C# 非顶端窗口截图

原文地址：http://blog.csdn.net/u013096568/article/details/53400389

panel上可以通过DrawToBitmap截图，不管是否在屏幕外是否有遮挡         

 Bitmap sourceBitmap = new Bitmap(400, 300);
            //Control ct = frmMain.mianForm.panel1 as Control;

            //ct.DrawToBitmap(sourceBitmap, new System.Drawing.Rectangle(0, 0, 400, 300));
            panel1.DrawToBitmap(sourceBitmap, new System.Drawing.Rectangle(0, 0, 400, 300));
            sourceBitmap.Save(@"e:123form2.bmp");

在图片上打水印

string strpath = @"e:1.bmp";
            Bitmap bmp = new Bitmap(strpath);
            Graphics graphics = Graphics.FromImage(bmp);

            System.Drawing.SolidBrush myBrush = new System.Drawing.SolidBrush(System.Drawing.Color.Red);
            graphics.FillEllipse(myBrush, new System.Drawing.Rectangle(150, 200, 10, 10));//画圆

            try
            {
                bmp.Save(@"e:
ew.bmp");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

　　

抓屏截图
         

   Image objImage = new Bitmap(400, 300);
            Graphics g = Graphics.FromImage(objImage);
            g.CopyFromScreen(new System.Drawing.Point(Cursor.Position.X - 150, Cursor.Position.Y - 25), new System.Drawing.Point(0, 0), new Size(400, 300));
            IntPtr dc1 = g.GetHdc();
            g.ReleaseHdc(dc1);

            objImage.Save("e:\test.jpg");

　　

非顶端窗口截图

用Windows热键截图然后保存的我就不说了,地球人都知道.

如何截取非前端窗体的截图，要先获取所要截图的窗口的句柄IntPtr PicWindow = this.Handle

首先说一下PrintWindow这个API的使用

      

  public static Bitmap GetWindowCapture(IntPtr hWnd)
        {
            IntPtr hscrdc = GetWindowDC(hWnd);
            RECT windowRect = new RECT();
            GetWindowRect(hWnd, ref windowRect);
            int width = windowRect.right - windowRect.left;
            int height = windowRect.bottom - windowRect.top;

            IntPtr hbitmap = CreateCompatibleBitmap(hscrdc, width, height);
            IntPtr hmemdc = CreateCompatibleDC(hscrdc);
            SelectObject(hmemdc, hbitmap);
            PrintWindow(hWnd, hmemdc, 0);
            Bitmap bmp = Bitmap.FromHbitmap(hbitmap);
            DeleteDC(hscrdc);//删除用过的对象
            DeleteDC(hmemdc);//删除用过的对象
            return bmp;
        }

        [DllImport("user32.dll")]
        public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);

        [DllImport("gdi32.dll")]
        public static extern IntPtr CreateDC(
         string lpszDriver,         // driver name驱动名
         string lpszDevice,         // device name设备名
         string lpszOutput,         // not used; should be NULL
         IntPtr lpInitData   // optional printer data
         );
        [DllImport("gdi32.dll")]
        public static extern int BitBlt(
         IntPtr hdcDest, // handle to destination DC目标设备的句柄
         int nXDest,   // x-coord of destination upper-left corner目标对象的左上角的X坐标
         int nYDest,   // y-coord of destination upper-left corner目标对象的左上角的Y坐标
         int nWidth,   // width of destination rectangle目标对象的矩形宽度
         int nHeight, // height of destination rectangle目标对象的矩形长度
         IntPtr hdcSrc,   // handle to source DC源设备的句柄
         int nXSrc,    // x-coordinate of source upper-left corner源对象的左上角的X坐标
         int nYSrc,    // y-coordinate of source upper-left corner源对象的左上角的Y坐标
         UInt32 dwRop   // raster operation code光栅的操作值
         );

        [DllImport("gdi32.dll")]
        public static extern IntPtr CreateCompatibleDC(
         IntPtr hdc // handle to DC
         );

        [DllImport("gdi32.dll")]
        public static extern IntPtr CreateCompatibleBitmap(
         IntPtr hdc,         // handle to DC
         int nWidth,      // width of bitmap, in pixels
         int nHeight      // height of bitmap, in pixels
         );

        [DllImport("gdi32.dll")]
        public static extern IntPtr SelectObject(
         IntPtr hdc,           // handle to DC
         IntPtr hgdiobj    // handle to object
         );

        [DllImport("gdi32.dll")]
        public static extern int DeleteDC(
         IntPtr hdc           // handle to DC
         );

        [DllImport("user32.dll")]
        public static extern bool PrintWindow(
         IntPtr hwnd,                // Window to copy,Handle to the window that will be copied.
         IntPtr hdcBlt,              // HDC to print into,Handle to the device context.
         UInt32 nFlags               // Optional flags,Specifies the drawing options. It can be one of the following values.
         );

        [DllImport("user32.dll")]
        public static extern IntPtr GetWindowDC(
         IntPtr hwnd
         );

　　

很遗憾,上面的确可以截取非前端窗体的截图,但是非GDI的程序是无法截图的比如DirectX

下面说一下BitBlt这个API的使用

   

  /// <summary>
    /// 提供全屏和指定窗口的截图 以及保存为文件的类
    /// </summary>
    public class ScreenCapture
    {
        /// <summary>
        /// 全屏截图
        /// </summary>
        /// <returns></returns>
        public Image CaptureScreen()
        {
            return CaptureWindow(User32.GetDesktopWindow());
        }
        /// <summary>
        /// 指定窗口截图
        /// </summary>
        /// <param name="handle">窗口句柄. (在windows应用程序中, 从Handle属性获得)</param>
        /// <returns></returns>
        public Image CaptureWindow(IntPtr handle)
        {
            IntPtr hdcSrc = User32.GetWindowDC(handle);
            User32.RECT windowRect = new User32.RECT();
            User32.GetWindowRect(handle, ref windowRect);
            int width = windowRect.right - windowRect.left;
            int height = windowRect.bottom - windowRect.top;
            IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
            IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, width, height);
            IntPtr hOld = GDI32.SelectObject(hdcDest, hBitmap);
            GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, GDI32.SRCCOPY);
            GDI32.SelectObject(hdcDest, hOld);
            GDI32.DeleteDC(hdcDest);