macOS: add the ability to change the mouse cursor

Cargo.toml

@@ -76,6 +76,7 @@ block2 = "0.6.2"
 objc2-foundation = { version = "0.3.2", default-features = false, features = ["std", "NSEnumerator", "block2", "NSOperation"] }
 objc2-app-kit = { version = "0.3.2", default-features = false, features = [
     "NSApplication",
+    "NSCursor",
     "NSDragging",
     "NSEvent",
     "NSGraphics",

src/macos/cursor.rs

@@ -0,0 +1,93 @@
+use objc2::__framework_prelude::Retained;
+use objc2::runtime::{MessageReceiver, Sel};
+use objc2::{msg_send, sel, ClassType};
+use objc2_app_kit::NSCursor;
+
+use crate::MouseCursor;
+
+#[derive(Debug)]
+pub enum Cursor {
+    Native(fn() -> Retained<NSCursor>),
+    Undocumented(Sel),
+}
+
+impl From<MouseCursor> for Cursor {
+    fn from(cursor: MouseCursor) -> Self {
+        match cursor {
+            MouseCursor::Default => Cursor::Native(NSCursor::arrowCursor),
+            MouseCursor::Hand => Cursor::Native(NSCursor::openHandCursor),
+            MouseCursor::HandGrabbing => Cursor::Native(NSCursor::closedHandCursor),
+            MouseCursor::Text => Cursor::Native(NSCursor::IBeamCursor),
+            MouseCursor::VerticalText => Cursor::Native(NSCursor::IBeamCursorForVerticalLayout),
+            MouseCursor::Copy => Cursor::Native(NSCursor::dragCopyCursor),
+            MouseCursor::Alias => Cursor::Native(NSCursor::dragLinkCursor),
+            MouseCursor::NotAllowed | MouseCursor::PtrNotAllowed => {
+                Cursor::Native(NSCursor::operationNotAllowedCursor)
+            }
+            MouseCursor::Crosshair => Cursor::Native(NSCursor::crosshairCursor),
+            #[allow(deprecated)]
+            MouseCursor::EResize => Cursor::Native(NSCursor::resizeRightCursor),
+            #[allow(deprecated)]
+            MouseCursor::NResize => Cursor::Native(NSCursor::resizeUpCursor),
+            #[allow(deprecated)]
+            MouseCursor::WResize => Cursor::Native(NSCursor::resizeLeftCursor),
+            #[allow(deprecated)]
+            MouseCursor::SResize => Cursor::Native(NSCursor::resizeDownCursor),
+            #[allow(deprecated)]
+            MouseCursor::EwResize | MouseCursor::ColResize => {
+                Cursor::Native(NSCursor::resizeLeftRightCursor)
+            }
+            #[allow(deprecated)]
+            MouseCursor::NsResize | MouseCursor::RowResize => {
+                Cursor::Native(NSCursor::resizeUpDownCursor)
+            }
+
+            MouseCursor::Help => Cursor::Undocumented(sel!(_helpCursor)),
+            MouseCursor::ZoomIn => Cursor::Undocumented(sel!(_zoomInCursor)),
+            MouseCursor::ZoomOut => Cursor::Undocumented(sel!(_zoomOutCursor)),
+            MouseCursor::NeResize => Cursor::Undocumented(sel!(_windowResizeNorthEastCursor)),
+            MouseCursor::NwResize => Cursor::Undocumented(sel!(_windowResizeNorthWestCursor)),
+            MouseCursor::SeResize => Cursor::Undocumented(sel!(_windowResizeSouthEastCursor)),
+            MouseCursor::SwResize => Cursor::Undocumented(sel!(_windowResizeSouthWestCursor)),
+            MouseCursor::NeswResize => {
+                Cursor::Undocumented(sel!(_windowResizeNorthEastSouthWestCursor))
+            }
+            MouseCursor::NwseResize => {
+                Cursor::Undocumented(sel!(_windowResizeNorthWestSouthEastCursor))
+            }
+
+            MouseCursor::Working | MouseCursor::PtrWorking => {
+                Cursor::Undocumented(sel!(busyButClickableCursor))
+            }
+
+            _ => Cursor::Native(NSCursor::arrowCursor),
+            // MouseCursor::Hidden => todo!(),
+            // MouseCursor::Move => todo!(),
+            // MouseCursor::AllScroll => todo!(),
+            // MouseCursor::Cell => todo!(),
+        }
+    }
+}
+
+impl Cursor {
+    pub fn load(&self) -> Retained<NSCursor> {
+        match self {
+            Cursor::Native(loader) => loader(),
+            Cursor::Undocumented(sel) => {
+                let class = NSCursor::class();
+
+                // NOTE: class.responds_to does not yield the same result (probably because NSCursor overrides respondsToSelector)
+                let responds_to: bool = unsafe { msg_send![class, respondsToSelector: *sel] };
+
+                if !responds_to {
+                    return NSCursor::arrowCursor();
+                }
+
+                let raw: *mut NSCursor = unsafe { class.send_message(*sel, ()) };
+                let cursor = unsafe { Retained::from_raw(raw) };
+
+                cursor.unwrap_or_else(NSCursor::arrowCursor)
+            }
+        }
+    }
+}

src/macos/mod.rs

@@ -1,3 +1,4 @@
+mod cursor;
 mod keyboard;
 mod view;
 mod window;

src/macos/window.rs

@@ -13,6 +13,7 @@ use raw_window_handle::{
     RawDisplayHandle, RawWindowHandle,
 };
 
+use super::cursor::Cursor;
 use crate::{MouseCursor, Size, WindowHandler, WindowInfo, WindowOpenOptions};
 
 #[cfg(feature = "opengl")]
@@ -153,8 +154,9 @@ impl<'a> Window<'a> {
         BaseviewView::resize(self.view.inner_ref(), size);
     }
 
-    pub fn set_mouse_cursor(&mut self, _mouse_cursor: MouseCursor) {
-        todo!()
+    pub fn set_mouse_cursor(&self, cursor: MouseCursor) {
+        let native_cursor = Cursor::from(cursor);
+        self.view.addCursorRect_cursor(self.view.bounds(), &native_cursor.load());
     }
 
     #[cfg(feature = "opengl")]