如何在 C++ 中将窗口的屏幕截图作为位图对象获取? [英] How to get screenshot of a window as bitmap object in C++?

问题描述

如何在 C++ 中将窗口的屏幕截图作为位图对象获取?假设我已经有了窗口句柄.我还想知道是否可以在窗口处于最小化状态时获取屏幕截图?

How to get screenshot of a window as bitmap object in C++? Supposed that I already have the window handle. And I want to know also whether it's possible to get the screenshot of a window when it's in minimized state?

这里的 C++ 是指 VC++ 以及与 Windows XP+ (win32) 相关的所有库.

C++ here means VC++ with all the libraries associated with Windows XP+ (win32).

推荐答案

你应该调用 PrintWindow API:

you should call the PrintWindow API:

void CScreenShotDlg::OnPaint()
{
    // device context for painting
    CPaintDC dc(this);

    // Get the window handle of calculator application.
    HWND hWnd = ::FindWindow( 0, _T( "Calculator" ));

    // Take screenshot.
    PrintWindow( hWnd,
                 dc.GetSafeHdc(),
                 0 );
}

看到这个问题:获取窗口截图windows API

如果你不使用 MFC，这里是纯 PrintWindow 签名:

if you are not using MFC, here the pure PrintWindow signature:

BOOL PrintWindow(
    HWND hwnd,
    HDC hdcBlt,
    UINT nFlags
);

有关更多详细信息，请参阅 MSDN:http:///msdn.microsoft.com/en-us/library/dd162869(v=vs.85).aspx

see MSDN for more details: http://msdn.microsoft.com/en-us/library/dd162869(v=vs.85).aspx

关于如何像Matteo所说的那样将其保存为位图取决于您使用的实际框架...

about how to save it as bitmap asMatteo said depends on the actual framework you are using...

这里是原始 C++ 中的完整示例

here full example in raw C++

#define _WIN32_WINNT    0x0501        //xp
#include <windows.h>

int main()
{ 
    RECT rc;
    HWND hwnd = FindWindow(TEXT("Notepad"), NULL);    //the window can't be min
    if (hwnd == NULL)
    {
        cout << "it can't find any 'note' window" << endl;
        return 0;
    }
    GetClientRect(hwnd, &rc);

    //create
    HDC hdcScreen = GetDC(NULL);
    HDC hdc = CreateCompatibleDC(hdcScreen);
    HBITMAP hbmp = CreateCompatibleBitmap(hdcScreen, 
        rc.right - rc.left, rc.bottom - rc.top);
    SelectObject(hdc, hbmp);

    //Print to memory hdc
    PrintWindow(hwnd, hdc, PW_CLIENTONLY);

    //copy to clipboard
    OpenClipboard(NULL);
    EmptyClipboard();
    SetClipboardData(CF_BITMAP, hbmp);
    CloseClipboard();

    //release
    DeleteDC(hdc);
    DeleteObject(hbmp);
    ReleaseDC(NULL, hdcScreen);

    cout << "success copy to clipboard, please paste it to the 'mspaint'" << endl;

    return 0;
}

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