using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace FederalCredit
{
    public class MZCapture
    {
        #region  DLL calls
        [DllImport("gdi32.dll")]
        static extern bool BitBlt(IntPtr hdcDest, int xDest, int yDest, int
        wDest, int hDest, IntPtr hdcSource, int xSrc, int ySrc, CopyPixelOperation rop);
        [DllImport("gdi32.dll")]
        static extern IntPtr DeleteDC(IntPtr hDc);
        [DllImport("gdi32.dll")]
        static extern IntPtr DeleteObject(IntPtr hDc);
        [DllImport("gdi32.dll")]
        static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int nWidth, int nHeight);
        [DllImport("gdi32.dll")]
        static extern IntPtr CreateCompatibleDC(IntPtr hdc);
        [DllImport("gdi32.dll")]
        static extern IntPtr SelectObject(IntPtr hdc, IntPtr bmp);
        [DllImport("user32.dll")]
        public static extern IntPtr GetDesktopWindow();
        [DllImport("user32.dll")]
        public static extern IntPtr GetWindowDC(IntPtr ptr);
        [DllImport("user32.dll")]
        public static extern bool PrintWindow(IntPtr hwnd, IntPtr hdcBlt, UInt32 nFlags);
        [DllImport("user32.dll")]
        static extern bool ReleaseDC(IntPtr hWnd, IntPtr hDc);
        #endregion

        /// <summary>
        ///  屏幕截图(全屏)
        /// </summary>
        /// <returns></returns>
        public static Bitmap CaptureScreen()
        {
            Size screenSize = Screen.PrimaryScreen.Bounds.Size;
            return CaptureScreen(0, 0, screenSize.Width, screenSize.Height);
        }

        /// <summary>
        /// 屏幕截图(指定区域)
        /// </summary>
        /// <param name="x">左上角的横坐标</param>
        /// <param name="y">左上角的纵坐标</param>
        /// <param name="width">抓取宽度</param>
        /// <param name="height">抓取高度</param>
        /// <returns></returns>
        public static Bitmap CaptureScreen(int x, int y, int width, int height)
        {
            Bitmap bmp = new Bitmap(width, height);
            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.CopyFromScreen(new Point(x, y), new Point(0, 0), bmp.Size);
                g.Dispose();
            }
            return bmp;
        }

        /// <summary>
        /// 控件截图
        /// </summary>
        /// <param name="control">需要被截图的控件</param>
        /// <remarks>使用BitBlt方法，控件被遮挡时也可以正确截图</remarks>
        public static Bitmap CaptureControl(Control control)
        {
            IntPtr hSrce = GetWindowDC(control.Handle);
            IntPtr hDest = CreateCompatibleDC(hSrce);
            IntPtr hBmp = CreateCompatibleBitmap(hSrce, control.Width, control.Height);
            IntPtr hOldBmp = SelectObject(hDest, hBmp);
            if (BitBlt(hDest, 0, 0, control.Width, control.Height, hSrce, 0, 0, CopyPixelOperation.SourceCopy | CopyPixelOperation.CaptureBlt))
            {
                Bitmap bmp = Image.FromHbitmap(hBmp);
                SelectObject(hDest, hOldBmp);
                DeleteObject(hBmp);
                DeleteDC(hDest);
                ReleaseDC(control.Handle, hSrce);
                // bmp.Save(@"a.png");
                // bmp.Dispose();
                return bmp;
            }
            return null;
        }

        /// <summary>
        /// 窗体截图
        /// </summary>
        /// <param name="control">需要被截图的窗口</param>
        /// <remarks>使用PrintWindow方法，被遮挡时也可以正确截图</remarks>
        public static Bitmap CaptureForm(Form form)
        {
            return GetWindow(form.Handle);
        }

        private static Bitmap GetWindow(IntPtr hWnd)
        {
            IntPtr hscrdc = GetWindowDC(hWnd);
            Control control = Control.FromHandle(hWnd);
            IntPtr hbitmap = CreateCompatibleBitmap(hscrdc, control.Width, control.Height);
            IntPtr hmemdc = CreateCompatibleDC(hscrdc);
            SelectObject(hmemdc, hbitmap);
            PrintWindow(hWnd, hmemdc, 0);
            Bitmap bmp = Bitmap.FromHbitmap(hbitmap);
            DeleteDC(hscrdc);
            DeleteDC(hmemdc);
            return bmp;
        }
    }
}