bug#54623: No scroll bars on macOS builds

[Alan Third <alan@idiocy.org>]

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On Fri, Apr 01, 2022 at 12:27:25AM +0200, Angelo Graziosi wrote:
> 
> > Il 31/03/2022 18:43 Alan Third ha scritto:
> > 
> > 
> > Can you try the new version attached to this email, please?
> > 
> 
> Now Emacs builds and does not crash but DOES NOT work and still NO scroll bars:
> 
> - when scrolling the text moving the mouse wheel the bottom lines remain fixed and then after a while the window contains garbage.
> 
> - trying to use C-x C-f, M-x ... does not work, no minibuffer opens: it continues to display the text "For information about..."
> 
> - trying to select text with the mouse (mouse-1 and dragging) does not work...

What about the attached?

-- 
Alan Third

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From be1e1165c94533ac47584639b544fd24acec284a Mon Sep 17 00:00:00 2001
From: Alan Third <alan@idiocy.org>
Date: Wed, 30 Mar 2022 22:40:03 +0100
Subject: [PATCH v3] Fix scrollbars on macOS 10.13 and below (bug#54623)

Make any build on macOS 10.13 and below follow the same drawing path
as the GNUstep port.  macOS 10.14 and above will use EmacsLayer.

* src/nsterm.h (EmacsLayer):
* src/nsterm.m ([EmacsView makeBackingLayer]):
([EmacsView unlockFocus]):
([EmacsView windowDidChangeBackingProperties:]):
([EmacsView copyRect:to:]): Remove any code required for macOS 10.13
and below, and fix the #if's to enforce strict separation of the
drawing paths.
---
 src/nsterm.h |   2 +-
 src/nsterm.m | 124 +++++++++++++++++++--------------------------------
 2 files changed, 47 insertions(+), 79 deletions(-)

diff --git a/src/nsterm.h b/src/nsterm.h
index f027646123..8452f3b3fa 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -698,7 +698,7 @@ #define NSTRACE_UNSILENCE()
 + (CGFloat)scrollerWidth;
 @end
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
 @interface EmacsLayer : CALayer
 {
   NSMutableArray *cache;
diff --git a/src/nsterm.m b/src/nsterm.m
index fd56094c28..2b98fb9489 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -7197,7 +7197,7 @@ - (instancetype) initFrameFromEmacs: (struct frame *)f
 
   [[EmacsWindow alloc] initWithEmacsFrame:f];
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
   /* These settings mean AppKit will retain the contents of the frame
      on resize.  Unfortunately it also means the frame will not be
      automatically marked for display, but we can do that ourselves in
@@ -7861,7 +7861,7 @@ - (instancetype)toggleToolbar: (id)sender
 }
 
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 10140
 - (CALayer *)makeBackingLayer;
 {
   EmacsLayer *l = [[EmacsLayer alloc]
@@ -7877,19 +7877,12 @@ - (void)lockFocus
 {
   NSTRACE ("[EmacsView lockFocus]");
 
-  if ([self wantsLayer])
-    {
-      CGContextRef context = [(EmacsLayer*)[self layer] getContext];
+  CGContextRef context = [(EmacsLayer*)[self layer] getContext];
 
-      [NSGraphicsContext
+  [NSGraphicsContext
         setCurrentContext:[NSGraphicsContext
                             graphicsContextWithCGContext:context
                                                  flipped:YES]];
-    }
-#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
-  else
-    [super lockFocus];
-#endif
 }
 
 
@@ -7897,18 +7890,8 @@ - (void)unlockFocus
 {
   NSTRACE ("[EmacsView unlockFocus]");
 
-  if ([self wantsLayer])
-    {
-      [NSGraphicsContext setCurrentContext:nil];
-      [self setNeedsDisplay:YES];
-    }
-#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
-  else
-    {
-      [super unlockFocus];
-      [super flushWindow];
-    }
-#endif
+  [NSGraphicsContext setCurrentContext:nil];
+  [self setNeedsDisplay:YES];
 }
 
 
@@ -7917,19 +7900,16 @@ - (void)windowDidChangeBackingProperties:(NSNotification *)notification
 {
   NSTRACE ("EmacsView windowDidChangeBackingProperties:]");
 
-  if ([self wantsLayer])
-    {
-      NSRect frame = [self frame];
-      EmacsLayer *layer = (EmacsLayer *)[self layer];
+  NSRect frame = [self frame];
+  EmacsLayer *layer = (EmacsLayer *)[self layer];
 
-      [layer setContentsScale:[[notification object] backingScaleFactor]];
-      [layer setColorSpace:[[[notification object] colorSpace] CGColorSpace]];
+  [layer setContentsScale:[[notification object] backingScaleFactor]];
+  [layer setColorSpace:[[[notification object] colorSpace] CGColorSpace]];
 
-      ns_clear_frame (emacsframe);
-      expose_frame (emacsframe, 0, 0, NSWidth (frame), NSHeight (frame));
-    }
+  ns_clear_frame (emacsframe);
+  expose_frame (emacsframe, 0, 0, NSWidth (frame), NSHeight (frame));
 }
-#endif /* NS_IMPL_COCOA */
+#endif
 
 
 - (void)copyRect:(NSRect)srcRect to:(NSPoint)dest
@@ -7941,57 +7921,45 @@ - (void)copyRect:(NSRect)srcRect to:(NSPoint)dest
   NSRect dstRect = NSMakeRect (dest.x, dest.y, NSWidth (srcRect),
                                NSHeight (srcRect));
 
-#ifdef NS_IMPL_COCOA
-  if ([self wantsLayer])
-    {
-      double scale = [[self window] backingScaleFactor];
-      CGContextRef context = [(EmacsLayer *)[self layer] getContext];
-      int bpp = CGBitmapContextGetBitsPerPixel (context) / 8;
-      void *pixels = CGBitmapContextGetData (context);
-      int rowSize = CGBitmapContextGetBytesPerRow (context);
-      int srcRowSize = NSWidth (srcRect) * scale * bpp;
-      void *srcPixels = (char *) pixels
-                        + (int) (NSMinY (srcRect) * scale * rowSize
-                                 + NSMinX (srcRect) * scale * bpp);
-      void *dstPixels = (char *) pixels
-                        + (int) (dest.y * scale * rowSize
-                                 + dest.x * scale * bpp);
-
-      if (NSIntersectsRect (srcRect, dstRect)
-          && NSMinY (srcRect) < NSMinY (dstRect))
-        for (int y = NSHeight (srcRect) * scale - 1 ; y >= 0 ; y--)
-          memmove ((char *) dstPixels + y * rowSize,
-                   (char *) srcPixels + y * rowSize,
-                   srcRowSize);
-      else
-        for (int y = 0 ; y < NSHeight (srcRect) * scale ; y++)
-          memmove ((char *) dstPixels + y * rowSize,
-                   (char *) srcPixels + y * rowSize,
-                   srcRowSize);
-
-    }
-#if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
+  double scale = [[self window] backingScaleFactor];
+  CGContextRef context = [(EmacsLayer *)[self layer] getContext];
+  int bpp = CGBitmapContextGetBitsPerPixel (context) / 8;
+  void *pixels = CGBitmapContextGetData (context);
+  int rowSize = CGBitmapContextGetBytesPerRow (context);
+  int srcRowSize = NSWidth (srcRect) * scale * bpp;
+  void *srcPixels = (char *) pixels
+    + (int) (NSMinY (srcRect) * scale * rowSize
+             + NSMinX (srcRect) * scale * bpp);
+  void *dstPixels = (char *) pixels
+    + (int) (dest.y * scale * rowSize
+             + dest.x * scale * bpp);
+
+  if (NSIntersectsRect (srcRect, dstRect)
+      && NSMinY (srcRect) < NSMinY (dstRect))
+    for (int y = NSHeight (srcRect) * scale - 1 ; y >= 0 ; y--)
+      memmove ((char *) dstPixels + y * rowSize,
+               (char *) srcPixels + y * rowSize,
+               srcRowSize);
   else
-    {
-#endif
-#endif /* NS_IMPL_COCOA */
+    for (int y = 0 ; y < NSHeight (srcRect) * scale ; y++)
+      memmove ((char *) dstPixels + y * rowSize,
+               (char *) srcPixels + y * rowSize,
+               srcRowSize);
 
-#if !defined (NS_IMPL_COCOA) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
-      hide_bell();              // Ensure the bell image isn't scrolled.
+#else
+  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_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED < 101400
-    }
+  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
 }
 
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
 /* If the frame has been garbaged but the toolkit wants to draw, for
    example when resizing the frame, we end up with a blank screen.
    Sometimes this results in an unpleasant flicker, so try to
@@ -9435,7 +9403,7 @@ - (void) scrollWheel: (NSEvent *)theEvent
 @end  /* EmacsScroller */
 
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
 
 /* ==========================================================================
 
-- 
2.35.1