[转] C++ CImage实现的全屏PNG截图

#include <atlimage.h>
#include <atltime.h>
#include <conio.h>

//截取全屏保存为png
CString ScreenShot()
{
    HDC hDCScreen = ::GetDC(NULL);//首先获取到屏幕的句柄    
    int nBitPerPixel = GetDeviceCaps(hDCScreen, BITSPIXEL);//获取到每个像素的bit数目
    int nWidthScreen = GetDeviceCaps(hDCScreen, HORZRES);
    int nHeightScreen = GetDeviceCaps(hDCScreen, VERTRES);
    //创建一个CImage的对象
    CImage m_MyImage;
    //Create实例化CImage，使得其内部的画布大小与屏幕一致
    m_MyImage.Create(nWidthScreen, nHeightScreen, nBitPerPixel);
    //获取到CImage的 HDC,但是需要手动ReleaseDC操作,下面是MSDN的说明
    //Because only one bitmap can be selected into a device context at a time, 
    //you must call ReleaseDC for each call to GetDC.
    HDC hDCImg = m_MyImage.GetDC();
    //使用bitblt 将屏幕的DC画布上的内容 拷贝到CImage上
    BitBlt(hDCImg, 0, 0, nWidthScreen, nHeightScreen, hDCScreen, 0, 0, SRCCOPY);

    //保存到的文件名
    CString strFileName("C:\\");
    strFileName += _T("ScreenShot\\");
    CreateDirectory((LPCTSTR)strFileName, NULL);
    CTime t = CTime::GetCurrentTime();
    CString tt = t.Format(_T("%Y-%m-%d_%H-%M-%S"));
    strFileName += tt;
    strFileName += _T(".PNG");

    //直接保存吧
    m_MyImage.Save(strFileName, Gdiplus::ImageFormatPNG);

    //前面调用了GetDC所以需要调用ReleaseDC释放掉
    //详情请参见MSDN
    m_MyImage.ReleaseDC();
    return strFileName;
}

void main()
{
    ScreenShot();
    _getch();
}