On Macos, Hide cursor only inside window (#1348)

* On MacOS, hide cursor by invisible cursor

* Add CHANGELOG

* Fix variable name

* Add comments for `CURSOR_BYTES`

CHANGELOG.md

@@ -1,5 +1,6 @@
 # Unreleased
 
+- On macOS, fix `set_cursor_visible` hides cursor outside of window.
 - On macOS, fix `CursorEntered` and `CursorLeft` events fired at old window size.
 - On macOS, fix error when `set_fullscreen` is called during fullscreen transition.
 - On all platforms except mobile and WASM, implement `Window::set_minimized`.

src/platform_impl/macos/util/cursor.rs

@@ -3,7 +3,8 @@ use cocoa::{
     base::{id, nil},
     foundation::{NSDictionary, NSPoint, NSString},
 };
-use objc::runtime::Sel;
+use objc::{runtime::Sel, runtime::NO};
+use std::cell::RefCell;
 
 use crate::window::CursorIcon;
 
@@ -126,3 +127,38 @@ pub unsafe fn load_webkit_cursor(cursor_name: &str) -> id {
         hotSpot:point
     ]
 }
+
+pub unsafe fn invisible_cursor() -> id {
+    // 16x16 GIF data for invisible cursor
+    // You can reproduce this via ImageMagick.
+    // $ convert -size 16x16 xc:none cursor.gif
+    static CURSOR_BYTES: &[u8] = &[
+        0x47, 0x49, 0x46, 0x38, 0x39, 0x61, 0x10, 0x00, 0x10, 0x00, 0xF0, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x21, 0xF9, 0x04, 0x01, 0x00, 0x00, 0x00, 0x00, 0x2C, 0x00, 0x00,
+        0x00, 0x00, 0x10, 0x00, 0x10, 0x00, 0x00, 0x02, 0x0E, 0x84, 0x8F, 0xA9, 0xCB, 0xED, 0x0F,
+        0xA3, 0x9C, 0xB4, 0xDA, 0x8B, 0xB3, 0x3E, 0x05, 0x00, 0x3B,
+    ];
+
+    thread_local! {
+        // We can't initialize this at startup.
+        static CURSOR_OBJECT: RefCell<id> = RefCell::new(nil);
+    }
+
+    CURSOR_OBJECT.with(|cursor_obj| {
+        if *cursor_obj.borrow() == nil {
+            // Create a cursor from `CURSOR_BYTES`
+            let cursor_data: id = msg_send![class!(NSData),
+                dataWithBytesNoCopy:CURSOR_BYTES as *const [u8]
+                length:CURSOR_BYTES.len()
+                freeWhenDone:NO
+            ];
+
+            let ns_image: id = msg_send![class!(NSImage), alloc];
+            let _: id = msg_send![ns_image, initWithData: cursor_data];
+            let cursor: id = msg_send![class!(NSCursor), alloc];
+            *cursor_obj.borrow_mut() =
+                msg_send![cursor, initWithImage:ns_image hotSpot: NSPoint::new(0.0, 0.0)];
+        }
+        *cursor_obj.borrow()
+    })
+}

src/platform_impl/macos/view.rs

@@ -35,9 +35,23 @@ use crate::{
     window::WindowId,
 };
 
+pub struct CursorState {
+    pub visible: bool,
+    pub cursor: util::Cursor,
+}
+
+impl Default for CursorState {
+    fn default() -> Self {
+        Self {
+            visible: true,
+            cursor: Default::default(),
+        }
+    }
+}
+
 struct ViewState {
     ns_window: id,
-    pub cursor: Arc<Mutex<util::Cursor>>,
+    pub cursor_state: Arc<Mutex<CursorState>>,
     ime_spot: Option<(f64, f64)>,
     raw_characters: Option<String>,
     is_key_down: bool,
@@ -45,12 +59,12 @@ struct ViewState {
     tracking_rect: Option<NSInteger>,
 }
 
-pub fn new_view(ns_window: id) -> (IdRef, Weak<Mutex<util::Cursor>>) {
-    let cursor = Default::default();
-    let cursor_access = Arc::downgrade(&cursor);
+pub fn new_view(ns_window: id) -> (IdRef, Weak<Mutex<CursorState>>) {
+    let cursor_state = Default::default();
+    let cursor_access = Arc::downgrade(&cursor_state);
     let state = ViewState {
         ns_window,
-        cursor,
+        cursor_state,
         ime_spot: None,
         raw_characters: None,
         is_key_down: false,
@@ -349,7 +363,12 @@ extern "C" fn reset_cursor_rects(this: &Object, _sel: Sel) {
         let state = &mut *(state_ptr as *mut ViewState);
 
         let bounds: NSRect = msg_send![this, bounds];
-        let cursor = state.cursor.lock().unwrap().load();
+        let cursor_state = state.cursor_state.lock().unwrap();
+        let cursor = if cursor_state.visible {
+            cursor_state.cursor.load()
+        } else {
+            util::invisible_cursor()
+        };
         let _: () = msg_send![this,
             addCursorRect:bounds
             cursor:cursor

src/platform_impl/macos/window.rs

@@ -20,6 +20,7 @@ use crate::{
         ffi,
         monitor::{self, MonitorHandle, VideoMode},
         util::{self, IdRef},
+        view::CursorState,
         view::{self, new_view},
         window_delegate::new_delegate,
         OsError,
@@ -90,8 +91,8 @@ fn create_app(activation_policy: ActivationPolicy) -> Option<id> {
 unsafe fn create_view(
     ns_window: id,
     pl_attribs: &PlatformSpecificWindowBuilderAttributes,
-) -> Option<(IdRef, Weak<Mutex<util::Cursor>>)> {
-    let (ns_view, cursor) = new_view(ns_window);
+) -> Option<(IdRef, Weak<Mutex<CursorState>>)> {
+    let (ns_view, cursor_state) = new_view(ns_window);
     ns_view.non_nil().map(|ns_view| {
         if !pl_attribs.disallow_hidpi {
             ns_view.setWantsBestResolutionOpenGLSurface_(YES);
@@ -108,7 +109,7 @@ unsafe fn create_view(
 
         ns_window.setContentView_(*ns_view);
         ns_window.makeFirstResponder_(*ns_view);
-        (ns_view, cursor)
+        (ns_view, cursor_state)
     })
 }
 
@@ -290,8 +291,7 @@ pub struct UnownedWindow {
     input_context: IdRef, // never changes
     pub shared_state: Arc<Mutex<SharedState>>,
     decorations: AtomicBool,
-    cursor: Weak<Mutex<util::Cursor>>,
-    cursor_visible: AtomicBool,
+    cursor_state: Weak<Mutex<CursorState>>,
 }
 
 unsafe impl Send for UnownedWindow {}
@@ -320,7 +320,7 @@ impl UnownedWindow {
             os_error!(OsError::CreationError("Couldn't create `NSWindow`"))
         })?;
 
-        let (ns_view, cursor) =
+        let (ns_view, cursor_state) =
             unsafe { create_view(*ns_window, &pl_attribs) }.ok_or_else(|| {
                 unsafe { pool.drain() };
                 os_error!(OsError::CreationError("Couldn't create `NSView`"))
@@ -368,8 +368,7 @@ impl UnownedWindow {
             input_context,
             shared_state: Arc::new(Mutex::new(win_attribs.into())),
             decorations: AtomicBool::new(decorations),
-            cursor,
-            cursor_visible: AtomicBool::new(true),
+            cursor_state,
         });
 
         let delegate = new_delegate(&window, fullscreen.is_some());
@@ -516,8 +515,8 @@ impl UnownedWindow {
 
     pub fn set_cursor_icon(&self, cursor: CursorIcon) {
         let cursor = util::Cursor::from(cursor);
-        if let Some(cursor_access) = self.cursor.upgrade() {
-            *cursor_access.lock().unwrap() = cursor;
+        if let Some(cursor_access) = self.cursor_state.upgrade() {
+            cursor_access.lock().unwrap().cursor = cursor;
         }
         unsafe {
             let _: () = msg_send![*self.ns_window,
@@ -535,16 +534,17 @@ impl UnownedWindow {
 
     #[inline]
     pub fn set_cursor_visible(&self, visible: bool) {
-        let cursor_class = class!(NSCursor);
-        // macOS uses a "hide counter" like Windows does, so we avoid incrementing it more than once.
-        // (otherwise, `hide_cursor(false)` would need to be called n times!)
-        if visible != self.cursor_visible.load(Ordering::Acquire) {
-            if visible {
-                let _: () = unsafe { msg_send![cursor_class, unhide] };
-            } else {
-                let _: () = unsafe { msg_send![cursor_class, hide] };
+        if let Some(cursor_access) = self.cursor_state.upgrade() {
+            let mut cursor_state = cursor_access.lock().unwrap();
+            if visible != cursor_state.visible {
+                cursor_state.visible = visible;
+                drop(cursor_state);
+                unsafe {
+                    let _: () = msg_send![*self.ns_window,
+                        invalidateCursorRectsForView:*self.ns_view
+                    ];
+                }
             }
-            self.cursor_visible.store(visible, Ordering::Release);
         }
     }