基于GDI和D3D的抓屏技术

GDI32Api、Direct3D屏幕截图

最近因为工作需要，认真研究了一下屏幕截图的方法。

最主要的方法有两种，一、调用windows GDI32 API函数。二、使用DirectX9.0来实现。

另外，光注了一下Microsoft Expression Encoder 4 Screen Capture这个微软新出的功能，Expression　Encoder 4 可实现屏幕录制，录制 文件格式为WMV ，为免费使用版本，Expression Encoder 4 Pro为 收费版本。

还 看了一下基于windows图形驱动技术的屏幕截图方法 ，文章链接地址：http://blog.csdn.net/jia162/article/details/2509974。实现起来可能比较困难与复杂。没找到实例参考及技术实现的算法，因此也就没有深入研究。

下面两种方法

一、GDI32 API截图，600*480大小生成Bitmap位图大概需要45ms左右，生成位图并save成bmp文件需要大概110ms左右，图片越大，耗费的时间越长，效率比较低。

二、DirectX截图，是把整个屏幕的拷贝到内存里，再进行截取，执行拷贝屏幕的方法g_pd3dDevice->GetFrontBufferData(0, g_pSurface)需要80ms-100ms，效率也比较低。

若那位技术牛人有好滴方法，请推荐一下哦！！！

方法一实现：

using System;

using System.Collections.Generic;

using System.Text;

using System.Runtime.InteropServices;



namespace DataFrameFetch

{

    public class WinGdi32Api

    {

        [DllImport("GDI32.dll")]

        public static extern bool BitBlt(int hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, int hdcSrc, int nXSrc, int nYSrc, int dwRop);

        [DllImport("GDI32.dll")]

        public static extern int CreateCompatibleBitmap(int hdc, int nWidth, int nHeight);

        [DllImport("GDI32.dll")]

        public static extern int CreateCompatibleDC(int hdc);

        [DllImport("GDI32.dll")]

        public static extern bool DeleteDC(int hdc);

        [DllImport("GDI32.dll")]

        public static extern bool DeleteObject(int hObject);

        [DllImport("GDI32.dll")]

        public static extern int GetDeviceCaps(int hdc, int nIndex);

        [DllImport("GDI32.dll")]

        public static extern int SelectObject(int hdc, int hgdiobj);

        [DllImport("User32.dll")]

        public static extern int GetDesktopWindow();

        [DllImport("User32.dll")]

        public static extern int GetWindowDC(int hWnd);

        [DllImport("User32.dll")]

        public static extern int GetDC(int hWnd);

        [DllImport("User32.dll")]

        public static extern int ReleaseDC(int hWnd, int hDC);

    }

}





 



 



using System;

using System.Collections.Generic;

using System.Text;

using System.Windows.Forms;

using System.Runtime.InteropServices;

using System.Drawing;

using System.Drawing.Imaging;

using System.IO;





namespace DataFrameFetch

{

    public class DataFetch

    {



        public DataFetch()

        { }



    



        /// <summary>

        /// 全屏截图

        /// </summary>

        /// <returns></returns>

        public Bitmap CaptureScreen()

        {

            DateTime dt_start = DateTime.Now;

            int source = WinGdi32Api.GetWindowDC(WinGdi32Api.GetDesktopWindow());

            int bitmap = WinGdi32Api.CreateCompatibleBitmap(source, WinGdi32Api.GetDeviceCaps(source, 8), WinGdi32Api.GetDeviceCaps(source, 10));



            int destination = WinGdi32Api.CreateCompatibleDC(source);

            WinGdi32Api.SelectObject(destination, bitmap);

            WinGdi32Api.BitBlt(destination, 0, 0, WinGdi32Api.GetDeviceCaps(source, 8), WinGdi32Api.GetDeviceCaps(source, 10), source, 0, 0, 0x00CC0020);

            Bitmap img = this.GetBitmap(bitmap);

            this.Cleanup(bitmap, source, destination);

            DateTime dt_end = DateTime.Now;

            TimeSpan ts = dt_end - dt_start;   

            System.Diagnostics.Debug.WriteLine(ts.Milliseconds.ToString());

            return img;

        }



        public Bitmap CaptureScreen(Control control)

        {

            DateTime dt_start = DateTime.Now;



            int source = WinGdi32Api.GetDC(control.Handle.ToInt32());

            int bitmap = WinGdi32Api.CreateCompatibleBitmap(source, control.Width,control.Height);



            int destination = WinGdi32Api.CreateCompatibleDC(source);

            WinGdi32Api.SelectObject(destination, bitmap);

            WinGdi32Api.BitBlt(destination, 0, 0, control.Width, control.Height, source, 0, 0, 0x00CC0020);

            Bitmap img = this.GetBitmap(bitmap);

            this.Cleanup(bitmap, source, destination);



            byte[] buffer = this.ConvertBitmapToRGBByteArray(img);



            string filename = "F:\img\" + dt_start.ToString("yyyyMMddHHmmss") + dt_start.Millisecond.ToString();



            FileStream fs = new FileStream(filename + ".olc", FileMode.Create);

            fs.Write(buffer, 0, buffer.Length);

            fs.Flush();

            fs.Close();



            //Bitmap bmp = this.FromRGB(buffer, img.Width, img.Height);

            //bmp.Save(filename + "_1.bmp");



            DateTime dt_end = DateTime.Now;

            TimeSpan ts = dt_end - dt_start;

            System.Diagnostics.Debug.WriteLine(ts.Milliseconds.ToString());

            return img;

        }



        private void Cleanup(int bitmap, int source, int destination)

        {

            WinGdi32Api.ReleaseDC(WinGdi32Api.GetDesktopWindow(), source);

            WinGdi32Api.DeleteDC(destination);

            WinGdi32Api.DeleteObject(bitmap);

        }



        private Bitmap GetBitmap(int hbitmap)

        {

            Bitmap bmp = new Bitmap(Image.FromHbitmap(new IntPtr(hbitmap)), Image.FromHbitmap(new IntPtr(hbitmap)).Width, Image.FromHbitmap(new IntPtr(hbitmap)).Height);

            return bmp;

        }       



        /// <summary>

        /// 将位图转换成数组

        /// </summary>

        /// <param name="bmp"></param>

        /// <returns></returns>

        private byte[] ConvertBitmapToRGBByteArray(Bitmap bmp)

        {

            Rectangle rect = new Rectangle(new Point(0,0),bmp.Size);

            BitmapData bmpdata = bmp.LockBits(rect, ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);



            int len = bmp.Width * bmp.Height * 3;

            byte[] buffer = new byte[len];

            int index = 0;

            unsafe

            {

                byte* color = (byte*)bmpdata.Scan0;

                for (int y = 0; y < bmp.Height; y++)

                {

                    for (int x = 0; x < bmp.Width; x++)

                    {

                        buffer[index++] = *color;

                        buffer[index++] = *(color + 1);

                        buffer[index++] = *(color + 2);

                        color += 3;

                    }

                    //color += bmpdata.Stride - bmpdata.Width * 3;

                }

            }

            bmp.UnlockBits(bmpdata);

            return buffer;

        }



 



        /// <summary>

        /// 图像象素数组转成位图

        /// </summary>

        /// <param name="buffer"></param>

        /// <param name="width"></param>

        /// <param name="height"></param>

        /// <returns></returns>

        public Bitmap ConvertRGBByteArrayToBitmap(byte[] buffer, int width, int height)

        {

            // 申请目标位图的变量，并将其内存区域锁定 

            Bitmap bmp = new Bitmap(width, height, PixelFormat.Format24bppRgb);//创建新图像 

            Rectangle rect = new Rectangle(0, 0, width, height);

            BitmapData bmpData = bmp.LockBits(rect,ImageLockMode.WriteOnly,PixelFormat.Format24bppRgb);

            //// 用Marshal的Copy方法，将刚才得到的内存字节数组复制到BitmapData中 

            Marshal.Copy(buffer, 0, bmpData.Scan0, buffer.Length);

            bmp.UnlockBits(bmpData);  // 解锁内存区域 

  

            return bmp;

        }

    }

}

方法二以VC++实现

BOOL ScreenShot(HWND hWnd, TCHAR* fileName)
 {
    HRESULT hr;

    
    IDirect3D9*   gpD3D=NULL;
    IDirect3DDevice9* gpd3dDevice=NULL;
    IDirect3DSurface9* gpSurface=NULL;

 D3DDISPLAYMODE ddm;
 D3DPRESENT_PARAMETERS d3dpp;

 if((gpD3D=Direct3DCreate9(D3D_SDK_VERSION))==NULL)
 {
  ErrorMessage("Unable to Create Direct3D ");
  return E_FAIL;
 }

 if(FAILED(gpD3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT,&ddm)))
 {
  ErrorMessage("Unable to Get Adapter Display Mode");
  return E_FAIL;
 } 

 ZeroMemory(&d3dpp,sizeof(D3DPRESENT_PARAMETERS));

 d3dpp.Windowed=WINDOW_MODE;
 d3dpp.Flags=D3DPRESENTFLAG_LOCKABLE_BACKBUFFER;
 d3dpp.BackBufferFormat=ddm.Format;
 d3dpp.BackBufferHeight=nDisplayHeight=gScreenRect.bottom =ddm.Height;
 d3dpp.BackBufferWidth=nDisplayWidth=gScreenRect.right =ddm.Width;
 d3dpp.MultiSampleType=D3DMULTISAMPLE_NONE;
 d3dpp.SwapEffect=D3DSWAPEFFECT_DISCARD;
 d3dpp.hDeviceWindow=hWnd;
 d3dpp.PresentationInterval=D3DPRESENT_INTERVAL_DEFAULT;
 d3dpp.FullScreen_RefreshRateInHz=D3DPRESENT_RATE_DEFAULT;

 if(FAILED(gpD3D->CreateDevice(D3DADAPTER_DEFAULT,D3DDEVTYPE_HAL,hWnd,D3DCREATE_SOFTWARE_VERTEXPROCESSING ,&d3dpp,&gpd3dDevice)))
 {
  ErrorMessage("Unable to Create Device");
  return E_FAIL;
 }

 if(FAILED(gpd3dDevice->CreateOffscreenPlainSurface(ddm.Width, ddm.Height, D3DFMT_A8R8G8B8, D3DPOOL_SCRATCH, &gpSurface, NULL)))
 {
  ErrorMessage("Unable to Create Surface");
  return E_FAIL;
 }
  if (FAILED(hr = gpd3dDevice->GetFrontBufferData(0, gpSurface))) 
    {
        gpSurface->Release() ;
        return hr ;
    }
 hr = D3DXSaveSurfaceToFile(fileName, D3DXIFF_BMP, gpSurface, NULL, NULL); 
    gpSurface->Release() ; 

   return hr ;
 }