实现内存抓图

 1 int nHeight = rc.Height();
 2     int nWidth = 0;
 3     //截图宽度必须为4的倍数
 4     if (rc.Width()%4)
 5     {
 6         nWidth = (rc.Width()/4+1)*4;
 7     }
 8     else 
 9     {
10         nWidth = rc.Width();
11     }
12     *height = nHeight;
13     *width = nWidth;
14 
15     HWND hWnd = ::GetDesktopWindow();
16     HDC hdcSrc = ::GetDC(hWnd);
17     HDC hdcMem = ::CreateCompatibleDC(hdcSrc);
18     HBITMAP hBitmap = ::CreateCompatibleBitmap(hdcSrc, nWidth, nHeight);
19     HGDIOBJ hOldbmp = ::SelectObject(hdcMem, hBitmap);
20     CDC::FromHandle(hdcMem)->FillSolidRect(&rc, RGB(255, 255, 255));
21     DrawPic(CDC::FromHandle(hdcMem), rc);
22     ::SelectObject(hdcMem, hOldbmp);
23     ::DeleteObject(hdcMem);
24     ::ReleaseDC(hWnd, hdcSrc);
25 
26     //从bitmap提取RGB数据
27     if (hBitmap!= NULL)
28     {
29         CBitmap *bitmap = CBitmap::FromHandle(hBitmap);
30         BITMAP bmp;
31         bitmap->GetBitmap(&bmp);
32         int bitmapSize = bmp.bmWidthBytes*bmp.bmWidthBytes;
33         if (pRGBBuf==NULL)
34         {
35             return false;
36         }
37         DWORD dwCount = bitmap->GetBitmapBits(bitmapSize, pRGBBuf);
38         bitmap->DeleteObject();
39         if (32 != m_nRGBBit)
40         {
41             //32位转24位
42             for (int nCount = 0; nCount < nWidth*nHeight*4;)
43             {
44                 memmove(&pRGBBuf[nCount/4*3], &pRGBBuf[nCount], 3);
45                 nCount += 4;
46             }
47         }
48         *nLen = nWidth*nHeight*m_nRGBBit/8;
49     }
50 
51     //把图像数据倒置
52     int n = m_nRGBBit/8;
53     char tmp[2048*4];
54     for(int i = 0; i < nHeight/2; i++) 
55     { 
56         memcpy(tmp, &(pRGBBuf[nWidth*i*n]), nWidth*n); 
57         memcpy(&(pRGBBuf[nWidth*i*n]), &(pRGBBuf[nWidth*(nHeight-1-i)*n]), nWidth*n); 
58         memcpy(&(pRGBBuf[nWidth*(nHeight-1-i)*n]), tmp, nWidth*n); 
59     }

 1 BOOL SaveRGBToFile(const char *pFileName, const char *pRGBBuf,  int nLen, int nWidth, int nHeight)
 2 {
 3     FILE *file = fopen(pFileName, "wb+");
 4     if (NULL == file)
 5     {
 6         TRACE("open file failed, file name is:%s\n", pFileName);
 7         return false;
 8     }
 9     //写文件头   
10     BITMAPFILEHEADER fileheader;  
11     ZeroMemory(&fileheader, sizeof(BITMAPFILEHEADER)); 
12     memcpy((char *)&fileheader.bfType, "BM", 2);
13     fileheader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + nWidth*nHeight*m_nRGBBit/8;  
14     fileheader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);  
15     if (sizeof(BITMAPFILEHEADER) != fwrite((char *)&fileheader, sizeof(char), sizeof(BITMAPFILEHEADER), file))
16     {
17         TRACE("write file error, file name is:%s\n", pFileName);
18         return false;
19     }
20     //写位图格式   
21     BITMAPINFOHEADER infoHeader;  
22     ZeroMemory(&infoHeader, sizeof(BITMAPINFOHEADER));  
23     infoHeader.biSize = sizeof(BITMAPINFOHEADER);  
24     infoHeader.biSizeImage = nWidth*nHeight*m_nRGBBit/8;  
25     infoHeader.biWidth = nWidth;  
26     infoHeader.biHeight = nHeight;  
27     infoHeader.biBitCount = m_nRGBBit; 
28     if (sizeof(BITMAPINFOHEADER) != fwrite((char *)&infoHeader, sizeof(char), sizeof(BITMAPINFOHEADER), file))
29     {
30         TRACE("write file error, file name is:%s\n", pFileName);
31         return false;
32     }
33     //写位图数据  
34     if (nWidth*nHeight*m_nRGBBit/8 != fwrite(pRGBBuf, sizeof(char), nWidth*nHeight*m_nRGBBit/8, file))
35     {
36         TRACE("write file error, file name is:%s\n", pFileName);
37         return false;
38     }
39     fclose(file);
40     return true;
41 }

 

实现在内存DC中绘图，然后对内存DC进行抓图并保存为bmp图片