[PATCH 1/1] winewayland: Fix pointer relative motion rounding

[Etaash Mathamsetty]

From: Etaash Mathamsetty

---
 dlls/winewayland.drv/wayland_pointer.c | 35 ++++++++++++++++++++------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/dlls/winewayland.drv/wayland_pointer.c b/dlls/winewayland.drv/wayland_pointer.c
index 6c852292c1d..e4af78f0396 100644
--- a/dlls/winewayland.drv/wayland_pointer.c
+++ b/dlls/winewayland.drv/wayland_pointer.c
@@ -257,6 +257,19 @@ static const struct wl_pointer_listener pointer_listener =
     pointer_handle_axis_discrete
 };

+/**********************************************************************
+ *          wayland_motion_delta_to_window
+ *
+ * Converts the surface-local delta to window (logical) coordinate delta.
+ */
+static void wayland_motion_delta_to_window(struct wayland_surface *surface,
+    double surface_x, double surface_y,
+    double *window_x, double *window_y)
+{
+    *window_x = surface_x * surface->window.scale;
+    *window_y = surface_y * surface->window.scale;
+}
+
 static void relative_pointer_v1_relative_motion(void *private,
                                                 struct zwp_relative_pointer_v1 *zwp_relative_pointer_v1,
                                                 uint32_t utime_hi, uint32_t utime_lo,
@@ -265,28 +278,36 @@ static void relative_pointer_v1_relative_motion(void *private,
 {
     INPUT input = {0};
     HWND hwnd;
-    POINT screen;
+    struct {
+        double x;
+        double y;
+    } screen = {0.0};
     struct wayland_win_data *data;
+    static double dx_accum = 0, dy_accum = 0;

if (!(hwnd = wayland_pointer_get_focused_hwnd())) return;
     if (!(data = wayland_win_data_get(hwnd))) return;

-    wayland_surface_coords_to_window(data->wayland_surface,
+    wayland_motion_delta_to_window(data->wayland_surface,
                                      wl_fixed_to_double(dx),
                                      wl_fixed_to_double(dy),
-                                     (int *)&screen.x, (int *)&screen.y);
-
+                                     &screen.x, &screen.y);
     wayland_win_data_release(data);

+    dx_accum += screen.x;
+    dy_accum += screen.y;

input.type = INPUT_MOUSE;
-    input.mi.dx = screen.x;
-    input.mi.dy = screen.y;
+    input.mi.dx = (int)dx_accum;
+    input.mi.dy = (int)dy_accum;
     input.mi.dwFlags = MOUSEEVENTF_MOVE;

TRACE("hwnd=%p wayland_dxdy=%.2f,%.2f screen_dxdy=%d,%d\n",
           hwnd, wl_fixed_to_double(dx), wl_fixed_to_double(dy),
-          (int)screen.x, (int)screen.y);
+          (int)dx_accum, (int)dy_accum);
+
+    dx_accum -= input.mi.dx;
+    dy_accum -= input.mi.dy;

NtUserSendHardwareInput(hwnd, 0, &input, 0);
 }