windows截屏

 #ifndef _CAPTURESCREEN_H

 #define _CAPTURESCREEN_H

 #include <windows.h>

 class  CaptureScreen

 {

 public:

     CaptureScreen()

     {};

     ~CaptureScreen(void)

     {};

     void ScreenInit();

     void ScreenFree();

     bool ScreenSetWindow(LPRECT lpRect);

     bool ScreenCopy(BYTE *dstBuf); 

     int rHeight;    //要获得的图像尺寸

     int rWidth;

 private:

     int nScreenWidth;

     int nScreenHeight;

     PRGBTRIPLE scan0;

     BITMAPINFO pbi;

     int stride;

     int top_x;

     int top_y;

     int bot_x;

     int bot_y;

 };

 #endif

 #include "CaptureScreen.h"

 void CaptureScreen::ScreenInit()

 {

     nScreenWidth = GetSystemMetrics(SM_CXSCREEN);

     nScreenHeight = GetSystemMetrics(SM_CYSCREEN);

     pbi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);

     pbi.bmiHeader.biWidth = nScreenWidth;

     pbi.bmiHeader.biHeight = nScreenHeight;

     pbi.bmiHeader.biPlanes = ;

     pbi.bmiHeader.biBitCount = ;

     pbi.bmiHeader.biCompression = BI_RGB;

     stride = ((nScreenWidth *  + ) & 0xffffffe0) / ;  // 24位图像扫描线宽度

     scan0 = (PRGBTRIPLE)malloc(stride * nScreenHeight);    // 图像数据缓冲区，应释放

 }

 void CaptureScreen::ScreenFree()

 {

     free(scan0);

 }

 bool CaptureScreen::ScreenSetWindow(LPRECT lpRect)

 {

      top_x = lpRect->left;

      top_y = lpRect->top;

      bot_x = lpRect->right;

      bot_y = lpRect->bottom;

     if(top_x >= bot_x)

     return false;

     if(top_y >= bot_y)

     return false;

     if(top_x< || bot_x>nScreenWidth)

     return false;

     if(top_y< || bot_y>nScreenHeight)

     return false;

     rHeight = bot_y-top_y;

     rWidth =  bot_x-top_x;

     return true;

 }

 bool CaptureScreen::ScreenCopy(BYTE *dstBuf)

 {

     HWND hDesktopWnd = GetDesktopWindow();

     HDC hDesktopDC = GetDC(hDesktopWnd);

     HDC hCaptureDC = CreateCompatibleDC(hDesktopDC);

     HBITMAP hCaptureBitmap =CreateCompatibleBitmap(hDesktopDC,nScreenWidth, nScreenHeight);

     SelectObject(hCaptureDC,hCaptureBitmap);

     BitBlt(hCaptureDC,,,nScreenWidth,nScreenHeight,hDesktopDC,,,SRCCOPY|NOMIRRORBITMAP);

     DeleteDC(hCaptureDC);

     GetDIBits(hDesktopDC, hCaptureBitmap, , nScreenHeight, scan0, &pbi, DIB_RGB_COLORS);

     ReleaseDC(hDesktopWnd,hDesktopDC);

     DeleteObject(hCaptureBitmap);

     BYTE *srcBuf = (BYTE*) scan0;

     int j;

     srcBuf += (nScreenHeight--top_y)*stride+top_x*;// scan0倒序

     for(j=;j<rHeight;j++)

     {

         memcpy(dstBuf,srcBuf,rWidth*);

         dstBuf += rWidth*;

         srcBuf -= stride;

     }

     return true;

 }

 #include "CaptureScreen.h"

 #include <stdio.h>

 #include <Mmsystem.h>

 #pragma comment( lib,"winmm.lib" )

 void SaveBmp2(BYTE *bgr32,int w,int h,int mode)

 {

     /////////////////////////////////////////////

     DWORD size=w*h*;

     LPSTR lpData=(LPSTR)GlobalAlloc(GPTR,size);

     /////////////////////////////////////////////

     BITMAPINFOHEADER bih;

     bih.biSize=sizeof(BITMAPINFOHEADER);

     bih.biWidth=w;

     bih.biHeight=h;

     bih.biPlanes=;

     bih.biBitCount=;

     bih.biCompression=;

     bih.biSizeImage=w*h*;//size;

     bih.biXPelsPerMeter=;

     bih.biYPelsPerMeter=;

     bih.biClrUsed=;

     bih.biClrImportant=;

     BITMAPFILEHEADER bfh;

     bfh.bfType=0x4D42;  // "BM"      // 设置位图文件头

        bfh.bfReserved1=bfh.bfReserved2=;

     bfh.bfSize=+size;

     bfh.bfOffBits=;

     if(mode == )

     {

     for(int i=;i<h;i++)

     {

         memcpy(lpData+(h--i)*w*,bgr32+i*w*,w*);

     }

     }

     else

         memcpy(lpData,bgr32,w*h*);

     static int filecount=;

     char filename[];

     sprintf(filename,"C:\\%d.bmp",filecount);

     FILE *fp=fopen(filename,"wb");

     if(fp)

     {

         fwrite(&bfh,,sizeof(BITMAPFILEHEADER),fp);

         fwrite(&bih,,sizeof(BITMAPINFOHEADER),fp);

         fwrite(lpData,,size,fp);

         fclose(fp);

         filecount++;

     }

     GlobalFree(lpData);

 }

 int main()

 {

     CaptureScreen myCapture;

     myCapture.ScreenInit();

     RECT dstRect={,,,};

     myCapture.ScreenSetWindow(&dstRect);

     BYTE *dstBuff = (BYTE*)malloc(myCapture.rWidth*myCapture.rHeight*);

     int lastTime = timeGetTime();

     myCapture.ScreenCopy(dstBuff);

     printf("time:%dms",timeGetTime()-lastTime);

     SaveBmp2((BYTE*)dstBuff,myCapture.rWidth,myCapture.rHeight,);

     myCapture.ScreenFree();

     return ;

 }