cursorsource: fix scaling with Xwayland

Before this commit, the device pixel ratio of the cursor was set to ignore
the Xwayland scale override, while the size of the cursor surface was scaled.
This change removes the scaling of the cursor surface size, to make the cursor
be no longer cut off in rendering.

BUG: 466094

src/cursorsource.cpp

@@ -6,6 +6,7 @@
 
 #include "cursorsource.h"
 #include "cursor.h"
+#include "wayland/clientconnection.h"
 #include "wayland/shmclientbuffer.h"
 #include "wayland/surface_interface.h"
 
@@ -143,6 +144,10 @@ void SurfaceCursorSource::update(KWaylandServer::SurfaceInterface *surface, cons
         m_hotspot = QPoint();
         m_surface = nullptr;
     } else {
+        // TODO Plasma 6: once Xwayland cursor scaling can be done correctly, remove this
+        // scaling is intentionally applied "wrong" here to make the cursor stay a consistent size even with un-scaled Xwayland:
+        // - the device pixel ratio of the image is not multiplied by scaleOverride
+        // - the surface size is scaled up with scaleOverride, to un-do the scaling done elsewhere
         auto buffer = qobject_cast<KWaylandServer::ShmClientBuffer *>(surface->buffer());
         if (buffer) {
             m_image = buffer->data().copy();
@@ -150,7 +155,7 @@ void SurfaceCursorSource::update(KWaylandServer::SurfaceInterface *surface, cons
         } else {
             m_image = QImage();
         }
-        m_size = surface->size().toSize();
+        m_size = (surface->size() * surface->client()->scaleOverride()).toSize();
         m_hotspot = hotspot;
         m_surface = surface;
     }