Added code to handle point size fonts in all QML widgets.

src/AutoPilotPlugins/PX4/FlightModesComponent.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.2
 import QtQuick.Controls 1.2
 import QtQuick.Controls.Styles 1.2
@@ -7,11 +30,13 @@ import QGroundControl.FactControls 1.0
 import QGroundControl.Palette 1.0
 import QGroundControl.Controls 1.0
 import QGroundControl.Controllers 1.0
+import QGroundControl.ScreenTools 1.0
 
 Item {
     Loader {
         property FlightModesComponentController controller: FlightModesComponentController { }
         property QGCPalette qgcPal: QGCPalette { colorGroupEnabled: true }
+        property ScreenTools screenTools: ScreenTools { }
         property bool loading: true
 
         anchors.fill: parent
@@ -357,7 +382,7 @@ Item {
 
                 QGCLabel {
                     text: "FLIGHT MODES CONFIG"
-                    font.pointSize: 20
+                    font.pointSize: 20 * screenTools.dpiFactor;
                 }
 
                 Item { height: 20; width: 10 } // spacer
@@ -848,7 +873,7 @@ Item {
 
                 QGCLabel {
                     text: "FLIGHT MODES CONFIG"
-                    font.pointSize: 20
+                    font.pointSize: 20 * screenTools.dpiFactor;
                 }
 
                 QGCLabel {

src/AutoPilotPlugins/PX4/SafetyComponent.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.2
 import QtQuick.Controls 1.2
 import QtQuick.Controls.Styles 1.2
@@ -6,6 +29,7 @@ import QGroundControl.FactSystem 1.0
 import QGroundControl.FactControls 1.0
 import QGroundControl.Palette 1.0
 import QGroundControl.Controls 1.0
+import QGroundControl.ScreenTools 1.0
 
 Rectangle {
     QGCPalette { id: palette; colorGroupEnabled: true }
@@ -14,6 +38,7 @@ Rectangle {
     height: 600
     color: palette.window
 
+    property ScreenTools screenTools: ScreenTools { }
     property int flightLineWidth: 2             // width of lines for flight graphic
     property int loiterAltitudeColumnWidth: 180 // width of loiter altitude column
     property int shadedMargin: 20               // margin inset for shaded areas
@@ -29,7 +54,7 @@ Rectangle {
 
         QGCLabel {
             text: "SAFETY CONFIG"
-            font.pointSize: 20
+            font.pointSize: 20 * screenTools.dpiFactor;
         }
 
         Item { height: 20; width: 10 } // spacer
@@ -37,7 +62,7 @@ Rectangle {
         //-----------------------------------------------------------------
         //-- Return Home Triggers
 
-        QGCLabel { text: "Triggers For Return Home"; color: palette.text; font.pointSize: 20 }
+        QGCLabel { text: "Triggers For Return Home"; color: palette.text; font.pointSize: 20 * screenTools.dpiFactor; }
 
         Item { height: 10; width: 10 } // spacer
 
@@ -96,7 +121,7 @@ Rectangle {
         //-----------------------------------------------------------------
         //-- Return Home Settings
 
-        QGCLabel { text: "Return Home Settings"; font.pointSize: 20 }
+        QGCLabel { text: "Return Home Settings"; font.pointSize: 20 * screenTools.dpiFactor; }
 
         Item { height: 10; width: 10 } // spacer
 
@@ -266,7 +291,7 @@ Rectangle {
         QGCLabel {
             property Fact fact: Fact { name: "NAV_RCL_OBC" }
             width: parent.width
-            font.pointSize: 14
+            font.pointSize: 14 * screenTools.dpiFactor;
             text: "Warning: You have an advanced safety configuration set using the NAV_RCL_OBC parameter. The above settings may not apply.";
             visible: fact.value != 0
             wrapMode: Text.Wrap
@@ -274,7 +299,7 @@ Rectangle {
         QGCLabel {
             property Fact fact: Fact { name: "NAV_DLL_OBC" }
             width: parent.width
-            font.pointSize: 14
+            font.pointSize: 14 * screenTools.dpiFactor;
             text: "Warning: You have an advanced safety configuration set using the NAV_DLL_OBC parameter. The above settings may not apply.";
             visible: fact.value != 0
             wrapMode: Text.Wrap

src/AutoPilotPlugins/PX4/SensorsComponent.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.2
 import QtQuick.Controls 1.2
 import QtQuick.Controls.Styles 1.2
@@ -6,9 +29,11 @@ import QGroundControl.FactSystem 1.0
 import QGroundControl.FactControls 1.0
 import QGroundControl.Palette 1.0
 import QGroundControl.Controls 1.0
+import QGroundControl.ScreenTools 1.0
 
 Rectangle {
     property QGCPalette qgcPal: QGCPalette { colorGroupEnabled: true }
+    property ScreenTools screenTools: ScreenTools { }
 
     readonly property int rotationColumnWidth: 200
     readonly property var rotations: [
@@ -62,7 +87,7 @@ Rectangle {
 
         QGCLabel {
             text: "SENSORS CONFIG"
-            font.pointSize: 20
+            font.pointSize: 20 * screenTools.dpiFactor;
         }
 
         Item { height: 20; width: 10 } // spacer

src/FactSystem/FactSystemTest.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.2
 import QtQuick.Controls 1.2
 import QGroundControl.FactSystem 1.0
+import QGroundControl.ScreenTools 1.0
 
 Item {
+    property ScreenTools screenTools: ScreenTools { }
     TextInput {
         objectName: "testControl"
         Fact { id: fact; name: "RC_MAP_THROTTLE" }
         text: fact.value
         font.family: "Helvetica"
-        font.pointSize: 24
+        font.pointSize: 24 * screenTools.dpiFactor;
         color: "red"
         focus: true
         onAccepted: { fact.value = text; }
     }
-}
+}
\ No newline at end of file

src/QmlControls/ScreenTools.cc

@@ -32,7 +32,7 @@ ScreenTools::ScreenTools()
     , _dpiFactor( 72.0 / 96.0)
 {
     // Get screen DPI to manage font sizes on different platforms
-    QScreen *srn = QGuiApplication::screens().at(0); // TODO: Find current monitor as opposed to picking first one
+    QScreen *srn = QGuiApplication::primaryScreen();
     if(srn && srn->logicalDotsPerInch() > 50.0) {
         _dotsPerInch = (double)srn->logicalDotsPerInch(); // Font point sizes are based on Mac 72dpi
         _dpiFactor = 72.0 / _dotsPerInch;

src/QmlControls/ScreenTools.h

@@ -30,6 +30,19 @@
 #include <QObject>
 #include <QCursor>
 
+/*!
+    @brief Screen helper tools for QML widgets
+    To use its functions, you need to import the module with the following line:
+    @code
+    import QGroundControl.ScreenTools 1.0
+    @endcode
+    @remark As for the screen density functions, QtQuick provides the \c Screen type (defined in QtQuick.Window)
+    but as of Qt 5.4 (QtQuick.Window 2.2), this only works if the main window is QtQuick. As QGC is primarily
+    a Qt application and only some of its UI elements are QLM widgets, this does not work. Hence, these function
+    defined here.
+    @sa <a href="http://doc.qt.io/qt-5/qml-qtquick-window-screen.html">Screen QML Type</a>
+*/
+
 /// This Qml control is used to return screen parameters
 class ScreenTools : public QObject
 {
@@ -37,10 +50,64 @@ class ScreenTools : public QObject
 public:
     ScreenTools();
 
+    //! Returns the screen density in Dots Per Inch
     Q_PROPERTY(double   screenDPI           READ screenDPI CONSTANT)
+    //! Returns a factor used to calculate the font point size to use
+    /*!
+      When defining fonts in point size, as in:
+      @code
+      Text {
+        text: "Foo Bar"
+        font.pointSize: 14
+      }
+      @endcode
+      The size is device dependent. If you define this based on a screen set to 72dpi (Mac OS), once
+      this is displayed on a different screen with a different pixel density, such as 96dpi (Windows),
+      the text will be displayed in the wrong size.
+      Use \c dpiFactor to accomodate for these differences. All font point sizes are given in 72dpi
+      and \c dpiFactor returns a factor to use for adjusting it to the current target screen.
+      @code
+      import QGroundControl.ScreenTools 1.0
+      property ScreenTools screenTools: ScreenTools { }
+      Text {
+        text: "Foo Bar"
+        font.pointSize: 14 * screenTools.dpiFactor
+      }
+      @endcode
+     */
     Q_PROPERTY(double   dpiFactor           READ dpiFactor CONSTANT)
+    //! Returns the global mouse X position
     Q_PROPERTY(int      mouseX              READ mouseX)
+    //! Returns the global mouse Y position
     Q_PROPERTY(int      mouseY              READ mouseY)
+    //! Used to trigger a \c Canvas element repaint.
+    /*!
+      There is a bug as of Qt 5.4 where a Canvas element defined within a QQuickWidget does not receive
+      repaint events. QGC's main window will emit these signals when a \c Canvas element needs to be
+      repainted.
+      If you use a \c Canvas element inside some QML widget, you can use this cod to handle repaint:
+      @code
+      import QGroundControl.ScreenTools 1.0
+      ...
+      property ScreenTools screenTools: ScreenTools { }
+      ...
+        Canvas {
+            id: myCanvas
+            height: 40
+            width:  40
+            Connections {
+                target: screenTools
+                onRepaintRequestedChanged: {
+                    myCanvas.requestPaint();
+                }
+            }
+            onPaint: {
+                var context = getContext("2d");
+                ...
+            }
+        }
+      @endcode
+     */
     Q_PROPERTY(bool     repaintRequested    READ repaintRequested   NOTIFY repaintRequestedChanged)
 
     double  screenDPI           () { return _dotsPerInch; }

src/QmlControls/VehicleRotationCal.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.2
 import QtQuick.Controls 1.2
 import QtQuick.Controls.Styles 1.2
 
 import QGroundControl.Palette 1.0
+import QGroundControl.ScreenTools 1.0
 
 Rectangle {
     property var __qgcPal: QGCPalette { colorGroupEnabled: enabled }
+    property ScreenTools screenTools: ScreenTools { }
 
     // Indicates whether calibration is valid for this control
     property bool calValid: false
@@ -43,7 +68,7 @@ Rectangle {
             height:                 parent.height
             horizontalAlignment:    Text.AlignHCenter
             verticalAlignment:      Text.AlignBottom
-            font.pointSize:         25
+            font.pointSize:         25 * screenTools.dpiFactor;
             font.bold:              true
             color:                  "black"
 
@@ -54,7 +79,7 @@ Rectangle {
             height:                 parent.height
             horizontalAlignment:    Text.AlignHCenter
             verticalAlignment:      Text.AlignBottom
-            font.pointSize:         25
+            font.pointSize:         25 * screenTools.dpiFactor;
             color:                  calInProgress ? "yellow" : "white"
 
             text: parent.calText

src/VehicleSetup/FirmwareUpgrade.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.3
 import QtQuick.Controls 1.2
 import QtQuick.Controls.Styles 1.2
@@ -6,12 +29,14 @@ import QGroundControl.Controls 1.0
 import QGroundControl.FactControls 1.0
 import QGroundControl.Palette 1.0
 import QGroundControl.FirmwareUpgradeController 1.0
+import QGroundControl.ScreenTools 1.0
 
 Rectangle {
     width: 600
     height: 600
 
     property var qgcPal: QGCPalette { colorGroupEnabled: true }
+    property ScreenTools screenTools: ScreenTools { }
     property FirmwareUpgradeController controller: FirmwareUpgradeController {
         upgradeButton: upgradeButton
         progressBar: progressBar
@@ -26,7 +51,7 @@ Rectangle {
 
         QGCLabel {
             text: "FIRMWARE UPDATE"
-            font.pointSize: 20
+            font.pointSize: 20 * screenTools.dpiFactor;
         }
 
         Item {

src/VehicleSetup/VehicleSummary.qml

+/*=====================================================================
+
+ QGroundControl Open Source Ground Control Station
+
+ (c) 2009 - 2015 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+
+ This file is part of the QGROUNDCONTROL project
+
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+
+ ======================================================================*/
+
 import QtQuick 2.2
 import QtQuick.Controls 1.2
 import QtQuick.Controls.Styles 1.2
@@ -5,12 +28,14 @@ import QtQuick.Controls.Styles 1.2
 import QGroundControl.FactSystem 1.0
 import QGroundControl.Palette 1.0
 import QGroundControl.Controls 1.0
+import QGroundControl.ScreenTools 1.0
 
 Rectangle {
     width: 600
     height: 400
 
     property var qgcPal: QGCPalette { id: palette; colorGroupEnabled: true }
+    property ScreenTools screenTools: ScreenTools { }
 
     id: topLevel
     objectName: "topLevel"
@@ -22,7 +47,7 @@ Rectangle {
 
         QGCLabel {
             text: "VEHICLE SUMMARY"
-            font.pointSize: 20
+            font.pointSize: 20 * screenTools.dpiFactor;
         }
 
         Item {