只捕获表单的一部分的屏幕截图

本文关键字：一部分 屏幕截图 表单 | 更新日期: 2023-09-27 18:07:10

我目前有一个winform，在运行时，我需要对它的一部分进行截图并将其保存为图像。特别是，我想要一个名为"panel1"面板的屏幕截图。我已经能够找到有关如何获得整个网页的截图，或整个屏幕的信息…但是我很难找到只获取屏幕一部分的信息。

有没有人能给我指出正确的方向?甚至在MSDN的网站上，我应该寻找的文档的名称将是一个巨大的帮助!谢谢!

只捕获表单的一部分的屏幕截图

Panel派生的Control类有一个方法DrawToBitmap()。你可以用它

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

查看Graphics.CopyFromScreen的文档。你传递给它2组X/Y坐标——屏幕上的坐标和位图中的坐标。

     #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;
    }
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