/* * Clutter. * * An OpenGL based 'interactive canvas' library. * * Copyright (C) 2009,2010 Intel Corporation. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library. If not, see . */ /** * SECTION:clutter-box * @short_description: A Generic layout container * * #ClutterBox is a #ClutterActor sub-class implementing the #ClutterContainer * interface. A Box delegates the whole size requisition and size allocation to * a #ClutterLayoutManager instance. * * * Using ClutterBox * The following code shows how to create a #ClutterBox with * a #ClutterLayoutManager sub-class, and how to add children to * it via clutter_box_pack(). * * ClutterActor *box; * ClutterLayoutManager *layout; * * /* Create the layout manager first */ * layout = clutter_box_layout_new (); * clutter_box_layout_set_homogeneous (CLUTTER_BOX_LAYOUT (layout), TRUE); * clutter_box_layout_set_spacing (CLUTTER_BOX_LAYOUT (layout), 12); * * /* Then create the ClutterBox actor. The Box will take * * ownership of the ClutterLayoutManager instance by sinking * * its floating reference * */ * box = clutter_box_new (layout); * * /* Now add children to the Box using the variadic arguments * * function clutter_box_pack() to set layout properties * */ * clutter_box_pack (CLUTTER_BOX (box), actor, * "x-align", CLUTTER_BOX_ALIGNMENT_CENTER, * "y-align", CLUTTER_BOX_ALIGNMENT_END, * "expand", TRUE, * NULL); * * * * #ClutterBox's clutter_box_pack() wraps the generic * clutter_container_add_actor() function, but it also allows setting * layout properties while adding the new child to the box. * * #ClutterBox is available since Clutter 1.2 */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include "clutter-box.h" #include "clutter-debug.h" #include "clutter-enum-types.h" #include "clutter-marshal.h" #include "clutter-private.h" #define CLUTTER_BOX_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), CLUTTER_TYPE_BOX, ClutterBoxPrivate)) struct _ClutterBoxPrivate { ClutterLayoutManager *manager; GList *children; guint changed_id; ClutterColor color; guint color_set : 1; }; enum { PROP_0, PROP_LAYOUT_MANAGER, PROP_COLOR, PROP_COLOR_SET }; static const ClutterColor default_box_color = { 255, 255, 255, 255 }; static void clutter_container_iface_init (ClutterContainerIface *iface); G_DEFINE_TYPE_WITH_CODE (ClutterBox, clutter_box, CLUTTER_TYPE_ACTOR, G_IMPLEMENT_INTERFACE (CLUTTER_TYPE_CONTAINER, clutter_container_iface_init)); static gint sort_by_depth (gconstpointer a, gconstpointer b) { gfloat depth_a = clutter_actor_get_depth ((ClutterActor *) a); gfloat depth_b = clutter_actor_get_depth ((ClutterActor *) b); if (depth_a < depth_b) return -1; if (depth_a > depth_b) return 1; return 0; } static void clutter_box_real_add (ClutterContainer *container, ClutterActor *actor) { ClutterBoxPrivate *priv = CLUTTER_BOX (container)->priv; GList *l, *prev = NULL; gfloat actor_depth; g_object_ref (actor); actor_depth = clutter_actor_get_depth (actor); /* Find the right place to insert the child so that it will still be sorted and the child will be after all of the actors at the same depth */ for (l = priv->children; l && (clutter_actor_get_depth (l->data) <= actor_depth); l = l->next) prev = l; /* Insert the node before the found node */ l = g_list_prepend (l, actor); /* Fixup the links */ if (prev) { prev->next = l; l->prev = prev; } else priv->children = l; clutter_actor_set_parent (actor, CLUTTER_ACTOR (container)); clutter_actor_queue_relayout (actor); g_signal_emit_by_name (container, "actor-added", actor); g_object_unref (actor); } static void clutter_box_real_remove (ClutterContainer *container, ClutterActor *actor) { ClutterBoxPrivate *priv = CLUTTER_BOX (container)->priv; g_object_ref (actor); priv->children = g_list_remove (priv->children, actor); clutter_actor_unparent (actor); clutter_actor_queue_relayout (CLUTTER_ACTOR (container)); g_signal_emit_by_name (container, "actor-removed", actor); g_object_unref (actor); } static void clutter_box_real_foreach (ClutterContainer *container, ClutterCallback callback, gpointer user_data) { ClutterBoxPrivate *priv = CLUTTER_BOX (container)->priv; /* Using g_list_foreach instead of iterating the list manually because it has better protection against the current node being removed. This will happen for example if someone calls clutter_container_foreach(container, clutter_actor_destroy) */ g_list_foreach (priv->children, (GFunc) callback, user_data); } static void clutter_box_real_raise (ClutterContainer *container, ClutterActor *actor, ClutterActor *sibling) { ClutterBoxPrivate *priv = CLUTTER_BOX (container)->priv; priv->children = g_list_remove (priv->children, actor); if (sibling == NULL) priv->children = g_list_append (priv->children, actor); else { gint index_ = g_list_index (priv->children, sibling) + 1; priv->children = g_list_insert (priv->children, actor, index_); } clutter_actor_queue_relayout (CLUTTER_ACTOR (container)); } static void clutter_box_real_lower (ClutterContainer *container, ClutterActor *actor, ClutterActor *sibling) { ClutterBoxPrivate *priv = CLUTTER_BOX (container)->priv; priv->children = g_list_remove (priv->children, actor); if (sibling == NULL) priv->children = g_list_prepend (priv->children, actor); else { gint index_ = g_list_index (priv->children, sibling); priv->children = g_list_insert (priv->children, actor, index_); } clutter_actor_queue_relayout (CLUTTER_ACTOR (container)); } static void clutter_box_real_sort_depth_order (ClutterContainer *container) { ClutterBoxPrivate *priv = CLUTTER_BOX (container)->priv; priv->children = g_list_sort (priv->children, sort_by_depth); clutter_actor_queue_relayout (CLUTTER_ACTOR (container)); } static void clutter_container_iface_init (ClutterContainerIface *iface) { iface->add = clutter_box_real_add; iface->remove = clutter_box_real_remove; iface->foreach = clutter_box_real_foreach; iface->raise = clutter_box_real_raise; iface->lower = clutter_box_real_lower; iface->sort_depth_order = clutter_box_real_sort_depth_order; } static void clutter_box_real_paint (ClutterActor *actor) { ClutterBoxPrivate *priv = CLUTTER_BOX (actor)->priv; if (priv->color_set) { ClutterActorBox box = { 0, }; gfloat width, height; guint8 tmp_alpha; clutter_actor_get_allocation_box (actor, &box); clutter_actor_box_get_size (&box, &width, &height); tmp_alpha = clutter_actor_get_paint_opacity (actor) * priv->color.alpha / 255; cogl_set_source_color4ub (priv->color.red, priv->color.green, priv->color.blue, tmp_alpha); cogl_rectangle (0, 0, width, height); } g_list_foreach (priv->children, (GFunc) clutter_actor_paint, NULL); } static void clutter_box_real_pick (ClutterActor *actor, const ClutterColor *pick) { ClutterBoxPrivate *priv = CLUTTER_BOX (actor)->priv; CLUTTER_ACTOR_CLASS (clutter_box_parent_class)->pick (actor, pick); g_list_foreach (priv->children, (GFunc) clutter_actor_paint, NULL); } static void clutter_box_real_get_preferred_width (ClutterActor *actor, gfloat for_height, gfloat *min_width, gfloat *natural_width) { ClutterBoxPrivate *priv = CLUTTER_BOX (actor)->priv; clutter_layout_manager_get_preferred_width (priv->manager, CLUTTER_CONTAINER (actor), for_height, min_width, natural_width); } static void clutter_box_real_get_preferred_height (ClutterActor *actor, gfloat for_width, gfloat *min_height, gfloat *natural_height) { ClutterBoxPrivate *priv = CLUTTER_BOX (actor)->priv; clutter_layout_manager_get_preferred_height (priv->manager, CLUTTER_CONTAINER (actor), for_width, min_height, natural_height); } static void clutter_box_real_allocate (ClutterActor *actor, const ClutterActorBox *allocation, ClutterAllocationFlags flags) { ClutterBoxPrivate *priv = CLUTTER_BOX (actor)->priv; ClutterActorClass *klass; klass = CLUTTER_ACTOR_CLASS (clutter_box_parent_class); klass->allocate (actor, allocation, flags); clutter_layout_manager_allocate (priv->manager, CLUTTER_CONTAINER (actor), allocation, flags); } static void clutter_box_destroy (ClutterActor *actor) { ClutterBoxPrivate *priv = CLUTTER_BOX (actor)->priv; /* destroy all our children */ g_list_foreach (priv->children, (GFunc) clutter_actor_destroy, NULL); if (CLUTTER_ACTOR_CLASS (clutter_box_parent_class)->destroy) CLUTTER_ACTOR_CLASS (clutter_box_parent_class)->destroy (actor); } static inline void set_layout_manager (ClutterBox *self, ClutterLayoutManager *manager) { ClutterBoxPrivate *priv = self->priv; if (priv->manager == manager) return; if (priv->manager != NULL) { if (priv->changed_id != 0) g_signal_handler_disconnect (priv->manager, priv->changed_id); clutter_layout_manager_set_container (priv->manager, NULL); g_object_unref (priv->manager); priv->manager = NULL; priv->changed_id = 0; } if (manager != NULL) { priv->manager = g_object_ref_sink (manager); clutter_layout_manager_set_container (manager, CLUTTER_CONTAINER (self)); priv->changed_id = g_signal_connect_swapped (priv->manager, "layout-changed", G_CALLBACK (clutter_actor_queue_relayout), self); } clutter_actor_queue_relayout (CLUTTER_ACTOR (self)); g_object_notify (G_OBJECT (self), "layout-manager"); } static void clutter_box_dispose (GObject *gobject) { ClutterBox *self = CLUTTER_BOX (gobject); set_layout_manager (self, NULL); G_OBJECT_CLASS (clutter_box_parent_class)->dispose (gobject); } static void clutter_box_set_property (GObject *gobject, guint prop_id, const GValue *value, GParamSpec *pspec) { ClutterBox *self = CLUTTER_BOX (gobject); switch (prop_id) { case PROP_LAYOUT_MANAGER: set_layout_manager (self, g_value_get_object (value)); break; case PROP_COLOR: clutter_box_set_color (self, clutter_value_get_color (value)); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec); break; } } static void clutter_box_get_property (GObject *gobject, guint prop_id, GValue *value, GParamSpec *pspec) { ClutterBoxPrivate *priv = CLUTTER_BOX (gobject)->priv; switch (prop_id) { case PROP_LAYOUT_MANAGER: g_value_set_object (value, priv->manager); break; case PROP_COLOR: clutter_value_set_color (value, &priv->color); break; case PROP_COLOR_SET: g_value_set_boolean (value, priv->color_set); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec); break; } } static void clutter_box_class_init (ClutterBoxClass *klass) { GObjectClass *gobject_class = G_OBJECT_CLASS (klass); ClutterActorClass *actor_class = CLUTTER_ACTOR_CLASS (klass); GParamSpec *pspec; g_type_class_add_private (klass, sizeof (ClutterBoxPrivate)); actor_class->get_preferred_width = clutter_box_real_get_preferred_width; actor_class->get_preferred_height = clutter_box_real_get_preferred_height; actor_class->allocate = clutter_box_real_allocate; actor_class->paint = clutter_box_real_paint; actor_class->pick = clutter_box_real_pick; actor_class->destroy = clutter_box_destroy; gobject_class->set_property = clutter_box_set_property; gobject_class->get_property = clutter_box_get_property; gobject_class->dispose = clutter_box_dispose; /** * ClutterBox:layout-manager: * * The #ClutterLayoutManager used by the #ClutterBox * * Since: 1.2 */ pspec = g_param_spec_object ("layout-manager", "Layout Manager", "The layout manager used by the box", CLUTTER_TYPE_LAYOUT_MANAGER, CLUTTER_PARAM_READWRITE | G_PARAM_CONSTRUCT); g_object_class_install_property (gobject_class, PROP_LAYOUT_MANAGER, pspec); /** * ClutterBox:color: * * The color to be used to paint the background of the * #ClutterBox. Setting this property will set the * #ClutterBox:color-set property as a side effect * * Since: 1.2 */ pspec = clutter_param_spec_color ("color", "Color", "The background color of the box", &default_box_color, CLUTTER_PARAM_READWRITE); g_object_class_install_property (gobject_class, PROP_COLOR, pspec); /** * ClutterBox:color-set: * * Whether the #ClutterBox:color property has been set * * Since: 1.2 */ pspec = g_param_spec_boolean ("color-set", "Color Set", "Whether the background color is set", FALSE, CLUTTER_PARAM_READWRITE); g_object_class_install_property (gobject_class, PROP_COLOR_SET, pspec); } static void clutter_box_init (ClutterBox *self) { self->priv = CLUTTER_BOX_GET_PRIVATE (self); self->priv->color = default_box_color; } /** * clutter_box_new: * @manager: a #ClutterLayoutManager * * Creates a new #ClutterBox. The children of the box will be layed * out by the passed @manager * * Return value: the newly created #ClutterBox actor * * Since: 1.0 */ ClutterActor * clutter_box_new (ClutterLayoutManager *manager) { g_return_val_if_fail (CLUTTER_IS_LAYOUT_MANAGER (manager), NULL); return g_object_new (CLUTTER_TYPE_BOX, "layout-manager", manager, NULL); } /** * clutter_box_set_layout_manager: * @box: a #ClutterBox * @manager: a #ClutterLayoutManager * * Sets the #ClutterLayoutManager for @box * * A #ClutterLayoutManager is a delegate object that controls the * layout of the children of @box * * Since: 1.2 */ void clutter_box_set_layout_manager (ClutterBox *box, ClutterLayoutManager *manager) { g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (CLUTTER_IS_LAYOUT_MANAGER (manager)); set_layout_manager (box, manager); } /** * clutter_box_get_layout_manager: * @box: a #ClutterBox * * Retrieves the #ClutterLayoutManager instance used by @box * * Return value: a #ClutterLayoutManager * * Since: 1.2 */ ClutterLayoutManager * clutter_box_get_layout_manager (ClutterBox *box) { g_return_val_if_fail (CLUTTER_IS_BOX (box), NULL); return box->priv->manager; } /** * clutter_box_packv: * @box: a #ClutterBox * @actor: a #ClutterActor * @n_properties: the number of properties to set * @properties: (array length=n_properties) (element-type utf8): a vector * containing the property names to set * @values: (array length=n_properties): a vector containing the property * values to set * * Vector-based variant of clutter_box_pack(), intended for language * bindings to use * * Since: 1.2 */ void clutter_box_packv (ClutterBox *box, ClutterActor *actor, guint n_properties, const gchar * const properties[], const GValue *values) { ClutterContainer *container; ClutterBoxPrivate *priv; ClutterLayoutMeta *meta; GObjectClass *klass; gint i; g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (CLUTTER_IS_ACTOR (actor)); container = CLUTTER_CONTAINER (box); clutter_container_add_actor (container, actor); priv = box->priv; meta = clutter_layout_manager_get_child_meta (priv->manager, container, actor); if (meta == NULL) return; klass = G_OBJECT_GET_CLASS (meta); for (i = 0; i < n_properties; i++) { const gchar *pname = properties[i]; GParamSpec *pspec; pspec = g_object_class_find_property (klass, pname); if (pspec == NULL) { g_warning ("%s: the layout property '%s' for managers " "of type '%s' (meta type '%s') does not exist", G_STRLOC, pname, G_OBJECT_TYPE_NAME (priv->manager), G_OBJECT_TYPE_NAME (meta)); break; } if (!(pspec->flags & G_PARAM_WRITABLE)) { g_warning ("%s: the layout property '%s' for managers " "of type '%s' (meta type '%s') is not writable", G_STRLOC, pspec->name, G_OBJECT_TYPE_NAME (priv->manager), G_OBJECT_TYPE_NAME (meta)); break; } clutter_layout_manager_child_set_property (priv->manager, container, actor, pname, &values[i]); } } static inline void clutter_box_set_property_valist (ClutterBox *box, ClutterActor *actor, const gchar *first_property, va_list var_args) { ClutterContainer *container = CLUTTER_CONTAINER (box); ClutterBoxPrivate *priv = box->priv; ClutterLayoutMeta *meta; GObjectClass *klass; const gchar *pname; if (priv->manager == NULL) return; meta = clutter_layout_manager_get_child_meta (priv->manager, container, actor); if (meta == NULL) return; klass = G_OBJECT_GET_CLASS (meta); pname = first_property; while (pname) { GValue value = { 0, }; GParamSpec *pspec; gchar *error; pspec = g_object_class_find_property (klass, pname); if (pspec == NULL) { g_warning ("%s: the layout property '%s' for managers " "of type '%s' (meta type '%s') does not exist", G_STRLOC, pname, G_OBJECT_TYPE_NAME (priv->manager), G_OBJECT_TYPE_NAME (meta)); break; } if (!(pspec->flags & G_PARAM_WRITABLE)) { g_warning ("%s: the layout property '%s' for managers " "of type '%s' (meta type '%s') is not writable", G_STRLOC, pspec->name, G_OBJECT_TYPE_NAME (priv->manager), G_OBJECT_TYPE_NAME (meta)); break; } #if GLIB_CHECK_VERSION (2, 23, 2) G_VALUE_COLLECT_INIT (&value, G_PARAM_SPEC_VALUE_TYPE (pspec), var_args, 0, &error); #else g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec)); G_VALUE_COLLECT (&value, var_args, 0, &error); #endif /* GLIB_CHECK_VERSION (2, 23, 2) */ if (error) { g_warning ("%s: %s", G_STRLOC, error); g_free (error); break; } clutter_layout_manager_child_set_property (priv->manager, container, actor, pspec->name, &value); g_value_unset (&value); pname = va_arg (var_args, gchar*); } } /** * clutter_box_pack: * @box: a #ClutterBox * @actor: a #ClutterActor * @first_property: the name of the first property to set, or %NULL * @Varargs: a list of property name and value pairs, terminated by %NULL * * Adds @actor to @box and sets layout properties at the same time, * if the #ClutterLayoutManager used by @box has them * * This function is a wrapper around clutter_container_add_actor() * and clutter_layout_manager_child_set() * * Language bindings should use the vector-based clutter_box_addv() * variant instead * * Since: 1.2 */ void clutter_box_pack (ClutterBox *box, ClutterActor *actor, const gchar *first_property, ...) { va_list var_args; g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (CLUTTER_IS_ACTOR (actor)); clutter_container_add_actor (CLUTTER_CONTAINER (box), actor); if (first_property == NULL || *first_property == '\0') return; va_start (var_args, first_property); clutter_box_set_property_valist (box, actor, first_property, var_args); va_end (var_args); } /** * clutter_box_pack_after: * @box: a #ClutterBox * @actor: a #ClutterActor * @sibling: (allow none): a #ClutterActor or %NULL * @first_property: the name of the first property to set, or %NULL * @Varargs: a list of property name and value pairs, terminated by %NULL * * Adds @actor to @box, placing it after @sibling, and sets layout * properties at the same time, if the #ClutterLayoutManager used by * @box supports them * * If @sibling is %NULL then @actor is placed at the end of the * list of children, to be allocated and painted after every other child * * This function is a wrapper around clutter_container_add_actor(), * clutter_container_raise_child() and clutter_layout_manager_child_set() * * Since: 1.2 */ void clutter_box_pack_after (ClutterBox *box, ClutterActor *actor, ClutterActor *sibling, const gchar *first_property, ...) { va_list var_args; g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (CLUTTER_IS_ACTOR (actor)); g_return_if_fail (sibling == NULL || CLUTTER_IS_ACTOR (sibling)); clutter_container_add_actor (CLUTTER_CONTAINER (box), actor); clutter_container_raise_child (CLUTTER_CONTAINER (box), actor, sibling); if (first_property == NULL || *first_property == '\0') return; va_start (var_args, first_property); clutter_box_set_property_valist (box, actor, first_property, var_args); va_end (var_args); } /** * clutter_box_pack_before: * @box: a #ClutterBox * @actor: a #ClutterActor * @sibling: (allow none): a #ClutterActor or %NULL * @first_property: the name of the first property to set, or %NULL * @Varargs: a list of property name and value pairs, terminated by %NULL * * Adds @actor to @box, placing it before @sibling, and sets layout * properties at the same time, if the #ClutterLayoutManager used by * @box supports them * * If @sibling is %NULL then @actor is placed at the beginning of the * list of children, to be allocated and painted below every other child * * This function is a wrapper around clutter_container_add_actor(), * clutter_container_lower_child() and clutter_layout_manager_child_set() * * Since: 1.2 */ void clutter_box_pack_before (ClutterBox *box, ClutterActor *actor, ClutterActor *sibling, const gchar *first_property, ...) { va_list var_args; g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (CLUTTER_IS_ACTOR (actor)); g_return_if_fail (sibling == NULL || CLUTTER_IS_ACTOR (sibling)); clutter_container_add_actor (CLUTTER_CONTAINER (box), actor); clutter_container_lower_child (CLUTTER_CONTAINER (box), actor, sibling); if (first_property == NULL || *first_property == '\0') return; va_start (var_args, first_property); clutter_box_set_property_valist (box, actor, first_property, var_args); va_end (var_args); } /** * clutter_box_pack_at: * @box: a #ClutterBox * @actor: a #ClutterActor * @position: the position to insert the @actor at * @first_property: the name of the first property to set, or %NULL * @Varargs: a list of property name and value pairs, terminated by %NULL * * Adds @actor to @box, placing it at @position, and sets layout * properties at the same time, if the #ClutterLayoutManager used by * @box supports them * * If @position is a negative number, or is larger than the number of * children of @box, the new child is added at the end of the list of * children * * Since: 1.2 */ void clutter_box_pack_at (ClutterBox *box, ClutterActor *actor, gint position, const gchar *first_property, ...) { ClutterBoxPrivate *priv; va_list var_args; g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (CLUTTER_IS_ACTOR (actor)); priv = box->priv; /* this is really clutter_box_add() with a different insert() */ priv->children = g_list_insert (priv->children, actor, position); clutter_actor_set_parent (actor, CLUTTER_ACTOR (box)); clutter_actor_queue_relayout (actor); g_signal_emit_by_name (box, "actor-added", actor); if (first_property == NULL || *first_property == '\0') return; va_start (var_args, first_property); clutter_box_set_property_valist (box, actor, first_property, var_args); va_end (var_args); } /** * clutter_box_set_color: * @box: a #ClutterBox * @color: (allow-none): the background color, or %NULL to unset * * Sets (or unsets) the background color for @box * * Since: 1.2 */ void clutter_box_set_color (ClutterBox *box, const ClutterColor *color) { ClutterBoxPrivate *priv; g_return_if_fail (CLUTTER_IS_BOX (box)); priv = box->priv; if (color) { priv->color = *color; priv->color_set = TRUE; } else priv->color_set = FALSE; clutter_actor_queue_redraw (CLUTTER_ACTOR (box)); g_object_notify (G_OBJECT (box), "color-set"); g_object_notify (G_OBJECT (box), "color"); } /** * clutter_box_get_color: * @box: a #ClutterBox * @color: (out): return location for a #ClutterColor * * Retrieves the background color of @box * * If the #ClutterBox:color-set property is set to %FALSE the * returned #ClutterColor is undefined * * Since: 1.2 */ void clutter_box_get_color (ClutterBox *box, ClutterColor *color) { g_return_if_fail (CLUTTER_IS_BOX (box)); g_return_if_fail (color != NULL); *color = box->priv->color; }