SDL/src/events/SDL_windowevents.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

// Window event handling code for SDL

#include "SDL_events_c.h"
#include "SDL_eventwatch_c.h"
#include "SDL_mouse_c.h"
#include "../tray/SDL_tray_utils.h"


#define NUM_WINDOW_EVENT_WATCH_PRIORITIES (SDL_WINDOW_EVENT_WATCH_NORMAL + 1)

static SDL_EventWatchList SDL_window_event_watchers[NUM_WINDOW_EVENT_WATCH_PRIORITIES];

void SDL_InitWindowEventWatch(void)
{
    for (int i = 0; i < SDL_arraysize(SDL_window_event_watchers); ++i) {
        SDL_InitEventWatchList(&SDL_window_event_watchers[i]);
    }
}

void SDL_QuitWindowEventWatch(void)
{
    for (int i = 0; i < SDL_arraysize(SDL_window_event_watchers); ++i) {
        SDL_QuitEventWatchList(&SDL_window_event_watchers[i]);
    }
}

void SDL_AddWindowEventWatch(SDL_WindowEventWatchPriority priority, SDL_EventFilter filter, void *userdata)
{
    SDL_AddEventWatchList(&SDL_window_event_watchers[priority], filter, userdata);
}

void SDL_RemoveWindowEventWatch(SDL_WindowEventWatchPriority priority, SDL_EventFilter filter, void *userdata)
{
    SDL_RemoveEventWatchList(&SDL_window_event_watchers[priority], filter, userdata);
}

static bool SDLCALL RemoveSupersededWindowEvents(void *userdata, SDL_Event *event)
{
    SDL_Event *new_event = (SDL_Event *)userdata;

    if (event->type == new_event->type &&
        event->window.windowID == new_event->window.windowID) {
        // We're about to post a new move event, drop the old one
        return false;
    }
    return true;
}

bool SDL_SendWindowEvent(SDL_Window *window, SDL_EventType windowevent, int data1, int data2)
{
    SDL_VideoDevice *_this;
    bool post_event = true;
    bool posted = false;

    if (!window) {
        return false;
    }
    SDL_assert(SDL_ObjectValid(window, SDL_OBJECT_TYPE_WINDOW));

    switch (windowevent) {
    case SDL_EVENT_WINDOW_SHOWN:
        if (!(window->flags & SDL_WINDOW_HIDDEN)) {
            return false;
        }
        window->flags &= ~(SDL_WINDOW_HIDDEN | SDL_WINDOW_MINIMIZED);
        break;
    case SDL_EVENT_WINDOW_HIDDEN:
        if (window->flags & SDL_WINDOW_HIDDEN) {
            return false;
        }
        window->flags |= SDL_WINDOW_HIDDEN;
        break;
    case SDL_EVENT_WINDOW_EXPOSED:
        window->flags &= ~SDL_WINDOW_OCCLUDED;
        break;
    case SDL_EVENT_WINDOW_MOVED:
        window->undefined_x = false;
        window->undefined_y = false;
        /* Clear the pending display if this move was not the result of an explicit request,
         * and the window is not scheduled to become fullscreen when shown.
         */
        if (!window->last_position_pending && !(window->pending_flags & SDL_WINDOW_FULLSCREEN)) {
            window->pending_displayID = 0;
        }
        window->last_position_pending = false;
        if (!(window->flags & SDL_WINDOW_FULLSCREEN)) {
            window->windowed.x = data1;
            window->windowed.y = data2;

            if (!(window->flags & SDL_WINDOW_MAXIMIZED) && !window->tiled) {
                window->floating.x = data1;
                window->floating.y = data2;
            }
        }
        if (data1 == window->x && data2 == window->y) {
            return false;
        }
        window->x = data1;
        window->y = data2;
        break;
    case SDL_EVENT_WINDOW_RESIZED:
        window->last_size_pending = false;
        if (!(window->flags & SDL_WINDOW_FULLSCREEN)) {
            window->windowed.w = data1;
            window->windowed.h = data2;

            if (!(window->flags & SDL_WINDOW_MAXIMIZED) && !window->tiled) {
                window->floating.w = data1;
                window->floating.h = data2;
            }
        }
        if (data1 == window->w && data2 == window->h) {
            SDL_CheckWindowPixelSizeChanged(window);
            return false;
        }
        window->w = data1;
        window->h = data2;
        break;
    case SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED:
        if (data1 == window->last_pixel_w && data2 == window->last_pixel_h) {
            return false;
        }
        window->last_pixel_w = data1;
        window->last_pixel_h = data2;
        break;
    case SDL_EVENT_WINDOW_MINIMIZED:
        if (window->flags & SDL_WINDOW_MINIMIZED) {
            return false;
        }
        window->flags &= ~SDL_WINDOW_MAXIMIZED;
        window->flags |= SDL_WINDOW_MINIMIZED;
        break;
    case SDL_EVENT_WINDOW_MAXIMIZED:
        if (window->flags & SDL_WINDOW_MAXIMIZED) {
            return false;
        }
        window->flags &= ~SDL_WINDOW_MINIMIZED;
        window->flags |= SDL_WINDOW_MAXIMIZED;
        break;
    case SDL_EVENT_WINDOW_RESTORED:
        if (!(window->flags & (SDL_WINDOW_MINIMIZED | SDL_WINDOW_MAXIMIZED))) {
            return false;
        }
        window->flags &= ~(SDL_WINDOW_MINIMIZED | SDL_WINDOW_MAXIMIZED);
        break;
    case SDL_EVENT_WINDOW_MOUSE_ENTER:
        if (window->flags & SDL_WINDOW_MOUSE_FOCUS) {
            return false;
        }
        window->flags |= SDL_WINDOW_MOUSE_FOCUS;
        break;
    case SDL_EVENT_WINDOW_MOUSE_LEAVE:
        if (!(window->flags & SDL_WINDOW_MOUSE_FOCUS)) {
            return false;
        }
        window->flags &= ~SDL_WINDOW_MOUSE_FOCUS;
        break;
    case SDL_EVENT_WINDOW_FOCUS_GAINED:
        if (window->flags & SDL_WINDOW_INPUT_FOCUS) {
            return false;
        }
        window->flags |= SDL_WINDOW_INPUT_FOCUS;
        break;
    case SDL_EVENT_WINDOW_FOCUS_LOST:
        if (!(window->flags & SDL_WINDOW_INPUT_FOCUS)) {
            return false;
        }
        window->flags &= ~SDL_WINDOW_INPUT_FOCUS;
        break;
    case SDL_EVENT_WINDOW_DISPLAY_CHANGED:
        if (data1 == 0 || (SDL_DisplayID)data1 == window->displayID) {
            return false;
        }
        window->update_fullscreen_on_display_changed = true;
        window->displayID = (SDL_DisplayID)data1;
        break;
    case SDL_EVENT_WINDOW_OCCLUDED:
        if (window->flags & SDL_WINDOW_OCCLUDED) {
            return false;
        }
        window->flags |= SDL_WINDOW_OCCLUDED;
        break;
    case SDL_EVENT_WINDOW_ENTER_FULLSCREEN:
        if (window->flags & SDL_WINDOW_FULLSCREEN) {
            return false;
        }
        window->flags |= SDL_WINDOW_FULLSCREEN;
        break;
    case SDL_EVENT_WINDOW_LEAVE_FULLSCREEN:
        if (!(window->flags & SDL_WINDOW_FULLSCREEN)) {
            return false;
        }
        window->flags &= ~SDL_WINDOW_FULLSCREEN;
        break;
    default:
        break;
    }

    if (window->is_destroying && windowevent != SDL_EVENT_WINDOW_DESTROYED) {
        return false;
    }

    // Only post if we are not currently quitting
    _this = SDL_GetVideoDevice();
    if (_this == NULL || _this->is_quitting) {
        post_event = false;
    }

    // Post the event, if desired
    SDL_Event event;
    event.type = windowevent;
    event.common.timestamp = 0;
    event.window.data1 = data1;
    event.window.data2 = data2;
    event.window.windowID = window->id;

    SDL_DispatchEventWatchList(&SDL_window_event_watchers[SDL_WINDOW_EVENT_WATCH_EARLY], &event);
    SDL_DispatchEventWatchList(&SDL_window_event_watchers[SDL_WINDOW_EVENT_WATCH_NORMAL], &event);

    if (post_event && SDL_EventEnabled(windowevent)) {
        // Fixes queue overflow with move/resize events that aren't processed
        if (windowevent == SDL_EVENT_WINDOW_MOVED ||
            windowevent == SDL_EVENT_WINDOW_RESIZED ||
            windowevent == SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED ||
            windowevent == SDL_EVENT_WINDOW_SAFE_AREA_CHANGED ||
            windowevent == SDL_EVENT_WINDOW_EXPOSED ||
            windowevent == SDL_EVENT_WINDOW_OCCLUDED) {
            SDL_FilterEvents(RemoveSupersededWindowEvents, &event);
        }
        posted = SDL_PushEvent(&event);
    }

    // Ensure that the window is still valid, as it may have been destroyed in an event handler.
    window = SDL_GetWindowFromID(event.window.windowID);

    if (window) {
        switch (windowevent) {
        case SDL_EVENT_WINDOW_SHOWN:
            SDL_OnWindowShown(window);
            break;
        case SDL_EVENT_WINDOW_HIDDEN:
            SDL_OnWindowHidden(window);
            break;
        case SDL_EVENT_WINDOW_MOVED:
            SDL_OnWindowMoved(window);
            break;
        case SDL_EVENT_WINDOW_RESIZED:
            SDL_OnWindowResized(window);
            break;
        case SDL_EVENT_WINDOW_PIXEL_SIZE_CHANGED:
            SDL_OnWindowPixelSizeChanged(window);
            break;
        case SDL_EVENT_WINDOW_MINIMIZED:
            SDL_OnWindowMinimized(window);
            break;
        case SDL_EVENT_WINDOW_MAXIMIZED:
            SDL_OnWindowMaximized(window);
            break;
        case SDL_EVENT_WINDOW_RESTORED:
            SDL_OnWindowRestored(window);
            break;
        case SDL_EVENT_WINDOW_MOUSE_ENTER:
            SDL_OnWindowEnter(window);
            break;
        case SDL_EVENT_WINDOW_MOUSE_LEAVE:
            SDL_OnWindowLeave(window);
            break;
        case SDL_EVENT_WINDOW_FOCUS_GAINED:
            SDL_OnWindowFocusGained(window);
            break;
        case SDL_EVENT_WINDOW_FOCUS_LOST:
            SDL_OnWindowFocusLost(window);
            break;
        case SDL_EVENT_WINDOW_DISPLAY_CHANGED:
            SDL_OnWindowDisplayChanged(window);
            break;
        default:
            break;
        }
    }

    if (windowevent == SDL_EVENT_WINDOW_CLOSE_REQUESTED && !SDL_HasActiveTrays()) {
        int count = window ? 0 : 1;
        for (SDL_Window *n = _this->windows; n; n = n->next) {
            if (!n->parent && !(n->flags & SDL_WINDOW_HIDDEN)) {
                ++count;
            }
        }

        if (count <= 1) {
            if (SDL_GetHintBoolean(SDL_HINT_QUIT_ON_LAST_WINDOW_CLOSE, true)) {
                SDL_SendQuit(); // This is the last window in the list, so send the SDL_EVENT_QUIT event
            }
        }
    }

    return posted;
}