1 files changed, 197 insertions, 0 deletions

diff --git a/src/nsterm.m b/src/nsterm.m
index 118463a13c9..e186c16e725 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -72,6 +72,12 @@ GNUstep port and post-20 update by Adrian Robert (arobert@cogsci.ucsd.edu)
 #include "macfont.h"
 #include <Carbon/Carbon.h>
 #include <IOSurface/IOSurface.h>
+/* ApplicationServices provides the macOS accessibility Zoom API
+   UAZoomEnabled and UAZoomChangeFocus (UniversalAccess framework).
+   Carbon.h already pulls in ApplicationServices on most SDK versions,
+   but the explicit import makes the dependency visible and guards
+   against SDK changes.  */
+#import <ApplicationServices/ApplicationServices.h>
 #endif
 
 static EmacsMenu *dockMenu;
@@ -1086,6 +1092,126 @@ ns_update_begin (struct frame *f)
   [view lockFocus];
 }
 
+/* --------------------------------------------------------------------------
+   macOS Accessibility Zoom Support
+   -------------------------------------------------------------------------- */
+#ifdef NS_IMPL_COCOA
+
+static BOOL ns_is_UAZoomEnabled = NO;
+static unsigned long ns_UAZoomEnabled_last_called_time_ns = 0;
+static const unsigned long NS_UAZOOMENABLED_CACHE_INTERVAL_NS =
+  (unsigned long)(500 * NSEC_PER_MSEC); /* 500ms.  */
+static NSTimeInterval NS_UAZOOMENABLED_DEFER_INTERVAL_SECS = 0.2; /* 200ms.  */
+static NSTimer *ns_deferred_UAZoomChangeFocus_timer = nil;
+
+static BOOL
+ns_ua_zoom_enabled_p (void)
+/* --------------------------------------------------------------------------
+   Return the cached result of UAZoomEnabled.  Refresh the cache every
+   NS_UAZOOMENABLED_CACHE_INTERVAL_NS nanoseconds.
+
+   We cache the result to avoid the macOS Mach IPC Accessibility Server
+   round trip cost on every Emacs cursor update.  Since enabling Zoom
+   requires an explicit user UI action that takes real user time, the
+   cache TTL should be invisible to the user.
+
+   Use clock_gettime_nsec_np not CFAbsoluteTimeGetCurrent which depends
+   on the wall clock which can be reset by the user or by NTP.
+
+   Main-thread-only and called from ns_update_end, below.
+   -------------------------------------------------------------------------- */
+{
+  /* User-space equivalent to mach_absolute_time.  */
+  unsigned long now_ns = clock_gettime_nsec_np (CLOCK_UPTIME_RAW);
+  if (now_ns - ns_UAZoomEnabled_last_called_time_ns
+      > NS_UAZOOMENABLED_CACHE_INTERVAL_NS)
+    {
+      ns_is_UAZoomEnabled = UAZoomEnabled ();
+      ns_UAZoomEnabled_last_called_time_ns = now_ns;
+    }
+  return ns_is_UAZoomEnabled;
+}
+
+static inline CGRect
+ns_cg_rect_flip_y (CGRect r)
+/* --------------------------------------------------------------------------
+   Convert a CGRect from Cocoa screen coordinates (origin at bottom-left
+   of the primary display) to CoreGraphics coordinates (origin at
+   top-left of the primary display).  CoreGraphics defines its
+   coordinate origin at the top-left corner of the primary display and
+   all screens share this global coordinate space, so the flip always
+   uses the primary display height regardless of which screen R is on.
+   -------------------------------------------------------------------------- */
+{
+  CGDirectDisplayID mainID = CGMainDisplayID ();
+  if (mainID == kCGNullDirectDisplay)
+    return r;
+  CGFloat primaryH = CGDisplayBounds (mainID).size.height;
+  if (primaryH <= 0)
+    return r;
+  r.origin.y = primaryH - r.origin.y - r.size.height;
+  return r;
+}
+
+/* Cache cursor rects to call UAZoomChangeFocus only when the cursor
+   position has changed, not merely when the cursor is blinking.
+   See ns_draw_window_cursor and ns_update_end.  */
+static NSRect ns_UAZoom_cursor_rect_new;
+static NSRect ns_UAZoom_cursor_rect_old;
+
+/* Track Zoom state per display cycle.  Update the macOS Zoom cursor
+   position when Zoom transitions to enabled.  */
+static BOOL ns_update_was_UAZoomEnabled = NO;
+
+static void
+ns_UAZoomChangeFocus (EmacsView *view, BOOL force)
+/* --------------------------------------------------------------------------
+   Advise macOS Accessibility Zoom UAZoomChangeFocus of a potentially
+   new cursor position.  Force an updated position when Zoom transitions
+   to enabled, or when the frame gets focus.
+   -------------------------------------------------------------------------- */
+{
+  if (ns_ua_zoom_enabled_p ())
+    {
+      force = force || !ns_update_was_UAZoomEnabled;
+      ns_update_was_UAZoomEnabled = YES;
+      if (NSIsEmptyRect (ns_UAZoom_cursor_rect_new))
+        return;
+      if (force || !NSEqualRects (ns_UAZoom_cursor_rect_new,
+                                  ns_UAZoom_cursor_rect_old))
+        {
+          ns_UAZoom_cursor_rect_old = ns_UAZoom_cursor_rect_new;
+          NSRect windowRect = [view convertRect:ns_UAZoom_cursor_rect_new
+                                         toView:nil];
+          NSRect screenRect = [[view window] convertRectToScreen:windowRect];
+          CGRect cgRect = ns_cg_rect_flip_y (NSRectToCGRect (screenRect));
+          /* Some versions of macOS can ignore tiny rects, so we
+             slightly expand a tiny one.  Since we care mostly about its
+             origin, this should be innocuous.  */
+          cgRect.size.width = MAX (cgRect.size.width, 6);
+          cgRect.size.height = MAX (cgRect.size.height, 10);
+          if (force)
+            {
+              /* UAZoomChangeFocus needs old and new cursor positions to
+                 be different, and also it sometimes needs a kick.  In
+                 both cases, we fake a cursor move followed by the real
+                 cursor move.  */
+              CGRect cgRectJiggle = CGRectOffset (cgRect, 1.0, 1.0);
+              if (UAZoomChangeFocus (&cgRectJiggle, NULL,
+                                     kUAZoomFocusTypeInsertionPoint))
+                NSLog (@"UAZoomChangeFocus jiggle failed");
+            }
+          if (UAZoomChangeFocus (&cgRect, NULL,
+                                 kUAZoomFocusTypeInsertionPoint))
+            NSLog (@"UAZoomChangeFocus failed");
+          NSAccessibilityPostNotification
+            (view, NSAccessibilityFocusedUIElementChangedNotification);
+        }
+    }
+  else
+    ns_update_was_UAZoomEnabled = NO;
+}
+#endif /* NS_IMPL_COCOA */
 
 static void
 ns_update_end (struct frame *f)
@@ -1108,6 +1234,10 @@ ns_update_end (struct frame *f)
   [[view window] flushWindow];
 #endif
 
+#ifdef NS_IMPL_COCOA
+  ns_UAZoomChangeFocus (view, false);
+#endif
+
   unblock_input ();
   ns_updating_frame = NULL;
 }
@@ -3238,6 +3368,16 @@ ns_draw_window_cursor (struct window *w, struct glyph_row *glyph_row,
   /* Prevent the cursor from being drawn outside the text area.  */
   r = NSIntersectionRect (r, ns_row_rect (w, glyph_row, TEXT_AREA));
 
+#ifdef NS_IMPL_COCOA
+  /* Cache the cursor rect for macOS Accessibility Zoom integration (see
+     ns_update_end).  Only store the rect for the active cursor ---
+     inactive windows must not overwrite the value because redisplay may
+     draw multiple windows per frame and the drawing order is not
+     guaranteed.  */
+  if (active_p)
+    ns_UAZoom_cursor_rect_new = r;
+#endif
+
   ns_focus (f, NULL, 0);
 
   NSGraphicsContext *ctx = [NSGraphicsContext currentContext];
@@ -6384,6 +6524,14 @@ ns_term_shutdown (int sig)
   }
 #endif
 
+#ifdef NS_IMPL_COCOA
+  /* Is accessibility enabled for this process/bundle?  */
+  if (AXIsProcessTrusted())
+    NSLog (@"Emacs is macOS AXIsProcessTrusted");
+  else
+    NSLog (@"Emacs is not macOS AXIsProcessTrusted");
+#endif
+
   ns_send_appdefined (-2);
 }
 
@@ -7300,6 +7448,12 @@ ns_create_font_panel_buttons (id target, SEL select, SEL cancel_action)
   return [self firstRectForCharacterRange: range];
 }
 
+- (NSRect)accessibilityFrame
+{
+  EmacsView *view = FRAME_NS_VIEW (*emacsframe);
+  return [[view window] convertRectToScreen: ns_UAZoom_cursor_rect_new];
+}
+
 #endif /* NS_IMPL_COCOA */
 
 /***********************************************************************
@@ -8257,12 +8411,48 @@ ns_in_echo_area (void)
   ns_frame_rehighlight (*emacsframe);
   [self adjustEmacsFrameRect];
 
+#ifdef NS_IMPL_COCOA
+  EmacsView *view = FRAME_NS_VIEW (*emacsframe);
+  /* Make sure we have focus and the timer isn't already scheduled.  */
+  if (self.window.firstResponder == view
+      && !ns_deferred_UAZoomChangeFocus_timer)
+    {
+      /* Calls to ns_UAZoomChangeFocus are synchronous.  We defer the
+         call to give macOS time to finish window compositing or the
+         calls can be silently ignored by the Zoom daemon and with no
+         errors reported.  This also helps ensure ns_draw_window_cursor
+         has populated ns_UAZoom_cursor_rect_new.  The 200 ms delay was
+         chosen as a balance between macOS headroom and user
+         perception.  */
+      ns_deferred_UAZoomChangeFocus_timer
+        = [[NSTimer
+             scheduledTimerWithTimeInterval:
+               NS_UAZOOMENABLED_DEFER_INTERVAL_SECS
+                                     target: self
+                                   selector:
+               @selector (deferred_UAZoomChangeFocus_handler:)
+                                   userInfo: 0
+                                    repeats: NO]
+            retain];
+    }
+#endif
+
   event.kind = FOCUS_IN_EVENT;
   XSETFRAME (event.frame_or_window, *emacsframe);
   kbd_buffer_store_event (&event);
   ns_send_appdefined (-1);  // Kick main loop
 }
 
+#ifdef NS_IMPL_COCOA
+- (void)deferred_UAZoomChangeFocus_handler: (NSTimer *)timer
+{
+  EmacsView *view = FRAME_NS_VIEW (*emacsframe);
+  ns_UAZoomChangeFocus (view, true);
+  [ns_deferred_UAZoomChangeFocus_timer invalidate];
+  [ns_deferred_UAZoomChangeFocus_timer release];
+  ns_deferred_UAZoomChangeFocus_timer = nil;
+}
+#endif
 
 - (void)windowDidResignKey: (NSNotification *)notification
 /* cf. x_detect_focus_change(), x_focus_changed(), x_new_focus_frame() */
@@ -8365,6 +8555,13 @@ ns_in_echo_area (void)
 
   FRAME_NS_VIEW (f) = self;
   *emacsframe = f;
+
+#ifdef NS_IMPL_COCOA
+  /* macOS Accessibility Zoom Support.  */
+  ns_UAZoom_cursor_rect_new = NSZeroRect;
+  ns_UAZoom_cursor_rect_old = NSZeroRect;
+#endif
+
 #ifdef NS_IMPL_COCOA
   old_title = 0;
   maximizing_resize = NO;