[gtk/wip/carlosg/im-text-location] gtkimcontextwayland: Add native surface offset to input coordinates

[Carlos Garnacho <carlosg src gnome org>]

commit 4dcd0114864886511e1a1a6f4b4f8b86ea19e341
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Mar 16 09:55:20 2022 +0100

    gtkimcontextwayland: Add native surface offset to input coordinates
    
    We were missing the surface offset (e.g. shadows) at the time of expressing
    the text caret location in surface coordinates. Add this offset so the
    coordinates are as expected by the compositor.
    
    Fixes: https://gitlab.gnome.org/GNOME/gtk/-/issues/4668

 gtk/gtkimcontextwayland.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkimcontextwayland.c b/gtk/gtkimcontextwayland.c
index 60e1e466bf..e0259d0182 100644
--- a/gtk/gtkimcontextwayland.c
+++ b/gtk/gtkimcontextwayland.c
@@ -357,7 +357,7 @@ notify_cursor_location (GtkIMContextWayland *context)
 {
   GtkIMContextWaylandGlobal *global;
   cairo_rectangle_int_t rect;
-  double x, y;
+  double x, y, sx, sy;
 
   global = gtk_im_context_wayland_get_global (context);
   if (global == NULL)
@@ -369,8 +369,11 @@ notify_cursor_location (GtkIMContextWayland *context)
                                     rect.x, rect.y,
                                     &x, &y);
 
-  rect.x = x;
-  rect.y = y;
+  gtk_native_get_surface_transform (gtk_widget_get_native (context->widget),
+                                    &sx, &sy);
+
+  rect.x = x + sx;
+  rect.y = y + sy;
   zwp_text_input_v3_set_cursor_rectangle (global->text_input,
                                           rect.x, rect.y,
                                           rect.width, rect.height);