OTHER: make balance slider work

Implemented balance handling and moved volume slider handling to
lib/xplayback.cpp

lib/xplayback.cpp

@@ -22,10 +22,17 @@
 #include <xmmsclient/xmmsclient++/playback.h>
 #include <xmmsclient/xmmsclient++/playlist.h>
 
+#include <QtDebug>
+
+#include <QStyle>
+
 XPlayback::XPlayback (XClient *client)
 {
 	m_client = client;
 
+	m_volume = 0;
+	m_balance = 0;
+
 	connect (client, SIGNAL (gotConnection (XClient *)),
 	         this, SLOT (on_connect (XClient *)));
 
@@ -41,6 +48,11 @@ XPlayback::on_connect (XClient *client)
 	        (Xmms::bind (&XPlayback::playback_status, this));
 	client->playback ()->broadcastStatus ()
 	        (Xmms::bind (&XPlayback::playback_status, this));
+
+	client->playback ()->volumeGet ()
+			(Xmms::bind (&XPlayback::volume_changed, this));
+	client->playback ()->broadcastVolumeChanged ()
+	        (Xmms::bind (&XPlayback::volume_changed, this));
 }
 
 void
@@ -136,3 +148,146 @@ XPlayback::playback_status (const Xmms::Playback::Status &status)
 	return true;
 }
 
+/*
+ * Volume
+ */
+inline int
+calcBalance (int left, int right)
+{
+	if (left == right)
+		return 0;
+	if (left == 0)
+		return MAX_BALANCE;
+	if (right == 0)
+		return -MAX_BALANCE;
+
+	//FIXME: This somehow works, but I'm not happy with it as
+	// QStyle::sliderValueFromPosition is not intended for this
+	if (left > right)
+		return -QStyle::sliderValueFromPosition(0, MAX_BALANCE, right, left, true);
+	else
+		return QStyle::sliderValueFromPosition(0, MAX_BALANCE, left, right, true);
+}
+
+bool
+XPlayback::volume_changed (const Xmms::Dict &volDict)
+{
+	QHash<QString, QVariant> levels = XClient::convert_dict (volDict);
+
+	if (levels.size () == 1) {
+		m_onechannel = true;
+		newVolume (levels.values ().first ().toInt ());
+		newBalance (0);
+	} else {
+		/*
+		 * I might add a configure option later, to map arbitrary keys to
+		 * left and right
+		 */
+		if (!levels.contains ("left") || !levels.contains ("right")) {
+			qWarning () << "Could not get volume levels, dict contains keys: "
+			            << levels.keys ();
+			// disable further updates. Otherwise we would spam the console
+			return false;
+		}
+		int left = levels["left"].toInt ();
+		int right = levels["right"].toInt ();
+		newVolume (qMax (right, left));
+		newBalance (calcBalance (left, right));
+	}
+
+
+	return true;
+}
+
+void
+XPlayback::newVolume (int new_volume)
+{
+	// only emit signal if the volume really changed
+	if (new_volume == m_volume)
+		return;
+
+	m_volume = new_volume;
+	emit volumeChanged (new_volume);
+}
+
+void
+XPlayback::newBalance (int new_balance)
+{
+	// only emit signal if balance really changed
+	if (new_balance == m_balance)
+		return;
+
+	m_balance = new_balance;
+	emit balanceChanged (new_balance);
+}
+
+
+int
+calcVolume (int volume, int balance)
+{
+	balance = qAbs (balance);
+	if (balance > MAX_BALANCE) {
+		qWarning () << "Error in calculating balance, value " << balance
+		            << "is outside valid range";
+		return 0;
+	}
+
+	if (balance == 0)
+		return volume;
+	if (balance == MAX_BALANCE)
+		return 0;
+
+	//FIXME: this somehow works, but I'm not happy with it as
+	// QStyle::sliderPositionFromValue is not intended for this
+	return QStyle::sliderPositionFromValue(0, MAX_BALANCE, balance, volume, true);
+}
+
+void
+XPlayback::setVolume (int new_volume)
+{
+	// Don't echo values the server sent us back to it
+	if (m_volume == new_volume)
+		return;
+
+	//TODO: some error checking
+	if (m_onechannel) {
+		m_client->playback ()->volumeSet ("master", new_volume);
+	} else {
+		int right, left;
+		if (m_balance < 0) {
+			left = new_volume;
+			right = calcVolume (new_volume, m_balance);
+		} else {
+			left = calcVolume (new_volume, m_balance);
+			right = new_volume;
+		}
+		m_client->playback ()->volumeSet ("left", left);
+		m_client->playback ()->volumeSet ("right", right);
+	}
+
+	m_volume = new_volume;
+}
+
+void
+XPlayback::setBalance (int new_balance)
+{
+	// Don't echo values the server sent back to the server
+	if ((m_balance == new_balance) || m_onechannel)
+		return;
+
+	if (new_balance < 0) {
+		if (m_balance > 0) {
+			m_client->playback ()->volumeSet ("left", m_volume);
+		}
+		m_client->playback ()->volumeSet ("right",
+		          calcVolume (m_volume, new_balance));
+	} else {
+		if (m_balance < 0) {
+			m_client->playback ()->volumeSet ("right", m_volume);
+		}
+		m_client->playback ()->volumeSet ("left",
+		          calcVolume (m_volume, new_balance));
+	}
+
+	m_balance = new_balance;
+}

lib/xplayback.h

@@ -22,6 +22,7 @@ class XClient;
 #include <xmmsclient/xmmsclient++.h>
 #include <QObject>
 
+static const int MAX_BALANCE = 20;
 
 /**
  * @class XPlayback
@@ -34,6 +35,9 @@ class XPlayback : public QObject {
 	public:
 		XPlayback (XClient *);
 
+		int getVolume () {return m_volume;}
+		int getBalance () {return m_balance;}
+
 	public slots:
 		void play ();
 		void pause ();
@@ -46,16 +50,29 @@ class XPlayback : public QObject {
 		void seekMs (uint milliseconds);
 		void seekMsRel (int milliseconds);
 
+		void setVolume (int new_volume);
+		void setBalance (int new_balance);
+
+		// callbacks for clientlib
 		bool playback_status (const Xmms::Playback::Status &status);
+		bool volume_changed (const Xmms::Dict &volDict);
 
 		void on_connect (XClient *);
 
 	signals:
 		void playbackStatusChanged (Xmms::Playback::Status status);
+		void volumeChanged (int volume);
+		void balanceChanged (int balance);
 
 	private:
 		XClient *m_client;
 		Xmms::Playback::Status m_status;
+
+		void newVolume (int new_volume);
+		void newBalance (int new_balance);
+		int m_volume;
+		int m_balance;
+		bool m_onechannel;
 };
 
 #endif