Add grid lines to video view

src/FlightDisplay/FlightDisplayViewVideo.qml

@@ -23,7 +23,9 @@ import QGroundControl.Controllers   1.0
 
 Item {
     id: root
-    property double _ar: QGroundControl.settingsManager.videoSettings.aspectRatio.rawValue
+    property double _ar:        QGroundControl.settingsManager.videoSettings.aspectRatio.rawValue
+    property bool _showGrid:    QGroundControl.settingsManager.videoSettings.gridLines.rawValue > 0
+
     Rectangle {
         id:             noVideo
         anchors.fill:   parent
@@ -50,4 +52,32 @@ Item {
             visible:        QGroundControl.videoManager.videoRunning
         }
     }
+    Rectangle {
+        color:  Qt.rgba(1,1,1,0.5)
+        height: parent.height
+        width:  1
+        x:      parent.width * 0.33
+        visible: _showGrid
+    }
+    Rectangle {
+        color:  Qt.rgba(1,1,1,0.5)
+        height: parent.height
+        width:  1
+        x:      parent.width * 0.66
+        visible: _showGrid
+    }
+    Rectangle {
+        color:  Qt.rgba(1,1,1,0.5)
+        width:  parent.width
+        height: 1
+        y:      parent.height * 0.33
+        visible: _showGrid
+    }
+    Rectangle {
+        color:  Qt.rgba(1,1,1,0.5)
+        width:  parent.width
+        height: 1
+        y:      parent.height * 0.66
+        visible: _showGrid
+    }
 }

src/Settings/Video.SettingsGroup.json

@@ -35,5 +35,14 @@
     "type":             "float",
     "decimalPlaces":    6,
     "defaultValue":     1.777777
+},
+{
+    "name":             "VideoGridLines",
+    "shortDescription": "Video Grid Lines",
+    "longDescription":  "Displays a grid overlayed over the video view.",
+    "type":             "uint32",
+    "enumStrings":      "Hide,Show",
+    "enumValues":       "1,0",
+    "defaultValue":     0
 }
 ]

src/Settings/VideoSettings.cc

@@ -24,6 +24,7 @@ const char* VideoSettings::udpPortName =            "VideoUDPPort";
 const char* VideoSettings::rtspUrlName =            "VideoRTSPUrl";
 const char* VideoSettings::videoSavePathName =      "VideoSavePath";
 const char* VideoSettings::videoAspectRatioName =   "VideoAspectRatio";
+const char* VideoSettings::videoGridLinesName =     "VideoGridLines";
 
 const char* VideoSettings::videoSourceNoVideo = "No Video Available";
 const char* VideoSettings::videoSourceUDP =     "UDP Video Stream";
@@ -36,6 +37,7 @@ VideoSettings::VideoSettings(QObject* parent)
     , _rtspUrlFact(NULL)
     , _videoSavePathFact(NULL)
     , _videoAspectRatioFact(NULL)
+    , _gridLinesFact(NULL)
 {
     QQmlEngine::setObjectOwnership(this, QQmlEngine::CppOwnership);
     qmlRegisterUncreatableType<VideoSettings>("QGroundControl.SettingsManager", 1, 0, "VideoSettings", "Reference only");
@@ -115,3 +117,12 @@ Fact* VideoSettings::aspectRatio(void)
 
     return _videoAspectRatioFact;
 }
+
+Fact* VideoSettings::gridLines(void)
+{
+    if (!_gridLinesFact) {
+        _gridLinesFact = _createSettingsFact(videoGridLinesName);
+    }
+
+    return _gridLinesFact;
+}

src/Settings/VideoSettings.h

@@ -24,12 +24,14 @@ public:
     Q_PROPERTY(Fact* rtspUrl        READ rtspUrl        CONSTANT)
     Q_PROPERTY(Fact* videoSavePath  READ videoSavePath  CONSTANT)
     Q_PROPERTY(Fact* aspectRatio    READ aspectRatio    CONSTANT)
+    Q_PROPERTY(Fact* gridLines      READ gridLines      CONSTANT)
 
     Fact* videoSource   (void);
     Fact* udpPort       (void);
     Fact* rtspUrl       (void);
     Fact* videoSavePath (void);
     Fact* aspectRatio   (void);
+    Fact* gridLines     (void);
 
     static const char* videoSettingsGroupName;
 
@@ -38,6 +40,7 @@ public:
     static const char* rtspUrlName;
     static const char* videoSavePathName;
     static const char* videoAspectRatioName;
+    static const char* videoGridLinesName;
 
     static const char* videoSourceNoVideo;
     static const char* videoSourceUDP;
@@ -49,6 +52,7 @@ private:
     SettingsFact* _rtspUrlFact;
     SettingsFact* _videoSavePathFact;
     SettingsFact* _videoAspectRatioFact;
+    SettingsFact* _gridLinesFact;
 };
 
 #endif

src/ui/preferences/GeneralSettings.qml

@@ -512,6 +512,20 @@ QGCView {
                                 fact:               QGroundControl.settingsManager.videoSettings.aspectRatio
                             }
                         }
+                        Row {
+                            spacing:    ScreenTools.defaultFontPixelWidth
+                            visible:    QGroundControl.videoManager.isGStreamer && videoSource.currentIndex < 2 && QGroundControl.settingsManager.videoSettings.gridLines.visible
+                            QGCLabel {
+                                anchors.baseline:   gridField.baseline
+                                text:               qsTr("Grid Lines:")
+                                width:              _labelWidth
+                            }
+                            FactComboBox {
+                                id:                 gridField
+                                width:              _editFieldWidth
+                                fact:               QGroundControl.settingsManager.videoSettings.gridLines
+                            }
+                        }
                         Row {
                             spacing:    ScreenTools.defaultFontPixelWidth
                             visible:    QGroundControl.settingsManager.videoSettings.videoSavePath.visible && QGroundControl.videoManager.isGStreamer && QGroundControl.videoManager.recordingEnabled