Subject: bug#39883: 28.0.50; macOS blank frame

From: Alan Third <[email-masked]>
Date: Sun, 12 Apr 2020 10:53:53 +0100

On Sun, Apr 12, 2020 at 11:54:53AM +0530, Ashish SHUKLA wrote:
> On Apr 11, 2020, at 18:59, Alan Third <[email-masked]> wrote:
> > 
> > You may have to set this CFLAG to enable the changes:
> > 
> >    -DMAC_OS_X_VERSION_MAX_ALLOWED=101500
> 
> Hi
> 
> Without setting CFLAGS following error occurred:
> 
> ==================================================================
>   CC       image.o
>   CC       json.o
>   CC       nsterm.o
>   CC       nsfns.o
>   CC       nsmenu.o
>   CC       nsselect.o
>   CC       nsimage.o
>   CC       macfont.o
>   CC       terminfo.o
>   CC       lastfile.o
> nsterm.m:6300:21: error: use of undeclared identifier 'drawingBuffer'
>   CGContextRelease (drawingBuffer);
>                     ^
> 1 error generated.

I’m surprised this didn’t show up before.

> In file included from <built-in>:360:
> <command line>:4:9: warning: 'MAC_OS_X_VERSION_MAX_ALLOWED' macro redefined [-Wmacro-redefined]
> #define MAC_OS_X_VERSION_MAX_ALLOWED 101500
>         ^
> <command line>:3:9: note: previous definition is here
> #define MAC_OS_X_VERSION_MAX_ALLOWED 101200
>         ^

This looks suspiciously like you’re already setting that define in
your configure command. If you’re building with nix check the build
script. You, or whoever created it, probably had to add the define to
101200 (which is macOS 10.12) so it would correctly handle some
features added since macOS 10.10. I know that John Weigley uses (or
used) that value.

There’s a possibility it will appear in a different form, but it will
be something that either has 101200 or 10.12.

> nsterm.m:1148:8: error: use of undeclared identifier 'self'
>   if ([self wantsUpdateLayer])
>        ^

Silly mistake on my part.

New patch attached. You still have to use the other patch from my last
email as well.
-- 
Alan Third
>From 7b0d5e99e0b12fd6792cf2cf76d539128687f520 Mon Sep 17 00:00:00 2001
From: Alan Third <[email-masked]>
Date: Sat, 11 Apr 2020 14:18:39 +0100
Subject: [PATCH v2] Allow dynamic choice of drawing path on NS (bug#39883)

* src/nsterm.h (NS_DRAW_TO_BUFFER): Let this be enabled on versions
older than 10.14.
* src/nsterm.m (ns_update_begin):
(ns_update_end):
(ns_focus):
(ns_unfocus):
([EmacsView viewDidResize:]):
([EmacsView createDrawingBuffer]):
([EmacsView windowDidChangeBackingProperties:]):
([EmacsView copyRect:to:]):
([EmacsView wantsUpdateLayer]): Dynamically switch between drawing to a
buffer and drawing to the screen, depending on the version of AppKit
in use.
([EmacsView dealloc]): We can't release the context unless
NS_DRAW_TO_BUFFER is defined.
---
 src/nsterm.h |  10 +--
 src/nsterm.m | 229 +++++++++++++++++++++++++++++++++++++--------------
 2 files changed, 167 insertions(+), 72 deletions(-)

diff --git a/src/nsterm.h b/src/nsterm.h
index e142dbd4f0..f5d3c32b8b 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -343,14 +343,8 @@ #define NSTRACE_UNSILENCE()
    therefore we draw to an offscreen buffer and swap it in when the
    toolkit wants to draw the frame. GNUstep and macOS 10.7 and below
    do not support this method, so we revert to drawing directly to the
-   glass.
-
-   FIXME: Should we make this macOS 10.8+, or macOS 10.14+?  I'm
-   inclined to go with 10.14+ as there have been some reports of funny
-   behaviour on 10.13 and below.  It may be worth adding a variable to
-   allow people in the overlapping region to switch between drawing
-   paths.  */
-#if defined (NS_IMPL_COCOA) && defined (MAC_OS_X_VERSION_10_14)
+   glass.  */
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MAX_ALLOWED >= 101400
 #define NS_DRAW_TO_BUFFER 1
 #endif
 
diff --git a/src/nsterm.m b/src/nsterm.m
index 9dd1a89d0c..f5cf033b4e 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1144,10 +1144,25 @@ static NSRect constrain_frame_rect(NSRect frameRect, bool isFullscreen)
 
   ns_updating_frame = f;
 #ifdef NS_DRAW_TO_BUFFER
-  [view focusOnDrawingBuffer];
-#else
-  [view lockFocus];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+  if ([FRAME_NS_VIEW (f) wantsUpdateLayer])
+    {
 #endif
+      [view focusOnDrawingBuffer];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+  else
+    {
+#endif
+#endif /* NS_DRAW_TO_BUFFER */
+
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+      [view lockFocus];
+#endif
+#if defined (NS_DRAW_TO_BUFFER) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+#endif
+
 }

@@ -1166,15 +1181,29 @@ static NSRect constrain_frame_rect(NSRect frameRect, bool isFullscreen)
   MOUSE_HL_INFO (f)->mouse_face_defer = 0;
 
 #ifdef NS_DRAW_TO_BUFFER
-  [NSGraphicsContext setCurrentContext:nil];
-  [view setNeedsDisplay:YES];
-#else
-  block_input ();
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+  if ([FRAME_NS_VIEW (f) wantsUpdateLayer])
+    {
+#endif
+      [NSGraphicsContext setCurrentContext:nil];
+      [view setNeedsDisplay:YES];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+  else
+    {
+#endif
+#endif /* NS_DRAW_TO_BUFFER */
 
-  [view unlockFocus];
-  [[view window] flushWindow];
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+      block_input ();
 
-  unblock_input ();
+      [view unlockFocus];
+      [[view window] flushWindow];
+
+      unblock_input ();
+#endif
+#if defined (NS_DRAW_TO_BUFFER) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
 #endif
   ns_updating_frame = NULL;
 }
@@ -1199,24 +1228,39 @@ static NSRect constrain_frame_rect(NSRect frameRect, bool isFullscreen)
     }
 
   if (f != ns_updating_frame)
-#ifdef NS_DRAW_TO_BUFFER
-    [view focusOnDrawingBuffer];
-#else
     {
-      if (view != focus_view)
+#ifdef NS_DRAW_TO_BUFFER
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+      if ([FRAME_NS_VIEW (f) wantsUpdateLayer])
         {
-          if (focus_view != NULL)
+#endif
+          [view focusOnDrawingBuffer];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+        }
+      else
+        {
+#endif
+#endif /* NS_DRAW_TO_BUFFER */
+
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+          if (view != focus_view)
             {
-              [focus_view unlockFocus];
-              [[focus_view window] flushWindow];
-            }
+              if (focus_view != NULL)
+                {
+                  [focus_view unlockFocus];
+                  [[focus_view window] flushWindow];
+                }
 
-          if (view)
-            [view lockFocus];
-          focus_view = view;
+              if (view)
+                [view lockFocus];
+              focus_view = view;
+            }
+#endif
+#if defined (NS_DRAW_TO_BUFFER) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
         }
-    }
 #endif
+    }
+
 
   /* clipping */
   if (r)
@@ -1246,16 +1290,30 @@ static NSRect constrain_frame_rect(NSRect frameRect, bool isFullscreen)
     }
 
 #ifdef NS_DRAW_TO_BUFFER
-  [FRAME_NS_VIEW (f) setNeedsDisplay:YES];
-#else
-  if (f != ns_updating_frame)
+  #if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+  if ([FRAME_NS_VIEW (f) wantsUpdateLayer])
+    {
+#endif
+      [FRAME_NS_VIEW (f) setNeedsDisplay:YES];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+  else
     {
-      if (focus_view != NULL)
+#endif
+#endif /* NS_DRAW_TO_BUFFER */
+
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+      if (f != ns_updating_frame)
         {
-          [focus_view unlockFocus];
-          [[focus_view window] flushWindow];
-          focus_view = NULL;
+          if (focus_view != NULL)
+            {
+              [focus_view unlockFocus];
+              [[focus_view window] flushWindow];
+              focus_view = NULL;
+            }
         }
+#endif
+#if defined (NS_DRAW_TO_BUFFER) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
     }
 #endif
 }
@@ -6239,7 +6297,9 @@ - (void)dealloc
               name:NSViewFrameDidChangeNotification
             object:nil];
 
+#ifdef NS_DRAW_TO_BUFFER
   CGContextRelease (drawingBuffer);
+#endif
 
   [toolbar release];
   if (fs_state == FULLSCREEN_BOTH)
@@ -7253,13 +7313,27 @@ - (void)viewDidResize:(NSNotification *)notification
     return;
 
 #ifdef NS_DRAW_TO_BUFFER
-  CGFloat scale = [[self window] backingScaleFactor];
-  oldw = (CGFloat)CGBitmapContextGetWidth (drawingBuffer) / scale;
-  oldh = (CGFloat)CGBitmapContextGetHeight (drawingBuffer) / scale;
-#else
-  oldw = FRAME_PIXEL_WIDTH (emacsframe);
-  oldh = FRAME_PIXEL_HEIGHT (emacsframe);
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+  if ([self wantsUpdateLayer])
+    {
+#endif
+      CGFloat scale = [[self window] backingScaleFactor];
+      oldw = (CGFloat)CGBitmapContextGetWidth (drawingBuffer) / scale;
+      oldh = (CGFloat)CGBitmapContextGetHeight (drawingBuffer) / scale;
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+  else
+    {
 #endif
+#endif /* NS_DRAW_TO_BUFFER */
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+      oldw = FRAME_PIXEL_WIDTH (emacsframe);
+      oldh = FRAME_PIXEL_HEIGHT (emacsframe);
+#endif
+#if defined (NS_DRAW_TO_BUFFER) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+#endif
+
   neww = (int)NSWidth (frame);
   newh = (int)NSHeight (frame);
 
@@ -8289,6 +8363,9 @@ - (void)createDrawingBuffer
 {
   NSTRACE ("EmacsView createDrawingBuffer]");
 
+  if (! [self wantsUpdateLayer])
+    return;
+
   NSGraphicsContext *screen;
   CGColorSpaceRef colorSpace = [[[self window] colorSpace] CGColorSpace];
   CGFloat scale = [[self window] backingScaleFactor];
@@ -8324,6 +8401,9 @@ - (void)windowDidChangeBackingProperties:(NSNotification *)notification
 {
   NSTRACE ("EmacsView windowDidChangeBackingProperties:]");
 
+  if (! [self wantsUpdateLayer])
+    return;
+
   CGFloat old = [[[notification userInfo]
                     objectForKey:@"NSBackingPropertyOldScaleFactorKey"]
                   doubleValue];
@@ -8347,41 +8427,56 @@ - (void)copyRect:(NSRect)srcRect to:(NSRect)dstRect
   NSTRACE_RECT ("Destination", dstRect);
 
 #ifdef NS_DRAW_TO_BUFFER
-  CGImageRef copy;
-  NSRect frame = [self frame];
-  NSAffineTransform *setOrigin = [NSAffineTransform transform];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+  if ([self wantsUpdateLayer])
+    {
+#endif
+      CGImageRef copy;
+      NSRect frame = [self frame];
+      NSAffineTransform *setOrigin = [NSAffineTransform transform];
 
-  [[NSGraphicsContext currentContext] saveGraphicsState];
+      [[NSGraphicsContext currentContext] saveGraphicsState];
 
-  /* Set the clipping before messing with the buffer's
-     orientation.  */
-  NSRectClip (dstRect);
+      /* Set the clipping before messing with the buffer's
+         orientation.  */
+      NSRectClip (dstRect);
 
-  /* Unflip the buffer as the copied image will be unflipped, and
-     offset the top left so when we draw back into the buffer the
-     correct part of the image is drawn.  */
-  CGContextScaleCTM(drawingBuffer, 1, -1);
-  CGContextTranslateCTM(drawingBuffer,
-                        NSMinX (dstRect) - NSMinX (srcRect),
-                        -NSHeight (frame) - (NSMinY (dstRect) - NSMinY (srcRect)));
+      /* Unflip the buffer as the copied image will be unflipped, and
+         offset the top left so when we draw back into the buffer the
+         correct part of the image is drawn.  */
+      CGContextScaleCTM(drawingBuffer, 1, -1);
+      CGContextTranslateCTM(drawingBuffer,
+                            NSMinX (dstRect) - NSMinX (srcRect),
+                            -NSHeight (frame) - (NSMinY (dstRect) - NSMinY (srcRect)));
 
-  /* Take a copy of the buffer and then draw it back to the buffer,
-     limited by the clipping rectangle.  */
-  copy = CGBitmapContextCreateImage (drawingBuffer);
-  CGContextDrawImage (drawingBuffer, frame, copy);
+      /* Take a copy of the buffer and then draw it back to the buffer,
+         limited by the clipping rectangle.  */
+      copy = CGBitmapContextCreateImage (drawingBuffer);
+      CGContextDrawImage (drawingBuffer, frame, copy);
 
-  CGImageRelease (copy);
+      CGImageRelease (copy);
 
-  [[NSGraphicsContext currentContext] restoreGraphicsState];
-  [self setNeedsDisplayInRect:dstRect];
-#else
-  hide_bell();              // Ensure the bell image isn't scrolled.
+      [[NSGraphicsContext currentContext] restoreGraphicsState];
+      [self setNeedsDisplayInRect:dstRect];
 
-  ns_focus (emacsframe, &dstRect, 1);
-  [self scrollRect: srcRect
-                by: NSMakeSize (dstRect.origin.x - srcRect.origin.x,
-                                dstRect.origin.y - srcRect.origin.y)];
-  ns_unfocus (emacsframe);
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
+  else
+    {
+#endif
+#endif /* NS_DRAW_TO_BUFFER */
+
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+      hide_bell();              // Ensure the bell image isn't scrolled.
+
+      ns_focus (emacsframe, &dstRect, 1);
+      [self scrollRect: srcRect
+                    by: NSMakeSize (dstRect.origin.x - srcRect.origin.x,
+                                    dstRect.origin.y - srcRect.origin.y)];
+      ns_unfocus (emacsframe);
+#endif
+#if defined (NS_DRAW_TO_BUFFER) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+    }
 #endif
 }
 
@@ -8389,7 +8484,13 @@ - (void)copyRect:(NSRect)srcRect to:(NSRect)dstRect
 #ifdef NS_DRAW_TO_BUFFER
 - (BOOL)wantsUpdateLayer
 {
-    return YES;
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+  if (NSAppKitVersionNumber < 1671)
+    return NO;
+#endif
+
+  /* Running on macOS 10.14 or above.  */
+  return YES;
 }

-- 
2.26.0