From 895713078a55e18a6357374c306b819debcc2d59 Mon Sep 17 00:00:00 2001
From: Lucas Kent <rubickent@gmail.com>
Date: Sat, 5 Mar 2022 13:35:57 +1100
Subject: [PATCH 1/5] Disable scrolling on web by default but provide method in
 builder to enable it

---
 CHANGELOG.md                            |  1 +
 src/platform/web.rs                     | 15 ++++++++++
 src/platform_impl/web/web_sys/canvas.rs | 38 +++++++++++++++++++------
 src/platform_impl/web/window.rs         |  2 ++
 4 files changed, 48 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf98276312..d87cd35b23 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -60,6 +60,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - Added `Window::is_decorated`.
 - On X11, fix for repeated event loop iteration when `ControlFlow` was `Wait`
 - On X11, fix scale factor calculation when the only monitor is reconnected
+- On web, by default, when the canvas is focused, scrolling of the webpage is disabled. It can however be enabled via the `WindowBuilderExtWebSys::enable_web_scroll` method.
 - On Wayland, report unaccelerated mouse deltas in `DeviceEvent::MouseMotion`.
 - On Web, a focused event is manually generated when a click occurs to emulate behaviour of other backends.
 - **Breaking:** Bump `ndk` version to 0.6, ndk-sys to `v0.3`, `ndk-glue` to `0.6`.
diff --git a/src/platform/web.rs b/src/platform/web.rs
index f78a01fb02..63004698f9 100644
--- a/src/platform/web.rs
+++ b/src/platform/web.rs
@@ -19,6 +19,15 @@ pub trait WindowExtWebSys {
 }
 
 pub trait WindowBuilderExtWebSys {
+    /// Enable scrolling of the web page the canvas is in when the canvas is focused.
+    ///
+    /// Scrolling is disabled by default because the scroll input on many mobile devices
+    /// is the same as click and dragging which is a very common input method for many applications.
+    ///
+    /// So only call this method if you know that you will never need to handle mouse wheel inputs
+    /// or click and dragging.
+    fn enable_web_scroll(self) -> Self;
+
     fn with_canvas(self, canvas: Option<HtmlCanvasElement>) -> Self;
 
     /// Whether `event.preventDefault` should be automatically called to prevent event propagation
@@ -34,6 +43,12 @@ pub trait WindowBuilderExtWebSys {
 }
 
 impl WindowBuilderExtWebSys for WindowBuilder {
+    fn enable_web_scroll(mut self) -> Self {
+        self.platform_specific.enable_web_scroll = true;
+
+        self
+    }
+
     fn with_canvas(mut self, canvas: Option<HtmlCanvasElement>) -> Self {
         self.platform_specific.canvas = canvas;
 
diff --git a/src/platform_impl/web/web_sys/canvas.rs b/src/platform_impl/web/web_sys/canvas.rs
index ebae672227..c5a5fd6762 100644
--- a/src/platform_impl/web/web_sys/canvas.rs
+++ b/src/platform_impl/web/web_sys/canvas.rs
@@ -30,6 +30,7 @@ pub struct Canvas {
     on_fullscreen_change: Option<EventListenerHandle<dyn FnMut(Event)>>,
     on_dark_mode: Option<MediaQueryListHandle>,
     mouse_state: MouseState,
+    disable_web_scroll: Option<[EventListenerHandle<dyn FnMut(Event)>; 5]>,
 }
 
 struct Common {
@@ -74,11 +75,34 @@ impl Canvas {
             MouseState::NoPointerEvent(mouse_handler::MouseHandler::new())
         };
 
+        let common = Common {
+            raw: canvas,
+            wants_fullscreen: Rc::new(RefCell::new(false)),
+        };
+
+        let disable_web_scroll = if !attr.enable_web_scroll {
+            Some([
+                common.add_event("pointermove", move |event: Event| {
+                    event.prevent_default();
+                }),
+                common.add_event("pointermove", move |event: Event| {
+                    event.prevent_default();
+                }),
+                common.add_event("touchstart", move |event: Event| {
+                    event.prevent_default();
+                }),
+                common.add_event("touchend", move |event: Event| {
+                    event.prevent_default();
+                }),
+                common.add_event("wheel", move |event: Event| {
+                    event.prevent_default();
+                }),
+            ])
+        } else {
+            None
+        };
+
         Ok(Canvas {
-            common: Common {
-                raw: canvas,
-                wants_fullscreen: Rc::new(RefCell::new(false)),
-            },
             on_blur: None,
             on_focus: None,
             on_keyboard_release: None,
@@ -88,6 +112,8 @@ impl Canvas {
             on_fullscreen_change: None,
             on_dark_mode: None,
             mouse_state,
+            disable_web_scroll,
+            common,
         })
     }
 
@@ -277,10 +303,6 @@ impl Canvas {
         F: 'static + FnMut(i32, MouseScrollDelta, ModifiersState),
     {
         self.on_mouse_wheel = Some(self.common.add_event("wheel", move |event: WheelEvent| {
-            if prevent_default {
-                event.prevent_default();
-            }
-
             if let Some(delta) = event::mouse_scroll_delta(&event) {
                 handler(0, delta, event::mouse_modifiers(&event));
             }
diff --git a/src/platform_impl/web/window.rs b/src/platform_impl/web/window.rs
index 6fe5839e9d..16b8f70434 100644
--- a/src/platform_impl/web/window.rs
+++ b/src/platform_impl/web/window.rs
@@ -414,6 +414,7 @@ pub struct PlatformSpecificWindowBuilderAttributes {
     pub(crate) canvas: Option<backend::RawCanvasType>,
     pub(crate) prevent_default: bool,
     pub(crate) focusable: bool,
+    pub(crate) enable_web_scroll: bool,
 }
 
 impl Default for PlatformSpecificWindowBuilderAttributes {
@@ -422,6 +423,7 @@ impl Default for PlatformSpecificWindowBuilderAttributes {
             canvas: None,
             prevent_default: true,
             focusable: true,
+            enable_web_scroll: false,
         }
     }
 }

From 6d95de02d15897dbdd58681e813dbd10ca24f234 Mon Sep 17 00:00:00 2001
From: Lucas Kent <rubickent@gmail.com>
Date: Sun, 24 Apr 2022 10:11:28 +1000
Subject: [PATCH 2/5] rename enable_web_scroll -> enable_web_page_scroll

---
 CHANGELOG.md                            |  2 +-
 src/platform/web.rs                     |  6 +++---
 src/platform_impl/web/web_sys/canvas.rs | 10 ++++++----
 src/platform_impl/web/window.rs         |  4 ++--
 4 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d87cd35b23..187fdca90e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - On Windows, added `WindowExtWindows::set_undecorated_shadow` and `WindowBuilderExtWindows::with_undecorated_shadow` to draw the drop shadow behind a borderless window.
 - On Windows, fixed default window features (ie snap, animations, shake, etc.) when decorations are disabled.
 - **Breaking:** On macOS, add support for two-finger touchpad magnification and rotation gestures with new events `WindowEvent::TouchpadMagnify` and `WindowEvent::TouchpadRotate`.
+- On web, by default, when the canvas is focused, scrolling of the webpage is disabled. It can however be enabled via the `WindowBuilderExtWebSys::enable_web_page_scroll` method.
 - On Wayland, `wayland-csd-adwaita` now uses `ab_glyph` instead of `crossfont` to render the title for decorations.
 - On Wayland, a new `wayland-csd-adwaita-crossfont` feature was added to use `crossfont` instead of `ab_glyph` for decorations.
 - On Wayland, if not otherwise specified use upstream automatic CSD theme selection.
@@ -60,7 +61,6 @@ And please only add new entries to the top of this list, right below the `# Unre
 - Added `Window::is_decorated`.
 - On X11, fix for repeated event loop iteration when `ControlFlow` was `Wait`
 - On X11, fix scale factor calculation when the only monitor is reconnected
-- On web, by default, when the canvas is focused, scrolling of the webpage is disabled. It can however be enabled via the `WindowBuilderExtWebSys::enable_web_scroll` method.
 - On Wayland, report unaccelerated mouse deltas in `DeviceEvent::MouseMotion`.
 - On Web, a focused event is manually generated when a click occurs to emulate behaviour of other backends.
 - **Breaking:** Bump `ndk` version to 0.6, ndk-sys to `v0.3`, `ndk-glue` to `0.6`.
diff --git a/src/platform/web.rs b/src/platform/web.rs
index 63004698f9..5ac83604a4 100644
--- a/src/platform/web.rs
+++ b/src/platform/web.rs
@@ -26,7 +26,7 @@ pub trait WindowBuilderExtWebSys {
     ///
     /// So only call this method if you know that you will never need to handle mouse wheel inputs
     /// or click and dragging.
-    fn enable_web_scroll(self) -> Self;
+    fn enable_web_page_scroll(self) -> Self;
 
     fn with_canvas(self, canvas: Option<HtmlCanvasElement>) -> Self;
 
@@ -43,8 +43,8 @@ pub trait WindowBuilderExtWebSys {
 }
 
 impl WindowBuilderExtWebSys for WindowBuilder {
-    fn enable_web_scroll(mut self) -> Self {
-        self.platform_specific.enable_web_scroll = true;
+    fn enable_web_page_scroll(mut self) -> Self {
+        self.platform_specific.enable_web_page_scroll = true;
 
         self
     }
diff --git a/src/platform_impl/web/web_sys/canvas.rs b/src/platform_impl/web/web_sys/canvas.rs
index c5a5fd6762..53655771b2 100644
--- a/src/platform_impl/web/web_sys/canvas.rs
+++ b/src/platform_impl/web/web_sys/canvas.rs
@@ -18,6 +18,8 @@ use web_sys::{
 mod mouse_handler;
 mod pointer_handler;
 
+type EventListener = EventListenerHandle<dyn FnMut(Event)>;
+
 #[allow(dead_code)]
 pub struct Canvas {
     common: Common,
@@ -27,10 +29,10 @@ pub struct Canvas {
     on_keyboard_press: Option<EventListenerHandle<dyn FnMut(KeyboardEvent)>>,
     on_received_character: Option<EventListenerHandle<dyn FnMut(KeyboardEvent)>>,
     on_mouse_wheel: Option<EventListenerHandle<dyn FnMut(WheelEvent)>>,
-    on_fullscreen_change: Option<EventListenerHandle<dyn FnMut(Event)>>,
+    on_fullscreen_change: Option<EventListener>,
     on_dark_mode: Option<MediaQueryListHandle>,
     mouse_state: MouseState,
-    disable_web_scroll: Option<[EventListenerHandle<dyn FnMut(Event)>; 5]>,
+    disable_web_scroll: Option<[EventListener; 5]>,
 }
 
 struct Common {
@@ -80,7 +82,7 @@ impl Canvas {
             wants_fullscreen: Rc::new(RefCell::new(false)),
         };
 
-        let disable_web_scroll = if !attr.enable_web_scroll {
+        let disable_web_scroll = if !attr.enable_web_page_scroll && attr.prevent_default {
             Some([
                 common.add_event("pointermove", move |event: Event| {
                     event.prevent_default();
@@ -298,7 +300,7 @@ impl Canvas {
         }
     }
 
-    pub fn on_mouse_wheel<F>(&mut self, mut handler: F, prevent_default: bool)
+    pub fn on_mouse_wheel<F>(&mut self, mut handler: F, _prevent_default: bool)
     where
         F: 'static + FnMut(i32, MouseScrollDelta, ModifiersState),
     {
diff --git a/src/platform_impl/web/window.rs b/src/platform_impl/web/window.rs
index 16b8f70434..70deaed36e 100644
--- a/src/platform_impl/web/window.rs
+++ b/src/platform_impl/web/window.rs
@@ -414,7 +414,7 @@ pub struct PlatformSpecificWindowBuilderAttributes {
     pub(crate) canvas: Option<backend::RawCanvasType>,
     pub(crate) prevent_default: bool,
     pub(crate) focusable: bool,
-    pub(crate) enable_web_scroll: bool,
+    pub(crate) enable_web_page_scroll: bool,
 }
 
 impl Default for PlatformSpecificWindowBuilderAttributes {
@@ -423,7 +423,7 @@ impl Default for PlatformSpecificWindowBuilderAttributes {
             canvas: None,
             prevent_default: true,
             focusable: true,
-            enable_web_scroll: false,
+            enable_web_page_scroll: false,
         }
     }
 }

From 455180fae206c4b37f202d6c516fbf0912198873 Mon Sep 17 00:00:00 2001
From: Lucas Kent <rubickent@gmail.com>
Date: Sat, 3 Sep 2022 19:36:15 +1000
Subject: [PATCH 3/5] move enable_web_page_scroll into prevent_default option

---
 CHANGELOG.md                            |  2 +-
 src/platform/web.rs                     | 15 ---------------
 src/platform_impl/web/web_sys/canvas.rs | 18 ++++++++----------
 src/platform_impl/web/window.rs         |  2 --
 4 files changed, 9 insertions(+), 28 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 187fdca90e..3dadb1c5bf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,7 +18,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - On Windows, added `WindowExtWindows::set_undecorated_shadow` and `WindowBuilderExtWindows::with_undecorated_shadow` to draw the drop shadow behind a borderless window.
 - On Windows, fixed default window features (ie snap, animations, shake, etc.) when decorations are disabled.
 - **Breaking:** On macOS, add support for two-finger touchpad magnification and rotation gestures with new events `WindowEvent::TouchpadMagnify` and `WindowEvent::TouchpadRotate`.
-- On web, by default, when the canvas is focused, scrolling of the webpage is disabled. It can however be enabled via the `WindowBuilderExtWebSys::enable_web_page_scroll` method.
+- On web, the `WindowBuilderExtWebSys::with_prevent_default` setting (enabled by default), now additionally prevents scrolling of the webpage in mobile browsers, previously it only disabled scrolling on desktop.
 - On Wayland, `wayland-csd-adwaita` now uses `ab_glyph` instead of `crossfont` to render the title for decorations.
 - On Wayland, a new `wayland-csd-adwaita-crossfont` feature was added to use `crossfont` instead of `ab_glyph` for decorations.
 - On Wayland, if not otherwise specified use upstream automatic CSD theme selection.
diff --git a/src/platform/web.rs b/src/platform/web.rs
index 5ac83604a4..f78a01fb02 100644
--- a/src/platform/web.rs
+++ b/src/platform/web.rs
@@ -19,15 +19,6 @@ pub trait WindowExtWebSys {
 }
 
 pub trait WindowBuilderExtWebSys {
-    /// Enable scrolling of the web page the canvas is in when the canvas is focused.
-    ///
-    /// Scrolling is disabled by default because the scroll input on many mobile devices
-    /// is the same as click and dragging which is a very common input method for many applications.
-    ///
-    /// So only call this method if you know that you will never need to handle mouse wheel inputs
-    /// or click and dragging.
-    fn enable_web_page_scroll(self) -> Self;
-
     fn with_canvas(self, canvas: Option<HtmlCanvasElement>) -> Self;
 
     /// Whether `event.preventDefault` should be automatically called to prevent event propagation
@@ -43,12 +34,6 @@ pub trait WindowBuilderExtWebSys {
 }
 
 impl WindowBuilderExtWebSys for WindowBuilder {
-    fn enable_web_page_scroll(mut self) -> Self {
-        self.platform_specific.enable_web_page_scroll = true;
-
-        self
-    }
-
     fn with_canvas(mut self, canvas: Option<HtmlCanvasElement>) -> Self {
         self.platform_specific.canvas = canvas;
 
diff --git a/src/platform_impl/web/web_sys/canvas.rs b/src/platform_impl/web/web_sys/canvas.rs
index 53655771b2..a2b27450f1 100644
--- a/src/platform_impl/web/web_sys/canvas.rs
+++ b/src/platform_impl/web/web_sys/canvas.rs
@@ -32,7 +32,7 @@ pub struct Canvas {
     on_fullscreen_change: Option<EventListener>,
     on_dark_mode: Option<MediaQueryListHandle>,
     mouse_state: MouseState,
-    disable_web_scroll: Option<[EventListener; 5]>,
+    disable_mobile_scroll: Option<[EventListener; 3]>,
 }
 
 struct Common {
@@ -82,11 +82,8 @@ impl Canvas {
             wants_fullscreen: Rc::new(RefCell::new(false)),
         };
 
-        let disable_web_scroll = if !attr.enable_web_page_scroll && attr.prevent_default {
+        let disable_mobile_scroll = if attr.prevent_default {
             Some([
-                common.add_event("pointermove", move |event: Event| {
-                    event.prevent_default();
-                }),
                 common.add_event("pointermove", move |event: Event| {
                     event.prevent_default();
                 }),
@@ -96,9 +93,6 @@ impl Canvas {
                 common.add_event("touchend", move |event: Event| {
                     event.prevent_default();
                 }),
-                common.add_event("wheel", move |event: Event| {
-                    event.prevent_default();
-                }),
             ])
         } else {
             None
@@ -114,7 +108,7 @@ impl Canvas {
             on_fullscreen_change: None,
             on_dark_mode: None,
             mouse_state,
-            disable_web_scroll,
+            disable_mobile_scroll,
             common,
         })
     }
@@ -300,11 +294,15 @@ impl Canvas {
         }
     }
 
-    pub fn on_mouse_wheel<F>(&mut self, mut handler: F, _prevent_default: bool)
+    pub fn on_mouse_wheel<F>(&mut self, mut handler: F, prevent_default: bool)
     where
         F: 'static + FnMut(i32, MouseScrollDelta, ModifiersState),
     {
         self.on_mouse_wheel = Some(self.common.add_event("wheel", move |event: WheelEvent| {
+            if prevent_default {
+                event.prevent_default();
+            }
+
             if let Some(delta) = event::mouse_scroll_delta(&event) {
                 handler(0, delta, event::mouse_modifiers(&event));
             }
diff --git a/src/platform_impl/web/window.rs b/src/platform_impl/web/window.rs
index 70deaed36e..6fe5839e9d 100644
--- a/src/platform_impl/web/window.rs
+++ b/src/platform_impl/web/window.rs
@@ -414,7 +414,6 @@ pub struct PlatformSpecificWindowBuilderAttributes {
     pub(crate) canvas: Option<backend::RawCanvasType>,
     pub(crate) prevent_default: bool,
     pub(crate) focusable: bool,
-    pub(crate) enable_web_page_scroll: bool,
 }
 
 impl Default for PlatformSpecificWindowBuilderAttributes {
@@ -423,7 +422,6 @@ impl Default for PlatformSpecificWindowBuilderAttributes {
             canvas: None,
             prevent_default: true,
             focusable: true,
-            enable_web_page_scroll: false,
         }
     }
 }

From 44fb4363959ca1ce6237cb016a9c63d31eea4cc0 Mon Sep 17 00:00:00 2001
From: Lucas Kent <rubickent@gmail.com>
Date: Sun, 4 Sep 2022 12:31:53 +1000
Subject: [PATCH 4/5] final approach

---
 .../web/event_loop/window_target.rs           | 36 +++++++-----
 src/platform_impl/web/web_sys/canvas.rs       | 58 +++++++++----------
 .../web/web_sys/canvas/pointer_handler.rs     | 11 +++-
 3 files changed, 59 insertions(+), 46 deletions(-)

diff --git a/src/platform_impl/web/event_loop/window_target.rs b/src/platform_impl/web/event_loop/window_target.rs
index 6b15e3dd22..c9863bf99c 100644
--- a/src/platform_impl/web/event_loop/window_target.rs
+++ b/src/platform_impl/web/event_loop/window_target.rs
@@ -63,6 +63,9 @@ impl<T> EventLoopWindowTarget<T> {
         let mut canvas = canvas.borrow_mut();
         canvas.set_attribute("data-raw-handle", &id.0.to_string());
 
+        canvas.on_touch_start(prevent_default);
+        canvas.on_touch_end(prevent_default);
+
         let runner = self.runner.clone();
         canvas.on_blur(move || {
             runner.send_event(Event::WindowEvent {
@@ -153,22 +156,25 @@ impl<T> EventLoopWindowTarget<T> {
         });
 
         let runner = self.runner.clone();
-        canvas.on_cursor_move(move |pointer_id, position, delta, modifiers| {
-            runner.send_event(Event::WindowEvent {
-                window_id: RootWindowId(id),
-                event: WindowEvent::CursorMoved {
+        canvas.on_cursor_move(
+            move |pointer_id, position, delta, modifiers| {
+                runner.send_event(Event::WindowEvent {
+                    window_id: RootWindowId(id),
+                    event: WindowEvent::CursorMoved {
+                        device_id: RootDeviceId(DeviceId(pointer_id)),
+                        position,
+                        modifiers,
+                    },
+                });
+                runner.send_event(Event::DeviceEvent {
                     device_id: RootDeviceId(DeviceId(pointer_id)),
-                    position,
-                    modifiers,
-                },
-            });
-            runner.send_event(Event::DeviceEvent {
-                device_id: RootDeviceId(DeviceId(pointer_id)),
-                event: DeviceEvent::MouseMotion {
-                    delta: (delta.x, delta.y),
-                },
-            });
-        });
+                    event: DeviceEvent::MouseMotion {
+                        delta: (delta.x, delta.y),
+                    },
+                });
+            },
+            prevent_default,
+        );
 
         let runner = self.runner.clone();
         canvas.on_mouse_press(move |pointer_id, position, button, modifiers| {
diff --git a/src/platform_impl/web/web_sys/canvas.rs b/src/platform_impl/web/web_sys/canvas.rs
index a2b27450f1..2e87587442 100644
--- a/src/platform_impl/web/web_sys/canvas.rs
+++ b/src/platform_impl/web/web_sys/canvas.rs
@@ -18,21 +18,20 @@ use web_sys::{
 mod mouse_handler;
 mod pointer_handler;
 
-type EventListener = EventListenerHandle<dyn FnMut(Event)>;
-
 #[allow(dead_code)]
 pub struct Canvas {
     common: Common,
+    on_touch_start: Option<EventListenerHandle<dyn FnMut(Event)>>,
+    on_touch_end: Option<EventListenerHandle<dyn FnMut(Event)>>,
     on_focus: Option<EventListenerHandle<dyn FnMut(FocusEvent)>>,
     on_blur: Option<EventListenerHandle<dyn FnMut(FocusEvent)>>,
     on_keyboard_release: Option<EventListenerHandle<dyn FnMut(KeyboardEvent)>>,
     on_keyboard_press: Option<EventListenerHandle<dyn FnMut(KeyboardEvent)>>,
     on_received_character: Option<EventListenerHandle<dyn FnMut(KeyboardEvent)>>,
     on_mouse_wheel: Option<EventListenerHandle<dyn FnMut(WheelEvent)>>,
-    on_fullscreen_change: Option<EventListener>,
+    on_fullscreen_change: Option<EventListenerHandle<dyn FnMut(Event)>>,
     on_dark_mode: Option<MediaQueryListHandle>,
     mouse_state: MouseState,
-    disable_mobile_scroll: Option<[EventListener; 3]>,
 }
 
 struct Common {
@@ -77,28 +76,13 @@ impl Canvas {
             MouseState::NoPointerEvent(mouse_handler::MouseHandler::new())
         };
 
-        let common = Common {
-            raw: canvas,
-            wants_fullscreen: Rc::new(RefCell::new(false)),
-        };
-
-        let disable_mobile_scroll = if attr.prevent_default {
-            Some([
-                common.add_event("pointermove", move |event: Event| {
-                    event.prevent_default();
-                }),
-                common.add_event("touchstart", move |event: Event| {
-                    event.prevent_default();
-                }),
-                common.add_event("touchend", move |event: Event| {
-                    event.prevent_default();
-                }),
-            ])
-        } else {
-            None
-        };
-
         Ok(Canvas {
+            common: Common {
+                raw: canvas,
+                wants_fullscreen: Rc::new(RefCell::new(false)),
+            },
+            on_touch_start: None,
+            on_touch_end: None,
             on_blur: None,
             on_focus: None,
             on_keyboard_release: None,
@@ -108,8 +92,6 @@ impl Canvas {
             on_fullscreen_change: None,
             on_dark_mode: None,
             mouse_state,
-            disable_mobile_scroll,
-            common,
         })
     }
 
@@ -154,6 +136,22 @@ impl Canvas {
         &self.common.raw
     }
 
+    pub fn on_touch_start(&mut self, prevent_default: bool) {
+        self.on_touch_start = Some(self.common.add_event("touchstart", move |event: Event| {
+            if prevent_default {
+                event.prevent_default();
+            }
+        }));
+    }
+
+    pub fn on_touch_end(&mut self, prevent_default: bool) {
+        self.on_touch_end = Some(self.common.add_event("touchend", move |event: Event| {
+            if prevent_default {
+                event.prevent_default();
+            }
+        }));
+    }
+
     pub fn on_blur<F>(&mut self, mut handler: F)
     where
         F: 'static + FnMut(),
@@ -284,12 +282,14 @@ impl Canvas {
         }
     }
 
-    pub fn on_cursor_move<F>(&mut self, handler: F)
+    pub fn on_cursor_move<F>(&mut self, handler: F, prevent_default: bool)
     where
         F: 'static + FnMut(i32, PhysicalPosition<f64>, PhysicalPosition<f64>, ModifiersState),
     {
         match &mut self.mouse_state {
-            MouseState::HasPointerEvent(h) => h.on_cursor_move(&self.common, handler),
+            MouseState::HasPointerEvent(h) => {
+                h.on_cursor_move(&self.common, handler, prevent_default)
+            }
             MouseState::NoPointerEvent(h) => h.on_cursor_move(&self.common, handler),
         }
     }
diff --git a/src/platform_impl/web/web_sys/canvas/pointer_handler.rs b/src/platform_impl/web/web_sys/canvas/pointer_handler.rs
index 85a99eb8ab..e907f54ebe 100644
--- a/src/platform_impl/web/web_sys/canvas/pointer_handler.rs
+++ b/src/platform_impl/web/web_sys/canvas/pointer_handler.rs
@@ -88,13 +88,20 @@ impl PointerHandler {
         ));
     }
 
-    pub fn on_cursor_move<F>(&mut self, canvas_common: &super::Common, mut handler: F)
-    where
+    pub fn on_cursor_move<F>(
+        &mut self,
+        canvas_common: &super::Common,
+        mut handler: F,
+        prevent_default: bool,
+    ) where
         F: 'static + FnMut(i32, PhysicalPosition<f64>, PhysicalPosition<f64>, ModifiersState),
     {
         self.on_cursor_move = Some(canvas_common.add_event(
             "pointermove",
             move |event: PointerEvent| {
+                if prevent_default {
+                    event.prevent_default();
+                }
                 handler(
                     event.pointer_id(),
                     event::mouse_position(&event).to_physical(super::super::scale_factor()),

From df205c0b716a7b00365846361291949891af6e4c Mon Sep 17 00:00:00 2001
From: Mads Marquart <mads@marquart.dk>
Date: Sun, 4 Sep 2022 05:32:44 +0200
Subject: [PATCH 5/5] Mark prevent_default change as breaking

---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3dadb1c5bf..0e648fd508 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,7 +18,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - On Windows, added `WindowExtWindows::set_undecorated_shadow` and `WindowBuilderExtWindows::with_undecorated_shadow` to draw the drop shadow behind a borderless window.
 - On Windows, fixed default window features (ie snap, animations, shake, etc.) when decorations are disabled.
 - **Breaking:** On macOS, add support for two-finger touchpad magnification and rotation gestures with new events `WindowEvent::TouchpadMagnify` and `WindowEvent::TouchpadRotate`.
-- On web, the `WindowBuilderExtWebSys::with_prevent_default` setting (enabled by default), now additionally prevents scrolling of the webpage in mobile browsers, previously it only disabled scrolling on desktop.
+- **Breaking:** On web, the `WindowBuilderExtWebSys::with_prevent_default` setting (enabled by default), now additionally prevents scrolling of the webpage in mobile browsers, previously it only disabled scrolling on desktop.
 - On Wayland, `wayland-csd-adwaita` now uses `ab_glyph` instead of `crossfont` to render the title for decorations.
 - On Wayland, a new `wayland-csd-adwaita-crossfont` feature was added to use `crossfont` instead of `ab_glyph` for decorations.
 - On Wayland, if not otherwise specified use upstream automatic CSD theme selection.