hyperion.ng/libsrc/leddevice/LedDevicePhilipsHue.cpp

// Local-Hyperion includes
#include "LedDevicePhilipsHue.h"

// jsoncpp includes
#include <json/json.h>

// qt includes
#include <QtCore/qmath.h>
#include <QUrl>
#include <QHttpRequestHeader>
#include <QEventLoop>

LedDevicePhilipsHue::LedDevicePhilipsHue(const std::string& output) :
		host(output.c_str()), username("newdeveloper") {
	http = new QHttp(host);
	timer.setInterval(1000);
	timer.setSingleShot(true);
	connect(&timer, SIGNAL(timeout()), this, SLOT(restoreStates()()));
}

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(getStateRoute(lightId), QString("{\"xy\": [%1, %2]}").arg(x).arg(y));
		// Send brightness color command in JSON format.
		put(getStateRoute(lightId), QString("{\"bri\": %1}").arg(qRound(b * 255.0f)));
		// Next light id.
		lightId++;
	}
	timer.start();
	return 0;
}

int LedDevicePhilipsHue::switchOff() {
	timer.stop();
	// If light states have been saved before, ...
	if (statesSaved()) {
		// ... restore them.
		restoreStates();
	}
	return 0;
}

void LedDevicePhilipsHue::put(QString route, QString content) {
	QString url = QString("/api/%1/%2").arg(username).arg(route);
	QHttpRequestHeader header("PUT", url);
	header.setValue("Host", host);
	header.setValue("Accept-Encoding", "identity");
	header.setValue("Connection", "keep-alive");
	header.setValue("Content-Length", QString("%1").arg(content.size()));
	QEventLoop loop;
	// Connect requestFinished signal to quit slot of the loop.
	loop.connect(http, SIGNAL(requestFinished(int, bool)), SLOT(quit()));
	// Perfrom request
	http->request(header, content.toAscii());
	// Go into the loop until the request is finished.
	loop.exec();
}

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 json;
		if (!reader.parse(QString(response).toStdString(), json)) {
			// Error occured, break loop.
			break;
		}
		// Save state object values which are subject to change.
		Json::Value state(Json::objectValue);
		state["xy"] = json["state"]["xy"];
		state["bri"] = json["state"]["bri"];
		// Save state object.
		states.push_back(QString(writer.write(state).c_str()).trimmed());
	}
}

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);
	// 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;
	float Z = red * 0.0000000f + green * 0.053077f + blue * 1.035763f;
	// Convert to x,y space.
	x = X / (X + Y + Z);
	y = Y / (X + Y + Z);
	if (isnan(x)) {
		x = 0.0f;
	}
	if (isnan(y)) {
		y = 0.0f;
	}
	// Brightness is simply Y in the XYZ space.
	brightness = Y;
}