[PATCH 0/1] MR7736: server: Fix the accumulation method when merging WM_MOUSEWHEEL message.

[Akihiro Sagawa (＠sgwaki)]

Otherwise, two MK_RBUTTON messages become MK_SHIFT.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7736

[PATCH 1/1] server: Fix the accumulation method when merging WM_MOUSEWHEEL message.

[Akihiro Sagawa]

From: Akihiro Sagawa <sagawa.aki(a)gmail.com>

---
 server/queue.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/server/queue.c b/server/queue.c
index 520659d377c..86f76a66a1f 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -823,11 +823,15 @@ static struct message *find_mouse_message( struct thread_input *input, const str
 static int merge_mousewheel( struct thread_input *input, const struct message *msg )
 {
     struct message *prev;
+    short delta;
 
     if (!(prev = find_mouse_message( input, msg ))) return 0;
     if (prev->x != msg->x || prev->y != msg->y) return 0; /* don't merge if cursor has moved */
 
-    prev->wparam += msg->wparam; /* accumulate wheel delta */
+    /* accumulate wheel delta */
+    delta = GET_WHEEL_DELTA_WPARAM(prev->wparam) + GET_WHEEL_DELTA_WPARAM(msg->wparam);
+
+    prev->wparam  = MAKEWPARAM(GET_KEYSTATE_WPARAM(msg->wparam), delta);
     prev->lparam  = msg->lparam;
     prev->x       = msg->x;
     prev->y       = msg->y;
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/7736

[Rémi Bernon]

Rémi Bernon (@rbernon) commented about server/queue.c:
> static int merge_mousewheel( struct thread_input *input, const struct message *msg )
>  {
>      struct message *prev;
> +    short delta;
>
> if (!(prev = find_mouse_message( input, msg ))) return 0;
>      if (prev->x != msg->x || prev->y != msg->y) return 0; /* don't merge if cursor has moved */
>
> -    prev->wparam += msg->wparam; /* accumulate wheel delta */
> +    /* accumulate wheel delta */
> +    delta = GET_WHEEL_DELTA_WPARAM(prev->wparam) + GET_WHEEL_DELTA_WPARAM(msg->wparam);
> Should we clamp it, or avoid merging on overflow maybe?

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https://gitlab.winehq.org/wine/wine/-/merge_requests/7736#note_99859

[Akihiro Sagawa (＠sgwaki)]

On Thu Apr  3 14:32:10 2025 +0000, Rémi Bernon wrote:
> Should we clamp it, or avoid merging on overflow maybe?
> Sure. I opted to avoid merging on overflow.
> Thanks for reviewing.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7736#note_99860