From f9acdb6edb7bc0c0b4d1a814283c7d908b0d4bba Mon Sep 17 00:00:00 2001
From: ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
Date: Tue, 25 Oct 2022 19:08:12 +0200
Subject: [PATCH] Repair commit e0c3fe9 to fix #521 which destroyed DnD from
 Wayland

It turns out it's necessary to memorize 2 event serial numbers :
- serial changed at each pointer and key event;
- pointer_enter_serial changed when pointer enters a surface
because this one and not any other is needed for exact cursor changes
by wl_pointer_set_cursor() in do_set_cursor().
---
 src/drivers/Wayland/Fl_Wayland_Screen_Driver.H   | 1 +
 src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.H b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.H
index e55531509..f08f9cd86 100644
--- a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.H
+++ b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.H
@@ -42,6 +42,7 @@ struct seat {
   struct wl_surface *pointer_focus;
   int pointer_scale;
   uint32_t serial;
+  uint32_t pointer_enter_serial;
   struct wl_data_device_manager *data_device_manager;
   struct wl_data_device *data_device;
   struct wl_data_source *data_source;
diff --git a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
index 68cbe50cc..0f76454a8 100644
--- a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
@@ -188,7 +188,7 @@ static void do_set_cursor(struct seat *seat, struct wl_cursor *wl_cursor = NULL)
   if (!wl_cursor) wl_cursor = seat->default_cursor;
   image = wl_cursor->images[0];
   buffer = wl_cursor_image_get_buffer(image);
-  wl_pointer_set_cursor(seat->wl_pointer, seat->serial,
+  wl_pointer_set_cursor(seat->wl_pointer, seat->pointer_enter_serial,
             seat->cursor_surface,
             image->hotspot_x / scale,
             image->hotspot_y / scale);
@@ -278,6 +278,7 @@ static void pointer_enter(void *data,
   struct seat *seat = (struct seat*)data;
   do_set_cursor(seat, cursor);
   seat->serial = serial;
+  seat->pointer_enter_serial = serial;
   set_event_xy(win);
   Fl::handle(FL_ENTER, win);
   //fprintf(stderr, "pointer_enter window=%p\n", win);
@@ -332,6 +333,7 @@ static void pointer_button(void *data,
          uint32_t state)
 {
   struct seat *seat = (struct seat*)data;
+  seat->serial = serial;
   int event = 0;
   Fl_Window *win = Fl_Wayland_Screen_Driver::surface_to_window(seat->pointer_focus);
   if (!win) return;
@@ -655,6 +657,7 @@ static void wl_keyboard_key(void *data, struct wl_keyboard *wl_keyboard,
                uint32_t serial, uint32_t time, uint32_t key, uint32_t state)
 {
   struct seat *seat = (struct seat*)data;
+  seat->serial = serial;
   static char buf[128];
   uint32_t keycode = key + 8;
   xkb_keysym_t sym = xkb_state_key_get_one_sym(seat->xkb_state, keycode);