st/bin: Delegate child allocation to layout manager

Since commit ed3b8d093e16, the actor's single-child policy is
enforced even when using the generic add/remove_child() methods.

This makes it possible to follow GTK/AdwBin's lead and replace
out custom child allocation with a BinLayout, without changing
the actor's semantics in a fundamental way.

However this does change slightly how the child is allocated, as
it now only expands according to its expand properties, not when
the alignment is set to FILL.

Even after the preparations in the previous commit, some fallout
is still likely, but it will be easy to address, and the cleanup
is significant enough to justify it.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3046>

diff --git a/src/st/st-bin.c b/src/st/st-bin.c
index 9dc3291209f4e10d003101e30b74247a8af2d06f..21c9c5ea0e81989caf268fce8f7096ed4e7082ec 100644 (file)
--- a/src/st/st-bin.c
+++ b/src/st/st-bin.c
@@ -67,115 +67,6 @@ st_bin_dispose (GObject *object)
   G_OBJECT_CLASS (st_bin_parent_class)->dispose (object);
 }
 
-static double
-get_align_factor (ClutterActorAlign align)
-{
-  switch (align)
-    {
-    case CLUTTER_ACTOR_ALIGN_CENTER:
-      return 0.5;
-
-    case CLUTTER_ACTOR_ALIGN_START:
-      return 0.0;
-
-    case CLUTTER_ACTOR_ALIGN_END:
-      return 1.0;
-
-    case CLUTTER_ACTOR_ALIGN_FILL:
-      break;
-   }
-
-  return 0.0;
-}
-
-static void
-st_bin_allocate (ClutterActor          *self,
-                 const ClutterActorBox *box)
-{
-  StBinPrivate *priv = st_bin_get_instance_private (ST_BIN (self));
-
-  clutter_actor_set_allocation (self, box);
-
-  if (priv->child && clutter_actor_is_visible (priv->child))
-    {
-      StThemeNode *theme_node = st_widget_get_theme_node (ST_WIDGET (self));
-      ClutterActorAlign x_align = clutter_actor_get_x_align (priv->child);
-      ClutterActorAlign y_align = clutter_actor_get_y_align (priv->child);
-      ClutterActorBox childbox;
-
-      st_theme_node_get_content_box (theme_node, box, &childbox);
-      clutter_actor_allocate_align_fill (priv->child, &childbox,
-                                         get_align_factor (x_align),
-                                         get_align_factor (y_align),
-                                         x_align == CLUTTER_ACTOR_ALIGN_FILL,
-                                         y_align == CLUTTER_ACTOR_ALIGN_FILL);
-    }
-}
-
-static void
-st_bin_get_preferred_width (ClutterActor *self,
-                            gfloat        for_height,
-                            gfloat       *min_width_p,
-                            gfloat       *natural_width_p)
-{
-  StBinPrivate *priv = st_bin_get_instance_private (ST_BIN (self));
-  StThemeNode *theme_node = st_widget_get_theme_node (ST_WIDGET (self));
-
-  st_theme_node_adjust_for_height (theme_node, &for_height);
-
-  if (priv->child == NULL || !clutter_actor_is_visible (priv->child))
-    {
-      if (min_width_p)
-        *min_width_p = 0;
-
-      if (natural_width_p)
-        *natural_width_p = 0;
-    }
-  else
-    {
-      ClutterActorAlign y_align = clutter_actor_get_y_align (priv->child);
-
-      _st_actor_get_preferred_width (priv->child, for_height,
-                                     y_align == CLUTTER_ACTOR_ALIGN_FILL,
-                                     min_width_p,
-                                     natural_width_p);
-    }
-
-  st_theme_node_adjust_preferred_width (theme_node, min_width_p, natural_width_p);
-}
-
-static void
-st_bin_get_preferred_height (ClutterActor *self,
-                             gfloat        for_width,
-                             gfloat       *min_height_p,
-                             gfloat       *natural_height_p)
-{
-  StBinPrivate *priv = st_bin_get_instance_private (ST_BIN (self));
-  StThemeNode *theme_node = st_widget_get_theme_node (ST_WIDGET (self));
-
-  st_theme_node_adjust_for_width (theme_node, &for_width);
-
-  if (priv->child == NULL || !clutter_actor_is_visible (priv->child))
-    {
-      if (min_height_p)
-        *min_height_p = 0;
-
-      if (natural_height_p)
-        *natural_height_p = 0;
-    }
-  else
-    {
-      ClutterActorAlign x_align = clutter_actor_get_x_align (priv->child);
-
-      _st_actor_get_preferred_height (priv->child, for_width,
-                                      x_align == CLUTTER_ACTOR_ALIGN_FILL,
-                                      min_height_p,
-                                      natural_height_p);
-    }
-
-  st_theme_node_adjust_preferred_height (theme_node, min_height_p, natural_height_p);
-}
-
 static void
 set_child (StBin *bin, ClutterActor *child)
 {
@@ -304,9 +195,6 @@ st_bin_class_init (StBinClass *klass)
   gobject_class->set_property = st_bin_set_property;
   gobject_class->get_property = st_bin_get_property;
 
-  actor_class->get_preferred_width = st_bin_get_preferred_width;
-  actor_class->get_preferred_height = st_bin_get_preferred_height;
-  actor_class->allocate = st_bin_allocate;
   actor_class->child_added = st_bin_child_added;
   actor_class->child_removed = st_bin_child_removed;
 
@@ -326,6 +214,8 @@ st_bin_class_init (StBinClass *klass)
                          ST_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
   g_object_class_install_properties (gobject_class, N_PROPS, props);
+
+  clutter_actor_class_set_layout_manager_type (actor_class, CLUTTER_TYPE_BIN_LAYOUT);
 }
 
 static void