video/out/w32_common: add --focus-on support for Windows

DOCS/man/options.rst

@@ -3488,9 +3488,13 @@ Window
     :level:   A level as integer.
 
 ``--focus-on=<never|open|all>``,
-    (X11 and macOS only)
+    (Windows, X11 and macOS only)
     Focus the video window and make it the front most window on specific events (default: open).
 
+    On Windows, due to the system's focus stealing prevention mechanism,
+    ``--force-window=immediate`` is recommended for ``open`` and ``all``
+    to work reliably.
+
     :never: Never focus the window on open or new file load events.
     :open:  Focus the window on creation, eg when a vo is initialised.
     :all:   Focus the window on open and new file load event.

player/loadfile.c

@@ -2052,8 +2052,11 @@ static void play_current_file(struct MPContext *mpctx)
                      current && current->reloading;
     if (current)
         current->reloading = false;
-    if (!reloading)
+    if (!reloading) {
+        if (mpctx->video_out)
+            vo_set_changing_file(mpctx->video_out);
         m_config_restore_backups(mpctx->mconfig);
+    }
 
     TA_FREEP(&mpctx->filter_root);
     talloc_free(mpctx->filtered_tags);

video/out/vo.c

@@ -139,6 +139,7 @@ struct vo_internal {
     bool paused;
     bool visible;
     bool wakeup_on_done;
+    bool changing_file;
     int queued_events;              // event mask for the user
     int internal_events;            // event mask for us
 
@@ -237,18 +238,32 @@ static void read_opts(struct vo *vo)
 static void update_opts(void *p)
 {
     struct vo *vo = p;
+    struct vo_internal *in = vo->in;
 
     if (m_config_cache_update(vo->opts_cache)) {
         read_opts(vo);
-        if (vo->driver->control) {
-            vo->driver->control(vo, VOCTRL_VO_OPTS_CHANGED, NULL);
+        vo->driver->control(vo, VOCTRL_VO_OPTS_CHANGED, NULL);
+        if (!in->changing_file) {
             // "Legacy" update of video position related options.
             // Unlike VOCTRL_VO_OPTS_CHANGED, often not propagated to backends.
             vo->driver->control(vo, VOCTRL_SET_PANSCAN, NULL);
         }
     }
 }
 
+static void handle_file_change(struct vo *vo)
+{
+    struct vo_internal *in = vo->in;
+
+    if (in->changing_file) {
+        in->changing_file = false;
+        vo->driver->control(vo, VOCTRL_SET_PANSCAN, NULL);
+
+        if (vo->opts->focus_on == 2)
+            vo->driver->control(vo, VOCTRL_BRING_FRONT, NULL);
+    }
+}
+
 // Does not include thread- and VO uninit.
 static void dealloc_vo(struct vo *vo)
 {
@@ -1014,6 +1029,8 @@ static bool render_frame(struct vo *vo)
 
         stats_time_start(in->stats, "video-flip");
 
+        handle_file_change(vo);
+
         vo->driver->flip_page(vo);
 
         struct vo_vsync_info vsync = {
@@ -1071,6 +1088,13 @@ static bool render_frame(struct vo *vo)
     return more_frames;
 }
 
+void vo_set_changing_file(struct vo *vo)
+{
+    mp_mutex_lock(&vo->in->lock);
+    vo->in->changing_file = true;
+    mp_mutex_unlock(&vo->in->lock);
+}
+
 static void do_redraw(struct vo *vo)
 {
     struct vo_internal *in = vo->in;

video/out/vo.h

@@ -133,6 +133,8 @@ enum mp_voctrl {
     // Clipboard
     VOCTRL_GET_CLIPBOARD,               // struct voctrl_clipboard*
     VOCTRL_SET_CLIPBOARD,
+
+    VOCTRL_BRING_FRONT,
 };
 
 // Helper to expose what kind of content is currently playing to the VO.
@@ -542,6 +544,7 @@ bool vo_want_redraw(struct vo *vo);
 void vo_seek_reset(struct vo *vo);
 void vo_destroy(struct vo *vo);
 void vo_set_paused(struct vo *vo, bool paused);
+void vo_set_changing_file(struct vo *vo);
 int64_t vo_get_drop_count(struct vo *vo);
 void vo_increment_drop_count(struct vo *vo, int64_t n);
 int64_t vo_get_delayed_count(struct vo *vo);

video/out/w32_common.c

@@ -1987,6 +1987,9 @@ static void window_resize(struct vo_w32_state *w32)
             ShowWindow(w32->window, SW_SHOWMINNOACTIVE);
         } else if (w32->opts->window_maximized && !w32->current_fs) {
             ShowWindow(w32->window, SW_SHOWMAXIMIZED);
+        } else if (w32->opts->focus_on == 0) {
+            ShowWindow(w32->window, SW_SHOWNOACTIVATE);
+            SetWindowPos(w32->window, HWND_BOTTOM, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
         } else {
             ShowWindow(w32->window, SW_SHOW);
         }
@@ -2305,6 +2308,7 @@ static bool gui_thread_control_supports(int request)
     case VOCTRL_BEGIN_DRAGGING:
     case VOCTRL_SHOW_MENU:
     case VOCTRL_UPDATE_MENU:
+    case VOCTRL_BRING_FRONT:
         return true;
     }
 
@@ -2499,12 +2503,17 @@ static int gui_thread_control(struct vo_w32_state *w32, int request, void *arg)
     case VOCTRL_SHOW_MENU:
         PostMessageW(w32->window, WM_SHOWMENU, 0, 0);
         return VO_TRUE;
-    case VOCTRL_UPDATE_MENU:;
+    case VOCTRL_UPDATE_MENU:
         const m_option_t menu_data_type = {.type = CONF_TYPE_NODE};
         m_option_free(&menu_data_type, &w32->menu_data);
         m_option_copy(&menu_data_type, &w32->menu_data, arg);
         talloc_steal(w32, node_get_alloc(&w32->menu_data));
         return VO_TRUE;
+    case VOCTRL_BRING_FRONT:
+        if (SetForegroundWindow(w32->window) != FALSE)
+            return VO_TRUE;
+
+        return VO_FALSE;
     }
 
     // Keep gui_thread_control_supports() in sync