fix(mac): OSK layers displayed consistently for hardware and OSK modifiers

mac/Keyman4MacIM/Keyman4MacIM/OnScreenKeyboard/OSKWindowController.m

@@ -15,9 +15,9 @@
 @interface OSKWindowController ()
 @property (nonatomic, strong) NSButton *helpButton;
 @property (nonatomic, strong) NSTimer *modFlagsTimer;
-@property (nonatomic, assign) BOOL xShiftState;
-@property (nonatomic, assign) BOOL xAltState;
-@property (nonatomic, assign) BOOL xCtrlState;
+@property (nonatomic, assign) BOOL previousShiftState;
+@property (nonatomic, assign) BOOL previousOptionState;
+@property (nonatomic, assign) BOOL previousControlState;
 @end
 
 @implementation OSKWindowController
@@ -58,7 +58,7 @@ - (void)windowDidLoad {
   [super windowDidLoad];
   [self.oskView setKvk:[self.AppDelegate kvk]];
   [self startTimerWithTimeInterval:0.1];
-  // Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
+  //  [self startTimerToTrackPhysicalModifierState:0.1];
 }
 
 - (void)windowDidResize:(NSNotification *)notification {
@@ -116,52 +116,73 @@ - (void)stopTimer {
   }
 }
 
+/**
+ * Called repeatedly by timer to track the state of the physical modifier keys.
+ * Changes in state are reported to the OSKView, so it can make corresponding updates to the OSK's appearance
+ * and apply the state as necessary when keys on the OSK are clicked.
+ */
 - (void)timerAction:(NSTimer *)timer {
   UInt32 modifiers = GetCurrentKeyModifiers();
+
+  [self trackPhysicalShiftKeyState: modifiers];
+  [self trackPhysicalOptionKeyState: modifiers];
+  [self trackPhysicalControlKeyState: modifiers];
+}
+
+- (void)trackPhysicalShiftKeyState:(UInt32) modifiers {
   if ((modifiers & shiftKey) == shiftKey) {
-    [self.oskView setShiftState:YES];
-    self.xShiftState = YES;
+    [self.oskView setPhysicalShiftState:YES];
+    self.previousShiftState = YES;
   }
   else {
-    [self.oskView setShiftState:NO];
-    if (self.xShiftState)
+    [self.oskView setPhysicalShiftState:NO];
+    if (self.previousShiftState) {
       [self.oskView setOskShiftState:NO];
-    self.xShiftState = NO;
+    }
+    self.previousShiftState = NO;
   }
-
+}
+
+- (void)trackPhysicalOptionKeyState:(UInt32) modifiers {
   if ((modifiers & optionKey) == optionKey) {
-    [self.oskView setAltState:YES];
-    self.xAltState = YES;
+    [self.oskView setPhysicalOptionState:YES];
+    self.previousOptionState = YES;
   }
   else {
-    [self.oskView setAltState:NO];
-    if (self.xAltState)
-      [self.oskView setOskAltState:NO];
-    self.xAltState = NO;
+    [self.oskView setPhysicalOptionState:NO];
+    if (self.previousOptionState) {
+      [self.oskView setOskOptionState:NO];
+    }
+    self.previousOptionState = NO;
   }
-
+}
+
+- (void)trackPhysicalControlKeyState:(UInt32) modifiers {
   if ((modifiers & controlKey) == controlKey) {
-    [self.oskView setCtrlState:YES];
-    self.xCtrlState = YES;
+    [self.oskView setPhysicalControlState:YES];
+    self.previousControlState = YES;
   }
   else {
-    [self.oskView setCtrlState:NO];
-    if (self.xCtrlState)
-      [self.oskView setOskCtrlState:NO];
-    self.xCtrlState = NO;
+    [self.oskView setPhysicalControlState:NO];
+    if (self.previousControlState) {
+      [self.oskView setOskControlState:NO];
+    }
+    self.previousControlState = NO;
   }
 }
 
 - (BOOL)hasHelpDocumentation {
   NSString *kvkPath = [self AppDelegate].kvk.filePath;
-  if (!kvkPath)
+  if (!kvkPath) {
     return NO;
+  }
 
   NSString *packagePath = [kvkPath stringByDeletingLastPathComponent];
   if (packagePath != nil) {
     NSString *welcomeFile = [packagePath stringByAppendingPathComponent:@"welcome.htm"];
-    if ([[NSFileManager defaultManager] fileExistsAtPath:welcomeFile])
+    if ([[NSFileManager defaultManager] fileExistsAtPath:welcomeFile]) {
       return YES;
+    }
   }
 
   return NO;

mac/KeymanEngine4Mac/KeymanEngine4Mac/KME/OnScreenKeyboard/OSKView.h

@@ -19,12 +19,12 @@
 + (BOOL)isOskKeyDownEvent:(CGEventRef)event;
 + (NSEventModifierFlags)extractModifierFlagsFromOskEvent:(CGEventRef)event;
 - (void)handleKeyEvent:(NSEvent *)event;
-- (void)setShiftState:(BOOL)shiftState;
+- (void)setPhysicalShiftState:(BOOL)shiftState;
 - (void)setOskShiftState:(BOOL)oskShiftState;
-- (void)setAltState:(BOOL)altState;
-- (void)setOskAltState:(BOOL)oskAltState;
-- (void)setCtrlState:(BOOL)ctrlState;
-- (void)setOskCtrlState:(BOOL)oskCtrlState;
+- (void)setPhysicalOptionState:(BOOL)altState;
+- (void)setOskOptionState:(BOOL)oskAltState;
+- (void)setPhysicalControlState:(BOOL)ctrlState;
+- (void)setOskControlState:(BOOL)oskCtrlState;
 - (void)resetOSK;
 - (void)resizeOSKLayout;
 - (int64_t)createOskEventUserData;