From 83985aa44c3ac2feeadc4159c3d8826341b6cef5 Mon Sep 17 00:00:00 2001
From: Boris Makogonyuk <madrivus@gmail.com>
Date: Sun, 13 Dec 2015 04:22:01 +0100
Subject: [PATCH] Added Pixel to Device Independent Pixel transformation to
 WindowIntelopHelper MainWindow GetWindowsTop and GetWindowsLeft will use DIP
 when searching for the center of the screen

---
 Wox/Helper/WindowIntelopHelper.cs | 28 ++++++++++++++++++++++++++++
 Wox/MainWindow.xaml.cs            | 31 ++++++++++---------------------
 2 files changed, 38 insertions(+), 21 deletions(-)

diff --git a/Wox/Helper/WindowIntelopHelper.cs b/Wox/Helper/WindowIntelopHelper.cs
index 4a0223a19e..a61665b54d 100644
--- a/Wox/Helper/WindowIntelopHelper.cs
+++ b/Wox/Helper/WindowIntelopHelper.cs
@@ -4,6 +4,8 @@ using System.Runtime.InteropServices;
 using System.Windows;
 using System.Windows.Forms;
 using System.Windows.Interop;
+using System.Windows.Media;
+using Point = System.Windows.Point;
 
 namespace Wox.Helper
 {
@@ -80,6 +82,32 @@ namespace Wox.Helper
             SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_SYSMENU);
         }
 
+        /// <summary>
+        /// Transforms pixels to Device Independent Pixels used by WPF
+        /// </summary>
+        /// <param name="visual">current window, required to get presentation source</param>
+        /// <param name="unitX">horizontal position in pixels</param>
+        /// <param name="unitY">vertical position in pixels</param>
+        /// <returns>point containing device independent pixels</returns>
+        public static Point TransformPixelsToDIP(Visual visual, double unitX, double unitY)
+        {
+            Matrix matrix;
+            var source = PresentationSource.FromVisual(visual);
+            if (source != null)
+            {
+                matrix = source.CompositionTarget.TransformFromDevice;
+            }
+            else
+            {
+                using (var src = new HwndSource(new HwndSourceParameters()))
+                {
+                    matrix = src.CompositionTarget.TransformFromDevice;
+                }
+            }
+            return new Point((int) (matrix.M11*unitX), (int) (matrix.M22*unitY));
+        }
+
+
         [StructLayout(LayoutKind.Sequential)]
         public struct RECT
         {
diff --git a/Wox/MainWindow.xaml.cs b/Wox/MainWindow.xaml.cs
index aef06b9eb5..dde25ebdba 100644
--- a/Wox/MainWindow.xaml.cs
+++ b/Wox/MainWindow.xaml.cs
@@ -260,34 +260,21 @@ namespace Wox
 
         private double GetWindowsLeft()
         {
-            var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
-            if (UserSettingStorage.Instance.RememberLastLaunchLocation)
-            {
-                var origScreen = Screen.FromRectangle(new Rectangle((int)Left, (int)Top, (int)ActualWidth, (int)ActualHeight));
-                var coordX = (Left - origScreen.WorkingArea.Left) / (origScreen.WorkingArea.Width - ActualWidth);
-                UserSettingStorage.Instance.WindowLeft = (screen.WorkingArea.Width - ActualWidth) * coordX + screen.WorkingArea.Left;
-            }
-            else
-            {
-                UserSettingStorage.Instance.WindowLeft = (screen.WorkingArea.Width - ActualWidth) / 2 + screen.WorkingArea.Left;
-            }
+            if (UserSettingStorage.Instance.RememberLastLaunchLocation) return UserSettingStorage.Instance.WindowLeft;
 
+            var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
+            var dipPoint = WindowIntelopHelper.TransformPixelsToDIP(this, screen.WorkingArea.Width, 0);
+            UserSettingStorage.Instance.WindowLeft = (dipPoint.X - ActualWidth)/2;
             return UserSettingStorage.Instance.WindowLeft;
         }
 
         private double GetWindowsTop()
         {
+            if (UserSettingStorage.Instance.RememberLastLaunchLocation) return UserSettingStorage.Instance.WindowTop;
+
             var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
-            if (UserSettingStorage.Instance.RememberLastLaunchLocation)
-            {
-                var origScreen = Screen.FromRectangle(new Rectangle((int)Left, (int)Top, (int)ActualWidth, (int)ActualHeight));
-                var coordY = (Top - origScreen.WorkingArea.Top) / (origScreen.WorkingArea.Height - ActualHeight);
-                UserSettingStorage.Instance.WindowTop = (screen.WorkingArea.Height - ActualHeight) * coordY + screen.WorkingArea.Top;
-            }
-            else
-            {
-                UserSettingStorage.Instance.WindowTop = (screen.WorkingArea.Height - tbQuery.ActualHeight) / 4 + screen.WorkingArea.Top;
-            }
+            var dipPoint = WindowIntelopHelper.TransformPixelsToDIP(this, 0, screen.WorkingArea.Height);
+            UserSettingStorage.Instance.WindowTop = (dipPoint.Y - tbQuery.ActualHeight)/4;
             return UserSettingStorage.Instance.WindowTop;
         }
 
@@ -534,6 +521,8 @@ namespace Wox
 
         private void HideWox()
         {
+            UserSettingStorage.Instance.WindowLeft = Left;
+            UserSettingStorage.Instance.WindowTop = Top;
             if (IsInContextMenuMode)
             {
                 BackToResultMode();