] %s", tag.c_str(), msg.c_str());
 }
 
+void IOSSystemAPI::setDarkMode(bool dark_mode) {
+	this->dark_mode = dark_mode;
+}
+
+bool IOSSystemAPI::isDarkMode() {
+	return dark_mode;
+}
+
 Result<std::unique_ptr<File>>
 IOSSystemAPI::openFile(std::string path, size_t start, size_t end) {
 	auto full_path =