Issue #12 Added transparent and opaque items to the Action button

Author: AlexanderPro

WindowTextExtractor/Forms/MainForm.Designer.cs

@@ -638,6 +638,14 @@ private void ActionButtonStripItemClicked(object sender, ToolStripItemClickedEve
                     User32.ShowWindow(windowHandle, ShowWindowCommands.SW_SHOW);
                     break;
 
+                case "miTransparent":
+                    WindowUtils.SetTransparency(windowHandle, 100);
+                    break;
+
+                case "miOpaque":
+                    WindowUtils.SetTransparency(windowHandle, 0);
+                    break;
+
                 case "miMinimize":
                     User32.PostMessage(windowHandle, Constants.WM_SYSCOMMAND, Constants.SC_MINIMIZE, 0);
                     break;

WindowTextExtractor/Forms/MainForm.cs

@@ -29,6 +29,12 @@ static class Constants
         public const int DWL_DLGPROC = 4;
         public const int DWL_USER = 8;
 
+        // LayeredWindowAttributes
+        public const int LWA_ALPHA = 0x00000002;
+
+        // WindowStyle
+        public const long WS_EX_LAYERED = 0x00080000L;
+
         public const int SC_MINIMIZE = 0xF020;
         public const int SC_MAXIMIZE = 0xF030;
         public const int SC_RESTORE = 0xF120;
@@ -40,7 +46,6 @@ static class Constants
         public const int CURSOR_SHOWING = 0x00000001;
 
         public const int DI_COMPAT = 0x0004;
-
         public const int DI_NORMAL = 0x0003;
     }
 }

WindowTextExtractor/Native/Constants.cs

@@ -60,10 +60,10 @@ static class User32
         public static extern IntPtr GetParent(IntPtr hWnd);
 
         [DllImport("user32.dll")]
-        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
+        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, long dwNewLong);
 
         [DllImport("user32.dll")]
-        public static extern int GetWindowLong(IntPtr hWnd, int nIndex);
+        public static extern long GetWindowLong(IntPtr hWnd, int nIndex);
 
         [DllImport("user32.dll")]
         public static extern int GetClassLong(IntPtr hWnd, int nIndex);
@@ -117,5 +117,8 @@ static class User32
 
         [DllImport("user32.dll")]
         public static extern bool RedrawWindow(IntPtr hWnd, IntPtr lprcUpdate, IntPtr hrgnUpdate, RedrawWindowFlags flags);
+
+        [DllImport("user32.dll")]
+        public static extern bool SetLayeredWindowAttributes(IntPtr hwnd, uint crKey, Byte bAlpha, uint dwFlags);
     }
 }

WindowTextExtractor/Native/User32.cs

@@ -310,6 +310,20 @@ public static Bitmap CaptureWindow(IntPtr handle, bool captureCursor = false)
             }
         }
 
+        public static void SetTransparency(IntPtr handle, int percent)
+        {
+            var opacity = (byte)Math.Round(255 * (100 - percent) / 100f, MidpointRounding.AwayFromZero);
+            SetOpacity(handle, opacity);
+        }
+
+
+        public static void SetOpacity(IntPtr handle, byte opacity)
+        {
+            var exStyle = User32.GetWindowLong(handle, Constants.GWL_EXSTYLE);
+            User32.SetWindowLong(handle, Constants.GWL_EXSTYLE, exStyle | Constants.WS_EX_LAYERED);
+            User32.SetLayeredWindowAttributes(handle, 0, opacity, Constants.LWA_ALPHA);
+        }
+
         private static string GetWindowText(IntPtr handle)
         {
             var builder = new StringBuilder(1024);