[Wayland] Add support for xdg_toplevel.configure_bounds() (#740)

This PR adds support for xdg_toplevel_configure_bounds(), which is aims to communicate the maximum size a surface should be created
with, and loosely corresponds to the concept of "work area" in the X11
world. It was introduced in v4 of xdg-shell protocol, so also bump it's version.

Adapted from Mutter: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2167

Author: Sunderland93

src/core/window-private.h

@@ -908,4 +908,8 @@ gboolean meta_window_shortcuts_inhibited (MetaWindow         *window,
                                           ClutterInputDevice *source);
 gboolean meta_window_is_stackable (MetaWindow *window);
 gboolean meta_window_is_focus_async (MetaWindow *window);
+
+gboolean meta_window_calculate_bounds (MetaWindow *window,
+                                       int        *bounds_width,
+                                       int        *bounds_height);
 #endif

src/core/window.c

@@ -1047,6 +1047,7 @@ _meta_window_shared_new (MetaDisplay         *display,
                          MetaCompEffect       effect,
                          XWindowAttributes   *attrs)
 {
+  MetaBackend *backend = meta_get_backend ();
   MetaWorkspaceManager *workspace_manager = display->workspace_manager;
   MetaWindow *window;
 
@@ -1241,7 +1242,11 @@ _meta_window_shared_new (MetaDisplay         *display,
 
   window->compositor_private = NULL;
 
-  window->monitor = meta_window_calculate_main_logical_monitor (window);
+  if (window->rect.width > 0 && window->rect.height > 0)
+    window->monitor = meta_window_calculate_main_logical_monitor (window);
+  else
+    window->monitor = meta_backend_get_current_logical_monitor (backend);
+
   if (window->monitor)
     window->preferred_output_winsys_id = window->monitor->winsys_id;
   else
@@ -9495,3 +9500,29 @@ meta_window_get_icon_name (MetaWindow *window)
 
     return window->theme_icon_name;
 }
+
+gboolean
+meta_window_calculate_bounds (MetaWindow *window,
+                              int        *bounds_width,
+                              int        *bounds_height)
+{
+  MetaLogicalMonitor *main_monitor;
+
+  main_monitor = meta_window_get_main_logical_monitor (window);
+  if (main_monitor)
+    {
+      MetaRectangle work_area;
+
+      meta_window_get_work_area_for_logical_monitor (window,
+                                                     main_monitor,
+                                                     &work_area);
+
+      *bounds_width = work_area.width;
+      *bounds_height = work_area.height;
+      return TRUE;
+    }
+  else
+    {
+      return FALSE;
+    }
+}

src/wayland/meta-wayland-versions.h

@@ -37,7 +37,7 @@
 /* Global/master objects (version exported by wl_registry and negotiated through bind) */
 #define META_WL_COMPOSITOR_VERSION          5
 #define META_WL_DATA_DEVICE_MANAGER_VERSION 3
-#define META_XDG_WM_BASE_VERSION            3
+#define META_XDG_WM_BASE_VERSION            4
 #define META_WL_SEAT_VERSION                5
 #define META_WL_OUTPUT_VERSION              4
 #define META_XSERVER_VERSION                1

src/wayland/meta-wayland-window-configuration.c

@@ -24,34 +24,64 @@
 
 static uint32_t global_serial_counter = 0;
 
+static gboolean
+is_window_size_fixed (MetaWindow *window)
+{
+  if (meta_window_is_fullscreen (window))
+    return TRUE;
+
+  if (meta_window_get_maximized (window) |
+      (META_MAXIMIZE_VERTICAL | META_MAXIMIZE_VERTICAL))
+    return TRUE;
+
+  if (meta_window_get_tile_mode (window) != META_TILE_NONE)
+    return TRUE;
+
+  return FALSE;
+}
+
 MetaWaylandWindowConfiguration *
-meta_wayland_window_configuration_new (int                 x,
-                                       int                 y,
-                                       int                 width,
-                                       int                 height,
-                                       int                 scale,
-                                       MetaMoveResizeFlags flags,
-                                       MetaGravity         gravity)
+meta_wayland_window_configuration_new (MetaWindow          *window,
+                                       MetaRectangle        rect,
+                                       int                  bounds_width,
+                                       int                  bounds_height,
+                                       int                  scale,
+                                       MetaMoveResizeFlags  flags,
+                                       MetaGravity          gravity)
 {
   MetaWaylandWindowConfiguration *configuration;
 
   configuration = g_new0 (MetaWaylandWindowConfiguration, 1);
   *configuration = (MetaWaylandWindowConfiguration) {
     .serial = ++global_serial_counter,
 
-    .has_position = TRUE,
-    .x = x,
-    .y = y,
-
-    .has_size = TRUE,
-    .width = width,
-    .height = height,
+    .bounds_height = bounds_height,
+    .bounds_width = bounds_width,
 
     .scale = scale,
     .gravity = gravity,
     .flags = flags,
   };
 
+  if (flags & META_MOVE_RESIZE_MOVE_ACTION ||
+      window->rect.x != rect.x ||
+      window->rect.y != rect.y)
+    {
+      configuration->has_position = TRUE;
+      configuration->x = rect.x;
+      configuration->y = rect.y;
+    }
+
+  if (flags & META_MOVE_RESIZE_RESIZE_ACTION ||
+      is_window_size_fixed (window) ||
+      window->rect.width != rect.width ||
+      window->rect.height != rect.height)
+    {
+      configuration->has_size = TRUE;
+      configuration->width = rect.width;
+      configuration->height = rect.height;
+    }
+
   return configuration;
 }
 
@@ -83,14 +113,17 @@ meta_wayland_window_configuration_new_relative (int rel_x,
 }
 
 MetaWaylandWindowConfiguration *
-meta_wayland_window_configuration_new_empty (void)
+meta_wayland_window_configuration_new_empty (int bounds_width,
+                                             int bounds_height)
 {
   MetaWaylandWindowConfiguration *configuration;
 
   configuration = g_new0 (MetaWaylandWindowConfiguration, 1);
   *configuration = (MetaWaylandWindowConfiguration) {
     .serial = ++global_serial_counter,
     .scale = 1,
+    .bounds_width = bounds_width,
+    .bounds_height = bounds_height,
   };
 
   return configuration;

src/wayland/meta-wayland-window-configuration.h

@@ -46,12 +46,15 @@ struct _MetaWaylandWindowConfiguration
   int scale;
   MetaGravity gravity;
   MetaMoveResizeFlags flags;
+
+  int bounds_width;
+  int bounds_height;
 };
 
-MetaWaylandWindowConfiguration * meta_wayland_window_configuration_new (int                 x,
-                                                                        int                 y,
-                                                                        int                 width,
-                                                                        int                 height,
+MetaWaylandWindowConfiguration * meta_wayland_window_configuration_new (MetaWindow          *window,
+                                                                        MetaRectangle        rect,
+                                                                        int                  max_width,
+                                                                        int                  max_height,
                                                                         int                 scale,
                                                                         MetaMoveResizeFlags flags,
                                                                         MetaGravity         gravity);
@@ -62,7 +65,8 @@ MetaWaylandWindowConfiguration * meta_wayland_window_configuration_new_relative
                                                                                  int height,
                                                                                  int scale);
 
-MetaWaylandWindowConfiguration * meta_wayland_window_configuration_new_empty (void);
+MetaWaylandWindowConfiguration * meta_wayland_window_configuration_new_empty (int bounds_width,
+                                                                              int bounds_height);
 
 void meta_wayland_window_configuration_free (MetaWaylandWindowConfiguration *configuration);
 

src/wayland/meta-wayland-xdg-shell.c

@@ -697,6 +697,18 @@ meta_wayland_xdg_toplevel_send_configure (MetaWaylandXdgToplevel         *xdg_to
   wl_array_init (&states);
   fill_states (xdg_toplevel, &states);
 
+  if (wl_resource_get_version (xdg_toplevel->resource) >=
+      XDG_TOPLEVEL_CONFIGURE_BOUNDS_SINCE_VERSION &&
+      configuration->bounds_width > 0 &&
+      configuration->bounds_height > 0)
+    {
+      xdg_toplevel_send_configure_bounds (xdg_toplevel->resource,
+                                          (configuration->bounds_width /
+                                           configuration->scale),
+                                          (configuration->bounds_height /
+                                           configuration->scale));
+    }
+
   xdg_toplevel_send_configure (xdg_toplevel->resource,
                                configuration->width / configuration->scale,
                                configuration->height / configuration->scale,
@@ -774,8 +786,18 @@ meta_wayland_xdg_toplevel_apply_state (MetaWaylandSurfaceRole  *surface_role,
   if (!xdg_surface_priv->configure_sent)
     {
       MetaWaylandWindowConfiguration *configuration;
+      int bounds_width;
+      int bounds_height;
+
+      if (!meta_window_calculate_bounds (window, &bounds_width, &bounds_height))
+        {
+          bounds_width = 0;
+          bounds_height = 0;
+        }
 
-      configuration = meta_wayland_window_configuration_new_empty ();
+            configuration =
+              meta_wayland_window_configuration_new_empty (bounds_width,
+                                                           bounds_height);
       meta_wayland_xdg_toplevel_send_configure (xdg_toplevel, configuration);
       meta_wayland_window_configuration_free (configuration);
       return;