Update fullscreen background color immediately

It is no longer necessary to exit and re-enter fullscreen to see changes
to the "background" setting in 'fopt'.

src/MacVim/MMBackend.h

@@ -111,6 +111,7 @@
 
 - (void)enterFullscreen:(int)fuoptions background:(int)bg;
 - (void)leaveFullscreen;
+- (void)setFullscreenBackgroundColor:(int)color;
 
 - (void)setAntialias:(BOOL)antialias;
 

src/MacVim/MMBackend.m

@@ -1019,6 +1019,15 @@ static NSString *MMSymlinkWarningString =
     [self queueMessage:LeaveFullscreenMsgID data:nil];
 }
 
+- (void)setFullscreenBackgroundColor:(int)color
+{
+    NSMutableData *data = [NSMutableData data];
+    color = MM_COLOR(color);
+    [data appendBytes:&color length:sizeof(int)];
+
+    [self queueMessage:SetFullscreenColorMsgID data:data];
+}
+
 - (void)setAntialias:(BOOL)antialias
 {
     int msgid = antialias ? EnableAntialiasMsgID : DisableAntialiasMsgID;

src/MacVim/MMVimController.m

@@ -923,6 +923,11 @@ static BOOL isUnsafeMessage(int msgid);
         }
     } else if (CloseWindowMsgID == msgid) {
         [self scheduleClose];
+    } else if (SetFullscreenColorMsgID == msgid) {
+        const int *bg = (const int*)[data bytes];
+        NSColor *color = [NSColor colorWithRgbInt:bg];
+
+        [windowController setFullscreenBackgroundColor:color];
     // IMPORTANT: When adding a new message, make sure to update
     // isUnsafeMessage() if necessary!
     } else {

src/MacVim/MMWindowController.h

@@ -62,6 +62,8 @@
 
 - (void)enterFullscreen:(int)fuoptions backgroundColor:(NSColor *)back;
 - (void)leaveFullscreen;
+- (void)setFullscreenBackgroundColor:(NSColor *)back;
+
 - (void)setBuffersModified:(BOOL)mod;
 
 - (IBAction)addNewTab:(id)sender;

src/MacVim/MMWindowController.m

@@ -571,6 +571,12 @@
     shouldResizeVimView = YES;
 }
 
+- (void)setFullscreenBackgroundColor:(NSColor *)back
+{
+    if (fullscreenEnabled)
+        [fullscreenWindow setBackgroundColor:back];
+}
+
 - (void)setBuffersModified:(BOOL)mod
 {
     // NOTE: We only set the document edited flag on the decorated window since

src/MacVim/MacVim.h

@@ -174,6 +174,7 @@ enum {
     OpenWithArgumentsMsgID,
     CloseWindowMsgID,
     InterruptMsgID,
+    SetFullscreenColorMsgID,
 };
 
 

src/MacVim/MacVim.m

@@ -81,6 +81,7 @@ char *MessageStrings[] =
     "OpenWithArgumentsMsgID",
     "CloseWindowMsgID",
     "InterruptMsgID",
+    "SetFullscreenColorMsgID",
 };
 
 

src/MacVim/gui_macvim.m

@@ -1599,6 +1599,20 @@ gui_mch_leave_fullscreen()
 }
 
 
+    void
+gui_mch_fuopt_update()
+{
+    guicolor_T fg, bg;
+    if (fuoptions_flags & FUOPT_BGCOLOR_HLGROUP) {
+        syn_id2colors(fuoptions_bgcolor, &fg, &bg);
+    } else {
+        bg = fuoptions_bgcolor;
+    }
+
+    [[MMBackend sharedInstance] setFullscreenBackgroundColor:bg];
+}
+
+
     void
 gui_macvim_update_modified_flag()
 {

src/option.c

@@ -10875,6 +10875,10 @@ check_fuoptions(p_fuoptions, flags, bgcolor)
 
     *flags = new_fuoptions_flags;
     *bgcolor = new_fuoptions_bgcolor;
+
+    /* Let the GUI know, in case the background color has changed. */
+    gui_mch_fuopt_update();
+
     return OK;
 }
 #endif

src/proto/gui_macvim.pro

@@ -192,6 +192,7 @@ int serverSendReply(char_u *serverid, char_u *str);
 
 void gui_mch_enter_fullscreen(int fuoptions_flags, guicolor_T bg);
 void gui_mch_leave_fullscreen(void);
+void gui_mch_fuopt_update(void);
 
 void gui_macvim_update_modified_flag();
 void gui_macvim_add_to_find_pboard(char_u *pat);