xwayland: set cursor scale

[ammen99]

Fixes #3011

@lilydjwg This was my first idea about how to fix the issue. I think it might not work very well with mixed DPI, however. Let me know whether this is the correct approach, or maybe we need to do something else?

[lilydjwg]

It doesn't work. The code is executed but nothing has changed.

[ammen99]

@lilydjwg Try the latest commit. Does it at least change things for xterm? Here, I can see quite a big difference.

[lilydjwg]

No, nothing has changed.

[ammen99]

No, nothing has changed.

What is your ini file? Also are you sure that firefox is running Xwayland mode to begin with? I just tested gedit and firefox with the x11 backend and the cursor has the same size as wayland native applications with my patch.

[lilydjwg]

Here is my wayfire.ini.

Besides Firefox, I also tested with xterm.

[lilydjwg]

I gave codex gpt-5.4 a try and it ended up copying some logic from wlroots' surface_finalize_pending, and it worked as expected. Here's a slightly-revised patch from codex:

diff --git a/src/view/xwayland.cpp b/src/view/xwayland.cpp
index 3fa17742..0fc60185 100644
--- a/src/view/xwayland.cpp
+++ b/src/view/xwayland.cpp
@@ -215,6 +215,39 @@ class xwayland_view_controller_t
 static wlr_xwayland *xwayland_handle = nullptr;
 static wf::wl_listener_wrapper on_xwayland_surface_created;
 static wf::wl_listener_wrapper on_xwayland_ready;
+
+static void update_xwayland_cursor_surface_scale(wlr_surface *surface, int32_t scale)
+{
+    if (!surface || (scale <= 0))
+    {
+        return;
+    }
+
+    surface->current.scale = scale;
+
+    int width  = surface->current.buffer_width;
+    int height = surface->current.buffer_height;
+    wlr_output_transform_coords(surface->current.transform, &width, &height);
+
+    if (surface->current.viewport.has_src)
+    {
+        width  = surface->current.viewport.src.width;
+        height = surface->current.viewport.src.height;
+    } else
+    {
+        width  /= scale;
+        height /= scale;
+    }
+
+    if (surface->current.viewport.has_dst)
+    {
+        width  = surface->current.viewport.dst_width;
+        height = surface->current.viewport.dst_height;
+    }
+
+    surface->current.width  = width;
+    surface->current.height = height;
+}
 #endif
 
 void wf::init_xwayland(bool lazy)
@@ -372,7 +405,7 @@ void wf::xwayland_adjust_cursor(wlr_surface *cursor_surface)
             {
                 auto& ol = wf::get_core().output_layout;
                 auto wo  = ol->find_closest_output(wf::get_core().get_cursor_position());
-                last_cursor_surface->current.scale = wo->handle->scale;
+                update_xwayland_cursor_surface_scale(last_cursor_surface, wo->handle->scale);
             });
 
             on_cursor_destroy.connect(&cursor_surface->events.destroy);

[ammen99]

I feel like the src/dst bits are wrong but we also need to scale the size, right. I am not sure why it seems to work here ...

[lilydjwg]

Maybe some code path isn't taken in my case? (I looked at this place yesterday but didn't figure out a working solution.)

[ammen99]

Maybe some code path isn't taken in my case? (I looked at this place yesterday but didn't figure out a working solution.)

Yes, I don't expect many if any clients at all use viewport for cursors, definitely not xwayland. If you delete all of these branches, does it still work? If yes, we could merge.

[lilydjwg]

Yes, I simplified the function to the following:

static void update_xwayland_cursor_surface_scale(wlr_surface *surface, int32_t scale)
{
    if (!surface || (scale <= 0))
    {
        return;
    }

    surface->current.scale = scale;

    int width  = surface->current.buffer_width;
    int height = surface->current.buffer_height;
    wlr_output_transform_coords(surface->current.transform, &width, &height);

    width  /= scale;
    height /= scale;

    surface->current.width  = width;
    surface->current.height = height;
}

And it still works.

[ammen99]

@lilydjwg Should I push the changes or will you send a PR to this branch?

[lilydjwg]

You can just push the changes.

[ammen99]

Hopefully I pushed everything correctly, let me know if I messed something up @lilydjwg