[launcher] Location and multi monitor support (#2446)

* Fixed left and top window

* Added dpi Aware launcher positioning code

* Code cleanup

* Added support to drag window

* Multi monitor support added

Remaining fix : Launcher doesn't open first time on changing monitor

* removed code handling change in DPI manually

* Code cleanup

* Fix to support multimonitor display

* Code cleanup

* Revert "Code cleanup"

This reverts commit 38f39924f0.

* Revert back to WOX helper for calculating normalized DPI

src/modules/launcher/PowerLauncher/MainWindow.xaml

@@ -23,9 +23,11 @@
         LocationChanged="OnLocationChanged"
         Deactivated="OnDeactivated"
         Background="Transparent"
+        Width="720"
         Visibility="{Binding MainWindowVisibility, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
         d:DataContext="{d:DesignInstance vm:MainViewModel}">
-    <Grid Width="720">
+    <Grid Width="720" 
+          MouseDown="OnMouseDown">
         <Grid.RowDefinitions>
             <RowDefinition Height="Auto"/>
             <RowDefinition Height="Auto"/>
@@ -39,7 +41,9 @@
             <Border.Effect>
                 <DropShadowEffect BlurRadius="16" Opacity="0.8" ShadowDepth="0" />
             </Border.Effect>
-            <xaml:WindowsXamlHost 
+            <xaml:WindowsXamlHost
+                Height="60"
+                x:Name="SearchBox" 
                 InitialTypeName="PowerLauncher.UI.LauncherControl" 
                 ChildChanged="WindowsXamlHostTextBox_ChildChanged" />
         </Border>
@@ -53,7 +57,8 @@
             <Border.Effect>
                 <DropShadowEffect BlurRadius="16" Opacity="0.8" ShadowDepth="0" />
             </Border.Effect>
-            <xaml:WindowsXamlHost 
+            <xaml:WindowsXamlHost
+                x:Name="ListBox"
                 InitialTypeName="PowerLauncher.UI.ResultList" 
                 ChildChanged="WindowsXamlHostListView_ChildChanged" 
                 PreviewMouseDown="WindowsXamlHost_PreviewMouseDown" />

src/modules/launcher/PowerLauncher/MainWindow.xaml.cs

@@ -23,6 +23,9 @@ using Windows.UI.Xaml;
 using Windows.UI.Core;
 using System.Windows.Media;
 using Windows.UI.Xaml.Data;
+using System.Diagnostics;
+using Mages.Core.Runtime.Converters;
+using System.Runtime.InteropServices;
 
 namespace PowerLauncher
 {
@@ -36,6 +39,9 @@ namespace PowerLauncher
         private MainViewModel _viewModel;
         private bool _isTextSetProgramatically;
         const int ROW_HEIGHT = 75;
+        const int MAX_LIST_HEIGHT = 300;
+        bool isDPIChanged = false;
+
         #endregion
 
         public MainWindow(Settings settings, MainViewModel mainVM)
@@ -68,9 +74,9 @@ namespace PowerLauncher
 
         private void InitializePosition()
         {
-            //Top = WindowTop();
+            Top = WindowTop();
             Left = WindowLeft();
-            //_settings.WindowTop = Top;
+            _settings.WindowTop = Top;
             _settings.WindowLeft = Left;
         }
 
@@ -106,8 +112,16 @@ namespace PowerLauncher
         {
             if (_settings.HideWhenDeactive)
             {
-                Hide();
+                if (isDPIChanged)
-            }
+                {
+                    isDPIChanged = false;
+                    InitializePosition();
+                }
+                else
+                {
+                    Hide();
+                }
+            }              
         }
 
         private void UpdatePosition()
@@ -119,8 +133,18 @@ namespace PowerLauncher
             }
             else
             {
+                double prevTop = Top;
+                double prevLeft = Left;               
+                Top = WindowTop();
                 Left = WindowLeft();
-                //Top = WindowTop();
+                if (prevTop != Top || prevLeft != Left)
+                {
+                    isDPIChanged = true;
+                }
+                else
+                {
+                    isDPIChanged = false;
+                }
             }
         }
 
@@ -133,15 +157,32 @@ namespace PowerLauncher
             }
         }
 
+        /// <summary>
+        /// Calculates X co-ordinate of main window top left corner.
+        /// </summary>
+        /// <returns>X co-ordinate of main window top left corner</returns>
         private double WindowLeft()
         {
             var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
-            var dip1 = WindowsInteropHelper.TransformPixelsToDIP(this, screen.WorkingArea.X, 0);
+            var dpi1 = WindowsInteropHelper.TransformPixelsToDIP(this, screen.WorkingArea.X, 0);
-            var dip2 = WindowsInteropHelper.TransformPixelsToDIP(this, screen.WorkingArea.Width, 0);
+            var dpi2 = WindowsInteropHelper.TransformPixelsToDIP(this, screen.WorkingArea.Width, 0);
-            var left = (dip2.X - ActualWidth) / 2 + dip1.X;
+            var left = (dpi2.X - this.Width) / 2 + dpi1.X;
             return left;
         }
 
+        /// <summary>
+        /// Calculates Y co-ordinate of main window top left corner 
+        /// </summary>
+        /// <returns>Y co-ordinate of main window top left corner</returns>
+        private double WindowTop()
+        {
+            var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
+            var dpi1 = WindowsInteropHelper.TransformPixelsToDIP(this, 0, screen.WorkingArea.Y);
+            var dpi2 = WindowsInteropHelper.TransformPixelsToDIP(this, 0, screen.WorkingArea.Height);
+            var totalHeight = this.SearchBoxBorder.Margin.Top + this.SearchBoxBorder.Margin.Bottom + this.SearchBox.Height + this.ListBoxBorder.Margin.Top + this.ListBoxBorder.Margin.Bottom + MAX_LIST_HEIGHT;
+            var top = (dpi2.Y - totalHeight) / 4 + dpi1.Y;
+            return top;
+        }
 
         private PowerLauncher.UI.LauncherControl _launcher = null;
         private void WindowsXamlHostTextBox_ChildChanged(object sender, EventArgs ev)
@@ -184,8 +225,6 @@ namespace PowerLauncher
             };           
         }
 
-       
-
         private void UserControl_PropertyChanged(object sender, PropertyChangedEventArgs e)
         {
             if (e.PropertyName == "SolidBorderBrush")