僅截取表單的一部分屏幕截圖？

Question

我目前有一個winform，在運行時，我需要截取一部分截圖並將其保存爲圖像。特別是，我想要一個名爲「panel1」的面板的屏幕截圖。我已經能夠找到關於如何獲取整個網絡表格或整個屏幕截圖的信息......但是我一直難以獲取有關獲取屏幕一部分的信息。

有沒有人有任何信息可以指向正確的方向？即使是我應該尋找的MSDN網站上的文檔名稱也是一個巨大的幫助！謝謝！

Answer 1

Control類別Panel派生的方法有DrawToBitmap()。你可以使用它。

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.drawtobitmap.aspx

Answer 2

看爲Graphics.CopyFromScreen的文檔。您將它傳遞給2組X/Y座標 - 屏幕上的座標和位圖中的座標。

Answer 3

 #region - Capture & Graphic API - 

     #region GDI32 
     public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter 

     [DllImport("gdi32.dll")] 
     public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest, 
      int nWidth, int nHeight, IntPtr hObjectSource, 
      int nXSrc, int nYSrc, int dwRop); 

     [DllImport("gdi32.dll")] 
     public static extern bool StretchBlt(
       IntPtr hdcDest,  // handle to destination DC 
       int nXOriginDest, // x-coord of destination upper-left corner 
       int nYOriginDest, // y-coord of destination upper-left corner 
       int nWidthDest, // width of destination rectangle 
       int nHeightDest, // height of destination rectangle 
       IntPtr hdcSrc,  // handle to source DC 
       int nXOriginSrc, // x-coord of source upper-left corner 
       int nYOriginSrc, // y-coord of source upper-left corner 
       int nWidthSrc, // width of source rectangle 
       int nHeightSrc, // height of source rectangle 
       int dwRop  // raster operation code 
      ); 


     [DllImport("gdi32.dll")] 
     public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth, 
      int nHeight); 
     [DllImport("gdi32.dll")] 
     public static extern IntPtr CreateCompatibleDC(IntPtr hDC); 
     [DllImport("gdi32.dll")] 
     public static extern bool DeleteDC(IntPtr hDC); 
     [DllImport("gdi32.dll")] 
     public static extern bool DeleteObject(IntPtr hObject); 
     [DllImport("gdi32.dll")] 
     public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject); 
     #endregion 

     #region - USER32 - 
     [StructLayout(LayoutKind.Sequential)] 
     public struct RECT 
     { 
      public int left; 
      public int top; 
      public int right; 
      public int bottom; 
     } 

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

     #endregion 

    #endregion 


    private void run_test() 
    { 

     Rectangle rc = new Rectangle(); 
     Image img = ScreenToImage(ref rc, false); 

     img.Save(filename, System.Drawing.Imaging.ImageFormat.Jpeg); 
     img.Dispose(); 

    } 


    private Image ScreenToImage(ref Rectangle rcDest, bool IsPapaer) 
    { 
     IntPtr handle = this.Handle; 

     //this.Handle 
     // get te hDC of the target window 
     IntPtr hdcSrc = GetWindowDC(handle); 
     // get the size 
     RECT windowRect = new RECT(); 
     GetWindowRect(handle, ref windowRect); 
     int nWidth = windowRect.right - windowRect.left; 
     int nHeight = windowRect.bottom - windowRect.top; 

     if (IsPapaer) 
     { 
      float fRate = (float)rcDest.Width/nWidth; 
      //float fHeight = nHeight * fRate; 
      //rcDest.Height = (int)(nHeight * fRate); 
      //rcDest.Width = (int)(rcDest.Width);// * fRate); 
      rcDest.X = 0; 
      rcDest.Y = 0; 
      rcDest.Height = (int)(nHeight * fRate); 
      //rcDest.Width = (int)(nWidth * fRate); 
     } 
     else 
     { 
      rcDest.X = 0; 
      rcDest.Y = 0; 
      rcDest.Height = nHeight; 
      rcDest.Width = nWidth; 
     } 

     // create a device context we can copy to 
     IntPtr hdcDest = CreateCompatibleDC(hdcSrc); 
     // create a bitmap we can copy it to, 
     // using GetDeviceCaps to get the width/height 
     IntPtr hBitmap = CreateCompatibleBitmap(hdcSrc, rcDest.Width, rcDest.Height); 
     // select the bitmap object 
     IntPtr hOld = SelectObject(hdcDest, hBitmap); 
     // bitblt over 
     StretchBlt(hdcDest, rcDest.X, rcDest.Y, rcDest.Width, rcDest.Height, hdcSrc, 0, 0, nWidth, nHeight, SRCCOPY); 
     // restore selection 
     SelectObject(hdcDest, hOld); 
     // clean up 
     DeleteDC(hdcDest); 
     ReleaseDC(handle, hdcSrc); 

     // get a .NET image object for it 
     Image img = Image.FromHbitmap(hBitmap); 
     // free up the Bitmap object 
     DeleteObject(hBitmap); 
     return img; 
    }