macosx: implemented option-click on playlist button to hide the playlist (refs #6122)

(cherry picked from commit 2eda8d45)

modules/gui/macosx/MainWindow.h

@@ -43,6 +43,7 @@
     IBOutlet id o_effects_btn;
     IBOutlet id o_fullscreen_btn;
     IBOutlet id o_search_fld;
+    IBOutlet id o_topbar_view;
     IBOutlet id o_volume_sld;
     IBOutlet id o_volume_track_view;
     IBOutlet id o_volume_down_btn;
@@ -74,6 +75,8 @@
     BOOL b_nativeFullscreenMode;
     BOOL b_video_playback_enabled;
     BOOL b_dropzone_active;
+    BOOL b_splitview_removed;
+    int i_lastSplitViewHeight;
     int i_lastShownVolume;
     input_state_e cachedInputState;
 

modules/gui/macosx/MainWindow.m

@@ -562,8 +562,45 @@ static VLCMainWindow *_o_sharedInstance = nil;
     [[VLCCoreInteraction sharedInstance] stop];
 }
 
+- (void)resizePlaylistAfterCollapse
+{
+    NSRect plrect;
+    plrect = [[o_playlist_table animator] frame];
+    plrect.size.height = i_lastSplitViewHeight - 22.0; // actual pl top bar height, which differs from its frame
+    [[o_playlist_table animator] setFrame: plrect];
+}
+
 - (IBAction)togglePlaylist:(id)sender
 {
+    if ((([[NSApp currentEvent] modifierFlags] & NSAlternateKeyMask) != 0) && !b_splitview_removed)
+    {
+        NSRect winrect = [self frame];
+        i_lastSplitViewHeight = [o_split_view frame].size.height;
+        winrect.size.height = winrect.size.height - i_lastSplitViewHeight;
+        winrect.origin.y = winrect.origin.y + i_lastSplitViewHeight;
+        [self setFrame: winrect display: YES animate: YES];
+        [self performSelector:@selector(hideDropZone) withObject:nil afterDelay:0.1];
+        b_splitview_removed = YES;
+    }
+    else
+    {
+        if (b_splitview_removed)
+        {
+            NSRect winrect;
+
+            winrect = [self frame];
+            winrect.size.height = winrect.size.height + i_lastSplitViewHeight;
+            winrect.origin.y = winrect.origin.y - i_lastSplitViewHeight;
+            [self setFrame: winrect display: YES animate: YES];
+
+            [self performSelector:@selector(resizePlaylistAfterCollapse) withObject: nil afterDelay:0.75];
+            if (b_dropzone_active)
+                [self performSelector:@selector(showDropZone) withObject: nil afterDelay:0.3];
+
+            b_splitview_removed = NO;
+            return;
+        }
+
         if (b_dropzone_active && ![[VLCMain sharedInstance] activeVideoPlayback])
         {
             b_dropzone_active = NO;
@@ -590,6 +627,7 @@ static VLCMainWindow *_o_sharedInstance = nil;
             [o_playlist_table setHidden: NO];
             [o_video_view setHidden: ![[VLCMain sharedInstance] activeVideoPlayback]];
         }
+    }
 }
 
 - (void)setRepeatOne