fix #438,add wheel events

--by using wheel events the volume can
be increased/decreased

plasmoid/contents/ui/AudioStream.qml

@@ -65,10 +65,9 @@ Item {
                 border.color: root.minimizedDotColor
                 radius: width/2
 
-                opacity: mainItemContainer.playingAudio && !mainItemContainer.muted ? 1 : 0.5
+                opacity: mainItemContainer.playingAudio && !mainItemContainer.muted && mainItemContainer.volume>0 ? 1 : 0.5
             }
 
-
             Latte.IconItem{
                 id: audioStreamIcon
                 anchors.fill: parent
@@ -87,7 +86,17 @@ Item {
 
                 MouseArea{
                     anchors.fill: parent
+
                     onClicked: mainItemContainer.toggleMuted();
+
+                    onWheel: {
+                        var angle = wheel.angleDelta.y / 8;
+
+                        if (angle > 12)
+                            mainItemContainer.increaseVolume();
+                        else if (angle < 12)
+                            mainItemContainer.decreaseVolume();
+                    }
                 }
             }
         }

plasmoid/contents/ui/PulseAudio.qml

@@ -29,6 +29,14 @@ QtObject {
     // It's a JS object so we can do key lookup and don't need to take care of filtering duplicates.
     property var pidMatches: ({})
 
+    property int maxVolumePercent: 125
+    property int maxVolumeValue: Math.round(maxVolumePercent * PulseAudio.NormalVolume / 100.0)
+    property int volumeStep: Math.round(3 * PulseAudio.NormalVolume / 100.0)
+
+    function boundVolume(volume) {
+        return Math.max(PulseAudio.MinimalVolume, Math.min(volume, maxVolumeValue));
+    }
+
     // TODO Evict cache at some point, preferably if all instances of an application closed.
     function registerPidMatch(appName) {
         if (!hasPidMatch(appName)) {
@@ -88,6 +96,15 @@ QtObject {
                 Muted = false
             }
 
+            function increaseVolume() {
+                var bVolume = pulseAudio.boundVolume(Volume + pulseAudio.volumeStep);
+                Volume = bVolume;
+            }
+
+            function decreaseVolume() {
+                var bVolume = pulseAudio.boundVolume(Volume - pulseAudio.volumeStep);
+                Volume = bVolume;
+            }
         }
 
         onObjectAdded: pulseAudio.streamsChanged()

plasmoid/contents/ui/TaskDelegate.qml

@@ -1197,6 +1197,14 @@ MouseArea{
         }
     }
 
+    function increaseVolume() {
+        mainItemContainer.audioStreams.forEach(function (item) { item.increaseVolume(); });
+    }
+
+    function decreaseVolume() {
+        mainItemContainer.audioStreams.forEach(function (item) { item.decreaseVolume(); });
+    }
+
     Connections {
         target: pulseAudio.item
         ignoreUnknownSignals: true // Plasma-PA might not be available