Map Scale as reusable control

qgroundcontrol.qrc

@@ -102,6 +102,7 @@
         <file alias="VirtualJoystick.qml">src/FlightDisplay/VirtualJoystick.qml</file>
         <file alias="QGroundControl/FlightMap/qmldir">src/FlightMap/qmldir</file>
         <file alias="QGroundControl/FlightMap/FlightMap.qml">src/FlightMap/FlightMap.qml</file>
+        <file alias="QGroundControl/FlightMap/MapScale.qml">src/FlightMap/MapScale.qml</file>
         <file alias="QGroundControl/FlightMap/MissionItemIndicator.qml">src/FlightMap/MapItems/MissionItemIndicator.qml</file>
         <file alias="QGroundControl/FlightMap/MissionItemView.qml">src/FlightMap/MapItems/MissionItemView.qml</file>
         <file alias="QGroundControl/FlightMap/MissionLineView.qml">src/FlightMap/MapItems/MissionLineView.qml</file>

src/FlightMap/MapScale.qml

+/****************************************************************************
+ *
+ *   (c) 2009-2016 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+ *
+ * QGroundControl is licensed according to the terms in the file
+ * COPYING.md in the root of the source code directory.
+ *
+ ****************************************************************************/
+
+import QtQuick          2.4
+import QtQuick.Controls 1.3
+
+import QGroundControl               1.0
+import QGroundControl.Controls      1.0
+import QGroundControl.ScreenTools   1.0
+
+/// Map scale control
+Item {
+    id:     scale
+    width:  rightEnd.x + rightEnd.width
+    height: rightEnd.y + rightEnd.height
+
+    property var    mapControl                                                          ///< Map control for which this scale control is being used
+
+    property variant _scaleLengths: [5, 10, 25, 50, 100, 150, 250, 500, 1000, 2000, 5000, 10000, 20000, 50000, 100000, 200000, 500000, 1000000, 2000000]
+
+    property bool   _isSatelliteMap:    mapControl.activeMapType.name.indexOf(qsTr("Street")) == -1    ///< Scale control being displayed over satellite map
+    property var    _color:             _isSatelliteMap ? "white" : "black"
+
+    function formatDistance(meters)
+    {
+        var dist = Math.round(meters)
+        if (dist > 1000 ){
+            if (dist > 100000){
+                dist = Math.round(dist / 1000)
+            }
+            else{
+                dist = Math.round(dist / 100)
+                dist = dist / 10
+            }
+            dist = dist + " km"
+        }
+        else{
+            dist = dist + " m"
+        }
+        return dist
+    }
+
+    function calculateScale() {
+        var scaleLineWidth = 100
+        var coord1, coord2, dist, text, f
+        f = 0
+        coord1 = mapControl.toCoordinate(Qt.point(0, scale.y))
+        coord2 = mapControl.toCoordinate(Qt.point(scaleLineWidth, scale.y))
+        dist = Math.round(coord1.distanceTo(coord2))
+        if (dist === 0) {
+            // not visible
+        } else {
+            for (var i = 0; i < _scaleLengths.length - 1; i++) {
+                if (dist < (_scaleLengths[i] + _scaleLengths[i+1]) / 2 ) {
+                    f = _scaleLengths[i] / dist
+                    dist = _scaleLengths[i]
+                    break;
+                }
+            }
+            if (f === 0) {
+                f = dist / _scaleLengths[i]
+                dist = _scaleLengths[i]
+            }
+        }
+        text = formatDistance(dist)
+        centerLine.width = (scaleLineWidth * f) - (2 * leftEnd.width)
+        scaleText.text = text
+    }
+
+    Connections {
+        target: mapControl
+
+        onWidthChanged: scaleTimer.restart()
+        onHeightChanged: scaleTimer.restart()
+        onZoomLevelChanged: scaleTimer.restart()
+    }
+
+    Timer {
+        id:         scaleTimer
+        interval:   100
+        running:    false
+        repeat:     false
+
+        onTriggered: calculateScale()
+    }
+
+    QGCLabel {
+        id:                     scaleText
+        color:                  _color
+        font.family:            ScreenTools.demiboldFontFamily
+        anchors.left:           parent.left
+        anchors.right:          parent.right
+        horizontalAlignment:    Text.AlignRight
+        text:                   "0 m"
+    }
+
+    Rectangle {
+        id:             leftEnd
+        anchors.top:    scaleText.bottom
+        anchors.left:   parent.left
+        width:          2
+        height:         ScreenTools.defaultFontPixelHeight
+        color:          _color
+    }
+
+    Rectangle {
+        id:                     centerLine
+        anchors.bottomMargin:   2
+        anchors.bottom:         leftEnd.bottom
+        anchors.left:           leftEnd.right
+        height:                 2
+        color:                  _color
+    }
+
+    Rectangle {
+        id:             rightEnd
+        anchors.top:    leftEnd.top
+        anchors.left:   centerLine.right
+        width:          2
+        height:         ScreenTools.defaultFontPixelHeight
+        color:          _color
+    }
+
+    Component.onCompleted: {
+        if (scale.visible) {
+            calculateScale();
+        }
+    }
+}

src/FlightMap/qmldir

@@ -6,6 +6,7 @@ QGCVideoBackground      1.0 QGCVideoBackground.qml
 
 # Widgets
 InstrumentSwipeView             1.0 InstrumentSwipeView.qml
+MapScale                        1.0 MapScale.qml
 QGCArtificialHorizon            1.0 QGCArtificialHorizon.qml
 QGCAttitudeHUD                  1.0 QGCAttitudeHUD.qml
 QGCAttitudeWidget               1.0 QGCAttitudeWidget.qml