Imported Tk 8.6.9

macosx/tkMacOSXEvent.c

@@ -112,14 +112,23 @@ enum {
  *
  * TkMacOSXFlushWindows --
  *
- *	This routine flushes all the visible windows of the application. It is
- *	called by XSync().
+ *	This routine is a stub called by XSync, which is called during the Tk
+ *      update command.  The language specification does not require that the
+ *      update command be synchronous but many of the tests assume that is the
+ *      case.  It is not naturally the case on macOS since many idle tasks are
+ *      run inside of the drawRect method of a window's contentView, and that
+ *      method will not be called until after this function returns.  To make
+ *      the tests work, we attempt to force this to be synchronous by waiting
+ *      until drawRect has been called for each window.  The mechanism we use
+ *      for this is to have drawRect post an ApplicationDefined NSEvent on the
+ *      AppKit event queue when it finishes drawing, and wait for it here.
  *
  * Results:
  *	None.
  *
  * Side effects:
- *	Flushes all visible Cocoa windows
+ *	Calls the drawRect method of the contentView of each visible
+ *      window.
  *
  *----------------------------------------------------------------------
  */
@@ -128,11 +137,14 @@ MODULE_SCOPE void
 TkMacOSXFlushWindows(void)
 {
     NSArray *macWindows = [NSApp orderedWindows];
-
+    if ([NSApp simulateDrawing]) {
+	[NSApp setSimulateDrawing:NO];
+	return;
+    }
     for (NSWindow *w in macWindows) {
-	if (TkMacOSXGetXWindow(w)) {
-	    [w flushWindow];
-	}
+    	if (TkMacOSXGetXWindow(w)) {
+    	    [w displayIfNeeded];
+    	}
     }
 }