Incorrect FOCUS_GAINED in Wine when a fullscreen window is minimized from focus loss

[madewokherd]

In some cases, when a fullscreen window loses focus, SDL will minimize it. If this happens in Wine, starting with SDL 2.0.18 (I also tested 2.0.20 and main), the window receives SDL_WINDOWEVENT_FOCUS_GAINED when it's minimized.

Here is a test program to reproduce the bug:

#include <SDL2/SDL.h>
#include <stdio.h>

int wmain(int argc, wchar_t* argv[])
{
    SDL_Window *window;
    int is_fullscreen = 0;

    SDL_Init(SDL_INIT_EVERYTHING);

    SDL_SetHint(SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS, "1");

    window = SDL_CreateWindow("Test", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 320, 240, 0);

    if (!window)
        return 1;

    while (1)
    {
        SDL_Event event;

        if (SDL_WaitEvent(&event))
        {
            switch (event.type)
            {
            case SDL_QUIT:
                printf("got SDL_QUIT\n");
                SDL_DestroyWindow(window);
                SDL_Quit();
                return 0;
            case SDL_MOUSEBUTTONDOWN:
                is_fullscreen = !is_fullscreen;
                printf("Setting fullscreen: %i\n", is_fullscreen);
                SDL_SetWindowFullscreen(window, is_fullscreen ? SDL_WINDOW_FULLSCREEN_DESKTOP : 0);
                printf("Done setting fullscreen\n");
                break;
            default:
                break;
            }
        }
        else
        {
            printf("SDL_WaitEvent failed %s\n", SDL_GetError());
        }
    }

    return 0;
}

This uses wmain because that was the easiest way I could get it to build in mingw. It should work the same with main or WinMain.

To reproduce the bug:

• Run the test program in Wine with SDL_EVENT_LOGGING=1.
• Click the window to fullscreen it.
• Alt+tab to another window.
• The last focus event logged was FOCUS_GAINED.

This appears to be a Wine bug, but I wanted to file it here so I could send in a work-around. I don't think this is really a regression, it's just that previous versions didn't detect the focus loss in Wine.

There is also a bug where the window does not restore to fullscreen correctly, but I will file that separately.

[madewokherd]

Winehq bug report: https://bugs.winehq.org/show_bug.cgi?id=52519

[madewokherd]

Filed #5320 for the fullscreen issue.