>From 171713fb172911416ac4615f4bf3ae1802a4e756 Mon Sep 17 00:00:00 2001
From: Alan Third <alan@idiocy.org>
Date: Thu, 8 Nov 2018 23:11:31 +0000
Subject: [PATCH] Further changes to NS drawing (bug#32932)

* src/nsterm.m (ns_update_begin): Get rid of the display at the start
of redisplay.
(ns_update_window_begin): Remove redundant code that never executes.
(ns_draw_window_cursor): Perform a display when not in redisplay.
([EmacsView drawRect:]): Show the rectangle being exposed.
* src/xdisp.c (expose_window_tree) [HAVE_NS]:
(expose_frame) [HAVE_NS]: Redraw even if the frame is garbaged.
---
 src/nsterm.m | 43 +++++++++----------------------------------
 src/xdisp.c  |  8 +++++++-
 2 files changed, 16 insertions(+), 35 deletions(-)

diff --git a/src/nsterm.m b/src/nsterm.m
index bb21be4a18..9e6779d4a3 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1061,17 +1061,6 @@ static NSRect constrain_frame_rect(NSRect frameRect, bool isFullscreen)
 
   ns_update_auto_hide_menu_bar ();
 
-  /* Flush any existing changes to screen before redisplay gets going.
-     If we don't do this then it's possible for redisplay to mark
-     areas as garbaged so they won't be redrawn in the next drawRect
-     call.
-
-     Is this a bad thing to do since we're effectively calling
-     frame_expose from within redisplay?  */
-  block_input ();
-  [FRAME_NS_VIEW (f) displayIfNeeded];
-  unblock_input ();
-
   if ([view isFullscreen] && [view fsIsNative])
   {
     // Fix reappearing tool bar in fullscreen for Mac OS X 10.7
@@ -1080,29 +1069,6 @@ static NSRect constrain_frame_rect(NSRect frameRect, bool isFullscreen)
     if (! tbar_visible != ! [toolbar isVisible])
       [toolbar setVisible: tbar_visible];
   }
-
-  /* drawRect may have been called for say the minibuffer, and then clip path
-     is for the minibuffer.  But the display engine may draw more because
-     we have set the frame as garbaged.  So reset clip path to the whole
-     view.  */
-  /* FIXME: I don't think we need to do this.  */
-  if ([NSView focusView] == FRAME_NS_VIEW (f))
-    {
-      NSBezierPath *bp;
-      NSRect r = [view frame];
-      NSRect cr = [[view window] frame];
-      /* If a large frame size is set, r may be larger than the window frame
-         before constrained.  In that case don't change the clip path, as we
-         will clear in to the tool bar and title bar.  */
-      if (r.size.height
-          + FRAME_NS_TITLEBAR_HEIGHT (f)
-          + FRAME_TOOLBAR_HEIGHT (f) <= cr.size.height)
-        {
-          bp = [[NSBezierPath bezierPathWithRect: r] retain];
-          [bp setClip];
-          [bp release];
-        }
-    }
 #endif
 }
 
@@ -3158,6 +3124,12 @@ Note that CURSOR_WIDTH is meaningful only for (h)bar cursors.
 
       ns_reset_clipping (f);
     }
+  else if (! redisplaying_p)
+    {
+      /* If this function is called outside redisplay, it probably
+         means we need an immediate update.  */
+      [FRAME_NS_VIEW (f) display];
+    }
 }
 
 
@@ -8120,6 +8092,9 @@ - (void)drawRect: (NSRect)rect
   for (int i = 0 ; i < numRects ; i++)
     {
       NSRect r = rectList[i];
+
+      NSTRACE_RECT ("r", r);
+
       expose_frame (emacsframe,
                     NSMinX (r), NSMinY (r),
                     NSWidth (r), NSHeight (r));
diff --git a/src/xdisp.c b/src/xdisp.c
index 357f0fb30c..a59a62fb93 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -32258,7 +32258,11 @@ expose_window_tree (struct window *w, XRectangle *r)
   struct frame *f = XFRAME (w->frame);
   bool mouse_face_overwritten_p = false;
 
-  while (w && !FRAME_GARBAGED_P (f))
+  while (w
+#if !defined (HAVE_NS)
+         && !FRAME_GARBAGED_P (f)
+#endif
+         )
     {
       mouse_face_overwritten_p
 	|= (WINDOWP (w->contents)
@@ -32286,12 +32290,14 @@ expose_frame (struct frame *f, int x, int y, int w, int h)
 
   TRACE ((stderr, "expose_frame "));
 
+#if !defined (HAVE_NS)
   /* No need to redraw if frame will be redrawn soon.  */
   if (FRAME_GARBAGED_P (f))
     {
       TRACE ((stderr, " garbaged\n"));
       return;
     }
+#endif
 
   /* If basic faces haven't been realized yet, there is no point in
      trying to redraw anything.  This can happen when we get an expose
-- 
2.19.1