Tidy up frame rate display in video examples

* Use a Column element to position QML and video frame rate counters.
* When using small-screen layouts, hide frame rate counters when dialogs
  or menus are displayed.
* Do not display instantaneous frame rate.  If changes in this rate
  trigger a repaint, then the rate itself is changed.  If the repaint
  occurs in less time than the QElapsedTimer resolution, the displayed
  instantaneous rate is always zero.
* Add a label, so it is clear which is the QML repaint rate, and which
  is the video frame rate.

Change-Id: Ie58ab162ab44bd7f1c4b297eed929b9baa73552c
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>

examples/video/snippets/frequencymonitor/qml/frequencymonitor/FrequencyItem.qml

@@ -55,7 +55,7 @@ Rectangle {
 
     border.width: 1
     border.color: "yellow"
-    width: 3.5 * root.textSize
+    width: 5.5 * root.textSize
     height: 3.0 * root.textSize
     color: "black"
     opacity: 0.5
@@ -74,20 +74,22 @@ Rectangle {
         samplingInterval: root.enabled ? root.samplingInterval : 0
         onAverageFrequencyChanged: {
             if (root.logging) trace()
-            instantaneousFrequencyText.text = monitor.instantaneousFrequency.toFixed(2)
             averageFrequencyText.text = monitor.averageFrequency.toFixed(2)
         }
     }
 
     Text {
-        id: instantaneousFrequencyText
+        id: labelText
         anchors {
-            right: parent.right
+            left: parent.left
             top: parent.top
             margins: 10
         }
         color: root.textColor
-        font.pixelSize: root.textSize
+        font.pixelSize: 0.6 * root.textSize
+        text: root.label
+        width: root.width - 2*anchors.margins
+        elide: Text.ElideRight
     }
 
     Text {

examples/video/snippets/performancemonitor/qml/performancemonitor/PerformanceItem.qml

@@ -46,65 +46,96 @@ Rectangle {
     property bool logging: true
     property bool displayed: true
     property bool videoActive
-    property int samplingInterval: 500
-    property color textColor: "yellow"
-    property int textSize: 28
     property int margins: 5
+    property bool enabled: true
 
     color: "transparent"
 
     // This should ensure that the monitor is on top of all other content
     z: 999
 
-    Loader {
-        id: videoFrameRateItemLoader
-        function init() {
-            source = "../frequencymonitor/FrequencyItem.qml"
-            item.label = "videoFrameRate"
-            item.parent = root
-            item.anchors.left = root.left
-            item.anchors.top = root.top
-            item.anchors.margins = root.margins
-            item.logging = root.logging
-            item.displayed = root.displayed
-            videoFrameRateActiveConnections.target = item
-        }
-
-        Connections {
-            id: videoFrameRateActiveConnections
-            ignoreUnknownSignals: true
-            onActiveChanged: root.videoActive = videoFrameRateActiveConnections.target.active
+    Column {
+        id: column
+        anchors {
+            fill: root
+            margins: 10
         }
+        spacing: 10
     }
 
-    Loader {
-        id: qmlFrameRateItemLoader
-        function init() {
-            source = "../frequencymonitor/FrequencyItem.qml"
-            item.label = "qmlFrameRate"
-            item.parent = root
-            item.anchors.left = root.left
-            item.anchors.bottom = root.bottom
-            item.anchors.margins = root.margins
-            item.logging = root.logging
-            item.displayed = root.displayed
-        }
+    QtObject {
+        id: d
+        property Item qmlFrameRateItem: null
+        property Item videoFrameRateItem: null
     }
 
+    Connections {
+        id: videoFrameRateActiveConnections
+        ignoreUnknownSignals: true
+        onActiveChanged: root.videoActive = videoFrameRateActiveConnections.target.active
+    }
+
+    states: [
+        State {
+            name: "hidden"
+            PropertyChanges {
+                target: root
+                opacity: 0
+            }
+        }
+    ]
+
+    transitions: [
+        Transition {
+            from: "*"
+            to: "*"
+            NumberAnimation {
+                properties: "opacity"
+                easing.type: Easing.OutQuart
+                duration: 500
+            }
+        }
+    ]
+
+    state: enabled ? "baseState" : "hidden"
+
+    function createQmlFrameRateItem() {
+        var component = Qt.createComponent("../frequencymonitor/FrequencyItem.qml")
+        if (component.status == Component.Ready)
+            d.qmlFrameRateItem = component.createObject(column, { label: "QML frame rate",
+                                                                   displayed: root.displayed,
+                                                                  logging: root.logging
+                                                                })
+    }
+
+    function createVideoFrameRateItem() {
+        var component = Qt.createComponent("../frequencymonitor/FrequencyItem.qml")
+        if (component.status == Component.Ready)
+            d.videoFrameRateItem = component.createObject(column, { label: "Video frame rate",
+                                                                     displayed: root.displayed,
+                                                                    logging: root.logging
+                                                                  })
+        videoFrameRateActiveConnections.target = d.videoFrameRateItem
+    }
+
+
     function init() {
-        videoFrameRateItemLoader.init()
-        qmlFrameRateItemLoader.init()
+        createQmlFrameRateItem()
+        createVideoFrameRateItem()
     }
 
     function videoFramePainted() {
-        videoFrameRateItemLoader.item.notify()
+        if (d.videoFrameRateItem)
+            d.videoFrameRateItem.notify()
     }
 
     function qmlFramePainted() {
-        qmlFrameRateItemLoader.item.notify()
+        if (d.qmlFrameRateItem)
+            d.qmlFrameRateItem.notify()
     }
 
     onVideoActiveChanged: {
-        videoFrameRateItemLoader.item.active = root.videoActive
+        if (d.videoFrameRateItem)
+            d.videoFrameRateItem.active = root.videoActive
     }
 }