From: Jordan Galby <gravemind2a+wine@gmail.com>

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=42631
From: Jordan Galby <gravemind2a+wine@gmail.com>
Signed-off-by: Derek Lesho <dereklesho52@Gmail.com>
---
v9:
  - Remove accumulation of raw mouse movement, as it was incorrect and raw events are always whole anyway.
  - Add accumulation for the mouse-wheel.
---
 dlls/winex11.drv/mouse.c  | 50 +++++++++++++++++++++++++++++----------
 dlls/winex11.drv/x11drv.h |  1 +
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/dlls/winex11.drv/mouse.c b/dlls/winex11.drv/mouse.c
index 9259907eb5..5cd8e07e21 100644
--- a/dlls/winex11.drv/mouse.c
+++ b/dlls/winex11.drv/mouse.c
@@ -259,6 +259,10 @@ static void update_relative_valuators(XIAnyClassInfo **valuators, int n_valuator
     thread_data->y_rel_valuator.number = -1;
     thread_data->wheel_valuator.number = -1;

+    thread_data->x_rel_valuator.accum = 0;
+    thread_data->y_rel_valuator.accum = 0;
+    thread_data->wheel_valuator.accum = 0;
+
     for (i = 0; i < n_valuators; i++)
     {
         XIValuatorClassInfo *class = (XIValuatorClassInfo *)valuators[i];
@@ -1755,8 +1759,6 @@ static BOOL X11DRV_RawMotion( XGenericEventCookie *xev )
     input.u.mi.dwFlags     = MOUSEEVENTF_MOVE;
     input.u.mi.time        = EVENT_x11_time_to_win32_time( event->time );
     input.u.mi.dwExtraInfo = 0;
-    input.u.mi.dx = 0;
-    input.u.mi.dy = 0;

     raw_input.header.dwType = RIM_TYPEMOUSE;
     raw_input.data.mouse.u.usButtonFlags = 0;
@@ -1774,18 +1776,18 @@ static BOOL X11DRV_RawMotion( XGenericEventCookie *xev )
         raw_val = *raw_values++;
         if (i == x_rel->number)
         {
-            input.u.mi.dx = dx = val;
+            dx = val;
             if (x_rel->min < x_rel->max)
-                input.u.mi.dx = val * (virtual_rect.right - virtual_rect.left)
+                dx = val * (virtual_rect.right - virtual_rect.left)
                                     / (x_rel->max - x_rel->min);

             raw_input.data.mouse.lLastX = raw_dx = raw_val;
         }
         if (i == y_rel->number)
         {
-            input.u.mi.dy = dy = val;
+            dy = val;
             if (y_rel->min < y_rel->max)
-                input.u.mi.dy = val * (virtual_rect.bottom - virtual_rect.top)
+                dy = val * (virtual_rect.bottom - virtual_rect.top)
                                     / (y_rel->max - y_rel->min);

             raw_input.data.mouse.lLastY = raw_dy = raw_val;
@@ -1796,20 +1798,44 @@ static BOOL X11DRV_RawMotion( XGenericEventCookie *xev )

     if (broken_rawevents && is_old_motion_event( xev->serial ))
     {
-        TRACE( "pos %d,%d old serial %lu, ignoring\n", input.u.mi.dx, input.u.mi.dy, xev->serial );
+        TRACE( "pos %d,%d old serial %lu, ignoring\n", (LONG) dx, (LONG) dy, xev->serial );
         return FALSE;
     }

-    if (thread_data->xi2_state == xi_extra)
+    /* Accumulate the *double* motions so sub-pixel motions
+     * wont be lost when sent/cast to *LONG* target fields.
+     */
+
+    x_rel->accum += dx;
+    y_rel->accum += dy;
+    if (fabs(x_rel->accum) < 1.0 && fabs(y_rel->accum) < 1.0)
     {
-        TRACE( "pos %d,%d (event %f,%f)\n", input.u.mi.dx, input.u.mi.dy, dx, dy );
-        __wine_send_input( 0, &input );
+        TRACE( "accumulating raw motion (event %f,%f, accum %f,%f)\n", dx, dy, x_rel->accum, y_rel->accum );
     }
+    else
+    {
+        input.u.mi.dx = x_rel->accum;
+        input.u.mi.dy = y_rel->accum;
+        x_rel->accum -= input.u.mi.dx;
+        y_rel->accum -= input.u.mi.dy;

-    if (dwheel)
+        if (thread_data->xi2_state == xi_extra)
+        {
+            TRACE( "pos %d,%d (event %f,%f)\n", input.u.mi.dx, input.u.mi.dy, dx, dy );
+            __wine_send_input( 0, &input );
+        }
+    }
+
+    wheel->accum += dwheel;
+    if (fabs(wheel->accum) < 1.0)
+    {
+        TRACE("accumulating wheel motion (event %f, accum %f)\n", dwheel, wheel->accum);
+    }
+    else
     {
         raw_input.data.mouse.u.usButtonFlags = RI_MOUSE_WHEEL;
-        raw_input.data.mouse.u.usButtonData  = dwheel;
+        raw_input.data.mouse.u.usButtonData  = wheel->accum;
+        wheel->accum -= dwheel;
     }

     TRACE("raw event %f,%f + %f\n",  raw_dx, raw_dy, dwheel);
diff --git a/dlls/winex11.drv/x11drv.h b/dlls/winex11.drv/x11drv.h
index 8af2ebfcef..565cf83b89 100644
--- a/dlls/winex11.drv/x11drv.h
+++ b/dlls/winex11.drv/x11drv.h
@@ -320,6 +320,7 @@ struct x11drv_valuator_data
     double min;
     double max;
     int number;
+    double accum;
 };

 struct x11drv_thread_data
--
2.22.0