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如何用C程式語言擷取全螢幕，並輸出成BMP檔案
2010/07/08 18:13
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問題：如何用C程式語言擷取全螢幕，並輸出成BMP檔案？
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解答：
void CaptureFullWindow(void)
{
    HDC  hScrDC, hMemDC;      
    int  width, height;

    //the pointer will save all pixel point's color value
    BYTE  *lpBitmapBits = NULL;
    //creates a device context for the screen device
    hScrDC = CreateDC(_T("DISPLAY"), NULL, NULL, NULL);

    //get the screen point size
    width = GetDeviceCaps(hScrDC, HORZRES);
    height = GetDeviceCaps(hScrDC, VERTRES);

    //creates a memory device context (DC) compatible with the screen device(hScrDC)
    hMemDC = CreateCompatibleDC(hScrDC);

     //initialise the struct BITMAPINFO for the bimap infomation，
     //in order to use the function CreateDIBSection
     // on wince os, each pixel stored by 24 bits(biBitCount=24)
     //and no compressing(biCompression=0)

    BITMAPINFO RGB24BitsBITMAPINFO;
    ZeroMemory(&RGB24BitsBITMAPINFO, sizeof(BITMAPINFO));
    RGB24BitsBITMAPINFO.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    RGB24BitsBITMAPINFO.bmiHeader.biWidth = width;
    RGB24BitsBITMAPINFO.bmiHeader.biHeight = height;
    RGB24BitsBITMAPINFO.bmiHeader.biPlanes = 1;
    RGB24BitsBITMAPINFO.bmiHeader.biBitCount = 24;
    //use the function CreateDIBSection and SelectObject
    //in order to get the bimap pointer : lpBitmapBits
    HBITMAP hBitmap = CreateDIBSection(hMemDC, (BITMAPINFO*)&RGB24BitsBITMAPINFO,
       DIB_RGB_COLORS, (void **)&lpBitmapBits, NULL, 0);
    HGDIOBJ hOldBitmap = SelectObject(hMemDC, hBitmap);

    // copy the screen dc to the memory dc
    BitBlt(hMemDC, 0, 0, width, height, hScrDC, 0, 0, SRCCOPY);
     //if you only want to get the every pixel color value,
     //you can begin here and the following part of this function will be unuseful;
     //the following part is in order to write file;

     //bimap file header in order to write bmp file
     BITMAPFILEHEADER bmBITMAPFILEHEADER;
     ZeroMemory(&bmBITMAPFILEHEADER, sizeof(BITMAPFILEHEADER));
     bmBITMAPFILEHEADER.bfType = 0x4d42;  //bmp
     bmBITMAPFILEHEADER.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
     bmBITMAPFILEHEADER.bfSize = bmBITMAPFILEHEADER.bfOffBits + ((width*height)*3); ///3=(24 / 8)

     DWORD dwNumBytes;

    HANDLE hFile = CreateFile( L"\\Storage Card\\capture.bmp",
                      GENERIC_WRITE,
             (DWORD) 0, NULL, CREATE_ALWAYS,
          FILE_ATTRIBUTE_NORMAL, NULL);

    if (hFile == INVALID_HANDLE_VALUE)
        return ;

    WriteFile(hFile, &bmBITMAPFILEHEADER, sizeof(BITMAPFILEHEADER), &dwNumBytes, NULL); // Write the file header
    WriteFile(hFile, &(RGB24BitsBITMAPINFO.bmiHeader), sizeof(BITMAPINFOHEADER), &dwNumBytes, NULL); // Write the DIB header
    WriteFile(hFile, lpBitmapBits, 3*width*height, &dwNumBytes, NULL); //Write DIB bits
    FlushFileBuffers(hFile);

    CloseHandle(hFile);

     //delete
     DeleteObject(hMemDC);
     DeleteObject(hScrDC);
     DeleteObject(hBitmap);
     DeleteObject(hOldBitmap);
}

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迴響（1） ：
1樓. W_T@guest
2010/10/07 22:44
Re: 如何用C程式語言擷取全螢幕，並輸出成BMP檔案
請問要如何用BCB擷取全螢幕
hScrDC = CreateDC(_T("DISPLAY"), NULL, NULL, NULL);
這裡會有問題耶