[gnome-remote-desktop] session-vnc: Add support for sessions with virtual monitors

[Jonas Ådahl <jadahl src gnome org>]

commit 2e08b39f0ced16758a159926d0d0cc44300e9e92
Author: Vasilis Liaskovitis <vliaskovitis suse com>
Date:   Wed Jul 6 11:57:15 2022 +0200

    session-vnc: Add support for sessions with virtual monitors
    
    The initial virtual monitor configuration and resolution is set
    by the VNC backend. The virtual monitor is also passed to the
    PipeWire stream instance.
    
    The maximum amount of virtual monitors is limited to 1 for now.
    
    Based on RDP virtual monitor commits by Pascal Nowack <Pascal Nowack gmx de>
    https://gitlab.gnome.org/GNOME/gnome-remote-desktop/-/merge_requests/69
    Closes: https://gitlab.gnome.org/GNOME/gnome-remote-desktop/-/issues/108

 src/grd-session-vnc.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++---
 src/grd-session-vnc.h |  1 +
 2 files changed, 67 insertions(+), 4 deletions(-)
---
diff --git a/src/grd-session-vnc.c b/src/grd-session-vnc.c
index e178f5b7..aa7fafe1 100644
--- a/src/grd-session-vnc.c
+++ b/src/grd-session-vnc.c
@@ -70,6 +70,8 @@ struct _GrdSessionVnc
   GHashTable *pressed_keys;
 
   GrdClipboardVnc *clipboard_vnc;
+  GrdVncScreenShareMode screen_share_mode;
+  GrdVncMonitorConfig *monitor_config;
 };
 
 G_DEFINE_TYPE (GrdSessionVnc, grd_session_vnc, GRD_TYPE_SESSION)
@@ -565,10 +567,11 @@ init_vnc_session (GrdSessionVnc *session_vnc)
   int screen_width;
   int screen_height;
   rfbScreenInfoPtr rfb_screen;
+  GrdVncMonitorConfig *monitor_config;
 
   /* Arbitrary framebuffer size, will get the proper size from the stream. */
-  screen_width = 800;
-  screen_height = 600;
+  screen_width = GRD_VNC_DEFAULT_WIDTH;
+  screen_height = GRD_VNC_DEFAULT_HEIGHT;
   rfb_screen = rfbGetScreen (0, NULL,
                              screen_width, screen_height,
                              8, 3, 4);
@@ -597,6 +600,35 @@ init_vnc_session (GrdSessionVnc *session_vnc)
   rfb_screen->frameBuffer = g_malloc0 (screen_width * screen_height * 4);
   memset (rfb_screen->frameBuffer, 0x1f, screen_width * screen_height * 4);
 
+  session_vnc->monitor_config = g_new0 (GrdVncMonitorConfig, 1);
+  monitor_config = session_vnc->monitor_config;
+  monitor_config->virtual_monitors = NULL;
+  /* No multi-monitor support yet */
+  monitor_config->monitor_count = 1;
+
+  if (session_vnc->screen_share_mode == GRD_VNC_SCREEN_SHARE_MODE_EXTEND)
+    {
+      monitor_config->is_virtual = TRUE;
+      monitor_config->virtual_monitors = g_new0 (GrdVncVirtualMonitor, 1);
+
+      monitor_config->virtual_monitors->pos_x = 0;
+      monitor_config->virtual_monitors->pos_y = 0;
+      monitor_config->virtual_monitors->width = GRD_VNC_CLAMP_DESKTOP_SIZE (screen_width);
+      monitor_config->virtual_monitors->height = GRD_VNC_CLAMP_DESKTOP_SIZE (screen_height);
+    }
+  else
+    {
+      monitor_config->is_virtual = FALSE;
+      g_autoptr (GStrvBuilder) connector_builder = NULL;
+      char **connectors;
+
+      connector_builder = g_strv_builder_new ();
+      g_strv_builder_add (connector_builder, "");
+      connectors = g_strv_builder_end (connector_builder);
+
+      session_vnc->monitor_config->connectors = connectors;
+    }
+
   rfbInitServer (rfb_screen);
   rfbProcessEvents (rfb_screen, 0);
 }
@@ -675,6 +707,7 @@ grd_session_vnc_new (GrdVncServer      *vnc_server,
 {
   GrdSessionVnc *session_vnc;
   GrdContext *context;
+  GrdSettings *settings;
 
   context = grd_vnc_server_get_context (vnc_server);
   session_vnc = g_object_new (GRD_TYPE_SESSION_VNC,
@@ -683,6 +716,9 @@ grd_session_vnc_new (GrdVncServer      *vnc_server,
 
   session_vnc->connection = g_object_ref (connection);
 
+  settings = grd_context_get_settings (context);
+  session_vnc->screen_share_mode = grd_settings_get_vnc_screen_share_mode (settings);
+
   grd_session_vnc_attach_source (session_vnc);
 
   init_vnc_session (session_vnc);
@@ -717,6 +753,7 @@ grd_session_vnc_stop (GrdSession *session)
   g_clear_object (&session_vnc->clipboard_vnc);
   g_clear_pointer (&session_vnc->rfb_screen->frameBuffer, g_free);
   g_clear_pointer (&session_vnc->rfb_screen, rfbScreenCleanup);
+  g_clear_pointer (&session_vnc->monitor_config, grd_vnc_monitor_config_free);
 
   g_clear_handle_id (&session_vnc->close_session_idle_id, g_source_remove);
 }
@@ -736,7 +773,30 @@ close_session_idle (gpointer user_data)
 static void
 grd_session_vnc_remote_desktop_session_started (GrdSession *session)
 {
-  grd_session_record_monitor (session, NULL, GRD_SCREEN_CAST_CURSOR_MODE_METADATA);
+  GrdSessionVnc *session_vnc = GRD_SESSION_VNC (session);
+
+  if (session_vnc->monitor_config->is_virtual)
+    g_debug ("[VNC] Remote Desktop session will use virtual monitors");
+  else
+    g_debug ("[VNC] Remote Desktop session will mirror the primary monitor");
+
+  /* Not supporting multi-monitor at the moment */
+  g_assert (session_vnc->monitor_config->monitor_count == 1);
+
+  if (session_vnc->monitor_config->is_virtual)
+    {
+      grd_session_record_virtual (session,
+                                  GRD_SCREEN_CAST_CURSOR_MODE_METADATA,
+                                  TRUE);
+    }
+  else
+    {
+      const char *connector;
+
+      connector = session_vnc->monitor_config->connectors[0];
+      grd_session_record_monitor (session, connector,
+                                  GRD_SCREEN_CAST_CURSOR_MODE_METADATA);
+    }
 }
 
 static void
@@ -754,12 +814,14 @@ grd_session_vnc_stream_ready (GrdSession *session,
 {
   GrdSessionVnc *session_vnc = GRD_SESSION_VNC (session);
   uint32_t pipewire_node_id;
+  GrdVncVirtualMonitor *virtual_monitor;
   g_autoptr (GError) error = NULL;
 
+  virtual_monitor = session_vnc->monitor_config->virtual_monitors;
   pipewire_node_id = grd_stream_get_pipewire_node_id (stream);
   session_vnc->pipewire_stream = grd_vnc_pipewire_stream_new (session_vnc,
                                                               pipewire_node_id,
-                                                              NULL,
+                                                              virtual_monitor,
                                                               &error);
   if (!session_vnc->pipewire_stream)
     {
diff --git a/src/grd-session-vnc.h b/src/grd-session-vnc.h
index fcc508db..be79cf4a 100644
--- a/src/grd-session-vnc.h
+++ b/src/grd-session-vnc.h
@@ -29,6 +29,7 @@
 
 #include "grd-session.h"
 #include "grd-types.h"
+#include "grd-vnc-monitor-config.h"
 
 #define GRD_TYPE_SESSION_VNC (grd_session_vnc_get_type ())
 G_DECLARE_FINAL_TYPE (GrdSessionVnc,