基于GDI和D3D的抓屏技术

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 ;
}