[client] wayland: implement libdecor pseudo-shell backend

This allows decorations to be drawn on GNOME and other crazy compositors
that do not support server-side decorations.

client/displayservers/Wayland/registry.c

@@ -38,11 +38,13 @@ static void registryGlobalHandler(void * data, struct wl_registry * registry,
     wlWm.shm = wl_registry_bind(wlWm.registry, name, &wl_shm_interface, 1);
   else if (!strcmp(interface, wl_compositor_interface.name) && version >= 3)
     wlWm.compositor = wl_registry_bind(wlWm.registry, name, &wl_compositor_interface, 3);
+#ifndef ENABLE_LIBDECOR
   else if (!strcmp(interface, xdg_wm_base_interface.name))
     wlWm.xdgWmBase = wl_registry_bind(wlWm.registry, name, &xdg_wm_base_interface, 1);
   else if (!strcmp(interface, zxdg_decoration_manager_v1_interface.name))
     wlWm.xdgDecorationManager = wl_registry_bind(wlWm.registry, name,
         &zxdg_decoration_manager_v1_interface, 1);
+#endif
   else if (!strcmp(interface, zwp_relative_pointer_manager_v1_interface.name))
     wlWm.relativePointerManager = wl_registry_bind(wlWm.registry, name,
         &zwp_relative_pointer_manager_v1_interface, 1);

client/displayservers/Wayland/shell_libdecor.c

@@ -0,0 +1,129 @@
+/*
+Looking Glass - KVM FrameRelay (KVMFR) Client
+Copyright (C) 2021 Guanzhong Chen (quantum2048@gmail.com)
+Copyright (C) 2021 Tudor Brindus (contact@tbrindus.ca)
+https://looking-glass.io
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include "wayland.h"
+
+#include <stdbool.h>
+#include <string.h>
+
+#include <libdecor.h>
+#include <wayland-client.h>
+
+#include "app.h"
+#include "common/debug.h"
+
+struct libdecor_configuration {
+  uint32_t serial;
+
+  bool has_window_state;
+  enum libdecor_window_state window_state;
+
+  bool has_size;
+  int window_width;
+  int window_height;
+};
+
+static void libdecorHandleError(struct libdecor * context, enum libdecor_error error,
+    const char *message)
+{
+  DEBUG_ERROR("Got libdecor error (%d): %s", error, message);
+}
+
+static struct libdecor_interface libdecorListener = {
+  libdecorHandleError,
+};
+
+static void libdecorFrameConfigure(struct libdecor_frame * frame,
+    struct libdecor_configuration * configuration, void * opaque)
+{
+  int width, height;
+  if (libdecor_configuration_get_content_size(configuration, frame, &width, &height)) {
+    wlWm.width = width;
+    wlWm.height = height;
+  }
+
+  enum libdecor_window_state windowState;
+  if (libdecor_configuration_get_window_state(configuration, &windowState))
+    wlWm.fullscreen = windowState & LIBDECOR_WINDOW_STATE_FULLSCREEN;
+
+  struct libdecor_state * state = libdecor_state_new(wlWm.width, wlWm.height);
+  libdecor_frame_commit(frame, state, wlWm.configured ? NULL : configuration);
+  libdecor_state_free(state);
+
+  if (wlWm.configured)
+  {
+    wlWm.needsResize = true;
+    wlWm.resizeSerial = configuration->serial;
+  }
+  else
+    wlWm.configured = true;
+}
+
+static void libdecorFrameClose(struct libdecor_frame * frame, void * opaque)
+{
+  app_handleCloseEvent();
+}
+
+static void libdecorFrameCommit(void * opaque)
+{
+}
+
+static struct libdecor_frame_interface libdecorFrameListener = {
+  libdecorFrameConfigure,
+  libdecorFrameClose,
+  libdecorFrameCommit,
+};
+
+bool waylandShellInit(const char * title, bool fullscreen, bool maximize, bool borderless)
+{
+  wlWm.libdecor = libdecor_new(wlWm.display, &libdecorListener);
+  wlWm.libdecorFrame = libdecor_decorate(wlWm.libdecor, wlWm.surface, &libdecorFrameListener, NULL);
+
+  libdecor_frame_set_app_id(wlWm.libdecorFrame, "looking-glass-client");
+  libdecor_frame_set_title(wlWm.libdecorFrame, title);
+  libdecor_frame_map(wlWm.libdecorFrame);
+
+  while (!wlWm.configured)
+    wl_display_roundtrip(wlWm.display);
+
+  return true;
+}
+
+void waylandShellAckConfigureIfNeeded(void)
+{
+  if (wlWm.resizeSerial)
+  {
+    xdg_surface_ack_configure(libdecor_frame_get_xdg_surface(wlWm.libdecorFrame), wlWm.resizeSerial);
+    wlWm.resizeSerial = 0;
+  }
+}
+
+void waylandSetFullscreen(bool fs)
+{
+  if (fs)
+    libdecor_frame_set_fullscreen(wlWm.libdecorFrame, NULL);
+  else
+    libdecor_frame_unset_fullscreen(wlWm.libdecorFrame);
+}
+
+bool waylandGetFullscreen(void)
+{
+  return wlWm.fullscreen;
+}

client/displayservers/Wayland/wayland.c

@@ -68,6 +68,8 @@ static bool waylandInit(const LG_DSInitParams params)
   wlWm.warpSupport = option_get_bool("wayland", "warpSupport");
 
   wlWm.display = wl_display_connect(NULL);
+  wlWm.width = params.w;
+  wlWm.height = params.h;
 
   if (!waylandPollInit())
     return false;

client/displayservers/Wayland/wayland.h

@@ -96,11 +96,16 @@ struct WaylandDSState
   EGLSurface glSurface;
 #endif
 
+#ifdef ENABLE_LIBDECOR
+  struct libdecor * libdecor;
+  struct libdecor_frame * libdecorFrame;
+#else
   struct xdg_wm_base * xdgWmBase;
   struct xdg_surface * xdgSurface;
   struct xdg_toplevel * xdgToplevel;
   struct zxdg_decoration_manager_v1 * xdgDecorationManager;
   struct zxdg_toplevel_decoration_v1 * xdgToplevelDecoration;
+#endif
 
   struct wl_surface * cursor;