cocoa/libmpv: allow to embed mpv GL view in another window

This is just temporary code but is a good base for future work (and baby
steps are required for these changes). The 'final destination' is embedding
the video view into any NSView but that requires some more work (the mechanism
will be the same: pass the view's pointer casted to int64_t through -wid).

For instance we will need to remove as much usage of the window instance
as possible, and use nil guards where not possible. For this reason I will
remove stuff like the mission control fullscreen feature (it's a cute feature
but annoying to support and quite limited, go make your GUIs), and a way to
lookup the current screen directly from the NSView absolute coordinates
(this is needed for ICC detection mostly, and reporting back the screen to
mpv's core).

Moreover the current view.m will need to be separated into 2 views: the actual
video view that will be embedded, and a parent view that will not be embedded
and will be responsibile for tracking events.

3 files changed, 81 insertions, 30 deletions

diff --git a/video/out/cocoa/window.h b/video/out/cocoa/window.h
index 88c054ac8d..e325be343e 100644
--- a/video/out/cocoa/window.h
+++ b/video/out/cocoa/window.h
@@ -18,13 +18,17 @@
 #import <Cocoa/Cocoa.h>
 #import "video/out/cocoa/mpvadapter.h"
 
-@interface MpvVideoWindow : NSWindow <NSWindowDelegate>
-@property(nonatomic, retain) MpvCocoaAdapter *adapter;
+@protocol MpvSizing
+- (void)queueNewVideoSize:(NSSize)newSize;
+@end
+
+@protocol MpvFullscreen
 - (void)setFullScreen:(BOOL)willBeFullscreen;
+@end
+
+@interface MpvVideoWindow : NSWindow <NSWindowDelegate, MpvSizing, MpvFullscreen>
+@property(nonatomic, retain) MpvCocoaAdapter *adapter;
 - (BOOL)canBecomeKeyWindow;
 - (BOOL)canBecomeMainWindow;
 - (void)mulSize:(float)multiplier;
-- (NSRect)frameRect:(NSRect)frameRect forCenteredContentSize:(NSSize)newSize;
-- (void)setCenteredContentSize:(NSSize)newSize;
-- (void)queueNewVideoSize:(NSSize)newSize;
 @end
diff --git a/video/out/cocoa/window.m b/video/out/cocoa/window.m
index ebd3eaf957..597fa35d58 100644
--- a/video/out/cocoa/window.m
+++ b/video/out/cocoa/window.m
@@ -27,6 +27,11 @@
 
 #include "window.h"
 
+@interface MpvVideoWindow()
+- (NSRect)frameRect:(NSRect)frameRect forCenteredContentSize:(NSSize)newSize;
+- (void)setCenteredContentSize:(NSSize)newSize;
+@end
+
 @implementation MpvVideoWindow {
     NSSize _queued_video_size;
 }
diff --git a/video/out/cocoa_common.m b/video/out/cocoa_common.m
index 7570f51637..9c81c1e8c0 100644
--- a/video/out/cocoa_common.m
+++ b/video/out/cocoa_common.m
@@ -57,7 +57,7 @@ static void cocoa_change_profile(struct vo *vo, char **store, NSScreen *screen);
 static void cocoa_rm_fs_screen_profile_observer(struct vo *vo);
 
 struct vo_cocoa_state {
-    MpvVideoWindow *window;
+    NSWindow *window;
     MpvVideoView *view;
     NSOpenGLContext *gl_ctx;
 
@@ -98,6 +98,15 @@ static void with_cocoa_lock_on_main_thread(struct vo *vo, void(^block)(void))
     });
 }
 
+static void queue_new_video_size(struct vo *vo, int w, int h)
+{
+    struct vo_cocoa_state *s = vo->cocoa;
+    if ([s->window conformsToProtocol: @protocol(MpvSizing)]) {
+        id<MpvSizing> win = (id<MpvSizing>) s->window;
+        [win queueNewVideoSize:NSMakeSize(w, h)];
+    }
+}
+
 void *vo_cocoa_glgetaddr(const char *s)
 {
     void *ret = NULL;
@@ -233,6 +242,12 @@ static void resize_window(struct vo *vo)
 static void vo_set_level(struct vo *vo, int ontop)
 {
     struct vo_cocoa_state *s = vo->cocoa;
+    struct mp_vo_opts *opts = vo->opts;
+
+    // completely ignore window level commands when the window is embedded
+    if (opts->WinID >= 0)
+        return;
+
     if (ontop) {
         // +1 is not enough as that will show the icon layer on top of the
         // menubar when the application is not frontmost. so use +2
@@ -252,28 +267,44 @@ static void vo_cocoa_ontop(struct vo *vo)
     vo_set_level(vo, opts->ontop);
 }
 
-static void create_window(struct vo *vo, struct mp_rect *win, int geo_flags)
+static MpvVideoWindow *create_window(NSRect rect, NSScreen *s, bool border,
+                                     MpvCocoaAdapter *adapter)
 {
-    struct vo_cocoa_state *s = vo->cocoa;
-    struct mp_vo_opts *opts  = vo->opts;
-
-    const NSRect contentRect =
-        NSMakeRect(win->x0, win->y0, win->x1 - win->x0, win->y1 - win->y0);
-
     int window_mask = 0;
-    if (opts->border) {
+    if (border) {
         window_mask = NSTitledWindowMask|NSClosableWindowMask|
                       NSMiniaturizableWindowMask|NSResizableWindowMask;
     } else {
         window_mask = NSBorderlessWindowMask|NSResizableWindowMask;
     }
 
-    s->window =
-        [[MpvVideoWindow alloc] initWithContentRect:contentRect
+    MpvVideoWindow *w =
+        [[MpvVideoWindow alloc] initWithContentRect:rect
                                           styleMask:window_mask
                                             backing:NSBackingStoreBuffered
                                               defer:NO
-                                             screen:s->current_screen];
+                                             screen:s];
+    w.adapter = adapter;
+    [w setDelegate: w];
+
+    return w;
+}
+
+static void create_ui(struct vo *vo, struct mp_rect *win, int geo_flags)
+{
+    struct vo_cocoa_state *s = vo->cocoa;
+    struct mp_vo_opts *opts  = vo->opts;
+
+    MpvCocoaAdapter *adapter = [[[MpvCocoaAdapter alloc] init] autorelease];
+    const NSRect contentRect =
+        NSMakeRect(win->x0, win->y0, win->x1 - win->x0, win->y1 - win->y0);
+
+    if (opts->WinID >= 0) {
+        s->window = (NSWindow *) opts->WinID;
+    } else {
+        s->window = create_window(contentRect, s->current_screen,
+                                  opts->border, adapter);
+    }
     s->view = [[[MpvVideoView alloc] initWithFrame:contentRect] autorelease];
 
     [s->view setWantsBestResolutionOpenGLSurface:YES];
@@ -286,20 +317,18 @@ static void create_window(struct vo *vo, struct mp_rect *win, int geo_flags)
     cocoa_register_menu_item_action(MPM_ZOOM,     @selector(performZoom:));
 #endif
 
-    [s->window setRestorable:NO];
     [s->window setContentView:s->view];
     [s->gl_ctx setView:s->view];
 
-    MpvCocoaAdapter *adapter = [[[MpvCocoaAdapter alloc] init] autorelease];
     adapter.vout = vo;
     s->view.adapter = adapter;
-    s->window.adapter = adapter;
-
-    [s->window setDelegate:s->window];
-    [s->window makeMainWindow];
 
-    [s->window makeKeyAndOrderFront:nil];
-    [NSApp activateIgnoringOtherApps:YES];
+    if (opts->WinID < 0) {
+        [s->window setRestorable:NO];
+        [s->window makeMainWindow];
+        [s->window makeKeyAndOrderFront:nil];
+        [NSApp activateIgnoringOtherApps:YES];
+    }
 
     vo_set_level(vo, opts->ontop);
 
@@ -312,6 +341,10 @@ static void create_window(struct vo *vo, struct mp_rect *win, int geo_flags)
 static void cocoa_set_window_title(struct vo *vo, const char *title)
 {
     struct vo_cocoa_state *s = vo->cocoa;
+    struct mp_vo_opts *opts  = vo->opts;
+    if (opts->WinID >= 0)
+        return;
+
     void *talloc_ctx   = talloc_new(NULL);
     struct bstr btitle = bstr_sanitize_utf8_latin1(talloc_ctx, bstr0(title));
     NSString *nstitle  = [NSString stringWithUTF8String:btitle.start];
@@ -381,16 +414,22 @@ int vo_cocoa_config_window(struct vo *vo, uint32_t flags, void *gl_ctx)
         s->old_dwidth  = width;
         s->old_dheight = height;
 
-        if (!(flags & VOFLAG_HIDDEN) && !s->window)
-            create_window(vo, &geo.win, geo.flags);
+        if (!(flags & VOFLAG_HIDDEN) && !s->window) {
+            create_ui(vo, &geo.win, geo.flags);
+        }
 
         if (s->window) {
             if (reset_size)
-                [s->window queueNewVideoSize:NSMakeSize(width, height)];
+                queue_new_video_size(vo, width, height);
             cocoa_set_window_title(vo, vo_get_window_title(vo));
             vo_cocoa_fullscreen(vo);
             cocoa_add_fs_screen_profile_observer(vo);
         }
+
+        // trigger a resize -> don't set vo->dwidth and vo->dheight directly
+        // since this block is executed asynchrolously to the video
+        // reconfiguration code.
+        s->did_resize = true;
     });
     return 0;
 }
@@ -460,7 +499,10 @@ static void vo_cocoa_fullscreen(struct vo *vo)
     vo_cocoa_update_screen_info(vo, NULL);
 
     if (opts->fs_missioncontrol) {
-        [s->window setFullScreen:opts->fullscreen];
+        if ([s->window conformsToProtocol:@protocol(MpvFullscreen)]) {
+            id<MpvFullscreen> win = (id<MpvFullscreen>) s->window;
+            [win setFullScreen:opts->fullscreen];
+        }
     } else {
         draw_changes_after_next_frame(vo);
         [s->view setFullScreen:opts->fullscreen];
@@ -606,7 +648,7 @@ int vo_cocoa_control(struct vo *vo, int *events, int request, void *arg)
     case VOCTRL_SET_UNFS_WINDOW_SIZE: {
         with_cocoa_lock(vo, ^{
             int *s = arg;
-            [vo->cocoa->window queueNewVideoSize:NSMakeSize(s[0], s[1])];
+            queue_new_video_size(vo, s[0], s[1]);
         });
         return VO_TRUE;
     }