Wayland: much lighter but partial implementation of the "GTK Shell" protocol

Only the middle-button click gesture is implemented which avoids interference
with what libdecor does with right-click and double-click.

3 files changed, 20 insertions, 10 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index fb90aec75..be2634d62 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -709,17 +709,15 @@ if (UNIX AND OPTION_USE_WAYLAND)
     list (APPEND STATIC_FILES "xdg-decoration-protocol.c")
     list (APPEND SHARED_FILES "xdg-decoration-protocol.c")
   endif (NOT OPTION_USE_SYSTEM_LIBDECOR)
-  if (GTK_FOUND AND (OPTION_USE_SYSTEM_LIBDECOR OR OPTION_ALLOW_GTK_PLUGIN))
-    add_custom_command(
+  add_custom_command(
       OUTPUT gtk-shell-protocol.c gtk-shell-client-protocol.h
       COMMAND wayland-scanner private-code ${CMAKE_CURRENT_SOURCE_DIR}/../libdecor/build/gtk-shell.xml gtk-shell-protocol.c
       COMMAND wayland-scanner client-header ${CMAKE_CURRENT_SOURCE_DIR}/../libdecor/build/gtk-shell.xml gtk-shell-client-protocol.h
       DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/../libdecor/build/gtk-shell.xml
       VERBATIM
-    )
-    list (APPEND STATIC_FILES "gtk-shell-protocol.c")
-    list (APPEND SHARED_FILES "gtk-shell-protocol.c")
-  endif (GTK_FOUND AND (OPTION_USE_SYSTEM_LIBDECOR OR OPTION_ALLOW_GTK_PLUGIN))
+  )
+  list (APPEND STATIC_FILES "gtk-shell-protocol.c")
+  list (APPEND SHARED_FILES "gtk-shell-protocol.c")
   add_custom_command(
     OUTPUT text-input-protocol.c text-input-client-protocol.h
     COMMAND wayland-scanner private-code ${PROTOCOLS}/unstable/text-input/text-input-unstable-v3.xml text-input-protocol.c
diff --git a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
index 5b4d97cf2..1cf52a5cd 100644
--- a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
@@ -39,6 +39,7 @@
 #include <xkbcommon/xkbcommon.h>
 #include <xkbcommon/xkbcommon-compose.h>
 #include "text-input-client-protocol.h"
+#include "gtk-shell-client-protocol.h"
 #include <assert.h>
 #include <sys/mman.h>
 #include <poll.h>
@@ -46,7 +47,6 @@
 #include <string.h> // for strerror()
 extern "C" {
   bool libdecor_get_cursor_settings(char **theme, int *size);
-  void bind_to_gtk_shell(struct wl_registry *, uint32_t);
 }
 
 
@@ -87,6 +87,8 @@ struct pointer_output {
 
 
 static Fl_Int_Vector key_vector; // used by Fl_Wayland_Screen_Driver::event_key()
+static struct gtk_shell1 *gtk_shell = NULL;
+static struct wl_surface *gtk_shell_surface = NULL;
 
 Fl_Wayland_Screen_Driver::compositor_name Fl_Wayland_Screen_Driver::compositor =
   Fl_Wayland_Screen_Driver::unspecified;
@@ -199,6 +201,7 @@ static Fl_Window *event_coords_from_surface(struct wl_surface *surface,
 static void pointer_enter(void *data, struct wl_pointer *wl_pointer, uint32_t serial,
         struct wl_surface *surface, wl_fixed_t surface_x, wl_fixed_t surface_y) {
   Fl_Window *win = event_coords_from_surface(surface, surface_x, surface_y);
+  if (!win && gtk_shell) gtk_shell_surface = surface;
   if (!win) return;
   // use custom cursor if present
   struct wl_cursor *cursor =
@@ -220,6 +223,7 @@ static void pointer_leave(void *data, struct wl_pointer *wl_pointer,
   struct Fl_Wayland_Screen_Driver::seat *seat = (struct Fl_Wayland_Screen_Driver::seat*)data;
   if (seat->pointer_focus == surface) seat->pointer_focus = NULL;
   Fl_Window *win = Fl_Wayland_Window_Driver::surface_to_window(surface);
+  gtk_shell_surface = NULL;
   if (win) {
     Fl::belowmouse(0);
     set_event_xy(win);
@@ -257,6 +261,15 @@ static void pointer_button(void *data,
 {
   struct Fl_Wayland_Screen_Driver::seat *seat =
     (struct Fl_Wayland_Screen_Driver::seat*)data;
+  if (gtk_shell_surface && state == WL_POINTER_BUTTON_STATE_PRESSED &&
+      button == BTN_MIDDLE) {
+    struct gtk_surface1 *gtk_surface = gtk_shell1_get_gtk_surface(gtk_shell, 
+                                                                  gtk_shell_surface);
+    gtk_surface1_titlebar_gesture(gtk_surface, serial, seat->wl_seat,
+                                  GTK_SURFACE1_GESTURE_MIDDLE_CLICK);
+    gtk_surface1_release(gtk_surface);
+    return;
+  }
   seat->serial = serial;
   int event = 0;
   Fl_Window *win = Fl_Wayland_Window_Driver::surface_to_window(seat->pointer_focus);
@@ -1148,7 +1161,8 @@ static void registry_handle_global(void *user_data, struct wl_registry *wl_regis
     Fl_Wayland_Screen_Driver::compositor = Fl_Wayland_Screen_Driver::MUTTER;
     //fprintf(stderr, "Running the Mutter compositor\n");
     if ( version >= 5) {
-      bind_to_gtk_shell(wl_registry, id);
+      gtk_shell = (struct gtk_shell1*)wl_registry_bind(wl_registry, id,
+                                                  &gtk_shell1_interface, 5);
     }
   } else if (strcmp(interface, "weston_desktop_shell") == 0) {
     Fl_Wayland_Screen_Driver::compositor = Fl_Wayland_Screen_Driver::WESTON;
diff --git a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
index 9082acf51..1345c17a2 100644
--- a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
@@ -44,7 +44,6 @@ struct cursor_image { // as in wayland-cursor.c of the Wayland project source co
 extern "C" {
 # include "../../../libdecor/src/libdecor-plugin.h"
   uchar *fl_libdecor_titlebar_buffer(struct libdecor_frame *frame, int *w, int *h, int *stride);
-  void use_FLTK_pointer_button(struct libdecor_frame *);
 }
 
 #define fl_max(a,b) ((a) > (b) ? (a) : (b))
@@ -854,7 +853,6 @@ static void handle_configure(struct libdecor_frame *frame,
 #ifdef LIBDECOR_MR131
   if (is_1st_run) use_FLTK_toplevel_configure_cb(frame);
 #endif
-  use_FLTK_pointer_button(frame);
   struct wl_output *wl_output = NULL;
   if (window->fl_win->fullscreen_active()) {
     if (!(window->state & LIBDECOR_WINDOW_STATE_FULLSCREEN)) {