Add master volume control slider

Adds support for a master volume control to the HomeScreen app.
The master volume slider appears when touching in the MediaArea
at the bottom of the screen. If there is no interaction with the
slider, it fades out after 5 seconds so that the AGL logo area
is not obscured. The volume slider is accessible across all
applications due to the MediaArea portion of HomeScreen always
being exposed to the screen.

The slider volume control is tied to the default PA sink and
applies proportional volume control across all channels of the
default sink when changed.  It also reacts to external volume
change events from other PA clients (e.g. Mixer app or pactl
CLI changes) and updates the master volume slider accordingly.

AGL-Bug: SPEC-550
Change-Id: I9bf55bc624f4bb95c162a79bd2eb314d8f945033
Signed-off-by: Matt Porter <mporter@konsulko.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/homescreen/src/mastervolume.h b/homescreen/src/mastervolume.h
new file mode 100644
index 0000000..edcdd8c
--- /dev/null
+++ b/homescreen/src/mastervolume.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <QtCore/QObject>
+#include <QQmlEngine>
+#include <QDebug>
+
+#include <pulse/pulseaudio.h>
+
+class MasterVolume : public QObject
+{
+	Q_OBJECT
+		Q_PROPERTY (uint32_t volume READ getVolume WRITE setVolume NOTIFY volumeChanged)
+
+	public:
+		MasterVolume(QObject *parent = 0)
+			: QObject(parent), m_volume(32768)
+		{
+		}
+
+		~MasterVolume() {}
+
+		uint32_t getVolume() const { return m_volume; }
+		void setVolume(pa_volume_t volume);
+
+	public slots:
+		void changeExternalVolume(int volume);
+
+	signals:
+		void volumeChanged(void);
+		void sliderVolumeChanged(int volume_delta);
+		void externalVolumeChanged(uint32_t volume);
+
+	private:
+		uint32_t m_volume;
+};