Feature added: Automatic transparency in click-through mode.

Some minor clean up.

OnTopReplica/MainForm.cs

@@ -188,8 +188,10 @@ namespace OnTopReplica {
 
                 case WM.NCHITTEST:
                     //Make transparent to hit-testing if in click through mode
-                    if (ClickThroughEnabled && (ModifierKeys & Keys.Alt) != Keys.Alt) {
+                    if (ClickThroughEnabled) {
                         m.Result = (IntPtr)HT.TRANSPARENT;
+
+                        RefreshClickThroughComeBack();
                         return;
                     }
                     break;

OnTopReplica/MainForm_Features.cs

@@ -1,10 +1,9 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
+using OnTopReplica.Native;
 using OnTopReplica.Properties;
-using WindowsFormsAero.TaskDialog;
+using System;
 using System.Drawing;
 using System.Windows.Forms;
+using WindowsFormsAero.TaskDialog;
 
 namespace OnTopReplica {
     //Contains some feature implementations of MainForm
@@ -36,6 +35,7 @@ namespace OnTopReplica {
         #region Click-through
 
         bool _clickThrough = false;
+
         readonly Color DefaultNonClickTransparencyKey;
 
         public bool ClickThroughEnabled {
@@ -43,21 +43,56 @@ namespace OnTopReplica {
                 return _clickThrough;
             }
             set {
-                //Adjust opacity if fully opaque
-                /*if (value && Opacity == 1.0)
-                    Opacity = 0.75;
-                if (!value)
-                    Opacity = 1.0;*/
-
-                //Enable transparency and force as top-most
                 TransparencyKey = (value) ? Color.Black : DefaultNonClickTransparencyKey;
-                if (value)
+                if (value) {
+                    //Re-force as top most (always helps in some cases)
                     TopMost = true;
+                }
 
                 _clickThrough = value;
             }
         }
 
+        //Must NOT be equal to any other valid opacity value
+        const double ClickThroughHoverOpacity = 0.6;
+
+        Timer _clickThroughComeBackTimer = null;
+        long _clickThroughComeBackTicks;
+        const int ClickThroughComeBackTimerInterval = 1000;
+
+        /// <summary>
+        /// When the mouse hovers over a fully opaque click-through form,
+        /// this fades the form to semi-transparency
+        /// and starts a timeout to get back to full opacity.
+        /// </summary>
+        private void RefreshClickThroughComeBack() {
+            if (this.Opacity == 1.0) {
+                this.Opacity = ClickThroughHoverOpacity;
+            }
+
+            if (_clickThroughComeBackTimer == null) {
+                _clickThroughComeBackTimer = new Timer();
+                _clickThroughComeBackTimer.Tick += _clickThroughComeBackTimer_Tick;
+                _clickThroughComeBackTimer.Interval = ClickThroughComeBackTimerInterval;
+            }
+            _clickThroughComeBackTicks = DateTime.UtcNow.Ticks;
+            _clickThroughComeBackTimer.Start();
+        }
+
+        void _clickThroughComeBackTimer_Tick(object sender, EventArgs e) {
+            var diff = DateTime.UtcNow.Subtract(new DateTime(_clickThroughComeBackTicks));
+            if (diff.TotalSeconds > 2) {
+                var mousePointer = WindowMethods.GetCursorPos();
+
+                if (!this.ContainsMousePointer(mousePointer)) {
+                    if (this.Opacity == ClickThroughHoverOpacity) {
+                        this.Opacity = 1.0;
+                    }
+                    _clickThroughComeBackTimer.Stop();
+                }
+            }
+        }
+
         #endregion
 
         #region Chrome

OnTopReplica/MainForm_MenuEvents.cs

@@ -73,11 +73,10 @@ namespace OnTopReplica {
         }
 
         private void Menu_Opacity_click(object sender, EventArgs e) {
-            //Get clicked menu item
-            ToolStripMenuItem tsi = sender as ToolStripMenuItem;
+            ToolStripMenuItem tsi = (ToolStripMenuItem)sender;
 
-            if (tsi != null && this.Visible) {
-                //Get opacity from the tag
+            if (this.Visible) {
+                //Target opacity is stored in the item's tag
                 this.Opacity = (double)tsi.Tag;
                 Program.Platform.OnFormStateChange(this);
             }

OnTopReplica/Native/WM.cs

@@ -21,6 +21,7 @@ namespace OnTopReplica.Native {
         public const int NCLBUTTONDOWN = 0x00A1;
         public const int NCLBUTTONDBLCLK = 0x00A3;
         public const int NCRBUTTONUP = 0x00A5;
+        public const int NCMOUSELEAVE = 0x02A2;
         public const int SYSCOMMAND = 0x0112;
         public const int GETTEXT = 0x000D;
         public const int GETTEXTLENGTH = 0x000E;

OnTopReplica/Native/WindowMethods.cs

@@ -9,6 +9,22 @@ namespace OnTopReplica.Native {
     /// </summary>
     static class WindowMethods {
 
+        public static System.Drawing.Point GetCursorPos() {
+            NPoint ret;
+            if (GetCursorPosInternal(out ret))
+                return ret.ToPoint();
+            else {
+#if DEBUG
+                throw new InvalidOperationException("Unable to GetCursorPos");
+#else
+                return default(System.Drawing.Point);
+#endif
+            }
+        }
+
+        [DllImport("user32.dll", EntryPoint="GetCursorPos")]
+        private static extern bool GetCursorPosInternal(out NPoint point);
+
         [DllImport("user32.dll", SetLastError = true)]
         public static extern bool GetClientRect(IntPtr handle, out NRectangle rect);
 

OnTopReplica/WindowsFormsExtensions.cs

@@ -46,5 +46,17 @@ namespace OnTopReplica {
             }
         }
 
+        /// <summary>
+        /// Checks whether a control contains a mouse pointer position in screen coordinates.
+        /// </summary>
+        /// <param name="screenCoordinates">Mouse pointer position in screen coordinates.</param>
+        public static bool ContainsMousePointer(this Control ctrl, System.Drawing.Point screenCoordinates) {
+            var bb = new System.Drawing.Rectangle(ctrl.Location, ctrl.Size);
+
+            //Console.Out.WriteLine("<{0},{1}> in {2}? {3}", screenCoordinates.X, screenCoordinates.Y, bb, bb.Contains(screenCoordinates));
+
+            return bb.Contains(screenCoordinates);
+        }
+
     }
 }