Move to a "more macOS" fullscreen mode (#5453)

Also fixes flickering and reported screen size issues (cannot find the number)
More info at glfw/glfw#2660

internal/driver/glfw/window_darwin.go

@@ -2,7 +2,18 @@
 
 package glfw
 
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Foundation -framework AppKit
+
+#import <stdbool.h>
+
+void setFullScreen(bool full, void *window);
+*/
+import "C"
 import (
+	"runtime"
+
 	"fyne.io/fyne/v2/driver"
 )
 
@@ -17,3 +28,11 @@ func (w *window) RunNative(f func(any)) {
 
 	f(context)
 }
+
+func (w *window) doSetFullScreen(full bool) {
+	if runtime.GOOS == "darwin" {
+		win := w.view().GetCocoaWindow()
+		C.setFullScreen(C.bool(full), win)
+		return
+	}
+}

internal/driver/glfw/window_darwin.m

@@ -0,0 +1,14 @@
+#import <Foundation/Foundation.h>
+#import <AppKit/AppKit.h>
+
+void setFullScreen(bool full, void *win) {
+    NSWindow *window = (NSWindow*)win;
+
+    NSUInteger masks = [window styleMask];
+    bool isFull = masks & NSWindowStyleMaskFullScreen;
+    if (isFull == full) {
+        return;
+    }
+
+    [window toggleFullScreen:NULL];
+}

internal/driver/glfw/window_desktop.go

@@ -116,22 +116,8 @@ type window struct {
 func (w *window) SetFullScreen(full bool) {
 	w.runOnMainWhenCreated(func() {
 		w.fullScreen = full
-		if !w.visible {
-			return
-		}
-
-		monitor := w.getMonitorForWindow()
-		mode := monitor.GetVideoMode()
 
-		if full {
-			w.viewport.SetMonitor(monitor, 0, 0, mode.Width, mode.Height, mode.RefreshRate)
-		} else {
-			if w.width == 0 && w.height == 0 { // if we were fullscreen on creation...
-				s := w.canvas.Size().Max(w.canvas.MinSize())
-				w.width, w.height = w.screenSize(s)
-			}
-			w.viewport.SetMonitor(nil, w.xpos, w.ypos, w.width, w.height, 0)
-		}
+		w.doSetFullScreen(full)
 	})
 }
 

internal/driver/glfw/window_notdarwin.go

@@ -0,0 +1,18 @@
+//go:build !darwin
+
+package glfw
+
+func (w *window) doSetFullScreen(full bool) {
+	monitor := w.getMonitorForWindow()
+	mode := monitor.GetVideoMode()
+
+	if full {
+		w.viewport.SetMonitor(monitor, 0, 0, mode.Width, mode.Height, mode.RefreshRate)
+	} else {
+		if w.width == 0 && w.height == 0 { // if we were fullscreen on creation...
+			s := w.canvas.Size().Max(w.canvas.MinSize())
+			w.width, w.height = w.screenSize(s)
+		}
+		w.viewport.SetMonitor(nil, w.xpos, w.ypos, w.width, w.height, 0)
+	}
+}