Color Dropper

now we can select color from everywhere

src/Shared/HandyControl_Shared/Controls/Other/ColorPicker.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
@@ -337,6 +338,7 @@ namespace HandyControl.Controls
             CommandBindings.Add(new CommandBinding(ControlCommands.Confirm, ButtonConfirm_OnClick));
             CommandBindings.Add(new CommandBinding(ControlCommands.Switch, ButtonSwitch_OnClick));
             CommandBindings.Add(new CommandBinding(ControlCommands.Cancel, ButtonCancel_OnClick));
+            CommandBindings.Add(new CommandBinding(ControlCommands.Dropper, ButtonDropper_OnClick));
 
             Loaded += (s, e) =>
             {
@@ -678,5 +680,38 @@ namespace HandyControl.Controls
         public void Dispose() => System.Windows.Window.GetWindow(this)?.Close();
 
         public bool CanDispose { get; } = true;
+
+        private void ButtonDropper_OnClick(object sender, RoutedEventArgs e)
+        {
+            MouseHook.Start();
+            MouseHook.MouseAction += MouseHook_MouseAction;
+        }
+
+        private void MouseHook_MouseAction(object sender, MouseHook.RawMouseEventArgs e)
+        {
+            SelectedBrush = new SolidColorBrush(GetColorAt(e.Point.x, e.Point.y));
+            if (e.Message == MouseHook.MouseMessages.WM_LBUTTONDOWN)
+            {
+                MouseHook.Stop();
+                MouseHook.MouseAction -= MouseHook_MouseAction;
+            }
+        }
+        [DllImport("user32.dll", SetLastError = true)]
+        public static extern IntPtr GetDesktopWindow();
+        [DllImport("user32.dll", SetLastError = true)]
+        public static extern IntPtr GetWindowDC(IntPtr window);
+        [DllImport("gdi32.dll", SetLastError = true)]
+        public static extern uint GetPixel(IntPtr dc, int x, int y);
+        [DllImport("user32.dll", SetLastError = true)]
+        public static extern int ReleaseDC(IntPtr window, IntPtr dc);
+
+        public static Color GetColorAt(int x, int y)
+        {
+            IntPtr desk = GetDesktopWindow();
+            IntPtr dc = GetWindowDC(desk);
+            int a = (int)GetPixel(dc, x, y);
+            ReleaseDC(desk, dc);
+            return Color.FromArgb(255, (byte)((a >> 0) & 0xff), (byte)((a >> 8) & 0xff), (byte)((a >> 16) & 0xff));
+        }
     }
 }

src/Shared/HandyControl_Shared/Controls/Other/MouseHook.cs

@@ -0,0 +1,102 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace HandyControl
+{
+    public static class MouseHook
+    {
+        //public static event EventHandler MouseAction = delegate { };
+        public static event EventHandler<RawMouseEventArgs> MouseAction = delegate { };
+        public class RawMouseEventArgs : EventArgs
+        {
+            internal MouseMessages Message { get; set; }
+            internal POINT Point { get; set; }
+        }
+
+        public static void Start()
+        {
+            _hookID = SetHook(_proc);
+        }
+        public static void Stop()
+        {
+            UnhookWindowsHookEx(_hookID);
+        }
+
+        private static LowLevelMouseProc _proc = HookCallback;
+        private static IntPtr _hookID = IntPtr.Zero;
+
+        private static IntPtr SetHook(LowLevelMouseProc proc)
+        {
+            using (Process curProcess = Process.GetCurrentProcess())
+            using (ProcessModule curModule = curProcess.MainModule)
+            {
+                return SetWindowsHookEx(WH_MOUSE_LL, proc,
+                  GetModuleHandle(curModule.ModuleName), 0);
+            }
+        }
+
+        private delegate IntPtr LowLevelMouseProc(int nCode, IntPtr wParam, IntPtr lParam);
+
+        private static IntPtr HookCallback(
+          int nCode, IntPtr wParam, IntPtr lParam)
+        {
+            if (nCode < 0) return CallNextHookEx(_hookID, nCode, wParam, lParam);
+            MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
+            MouseAction(null, new RawMouseEventArgs() { Message = (MouseMessages)wParam, Point = hookStruct.pt });
+            
+            return CallNextHookEx(_hookID, nCode, wParam, lParam);
+        }
+
+        private const int WH_MOUSE_LL = 14;
+
+        public enum MouseMessages
+        {
+            WM_LBUTTONDOWN = 0x0201,
+            WM_LBUTTONUP = 0x0202,
+            WM_MOUSEMOVE = 0x0200,
+            WM_MOUSEWHEEL = 0x020A,
+            WM_RBUTTONDOWN = 0x0204,
+            WM_RBUTTONUP = 0x0205
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        public struct POINT
+        {
+            public int x;
+            public int y;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct MSLLHOOKSTRUCT
+        {
+            public POINT pt;
+            public uint mouseData;
+            public uint flags;
+            public uint time;
+            public IntPtr dwExtraInfo;
+        }
+
+        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+        private static extern IntPtr SetWindowsHookEx(int idHook,
+          LowLevelMouseProc lpfn, IntPtr hMod, uint dwThreadId);
+
+        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool UnhookWindowsHookEx(IntPtr hhk);
+
+        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
+          IntPtr wParam, IntPtr lParam);
+
+        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
+        private static extern IntPtr GetModuleHandle(string lpModuleName);
+
+
+    }
+
+}