Send CursorMove before mouse press event and note that touch is unimplemented on web target (#1668)

* Change to send CursorMove before mouse press event on web target

* Fix feature matrix to indicate touch being unimplemented on web

FEATURES.md

@@ -198,9 +198,9 @@ Legend:
 |Mouse set location      |✔️       |✔️      |✔️       |❓           |**N/A**|**N/A**|**N/A**|
 |Cursor grab             |✔️       |▢[#165] |▢[#242]  |✔️         |**N/A**|**N/A**|❓        |
 |Cursor icon             |✔️       |✔️      |✔️       |✔️           |**N/A**|**N/A**|✔️        |
-|Touch events            |✔️       |❌      |✔️       |✔️          |✔️    |✔️     |✔️        |
+|Touch events            |✔️       |❌      |✔️       |✔️          |✔️    |✔️     |❌        |
-|Touch pressure          |✔️       |❌      |❌       |❌          |❌    |✔️     |✔️        |
+|Touch pressure          |✔️       |❌      |❌       |❌          |❌    |✔️     |❌        |
-|Multitouch              |✔️       |❌      |✔️       |✔️          |❓     |✔️     |✔️        |
+|Multitouch              |✔️       |❌      |✔️       |✔️          |❓     |✔️     |❌        |
 |Keyboard events         |✔️       |✔️      |✔️       |✔️          |❓     |❌     |✔️        |
 |Drag & Drop             |▢[#720]  |▢[#720] |▢[#720]  |❌[#306]    |**N/A**|**N/A**|❓        |
 |Raw Device Events       |▢[#750]  |▢[#750] |▢[#750]  |❌          |❌    |❌     |❓        |

src/platform_impl/web/event_loop/window_target.rs

@@ -133,7 +133,18 @@ impl<T> WindowTarget<T> {
         });
 
         let runner = self.runner.clone();
-        canvas.on_mouse_press(move |pointer_id, button, modifiers| {
+        canvas.on_mouse_press(move |pointer_id, position, button, modifiers| {
+            // 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_event(Event::WindowEvent {
+                window_id: WindowId(id),
+                event: WindowEvent::CursorMoved {
+                    device_id: DeviceId(device::Id(pointer_id)),
+                    position,
+                    modifiers,
+                },
+            });
             runner.send_event(Event::WindowEvent {
                 window_id: WindowId(id),
                 event: WindowEvent::MouseInput {

src/platform_impl/web/stdweb/canvas.rs

@@ -200,11 +200,12 @@ impl Canvas {
 
     pub fn on_mouse_press<F>(&mut self, mut handler: F)
     where
-        F: 'static + FnMut(i32, MouseButton, ModifiersState),
+        F: 'static + FnMut(i32, PhysicalPosition<f64>, MouseButton, ModifiersState),
     {
         self.on_mouse_press = Some(self.add_user_event(move |event: PointerDownEvent| {
             handler(
                 event.pointer_id(),
+                event::mouse_position(&event).to_physical(super::scale_factor()),
                 event::mouse_button(&event),
                 event::mouse_modifiers(&event),
             );

src/platform_impl/web/web_sys/canvas.rs

@@ -248,7 +248,7 @@ impl Canvas {
 
     pub fn on_mouse_press<F>(&mut self, mut handler: F)
     where
-        F: 'static + FnMut(i32, MouseButton, ModifiersState),
+        F: 'static + FnMut(i32, PhysicalPosition<f64>, MouseButton, ModifiersState),
     {
         if has_pointer_event() {
             self.on_pointer_press = Some(self.add_user_event(
@@ -256,6 +256,7 @@ impl Canvas {
                 move |event: PointerEvent| {
                     handler(
                         event.pointer_id(),
+                        event::mouse_position(&event).to_physical(super::scale_factor()),
                         event::mouse_button(&event),
                         event::mouse_modifiers(&event),
                     );
@@ -266,6 +267,7 @@ impl Canvas {
                 Some(self.add_user_event("mousedown", move |event: MouseEvent| {
                     handler(
                         0,
+                        event::mouse_position(&event).to_physical(super::scale_factor()),
                         event::mouse_button(&event),
                         event::mouse_modifiers(&event),
                     );