ScreenShot.h

#include <atlimage.h>
void ScreenShot(LPCTSTR s);

ScreenShot.cpp

#include "ScreenShot.h"
#include <atlimage.h>
void ScreenShot(LPCTSTR s)
{
    HDC hdcSrc = GetDC(NULL);
    int nBitPerPixel = GetDeviceCaps(hdcSrc, BITSPIXEL);
    int nWidth = GetDeviceCaps(hdcSrc, HORZRES);
    int
 
 nHeight = GetDeviceCaps(hdcSrc, VERTRES);
    CImage image;
    image.Create(nWidth, nHeight, nBitPerPixel);
    BitBlt(image.GetDC(), 0, 0, nWidth, nHeight, hdcSrc, 0, 0, SRCCOPY);
    ReleaseDC(NULL, hdcSrc);
    image.ReleaseDC();
    image.Save(s, Gdiplus::ImageFormatPNG);//ImageFormatJPEG
}

呼叫

    const
 
 char *str = "D:\\test11.bmp";//多位元組字符集可以這麼做，如果是Unicode編碼，則需要轉換成CString後賦值給LPCTSTR
    ScreenShot((LPCTSTR)(CString)str);
    ScreenShot(str);

還有一點注意的是，如果在win10裡設定了縮放，比如縮放125%，那麼擷取的就不是完整的螢幕了。因為GetDeviceCaps返回的是除以125%的結果，1920變成了1536。解決方法目前只有手動指定bitmap的大小了.

第二種方法

#include <windows.h>
HBITMAP CopyScreenToBitmap(LPRECT lpRect)
{

    HDC   hScrDC, hMemDC;
    //   螢幕和記憶體裝置描述表   
 

    HBITMAP   hBitmap, hOldBitmap;
    //   點陣圖控制代碼   
    int               nX, nY, nX2, nY2;
    //   選定區域座標   
    int               nWidth, nHeight;
    //   點陣圖寬度和高度   
    int               xScrn, yScrn;
    //   螢幕解析度   
    //   確保選定區域不為空矩形   
    if (IsRectEmpty(lpRect))
        return   NULL;
    //為螢幕建立裝置描述表   
    hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
    //為螢幕裝置描述表建立相容的記憶體裝置描述表   
    hMemDC = CreateCompatibleDC(hScrDC);
    //   獲得選定區域座標   
    nX = lpRect->left;
    nY = lpRect->top;
    nX2 = lpRect->right;
    nY2 = lpRect->bottom;
    //   獲得螢幕解析度   
    xScrn = GetDeviceCaps(hScrDC, HORZRES);
    yScrn = GetDeviceCaps(hScrDC, VERTRES);
    //確保選定區域是可見的   
    if (nX   <   0)
        nX = 0;
    if (nY   <   0)
        nY = 0;
    if (nX2   >   xScrn)
        nX2 = xScrn;
    if (nY2   >   yScrn)
        nY2 = yScrn;
    nWidth = nX2 - nX;
    nHeight = nY2 - nY;
    //   建立一個與螢幕裝置描述表相容的點陣圖   
    hBitmap = CreateCompatibleBitmap(hScrDC, nWidth, nHeight);
    // hBitmap = (HBITMAP)LoadImage(NULL, ".//MyData//SnapStill.bmp", IMAGE_BITMAP,
    //  0, 0, LR_CREATEDIBSECTION|LR_DEFAULTSIZE|LR_LOADFROMFILE);
    //   把新點陣圖選到記憶體裝置描述表中   
    hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
    //   把螢幕裝置描述表拷貝到記憶體裝置描述表中   
    BitBlt(hMemDC, 0, 0, nWidth, nHeight, hScrDC, nX, nY, SRCCOPY);
    //得到螢幕點陣圖的控制代碼   
    hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
    //清除     
    DeleteDC(hScrDC);
    DeleteDC(hMemDC);
    //   返回點陣圖控制代碼   

    return   hBitmap;

}

BOOL SaveToFile(HBITMAP hBitmap, LPCTSTR lpszFileName)
{
    HDC hDC;
    //當前解析度下每象素所佔位元組數
    int iBits;
    //點陣圖中每象素所佔位元組數
    WORD wBitCount;
    //定義調色盤大小， 點陣圖中畫素位元組大小 ，點陣圖檔案大小 ， 寫入檔案位元組數
    DWORD dwPaletteSize = 0, dwBmBitsSize = 0, dwDIBSize = 0, dwWritten = 0;
    //點陣圖屬性結構
    BITMAP Bitmap;
    //點陣圖檔案頭結構
    BITMAPFILEHEADER bmfHdr;
    //點陣圖資訊頭結構
    BITMAPINFOHEADER bi;
    //指向點陣圖資訊頭結構
    LPBITMAPINFOHEADER lpbi;
    //定義檔案，分配記憶體控制代碼，調色盤控制代碼
    HANDLE fh, hDib, hPal, hOldPal = NULL;

    //計算點陣圖檔案每個畫素所佔位元組數
    hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
    iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);
    DeleteDC(hDC);
    if (iBits <= 1)
        wBitCount = 1;
    else if (iBits <= 4)
        wBitCount = 4;
    else if (iBits <= 8)
        wBitCount = 8;
    else
        wBitCount = 24;
    GetObject(hBitmap, sizeof(Bitmap), (LPSTR)&Bitmap);
    bi.biSize = sizeof(BITMAPINFOHEADER);
    bi.biWidth = Bitmap.bmWidth;
    bi.biHeight = Bitmap.bmHeight;
    bi.biPlanes = 1;
    bi.biBitCount = wBitCount;
    bi.biCompression = BI_RGB;
    bi.biSizeImage = 0;
    bi.biXPelsPerMeter = 0;
    bi.biYPelsPerMeter = 0;
    bi.biClrImportant = 0;
    bi.biClrUsed = 0;
    dwBmBitsSize = ((Bitmap.bmWidth * wBitCount + 31) / 32) * 4 * Bitmap.bmHeight;
    //為點陣圖內容分配記憶體 
    hDib = GlobalAlloc(GHND, dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
    lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
    *lpbi = bi;
    // 處理調色盤  
    hPal = GetStockObject(DEFAULT_PALETTE);
    if (hPal)
    {
        hDC = GetDC(NULL);
        hOldPal = SelectPalette(hDC, (HPALETTE)hPal, FALSE);
        RealizePalette(hDC);
    }

    // 獲取該調色盤下新的畫素值
    GetDIBits(hDC, hBitmap, 0, (UINT)Bitmap.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
        + dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);
    //恢復調色盤
    if (hOldPal)
    {
        SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
        RealizePalette(hDC);
        ReleaseDC(NULL, hDC);
    }
    //建立點陣圖檔案  
    fh = CreateFile(lpszFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,
        FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);

    if (fh == INVALID_HANDLE_VALUE)
        return FALSE;
    // 設定點陣圖檔案頭 
    bmfHdr.bfType = 0x4D42; // "BM"
    dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;
    bmfHdr.bfSize = dwDIBSize;
    bmfHdr.bfReserved1 = 0;
    bmfHdr.bfReserved2 = 0;
    bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;
    // 寫入點陣圖檔案頭
    WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
    // 寫入點陣圖檔案其餘內容
    WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);
    //清除
    GlobalUnlock(hDib);
    GlobalFree(hDib);
    CloseHandle(fh);
    return TRUE;
}
int main()
{
    //HDC fullScreen = GetDC(NULL);
    HDC hdc = GetDC(NULL);
    RECT rect = { 0, 0, GetDeviceCaps(hdc, HORZRES), GetDeviceCaps(hdc, VERTRES) };

    SaveToFile(CopyScreenToBitmap(&rect), "c:\\users\\asus\\desktop\\a.bmp");

    return 0;
}