From a6d180cefbc1b5046e324e033c93f529f416fdda Mon Sep 17 00:00:00 2001
From: Kirill Chibisov <contact@kchibisov.com>
Date: Sat, 11 Jan 2020 11:45:52 +0300
Subject: [PATCH] On Wayland, fix coordinates in mouse events when scale factor
 isn't 1 (#1385)

* On Wayland, fix coordinates in mouse events when scale factor isn't 1

* Refactor mouse_focus to be a surface instead of WindowId
---
 CHANGELOG.md                               |  1 +
 src/platform_impl/linux/wayland/pointer.rs | 28 +++++++++++++++-------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dec9f155..029bf121 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - On X11, fix deadlock on window state when handling certain window events.
 - `WindowBuilder` now implements `Default`.
 - **Breaking:** `WindowEvent::CursorMoved` changed to `f64` units, preserving high-precision data supplied by most backends
+- On Wayland, fix coordinates in mouse events when scale factor isn't 1
 
 # 0.20.0 (2020-01-05)
 
diff --git a/src/platform_impl/linux/wayland/pointer.rs b/src/platform_impl/linux/wayland/pointer.rs
index f84264c3..2ba6c934 100644
--- a/src/platform_impl/linux/wayland/pointer.rs
+++ b/src/platform_impl/linux/wayland/pointer.rs
@@ -7,10 +7,13 @@ use crate::event::{
 
 use super::{
     event_loop::{CursorManager, EventsSink},
+    make_wid,
     window::WindowStore,
     DeviceId,
 };
 
+use smithay_client_toolkit::surface;
+
 use smithay_client_toolkit::reexports::client::protocol::{
     wl_pointer::{self, Event as PtrEvent, WlPointer},
     wl_seat,
@@ -36,6 +39,7 @@ pub fn implement_pointer(
     cursor_manager: Arc<Mutex<CursorManager>>,
 ) -> WlPointer {
     seat.get_pointer(|pointer| {
+        // Currently focused winit surface
         let mut mouse_focus = None;
         let mut axis_buffer = None;
         let mut axis_discrete_buffer = None;
@@ -53,8 +57,10 @@ pub fn implement_pointer(
                         ..
                     } => {
                         let wid = store.find_wid(&surface);
+
                         if let Some(wid) = wid {
-                            mouse_focus = Some(wid);
+                            let scale_factor = surface::get_dpi_factor(&surface) as f64;
+                            mouse_focus = Some(surface);
 
                             // Reload cursor style only when we enter winit's surface. Calling
                             // this function every time on `PtrEvent::Enter` could interfere with
@@ -75,7 +81,8 @@ pub fn implement_pointer(
                                     device_id: crate::event::DeviceId(
                                         crate::platform_impl::DeviceId::Wayland(DeviceId),
                                     ),
-                                    position: (surface_x, surface_y).into(),
+                                    position: (surface_x * scale_factor, surface_y * scale_factor)
+                                        .into(),
                                     modifiers: modifiers_tracker.lock().unwrap().clone(),
                                 },
                                 wid,
@@ -101,13 +108,16 @@ pub fn implement_pointer(
                         surface_y,
                         ..
                     } => {
-                        if let Some(wid) = mouse_focus {
+                        if let Some(surface) = mouse_focus.as_ref() {
+                            let scale_factor = surface::get_dpi_factor(&surface) as f64;
+                            let wid = make_wid(surface);
                             sink.send_window_event(
                                 WindowEvent::CursorMoved {
                                     device_id: crate::event::DeviceId(
                                         crate::platform_impl::DeviceId::Wayland(DeviceId),
                                     ),
-                                    position: (surface_x, surface_y).into(),
+                                    position: (surface_x * scale_factor, surface_y * scale_factor)
+                                        .into(),
                                     modifiers: modifiers_tracker.lock().unwrap().clone(),
                                 },
                                 wid,
@@ -115,7 +125,7 @@ pub fn implement_pointer(
                         }
                     }
                     PtrEvent::Button { button, state, .. } => {
-                        if let Some(wid) = mouse_focus {
+                        if let Some(surface) = mouse_focus.as_ref() {
                             let state = match state {
                                 wl_pointer::ButtonState::Pressed => ElementState::Pressed,
                                 wl_pointer::ButtonState::Released => ElementState::Released,
@@ -137,12 +147,13 @@ pub fn implement_pointer(
                                     button,
                                     modifiers: modifiers_tracker.lock().unwrap().clone(),
                                 },
-                                wid,
+                                make_wid(surface),
                             );
                         }
                     }
                     PtrEvent::Axis { axis, value, .. } => {
-                        if let Some(wid) = mouse_focus {
+                        if let Some(surface) = mouse_focus.as_ref() {
+                            let wid = make_wid(surface);
                             if pointer.as_ref().version() < 5 {
                                 let (mut x, mut y) = (0.0, 0.0);
                                 // old seat compatibility
@@ -184,7 +195,8 @@ pub fn implement_pointer(
                     PtrEvent::Frame => {
                         let axis_buffer = axis_buffer.take();
                         let axis_discrete_buffer = axis_discrete_buffer.take();
-                        if let Some(wid) = mouse_focus {
+                        if let Some(surface) = mouse_focus.as_ref() {
+                            let wid = make_wid(surface);
                             if let Some((x, y)) = axis_discrete_buffer {
                                 sink.send_window_event(
                                     WindowEvent::MouseWheel {