CODEWITHSUNDEEP
winapirust
MindSwipe
MindSwipe

Reputation: 7855

How to pass RawWindowHandle::Windows to winapi::winuser::SetWindowPos

I'm trying to make a window I created using the winit crate be always on top (HWND_TOPMOST). I'm creating my window, and getting the RawWindowHandle::Windows from it. That struct has a pub hwnd which is a *mut c_void. And my question now is, how can I convert that *mut c_void to a *mut winapi::shared::windef::HWND__ so I can pass it to winapi::winuser::SetWindowPos(...)?

Here's my code for getting the raw window handle:

let win_handle = match window.raw_window_handle() {
    RawWindowHandle::Windows(windows_handle) => windows_handle.hwnd,
    _ => panic!("Unsupported platform!"),
};

And this is my code passing win_handle to SetWindowPos:

unsafe {
    if winuser::SetWindowPos(win_handle, winuser::HWND_TOPMOST, 0, 0, 0, 0, winuser::SWP_NOMOVE | winuser::SWP_NOSIZE) == 1 {
        println!("Success");
    } else {
        println!("Failure");
    }
}

What am I doing wrong?

Upvotes: 0

Views: 947

Answers (1)

MindSwipe
MindSwipe

Reputation: 7855

Turns out, there is a HWND struct to which you can simply cast the *mut c_void, like so:

let winapi_handle = win_handle as winuser::shared::windef::HWND;

// Or even simple, cast it in the call with 'as _'
// Shoutout to @IInspectable
SetWindowPos(win_handle as _, winuser::HWND_TOPMOST, 0, 0, 0, 0, winuser::SWP_NOMOVE | winuser::SWP_NOSIZE)

Edit: It was only after I tried this that I actually googled "Winit set window always on top" and found this. So, when constructing your window using a WindowBuilder you can simply call

window_builder.with_always_on_top(true)

And it will do it for you on all supported platforms (Linux, Windows and MacOS. Adnroid, iOS and the Web do not support it)

Upvotes: 1

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