如何使用 Qt 自动捕获 window

Question

I am using Qt to build a screenshot program.

The question is:

How to obtain the window handle below the mouse cursor? Firstly, I created a full-screen Qt widget to display the fullscreen screenshot. When I move the mouse cursor, how to obtain the handle of window under the cursor? Of course, the full-screen Qt widget should be ignored.

I tried to use win32 API, such as WindowFromPointEx() by filtering the windows with WS_EX_LAYERED attribute. However, I cannot set Qt widget as WS_EX_LAYERED attribute.

What should I do to obtain the handle of the window?

Answer 1

On windows you can use to add WS_EX_TRANSPARENT attribute for QT full screen program, and this will make Qt widget ignore keyboard or mouse events.

Then you can use WindowFromPoint to obtain the handle of window under the cursor.

I have tested it on the win32 desktop program and it works for me. Because I am not familiar with the use of QT, but some similar examples show that this method is feasible.

Refer @JProgrammer's answer ,

To do this in Qt use the following code:

Include the header,

#if _WIN32
    #include <windows.h>
#endif

and put the following code into the constructor.

#if _WIN32
    HWND hwnd = (HWND) winId();
    LONG styles = GetWindowLong(hwnd, GWL_EXSTYLE);
    SetWindowLong(hwnd, GWL_EXSTYLE, styles | WS_EX_TRANSPARENT);
#endif

Or refer @mxttie's answer ,

setWindowFlags(windowFlags() | Qt::WindowTransparentForInput);