Fix pointer deltas on Firefox and send coalesced events together (#2878)

Cargo.toml

@@ -129,7 +129,7 @@ redox_syscall = "0.3"
 
 [target.'cfg(target_family = "wasm")'.dependencies.web_sys]
 package = "web-sys"
-version = "0.3.22"
+version = "0.3"
 features = [
     'console',
     'CssStyleDeclaration',
@@ -151,8 +151,8 @@ features = [
 
 [target.'cfg(target_family = "wasm")'.dependencies]
 atomic-waker = "1"
-js-sys = "0.3"
+js-sys = "0.3.64"
-wasm-bindgen = "0.2.45"
+wasm-bindgen = "0.2"
 wasm-bindgen-futures = "0.4"
 web-time = "0.2"
 

src/platform_impl/web/event_loop/window_target.rs

@@ -194,65 +194,63 @@ impl<T> EventLoopWindowTarget<T> {
             prevent_default,
         );
 
-        canvas.on_cursor_leave(
+        canvas.on_cursor_leave({
-            {
             let runner = self.runner.clone();
             let has_focus = has_focus.clone();
             let modifiers = self.modifiers.clone();
 
-                move |active_modifiers| {
+            move |active_modifiers, pointer_id| {
-                    if has_focus.load(Ordering::Relaxed) && modifiers.get() != active_modifiers {
+                let focus = (has_focus.load(Ordering::Relaxed)
+                    && modifiers.get() != active_modifiers)
+                    .then(|| {
                         modifiers.set(active_modifiers);
-                        runner.send_event(Event::WindowEvent {
+                        Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                        }
                     });
-                    }
-                }
-            },
-            {
-                let runner = self.runner.clone();
 
-                move |pointer_id| {
+                let pointer = pointer_id.map(|pointer_id| Event::WindowEvent {
-                    runner.send_event(Event::WindowEvent {
                     window_id: RootWindowId(id),
                     event: WindowEvent::CursorLeft {
                         device_id: RootDeviceId(DeviceId(pointer_id)),
                     },
                 });
-                }
-            },
-        );
 
-        canvas.on_cursor_enter(
+                if focus.is_some() || pointer.is_some() {
-            {
+                    runner.send_events(focus.into_iter().chain(pointer))
+                }
+            }
+        });
+
+        canvas.on_cursor_enter({
             let runner = self.runner.clone();
             let has_focus = has_focus.clone();
             let modifiers = self.modifiers.clone();
 
-                move |active_modifiers| {
+            move |active_modifiers, pointer_id| {
-                    if has_focus.load(Ordering::Relaxed) && modifiers.get() != active_modifiers {
+                let focus = (has_focus.load(Ordering::Relaxed)
+                    && modifiers.get() != active_modifiers)
+                    .then(|| {
                         modifiers.set(active_modifiers);
-                        runner.send_event(Event::WindowEvent {
+                        Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                        }
                     });
-                    }
-                }
-            },
-            {
-                let runner = self.runner.clone();
 
-                move |pointer_id| {
+                let pointer = pointer_id.map(|pointer_id| Event::WindowEvent {
-                    runner.send_event(Event::WindowEvent {
                     window_id: RootWindowId(id),
                     event: WindowEvent::CursorEntered {
                         device_id: RootDeviceId(DeviceId(pointer_id)),
                     },
                 });
+
+                if focus.is_some() || pointer.is_some() {
+                    runner.send_events(focus.into_iter().chain(pointer))
                 }
-            },
+            }
-        );
+        });
 
         canvas.on_cursor_move(
             {
@@ -272,30 +270,61 @@ impl<T> EventLoopWindowTarget<T> {
             },
             {
                 let runner = self.runner.clone();
+                let has_focus = has_focus.clone();
+                let modifiers = self.modifiers.clone();
 
-                move |pointer_id, position, delta| {
+                move |active_modifiers, pointer_id, events| {
-                    runner.send_events([
+                    let modifiers = (has_focus.load(Ordering::Relaxed)
+                        && modifiers.get() != active_modifiers)
+                        .then(|| {
+                            modifiers.set(active_modifiers);
                             Event::WindowEvent {
                                 window_id: RootWindowId(id),
-                            event: WindowEvent::CursorMoved {
+                                event: WindowEvent::ModifiersChanged(active_modifiers.into()),
-                                device_id: RootDeviceId(DeviceId(pointer_id)),
+                            }
-                                position,
+                        });
-                            },
+
-                        },
+                    runner.send_events(modifiers.into_iter().chain(events.flat_map(
+                        |(position, delta)| {
+                            let device_id = RootDeviceId(DeviceId(pointer_id));
+
+                            [
                                 Event::DeviceEvent {
-                            device_id: RootDeviceId(DeviceId(pointer_id)),
+                                    device_id,
                                     event: DeviceEvent::MouseMotion {
                                         delta: (delta.x, delta.y),
                                     },
                                 },
-                    ]);
+                                Event::WindowEvent {
+                                    window_id: RootWindowId(id),
+                                    event: WindowEvent::CursorMoved {
+                                        device_id,
+                                        position,
+                                    },
+                                },
+                            ]
+                        },
+                    )));
                 }
             },
             {
                 let runner = self.runner.clone();
+                let has_focus = has_focus.clone();
+                let modifiers = self.modifiers.clone();
 
-                move |device_id, location, force| {
+                move |active_modifiers, device_id, events| {
-                    runner.send_event(Event::WindowEvent {
+                    let modifiers = (has_focus.load(Ordering::Relaxed)
+                        && modifiers.get() != active_modifiers)
+                        .then(|| {
+                            modifiers.set(active_modifiers);
+                            Event::WindowEvent {
+                                window_id: RootWindowId(id),
+                                event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                            }
+                        });
+
+                    runner.send_events(modifiers.into_iter().chain(events.map(
+                        |(location, force)| Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::Touch(Touch {
                                 id: device_id as u64,
@@ -304,13 +333,30 @@ impl<T> EventLoopWindowTarget<T> {
                                 force: Some(force),
                                 location,
                             }),
-                    });
+                        },
+                    )));
                 }
             },
             {
                 let runner = self.runner.clone();
+                let has_focus = has_focus.clone();
+                let modifiers = self.modifiers.clone();
+
+                move |active_modifiers,
+                      pointer_id,
+                      position: crate::dpi::PhysicalPosition<f64>,
+                      buttons,
+                      button| {
+                    let modifiers = (has_focus.load(Ordering::Relaxed)
+                        && modifiers.get() != active_modifiers)
+                        .then(|| {
+                            modifiers.set(active_modifiers);
+                            Event::WindowEvent {
+                                window_id: RootWindowId(id),
+                                event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                            }
+                        });
 
-                move |pointer_id, position: crate::dpi::PhysicalPosition<f64>, buttons, button| {
                     let button_event = if buttons.contains(button.into()) {
                         Event::WindowEvent {
                             window_id: RootWindowId(id),
@@ -334,7 +380,7 @@ impl<T> EventLoopWindowTarget<T> {
                     // A chorded button event may come in without any prior CursorMoved events,
                     // therefore we should send a CursorMoved event to make sure that the
                     // user code has the correct cursor position.
-                    runner.send_events([
+                    runner.send_events(modifiers.into_iter().chain([
                         Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::CursorMoved {
@@ -343,7 +389,7 @@ impl<T> EventLoopWindowTarget<T> {
                             },
                         },
                         button_event,
-                    ]);
+                    ]));
                 }
             },
             prevent_default,
@@ -366,12 +412,21 @@ impl<T> EventLoopWindowTarget<T> {
             },
             {
                 let runner = self.runner.clone();
+                let modifiers = self.modifiers.clone();
+
+                move |active_modifiers, pointer_id, position, button| {
+                    let modifiers = (modifiers.get() != active_modifiers).then(|| {
+                        modifiers.set(active_modifiers);
+                        Event::WindowEvent {
+                            window_id: RootWindowId(id),
+                            event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                        }
+                    });
 
-                move |pointer_id, position, button| {
                     // A mouse down event may come in without any prior CursorMoved events,
                     // therefore we should send a CursorMoved event to make sure that the
                     // user code has the correct cursor position.
-                    runner.send_events([
+                    runner.send_events(modifiers.into_iter().chain([
                         Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::CursorMoved {
@@ -387,14 +442,24 @@ impl<T> EventLoopWindowTarget<T> {
                                 button,
                             },
                         },
-                    ]);
+                    ]));
                 }
             },
             {
                 let runner = self.runner.clone();
+                let modifiers = self.modifiers.clone();
 
-                move |device_id, location, force| {
+                move |active_modifiers, device_id, location, force| {
-                    runner.send_event(Event::WindowEvent {
+                    let modifiers = (modifiers.get() != active_modifiers).then(|| {
+                        modifiers.set(active_modifiers);
+                        Event::WindowEvent {
+                            window_id: RootWindowId(id),
+                            event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                        }
+                    });
+
+                    runner.send_events(modifiers.into_iter().chain(iter::once(
+                        Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::Touch(Touch {
                                 id: device_id as u64,
@@ -403,7 +468,8 @@ impl<T> EventLoopWindowTarget<T> {
                                 force: Some(force),
                                 location,
                             }),
-                    })
+                        },
+                    )))
                 }
             },
             prevent_default,
@@ -427,12 +493,24 @@ impl<T> EventLoopWindowTarget<T> {
             },
             {
                 let runner = self.runner.clone();
+                let has_focus = has_focus.clone();
+                let modifiers = self.modifiers.clone();
+
+                move |active_modifiers, pointer_id, position, button| {
+                    let modifiers = (has_focus.load(Ordering::Relaxed)
+                        && modifiers.get() != active_modifiers)
+                        .then(|| {
+                            modifiers.set(active_modifiers);
+                            Event::WindowEvent {
+                                window_id: RootWindowId(id),
+                                event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                            }
+                        });
 
-                move |pointer_id, position, button| {
                     // A mouse up event may come in without any prior CursorMoved events,
                     // therefore we should send a CursorMoved event to make sure that the
                     // user code has the correct cursor position.
-                    runner.send_events([
+                    runner.send_events(modifiers.into_iter().chain([
                         Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::CursorMoved {
@@ -448,14 +526,27 @@ impl<T> EventLoopWindowTarget<T> {
                                 button,
                             },
                         },
-                    ]);
+                    ]));
                 }
             },
             {
                 let runner_touch = self.runner.clone();
+                let has_focus = has_focus.clone();
+                let modifiers = self.modifiers.clone();
 
-                move |device_id, location, force| {
+                move |active_modifiers, device_id, location, force| {
-                    runner_touch.send_event(Event::WindowEvent {
+                    let modifiers = (has_focus.load(Ordering::Relaxed)
+                        && modifiers.get() != active_modifiers)
+                        .then(|| {
+                            modifiers.set(active_modifiers);
+                            Event::WindowEvent {
+                                window_id: RootWindowId(id),
+                                event: WindowEvent::ModifiersChanged(active_modifiers.into()),
+                            }
+                        });
+
+                    runner_touch.send_events(modifiers.into_iter().chain(iter::once(
+                        Event::WindowEvent {
                             window_id: RootWindowId(id),
                             event: WindowEvent::Touch(Touch {
                                 id: device_id as u64,
@@ -464,7 +555,8 @@ impl<T> EventLoopWindowTarget<T> {
                                 force: Some(force),
                                 location,
                             }),
-                    });
+                        },
+                    )));
                 }
             },
         );

src/platform_impl/web/web_sys/canvas.rs

@@ -224,22 +224,18 @@ impl Canvas {
         ));
     }
 
-    pub fn on_cursor_leave<MOD, M>(&mut self, modifier_handler: MOD, mouse_handler: M)
+    pub fn on_cursor_leave<F>(&mut self, handler: F)
     where
-        MOD: 'static + FnMut(ModifiersState),
+        F: 'static + FnMut(ModifiersState, Option<i32>),
-        M: 'static + FnMut(i32),
     {
-        self.pointer_handler
+        self.pointer_handler.on_cursor_leave(&self.common, handler)
-            .on_cursor_leave(&self.common, modifier_handler, mouse_handler)
     }
 
-    pub fn on_cursor_enter<MOD, M>(&mut self, modifier_handler: MOD, mouse_handler: M)
+    pub fn on_cursor_enter<F>(&mut self, handler: F)
     where
-        MOD: 'static + FnMut(ModifiersState),
+        F: 'static + FnMut(ModifiersState, Option<i32>),
-        M: 'static + FnMut(i32),
     {
-        self.pointer_handler
+        self.pointer_handler.on_cursor_enter(&self.common, handler)
-            .on_cursor_enter(&self.common, modifier_handler, mouse_handler)
     }
 
     pub fn on_mouse_release<MOD, M, T>(
@@ -249,8 +245,8 @@ impl Canvas {
         touch_handler: T,
     ) where
         MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32, PhysicalPosition<f64>, MouseButton),
+        M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
-        T: 'static + FnMut(i32, PhysicalPosition<f64>, Force),
+        T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
         self.pointer_handler.on_mouse_release(
             &self.common,
@@ -268,8 +264,8 @@ impl Canvas {
         prevent_default: bool,
     ) where
         MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32, PhysicalPosition<f64>, MouseButton),
+        M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
-        T: 'static + FnMut(i32, PhysicalPosition<f64>, Force),
+        T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
         self.pointer_handler.on_mouse_press(
             &self.common,
@@ -289,9 +285,15 @@ impl Canvas {
         prevent_default: bool,
     ) where
         MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32, PhysicalPosition<f64>, PhysicalPosition<f64>),
+        M: 'static
-        T: 'static + FnMut(i32, PhysicalPosition<f64>, Force),
+            + FnMut(
-        B: 'static + FnMut(i32, PhysicalPosition<f64>, ButtonsState, MouseButton),
+                ModifiersState,
+                i32,
+                &mut dyn Iterator<Item = (PhysicalPosition<f64>, PhysicalPosition<f64>)>,
+            ),
+        T: 'static
+            + FnMut(ModifiersState, i32, &mut dyn Iterator<Item = (PhysicalPosition<f64>, Force)>),
+        B: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, ButtonsState, MouseButton),
     {
         self.pointer_handler.on_cursor_move(
             &self.common,

src/platform_impl/web/web_sys/event.rs

@@ -2,8 +2,11 @@ use crate::dpi::LogicalPosition;
 use crate::event::{MouseButton, MouseScrollDelta};
 use crate::keyboard::{Key, KeyCode, KeyLocation, ModifiersState};
 
+use once_cell::unsync::OnceCell;
 use smol_str::SmolStr;
 use std::convert::TryInto;
+use wasm_bindgen::prelude::wasm_bindgen;
+use wasm_bindgen::{JsCast, JsValue};
 use web_sys::{HtmlCanvasElement, KeyboardEvent, MouseEvent, PointerEvent, WheelEvent};
 
 bitflags! {
@@ -61,12 +64,50 @@ pub fn mouse_position(event: &MouseEvent) -> LogicalPosition<f64> {
     }
 }
 
-pub fn mouse_delta(event: &MouseEvent) -> LogicalPosition<f64> {
+// TODO: Remove this when Firefox supports correct movement values in coalesced events.
+// See <https://bugzilla.mozilla.org/show_bug.cgi?id=1753724>.
+pub struct MouseDelta(Option<MouseDeltaInner>);
+
+pub struct MouseDeltaInner {
+    old_position: LogicalPosition<f64>,
+    old_delta: LogicalPosition<f64>,
+}
+
+impl MouseDelta {
+    pub fn init(window: &web_sys::Window, event: &PointerEvent) -> Self {
+        // Firefox has wrong movement values in coalesced events, we will detect that by checking
+        // for `pointerrawupdate` support. Presumably an implementation of `pointerrawupdate`
+        // should require correct movement values, otherwise uncoalesced events might be broken as
+        // well.
+        Self(
+            (!has_pointer_raw_support(window) && has_coalesced_events_support(event)).then(|| {
+                MouseDeltaInner {
+                    old_position: mouse_position(event),
+                    old_delta: LogicalPosition {
+                        x: event.movement_x() as f64,
+                        y: event.movement_y() as f64,
+                    },
+                }
+            }),
+        )
+    }
+
+    pub fn delta(&mut self, event: &MouseEvent) -> LogicalPosition<f64> {
+        if let Some(inner) = &mut self.0 {
+            let new_position = mouse_position(event);
+            let x = new_position.x - inner.old_position.x + inner.old_delta.x;
+            let y = new_position.y - inner.old_position.y + inner.old_delta.y;
+            inner.old_position = new_position;
+            inner.old_delta = LogicalPosition::new(0., 0.);
+            LogicalPosition::new(x, y)
+        } else {
             LogicalPosition {
                 x: event.movement_x() as f64,
                 y: event.movement_y() as f64,
             }
         }
+    }
+}
 
 pub fn mouse_position_by_client(
     event: &MouseEvent,
@@ -172,3 +213,67 @@ pub fn mouse_modifiers(event: &MouseEvent) -> ModifiersState {
 pub fn touch_position(event: &PointerEvent, canvas: &HtmlCanvasElement) -> LogicalPosition<f64> {
     mouse_position_by_client(event, canvas)
 }
+
+pub fn pointer_move_event(event: PointerEvent) -> impl Iterator<Item = PointerEvent> {
+    // make a single iterator depending on the availability of coalesced events
+    if has_coalesced_events_support(&event) {
+        None.into_iter().chain(
+            Some(
+                event
+                    .get_coalesced_events()
+                    .into_iter()
+                    .map(PointerEvent::unchecked_from_js),
+            )
+            .into_iter()
+            .flatten(),
+        )
+    } else {
+        Some(event).into_iter().chain(None.into_iter().flatten())
+    }
+}
+
+// TODO: Remove when all browsers implement it correctly.
+// See <https://github.com/rust-windowing/winit/issues/2875>.
+pub fn has_pointer_raw_support(window: &web_sys::Window) -> bool {
+    thread_local! {
+        static POINTER_RAW_SUPPORT: OnceCell<bool> = OnceCell::new();
+    }
+
+    POINTER_RAW_SUPPORT.with(|support| {
+        *support.get_or_init(|| {
+            #[wasm_bindgen]
+            extern "C" {
+                type PointerRawSupport;
+
+                #[wasm_bindgen(method, getter, js_name = onpointerrawupdate)]
+                fn has_on_pointerrawupdate(this: &PointerRawSupport) -> JsValue;
+            }
+
+            let support: &PointerRawSupport = window.unchecked_ref();
+            !support.has_on_pointerrawupdate().is_undefined()
+        })
+    })
+}
+
+// TODO: Remove when Safari supports `getCoalescedEvents`.
+// See <https://bugs.webkit.org/show_bug.cgi?id=210454>.
+pub fn has_coalesced_events_support(event: &PointerEvent) -> bool {
+    thread_local! {
+        static COALESCED_EVENTS_SUPPORT: OnceCell<bool> = OnceCell::new();
+    }
+
+    COALESCED_EVENTS_SUPPORT.with(|support| {
+        *support.get_or_init(|| {
+            #[wasm_bindgen]
+            extern "C" {
+                type PointerCoalescedEventsSupport;
+
+                #[wasm_bindgen(method, getter, js_name = getCoalescedEvents)]
+                fn has_get_coalesced_events(this: &PointerCoalescedEventsSupport) -> JsValue;
+            }
+
+            let support: &PointerCoalescedEventsSupport = event.unchecked_ref();
+            !support.has_get_coalesced_events().is_undefined()
+        })
+    })
+}

src/platform_impl/web/web_sys/pointer.rs

@@ -6,8 +6,6 @@ use crate::event::{Force, MouseButton};
 use crate::keyboard::ModifiersState;
 
 use event::ButtonsState;
-use wasm_bindgen::prelude::wasm_bindgen;
-use wasm_bindgen::{JsCast, JsValue};
 use web_sys::PointerEvent;
 
 #[allow(dead_code)]
@@ -32,54 +30,40 @@ impl PointerHandler {
         }
     }
 
-    pub fn on_cursor_leave<MOD, M>(
+    pub fn on_cursor_leave<F>(&mut self, canvas_common: &Common, mut handler: F)
-        &mut self,
+    where
-        canvas_common: &Common,
+        F: 'static + FnMut(ModifiersState, Option<i32>),
-        mut modifier_handler: MOD,
-        mut mouse_handler: M,
-    ) where
-        MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32),
     {
         self.on_cursor_leave = Some(canvas_common.add_event(
             "pointerout",
             move |event: PointerEvent| {
-                modifier_handler(event::mouse_modifiers(&event));
+                let modifiers = event::mouse_modifiers(&event);
 
                 // touch events are handled separately
                 // handling them here would produce duplicate mouse events, inconsistent with
                 // other platforms.
-                if event.pointer_type() != "mouse" {
+                let pointer_id = (event.pointer_type() == "mouse").then(|| event.pointer_id());
-                    return;
-                }
 
-                mouse_handler(event.pointer_id());
+                handler(modifiers, pointer_id);
             },
         ));
     }
 
-    pub fn on_cursor_enter<MOD, M>(
+    pub fn on_cursor_enter<F>(&mut self, canvas_common: &Common, mut handler: F)
-        &mut self,
+    where
-        canvas_common: &Common,
+        F: 'static + FnMut(ModifiersState, Option<i32>),
-        mut modifier_handler: MOD,
-        mut mouse_handler: M,
-    ) where
-        MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32),
     {
         self.on_cursor_enter = Some(canvas_common.add_event(
             "pointerover",
             move |event: PointerEvent| {
-                modifier_handler(event::mouse_modifiers(&event));
+                let modifiers = event::mouse_modifiers(&event);
 
                 // touch events are handled separately
                 // handling them here would produce duplicate mouse events, inconsistent with
                 // other platforms.
-                if event.pointer_type() != "mouse" {
+                let pointer_id = (event.pointer_type() == "mouse").then(|| event.pointer_id());
-                    return;
-                }
 
-                mouse_handler(event.pointer_id());
+                handler(modifiers, pointer_id);
             },
         ));
     }
@@ -92,29 +76,31 @@ impl PointerHandler {
         mut touch_handler: T,
     ) where
         MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32, PhysicalPosition<f64>, MouseButton),
+        M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
-        T: 'static + FnMut(i32, PhysicalPosition<f64>, Force),
+        T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
         let window = canvas_common.window.clone();
         let canvas = canvas_common.raw.clone();
         self.on_pointer_release = Some(canvas_common.add_user_event(
             "pointerup",
             move |event: PointerEvent| {
-                modifier_handler(event::mouse_modifiers(&event));
+                let modifiers = event::mouse_modifiers(&event);
 
                 match event.pointer_type().as_str() {
                     "touch" => touch_handler(
+                        modifiers,
                         event.pointer_id(),
                         event::touch_position(&event, &canvas)
                             .to_physical(super::scale_factor(&window)),
                         Force::Normalized(event.pressure() as f64),
                     ),
                     "mouse" => mouse_handler(
+                        modifiers,
                         event.pointer_id(),
                         event::mouse_position(&event).to_physical(super::scale_factor(&window)),
                         event::mouse_button(&event).expect("no mouse button released"),
                     ),
-                    _ => (),
+                    _ => modifier_handler(modifiers),
                 }
             },
         ));
@@ -129,8 +115,8 @@ impl PointerHandler {
         prevent_default: bool,
     ) where
         MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32, PhysicalPosition<f64>, MouseButton),
+        M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
-        T: 'static + FnMut(i32, PhysicalPosition<f64>, Force),
+        T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
         let window = canvas_common.window.clone();
         let canvas = canvas_common.raw.clone();
@@ -144,11 +130,12 @@ impl PointerHandler {
                     let _ = canvas.focus();
                 }
 
-                modifier_handler(event::mouse_modifiers(&event));
+                let modifiers = event::mouse_modifiers(&event);
 
                 match event.pointer_type().as_str() {
                     "touch" => {
                         touch_handler(
+                            modifiers,
                             event.pointer_id(),
                             event::touch_position(&event, &canvas)
                                 .to_physical(super::scale_factor(&window)),
@@ -157,6 +144,7 @@ impl PointerHandler {
                     }
                     "mouse" => {
                         mouse_handler(
+                            modifiers,
                             event.pointer_id(),
                             event::mouse_position(&event).to_physical(super::scale_factor(&window)),
                             event::mouse_button(&event).expect("no mouse button pressed"),
@@ -167,7 +155,7 @@ impl PointerHandler {
                         // this could fail, that we care if it fails.
                         let _e = canvas.set_pointer_capture(event.pointer_id());
                     }
-                    _ => (),
+                    _ => modifier_handler(modifiers),
                 }
             },
         ));
@@ -183,32 +171,29 @@ impl PointerHandler {
         prevent_default: bool,
     ) where
         MOD: 'static + FnMut(ModifiersState),
-        M: 'static + FnMut(i32, PhysicalPosition<f64>, PhysicalPosition<f64>),
+        M: 'static
-        T: 'static + FnMut(i32, PhysicalPosition<f64>, Force),
+            + FnMut(
-        B: 'static + FnMut(i32, PhysicalPosition<f64>, ButtonsState, MouseButton),
+                ModifiersState,
+                i32,
+                &mut dyn Iterator<Item = (PhysicalPosition<f64>, PhysicalPosition<f64>)>,
+            ),
+        T: 'static
+            + FnMut(ModifiersState, i32, &mut dyn Iterator<Item = (PhysicalPosition<f64>, Force)>),
+        B: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, ButtonsState, MouseButton),
     {
         let window = canvas_common.window.clone();
         let canvas = canvas_common.raw.clone();
         self.on_cursor_move = Some(canvas_common.add_event(
             "pointermove",
             move |event: PointerEvent| {
-                // coalesced events are not available on Safari
+                let modifiers = event::mouse_modifiers(&event);
-                #[wasm_bindgen]
-                extern "C" {
-                    #[wasm_bindgen(extends = PointerEvent)]
-                    type PointerEventExt;
-
-                    #[wasm_bindgen(method, getter, js_name = getCoalescedEvents)]
-                    fn has_get_coalesced_events(this: &PointerEventExt) -> JsValue;
-                }
-
-                modifier_handler(event::mouse_modifiers(&event));
 
                 let pointer_type = event.pointer_type();
 
-                match pointer_type.as_str() {
+                if let "touch" | "mouse" = pointer_type.as_str() {
-                    "touch" | "mouse" => (),
+                } else {
-                    _ => return,
+                    modifier_handler(modifiers);
+                    return;
                 }
 
                 let id = event.pointer_id();
@@ -228,6 +213,7 @@ impl PointerHandler {
                     }
 
                     button_handler(
+                        modifiers,
                         id,
                         event::mouse_position(&event).to_physical(super::scale_factor(&window)),
                         event::mouse_buttons(&event),
@@ -238,40 +224,36 @@ impl PointerHandler {
                 }
 
                 // pointer move event
-
+                let scale = super::scale_factor(&window);
-                let event: PointerEventExt = event.unchecked_into();
-
-                // store coalesced events to extend it's lifetime
-                let events = (!event.has_get_coalesced_events().is_undefined())
-                    .then(|| event.get_coalesced_events());
-
-                // make a single iterator depending on the availability of coalesced events
-                let events = if let Some(events) = &events {
-                    None.into_iter().chain(
-                        Some(events.iter().map(PointerEventExt::unchecked_from_js))
-                            .into_iter()
-                            .flatten(),
-                    )
-                } else {
-                    Some(event).into_iter().chain(None.into_iter().flatten())
-                };
-
-                for event in events {
                 match pointer_type.as_str() {
-                        "mouse" => mouse_handler(
+                    "mouse" => {
+                        let mut delta = event::MouseDelta::init(&window, &event);
+
+                        mouse_handler(
+                            modifiers,
                             id,
-                            event::mouse_position(&event).to_physical(super::scale_factor(&window)),
+                            &mut event::pointer_move_event(event).map(|event| {
-                            event::mouse_delta(&event).to_physical(super::scale_factor(&window)),
+                                let position = event::mouse_position(&event).to_physical(scale);
-                        ),
+                                let delta = delta
+                                    .delta(&event)
+                                    .to_physical(super::scale_factor(&window));
+
+                                (position, delta)
+                            }),
+                        )
+                    }
                     "touch" => touch_handler(
+                        modifiers,
                         id,
-                            event::touch_position(&event, &canvas)
+                        &mut event::pointer_move_event(event).map(|event| {
-                                .to_physical(super::scale_factor(&window)),
+                            (
+                                event::touch_position(&event, &canvas).to_physical(scale),
                                 Force::Normalized(event.pressure() as f64),
+                            )
+                        }),
                     ),
                     _ => unreachable!("didn't return early before"),
-                    }
+                };
-                }
             },
         ));
     }