master 9d20b47ad3: Fix scrollbars on macOS 10.13 and below (bug#54623)

[Alan Third]

branch: master
commit 9d20b47ad34ff8b409e83198406883f70782c295
Author: Alan Third <alan@idiocy.org>
Commit: Alan Third <alan@idiocy.org>

    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.
    (ns_update_end):
    (ns_unfocus): Fix #ifs so that flushWindow is called on old macOS
    versions as well as GNUstep.
---
 src/nsterm.h |   4 +-
 src/nsterm.m | 128 ++++++++++++++++++++++-------------------------------------
 2 files changed, 50 insertions(+), 82 deletions(-)

diff --git a/src/nsterm.h b/src/nsterm.h
index f027646123..4cba5c0be8 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -487,7 +487,7 @@ typedef id instancetype;
 #endif
 - (int)fullscreenState;
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
 - (void)lockFocus;
 - (void)unlockFocus;
 #endif
@@ -698,7 +698,7 @@ typedef id instancetype;
 + (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 36e2ff55ac..550f29212e 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1060,7 +1060,7 @@ ns_update_end (struct frame *f)
   block_input ();
 
   [view unlockFocus];
-#if defined (NS_IMPL_GNUSTEP)
+#if defined (NS_IMPL_GNUSTEP) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
   [[view window] flushWindow];
 #endif
 
@@ -1127,7 +1127,7 @@ ns_unfocus (struct frame *f)
     {
       EmacsView *view = FRAME_NS_VIEW (f);
       [view unlockFocus];
-#if defined (NS_IMPL_GNUSTEP)
+#if defined (NS_IMPL_GNUSTEP) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
       [[view window] flushWindow];
 #endif
     }
@@ -7208,7 +7208,7 @@ not_in_argv (NSString *arg)
 
   [[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
@@ -7872,7 +7872,7 @@ not_in_argv (NSString *arg)
 }
 
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
 - (CALayer *)makeBackingLayer
 {
   EmacsLayer *l = [[EmacsLayer alloc]
@@ -7888,19 +7888,12 @@ not_in_argv (NSString *arg)
 {
   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
 }
 
 
@@ -7908,18 +7901,8 @@ not_in_argv (NSString *arg)
 {
   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];
 }
 
 
@@ -7928,19 +7911,16 @@ not_in_argv (NSString *arg)
 {
   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
@@ -7952,57 +7932,45 @@ not_in_argv (NSString *arg)
   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
@@ -9477,7 +9445,7 @@ nswindow_orderedIndex_sort (id w1, id w2, void *c)
 @end  /* EmacsScroller */
 
 
-#ifdef NS_IMPL_COCOA
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MIN_REQUIRED >= 101400
 
 /* ==========================================================================