From 0122cf27ceb25804f3f20796509e3a0abadd20df Mon Sep 17 00:00:00 2001
From: Joonas Satka <joonas.satka@gmail.com>
Date: Thu, 20 Jan 2022 23:03:37 +0200
Subject: [PATCH] Add touchpad rotate support for macOS

---
 CHANGELOG.md                                  |  2 +-
 ...uchpad_magnify.rs => touchpad_gestures.rs} |  9 ++++-
 src/event.rs                                  | 30 ++++++++++++++++
 src/platform_impl/macos/view.rs               | 35 +++++++++++++++++--
 4 files changed, 72 insertions(+), 4 deletions(-)
 rename examples/{touchpad_magnify.rs => touchpad_gestures.rs} (75%)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4edcb1ca909..1862830e9c0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,7 @@
 # Unreleased
 
 - **Breaking:** Rename the `Exit` variant of `ControlFlow` to `ExitWithCode`, which holds a value to control the exit code after running. Add an `Exit` constant which aliases to `ExitWithCode(0)` instead to avoid major breakage. This shouldn't affect most existing programs.
-- On macOS, add support for touchpad magnification gesture with new event `WindowEvent::TouchpadMagnify`.
+- On macOS, add support for touchpad magnification and rotation gestures with new events `WindowEvent::TouchpadMagnify` and `WindowEvent::TouchpadRotate`.
 
 # 0.26.1 (2022-01-05)
 
diff --git a/examples/touchpad_magnify.rs b/examples/touchpad_gestures.rs
similarity index 75%
rename from examples/touchpad_magnify.rs
rename to examples/touchpad_gestures.rs
index 801b3ade30e..0086c4f49fa 100644
--- a/examples/touchpad_magnify.rs
+++ b/examples/touchpad_gestures.rs
@@ -10,7 +10,7 @@ fn main() {
     let event_loop = EventLoop::new();
 
     let _window = WindowBuilder::new()
-        .with_title("Touchpad magnify events")
+        .with_title("Touchpad gestures")
         .build(&event_loop)
         .unwrap();
 
@@ -29,6 +29,13 @@ fn main() {
                         println!("Zoomed out {}", delta);
                     }
                 },
+                WindowEvent::TouchpadRotate { delta, .. } => {
+                    if delta > 0.0 {
+                        println!("Rotated left {}", delta);
+                    } else {
+                        println!("Rotated right {}", delta);
+                    }
+                },
                 _ => (),
             },
             _ => (),
diff --git a/src/event.rs b/src/event.rs
index eeb9a52a666..a19eb55ded0 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -318,6 +318,18 @@ pub enum WindowEvent<'a> {
         phase: TouchPhase,
     },
 
+    /// Touchpad rotation event with two-finger rotation gesture.
+    ///
+    /// Positive delta values indicate rotation to left (counterclockwise) and
+    /// negative delta values indicate rotation to right (clockwise).
+    ///
+    /// At the moment, only supported on macOS.
+    TouchpadRotate {
+        device_id: DeviceId,
+        delta: f32,
+        phase: TouchPhase,
+    },
+
     /// Touchpad pressure event.
     ///
     /// At the moment, only supported on Apple forcetouch-capable macbooks.
@@ -439,6 +451,15 @@ impl Clone for WindowEvent<'static> {
                 delta: *delta,
                 phase: *phase,
             },
+            TouchpadRotate {
+                device_id,
+                delta,
+                phase
+            } => TouchpadRotate {
+                device_id: *device_id,
+                delta: *delta,
+                phase: *phase,
+            },
             TouchpadPressure {
                 device_id,
                 pressure,
@@ -534,6 +555,15 @@ impl<'a> WindowEvent<'a> {
                 delta,
                 phase,
             }),
+            TouchpadRotate {
+                device_id,
+                delta,
+                phase
+            } => Some(TouchpadRotate {
+                device_id,
+                delta,
+                phase,
+            }),
             TouchpadPressure {
                 device_id,
                 pressure,
diff --git a/src/platform_impl/macos/view.rs b/src/platform_impl/macos/view.rs
index 035981cb269..38ba634aa93 100644
--- a/src/platform_impl/macos/view.rs
+++ b/src/platform_impl/macos/view.rs
@@ -241,6 +241,10 @@ lazy_static! {
             sel!(magnifyWithEvent:),
             magnify_with_event as extern "C" fn(&Object, Sel, id),
         );
+        decl.add_method(
+            sel!(rotateWithEvent:),
+            rotate_with_event as extern "C" fn(&Object, Sel, id),
+        );
         decl.add_method(
             sel!(pressureChangeWithEvent:),
             pressure_change_with_event as extern "C" fn(&Object, Sel, id),
@@ -1053,8 +1057,6 @@ extern "C" fn scroll_wheel(this: &Object, _sel: Sel, event: id) {
 extern "C" fn magnify_with_event(this: &Object, _sel: Sel, event: id) {
     trace!("Triggered `magnifyWithEvent`");
 
-    mouse_motion(this, event);
-
     unsafe {
         let state_ptr: *mut c_void = *this.get_ivar("winitState");
         let state = &mut *(state_ptr as *mut ViewState);
@@ -1081,6 +1083,35 @@ extern "C" fn magnify_with_event(this: &Object, _sel: Sel, event: id) {
     trace!("Completed `magnifyWithEvent`");
 }
 
+extern "C" fn rotate_with_event(this: &Object, _sel: Sel, event: id) {
+    trace!("Triggered `rotateWithEvent`");
+
+    unsafe {
+        let state_ptr: *mut c_void = *this.get_ivar("winitState");
+        let state = &mut *(state_ptr as *mut ViewState);
+
+        let delta = event.rotation();
+        let phase = match event.phase() {
+            NSEventPhase::NSEventPhaseBegan => TouchPhase::Started,
+            NSEventPhase::NSEventPhaseChanged => TouchPhase::Moved,
+            NSEventPhase::NSEventPhaseEnded => TouchPhase::Ended,
+            _ => return
+        };
+
+        let window_event = Event::WindowEvent {
+            window_id: WindowId(get_window_id(state.ns_window)),
+            event: WindowEvent::TouchpadRotate {
+                device_id: DEVICE_ID,
+                delta,
+                phase,
+            },
+        };
+
+        AppState::queue_event(EventWrapper::StaticEvent(window_event));
+    }
+    trace!("Completed `rotateWithEvent`");
+}
+
 extern "C" fn pressure_change_with_event(this: &Object, _sel: Sel, event: id) {
     trace!("Triggered `pressureChangeWithEvent`");