Add set_mouse_cursor for MacOS

Based on: RustAudio#128

Author: andrewmcveigh

src/macos/cursor.rs

@@ -0,0 +1,77 @@
+use cocoa::base::id;
+use objc::{runtime::Sel, msg_send, sel, sel_impl, class};
+
+use crate::MouseCursor;
+
+#[derive(Debug)]
+pub enum Cursor {
+    Native(&'static str),
+    Undocumented(&'static str),
+}
+
+impl From<MouseCursor> for Cursor {
+    fn from(cursor: MouseCursor) -> Self {
+        match cursor {
+            MouseCursor::Default => Cursor::Native("arrowCursor"),
+            MouseCursor::Hand => Cursor::Native("pointingHandCursor"),
+            MouseCursor::HandGrabbing => Cursor::Native("closedHandCursor"),
+            MouseCursor::Text => Cursor::Native("IBeamCursor"),
+            MouseCursor::VerticalText => Cursor::Native("IBeamCursorForVerticalLayout"),
+            MouseCursor::Copy => Cursor::Native("dragCopyCursor"),
+            MouseCursor::Alias => Cursor::Native("dragLinkCursor"),
+            MouseCursor::NotAllowed | MouseCursor::PtrNotAllowed => {
+                Cursor::Native("operationNotAllowedCursor")
+            }
+            // MouseCursor:: => Cursor::Native("contextualMenuCursor"),
+            MouseCursor::Crosshair => Cursor::Native("crosshairCursor"),
+            MouseCursor::EResize => Cursor::Native("resizeRightCursor"),
+            MouseCursor::NResize => Cursor::Native("resizeUpCursor"),
+            MouseCursor::WResize => Cursor::Native("resizeLeftCursor"),
+            MouseCursor::SResize => Cursor::Native("resizeDownCursor"),
+            MouseCursor::EwResize | MouseCursor::ColResize => Cursor::Native("resizeLeftRightCursor"),
+            MouseCursor::NsResize | MouseCursor::RowResize => Cursor::Native("resizeUpDownCursor"),
+
+            MouseCursor::Help => Cursor::Undocumented("_helpCursor"),
+            MouseCursor::ZoomIn => Cursor::Undocumented("_zoomInCursor"),
+            MouseCursor::ZoomOut => Cursor::Undocumented("_zoomOutCursor"),
+            MouseCursor::NeResize => Cursor::Undocumented("_windowResizeNorthEastCursor"),
+            MouseCursor::NwResize => Cursor::Undocumented("_windowResizeNorthWestCursor"),
+            MouseCursor::SeResize => Cursor::Undocumented("_windowResizeSouthEastCursor"),
+            MouseCursor::SwResize => Cursor::Undocumented("_windowResizeSouthWestCursor"),
+            MouseCursor::NeswResize => Cursor::Undocumented("_windowResizeNorthEastSouthWestCursor"),
+            MouseCursor::NwseResize => Cursor::Undocumented("_windowResizeNorthWestSouthEastCursor"),
+
+            MouseCursor::Working | MouseCursor::PtrWorking => {
+                Cursor::Undocumented("busyButClickableCursor")
+            }
+
+            _ => Cursor::Native("arrowCursor"),
+
+            // MouseCursor::Hidden => todo!(),
+            // MouseCursor::Move => todo!(),
+            // MouseCursor::AllScroll => todo!(),
+            // MouseCursor::Cell => todo!(),
+        }
+    }
+}
+
+impl Cursor {
+    pub unsafe fn load(&self) -> id {
+        match self {
+            Cursor::Native(cursor_name) => {
+                let sel = Sel::register(cursor_name);
+                msg_send![class!(NSCursor), performSelector: sel]
+            }
+            Cursor::Undocumented(cursor_name) => {
+                let class = class!(NSCursor);
+                let sel = Sel::register(cursor_name);
+                let sel = if msg_send![class, respondsToSelector: sel] {
+                    sel
+                } else {
+                    sel!(arrowCursor)
+                };
+                msg_send![class, performSelector: sel]
+            }
+        }
+    }
+}

src/macos/mod.rs

@@ -2,6 +2,7 @@
 // Eventually we should migrate to the objc2 crate and remove this.
 #![allow(unexpected_cfgs)]
 
+mod cursor;
 mod keyboard;
 mod view;
 mod window;

src/macos/window.rs

@@ -26,6 +26,7 @@ use crate::{
     WindowScalePolicy,
 };
 
+use super::cursor::Cursor;
 use super::keyboard::KeyboardState;
 use super::view::{create_view, BASEVIEW_STATE_IVAR};
 
@@ -334,8 +335,16 @@ impl<'a> Window<'a> {
         }
     }
 
-    pub fn set_mouse_cursor(&mut self, _mouse_cursor: MouseCursor) {
-        todo!()
+    pub fn set_mouse_cursor(&mut self, mouse_cursor: MouseCursor) {
+        let native_cursor = Cursor::from(mouse_cursor);
+        unsafe {
+            let bounds: NSRect = msg_send![self.inner.ns_view as id, bounds];
+            let cursor = native_cursor.load();
+            let _: () = msg_send![self.inner.ns_view as id,
+            addCursorRect:bounds
+                cursor:cursor
+            ];
+        }
     }
 
     #[cfg(feature = "opengl")]