State of all lights is saved and restored on switchOff().

Author: Tim Niggemann

libsrc/leddevice/LedDevicePhilipsHue.cpp

@@ -1,39 +1,51 @@
 // Local-Hyperion includes
 #include "LedDevicePhilipsHue.h"
 
-#include <iostream>
+// jsoncpp includes
+#include <json/json.h>
 
+// qt includes
 #include <QtCore/qmath.h>
 #include <QUrl>
 #include <QHttpRequestHeader>
-#include <QThread>
+#include <QEventLoop>
 
 LedDevicePhilipsHue::LedDevicePhilipsHue(const std::string& output) :
-	host(output.c_str()), username("newdeveloper") {
-	http = new QHttp(host, 80);
+		host(output.c_str()), username("newdeveloper") {
+	http = new QHttp(host);
 }
 
 LedDevicePhilipsHue::~LedDevicePhilipsHue() {
 	delete http;
 }
 
 int LedDevicePhilipsHue::write(const std::vector<ColorRgb> & ledValues) {
+	// Save light states if not done before.
+	if (!statesSaved()) {
+		saveStates(ledValues.size());
+	}
+	// Iterate through colors and set light states.
 	unsigned int lightId = 1;
 	for (const ColorRgb& color : ledValues) {
 		float x, y, b;
 		// Scale colors from [0, 255] to [0, 1] and convert to xy space.
 		rgbToXYBrightness(color.red / 255.0f, color.green / 255.0f, color.blue / 255.0f, x, y, b);
 		// Send adjust color command in JSON format.
-		put(getRoute(lightId), QString("{\"xy\": [%1, %2]}").arg(x).arg(y));
+		put(getStateRoute(lightId), QString("{\"xy\": [%1, %2]}").arg(x).arg(y));
 		// Send brightness color command in JSON format.
-		put(getRoute(lightId), QString("{\"bri\": %1}").arg(qRound(b * 255.0f)));
+		put(getStateRoute(lightId), QString("{\"bri\": %1}").arg(qRound(b * 255.0f)));
 		// Next light id.
 		lightId++;
 	}
 	return 0;
 }
 
 int LedDevicePhilipsHue::switchOff() {
+	// If light states have been saved before, ...
+	if (statesSaved()) {
+		// ... restore them.
+		restoreStates();
+	}
 	return 0;
 }
 
@@ -47,15 +59,68 @@ void LedDevicePhilipsHue::put(QString route, QString content) {
 	http->request(header, content.toAscii());
 }
 
-QString LedDevicePhilipsHue::getRoute(unsigned int lightId) {
+QByteArray LedDevicePhilipsHue::get(QString route) {
+	QString url = QString("/api/%1/%2").arg(username).arg(route);
+	// Event loop to block until request finished.
+	QEventLoop loop;
+	// Connect requestFinished signal to quit slot of the loop.
+	loop.connect(http, SIGNAL(requestFinished(int, bool)), SLOT(quit()));
+	// Perfrom request
+	http->get(url);
+	// Go into the loop until the request is finished.
+	loop.exec();
+	// Read all data of the response.
+	return http->readAll();
+}
+
+QString LedDevicePhilipsHue::getStateRoute(unsigned int lightId) {
 	return QString("lights/%1/state").arg(lightId);
 }
 
+QString LedDevicePhilipsHue::getRoute(unsigned int lightId) {
+	return QString("lights/%1").arg(lightId);
+}
+
+void LedDevicePhilipsHue::saveStates(unsigned int nLights) {
+	// Clear saved light states.
+	states.clear();
+	// Use json parser to parse reponse.
+	Json::Reader reader;
+	Json::FastWriter writer;
+	// Iterate lights.
+	for (unsigned int i = 0; i < nLights; i++) {
+		// Read the response.
+		QByteArray response = get(getRoute(i + 1));
+		// Parse JSON.
+		Json::Value state;
+		if (!reader.parse(QString(response).toStdString(), state)) {
+			// Error occured, break loop.
+			break;
+		}
+		// Save state object.
+		states.push_back(QString(writer.write(state["state"]).c_str()));
+	}
+}
+
+void LedDevicePhilipsHue::restoreStates() {
+	unsigned int lightId = 1;
+	for (QString state : states) {
+		put(getStateRoute(lightId), state);
+		lightId++;
+	}
+	// Clear saved light states.
+	states.clear();
+}
+
+bool LedDevicePhilipsHue::statesSaved() {
+	return !states.empty();
+}
+
 void LedDevicePhilipsHue::rgbToXYBrightness(float red, float green, float blue, float& x, float& y, float& brightness) {
 	// Apply gamma correction.
 	red = (red > 0.04045f) ? qPow((red + 0.055f) / (1.0f + 0.055f), 2.4f) : (red / 12.92f);
-	green = (green > 0.04045f) ? qPow ((green + 0.055f) / (1.0f + 0.055f), 2.4f) : (green / 12.92f);
-	blue = (blue > 0.04045f) ? qPow ((blue + 0.055f) / (1.0f + 0.055f), 2.4f) : (blue / 12.92f);
+	green = (green > 0.04045f) ? qPow((green + 0.055f) / (1.0f + 0.055f), 2.4f) : (green / 12.92f);
+	blue = (blue > 0.04045f) ? qPow((blue + 0.055f) / (1.0f + 0.055f), 2.4f) : (blue / 12.92f);
 	// Convert to XYZ space.
 	float X = red * 0.649926f + green * 0.103455f + blue * 0.197109f;
 	float Y = red * 0.234327f + green * 0.743075f + blue * 0.022598f;

libsrc/leddevice/LedDevicePhilipsHue.h

@@ -9,7 +9,7 @@
 
 // Leddevice includes
 #include <leddevice/LedDevice.h>
-		
+
 /**
  * Implementation for the Philips Hue system.
  * 
@@ -18,8 +18,7 @@
  * Framegrabber must be limited to 10 Hz / numer of lights to avoid rate limitation by the hue bridge.
  * Create a new API user name "newdeveloper" on the bridge (http://developers.meethue.com/gettingstarted.html)
  */
-class LedDevicePhilipsHue : public LedDevice
-{
+class LedDevicePhilipsHue: public LedDevice {
 public:
 	///
 	/// Constructs the device.
@@ -46,14 +45,26 @@ class LedDevicePhilipsHue : public LedDevice
 	virtual int switchOff();
 
 private:
+	/// Array to save the light states.
+	std::vector<QString> states;
 	/// Ip address of the bridge
 	QString host;
 	/// User name for the API ("newdeveloper")
 	QString username;
+	/// Qhttp object for sending requests.
 	QHttp* http;
 
 	///
-	/// Sends a HTTP PUT request
+	/// Sends a HTTP GET request (blocking).
+	///
+	/// @param route the URI of the request
+	///
+	/// @return response of the request
+	///
+	QByteArray get(QString route);
+
+	///
+	/// Sends a HTTP PUT request (non-blocking).
 	///
 	/// @param route the URI of the request
 	///
@@ -64,10 +75,32 @@ class LedDevicePhilipsHue : public LedDevice
 	///
 	/// @param lightId the id of the hue light (starting from 1)
 	///
-	/// @return the URI of the light
+	/// @return the URI of the light state for PUT requests.
+	///
+	QString getStateRoute(unsigned int lightId);
+
+	///
+	/// @param lightId the id of the hue light (starting from 1)
+	///
+	/// @return the URI of the light for GET requests.
 	///
 	QString getRoute(unsigned int lightId);
 
+	///
+	/// Queries the status of all lights and saves it.
+	///
+	/// @param nLights the number of lights
+	///
+	void saveStates(unsigned int nLights);
+
+	/// Restores the status of all lights.
+	void restoreStates();
+
+	///
+	/// @return true if light states have been saved.
+	///
+	bool statesSaved();
+
 	///
 	/// Converts an RGB color to the Hue xy color space and brightness
 	/// https://github.com/PhilipsHue/PhilipsHueSDK-iOS-OSX/blob/master/ApplicationDesignNotes/RGB%20to%20xy%20Color%20conversion.md
@@ -84,7 +117,6 @@ class LedDevicePhilipsHue : public LedDevice
 	///
 	/// @param brightness converted brightness component
 	///
-	void rgbToXYBrightness(float red, float green, float blue, 
-			float& x, float& y, float& brightness);
+	void rgbToXYBrightness(float red, float green, float blue, float& x, float& y, float& brightness);
 
 };