moving trunk for module inkscape

(bzr r1)

1 files changed, 699 insertions, 0 deletions

diff --git a/src/sp-item-group.cpp b/src/sp-item-group.cpp
new file mode 100644
index 000000000..c093c569b
--- /dev/null
+++ b/src/sp-item-group.cpp
@@ -0,0 +1,699 @@
+#define __SP_GROUP_C__
+
+/*
+ * SVG <g> implementation
+ *
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   bulia byak <buliabyak@users.sf.net>
+ *
+ * Copyright (C) 1999-2005 authors
+ * Copyright (C) 2000-2001 Ximian, Inc.
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#if defined(WIN32) || defined(__APPLE__)
+# include <glibmm/i18n.h>
+#endif
+
+#include "display/nr-arena-group.h"
+#include "libnr/nr-matrix-ops.h"
+#include "libnr/nr-matrix-fns.h"
+#include "xml/repr.h"
+#include "svg/svg.h"
+#include "document.h"
+#include "style.h"
+#include "attributes.h"
+
+#include "sp-root.h"
+#include "sp-use.h"
+#include "prefs-utils.h"
+
+static void sp_group_class_init (SPGroupClass *klass);
+static void sp_group_init (SPGroup *group);
+static void sp_group_build(SPObject *object, SPDocument *document, Inkscape::XML::Node *repr);
+static void sp_group_release(SPObject *object);
+static void sp_group_dispose (GObject *object);
+
+static void sp_group_child_added (SPObject * object, Inkscape::XML::Node * child, Inkscape::XML::Node * ref);
+static void sp_group_remove_child (SPObject * object, Inkscape::XML::Node * child);
+static void sp_group_order_changed (SPObject * object, Inkscape::XML::Node * child, Inkscape::XML::Node * old_ref, Inkscape::XML::Node * new_ref);
+static void sp_group_update (SPObject *object, SPCtx *ctx, guint flags);
+static void sp_group_modified (SPObject *object, guint flags);
+static Inkscape::XML::Node *sp_group_write (SPObject *object, Inkscape::XML::Node *repr, guint flags);
+static void sp_group_set(SPObject *object, unsigned key, char const *value);
+
+static void sp_group_bbox(SPItem const *item, NRRect *bbox, NR::Matrix const &transform, unsigned const flags);
+static void sp_group_print (SPItem * item, SPPrintContext *ctx);
+static gchar * sp_group_description (SPItem * item);
+static NRArenaItem *sp_group_show (SPItem *item, NRArena *arena, unsigned int key, unsigned int flags);
+static void sp_group_hide (SPItem * item, unsigned int key);
+static void sp_group_snappoints (SPItem const *item, SnapPointsIter p);
+
+static SPItemClass * parent_class;
+
+GType
+sp_group_get_type (void)
+{
+	static GType group_type = 0;
+	if (!group_type) {
+		GTypeInfo group_info = {
+			sizeof (SPGroupClass),
+			NULL,	/* base_init */
+			NULL,	/* base_finalize */
+			(GClassInitFunc) sp_group_class_init,
+			NULL,	/* class_finalize */
+			NULL,	/* class_data */
+			sizeof (SPGroup),
+			16,	/* n_preallocs */
+			(GInstanceInitFunc) sp_group_init,
+			NULL,	/* value_table */
+		};
+		group_type = g_type_register_static (SP_TYPE_ITEM, "SPGroup", &group_info, (GTypeFlags)0);
+	}
+	return group_type;
+}
+
+static void
+sp_group_class_init (SPGroupClass *klass)
+{
+	GObjectClass * object_class;
+	SPObjectClass * sp_object_class;
+	SPItemClass * item_class;
+
+	object_class = (GObjectClass *) klass;
+	sp_object_class = (SPObjectClass *) klass;
+	item_class = (SPItemClass *) klass;
+
+	parent_class = (SPItemClass *)g_type_class_ref (SP_TYPE_ITEM);
+
+	object_class->dispose = sp_group_dispose;
+
+	sp_object_class->child_added = sp_group_child_added;
+	sp_object_class->remove_child = sp_group_remove_child;
+	sp_object_class->order_changed = sp_group_order_changed;
+	sp_object_class->update = sp_group_update;
+	sp_object_class->modified = sp_group_modified;
+	sp_object_class->set = sp_group_set;
+	sp_object_class->write = sp_group_write;
+	sp_object_class->release = sp_group_release;
+	sp_object_class->build = sp_group_build;
+
+	item_class->bbox = sp_group_bbox;
+	item_class->print = sp_group_print;
+	item_class->description = sp_group_description;
+	item_class->show = sp_group_show;
+	item_class->hide = sp_group_hide;
+	item_class->snappoints = sp_group_snappoints;
+}
+
+static void
+sp_group_init (SPGroup *group)
+{
+	group->_layer_mode = SPGroup::GROUP;
+	new (&group->_display_modes) std::map<unsigned int, SPGroup::LayerMode>();
+}
+
+static void sp_group_build(SPObject *object, SPDocument *document, Inkscape::XML::Node *repr)
+{
+	sp_object_read_attr(object, "inkscape:groupmode");
+
+	if (((SPObjectClass *)parent_class)->build) {
+		((SPObjectClass *)parent_class)->build(object, document, repr);
+	}
+}
+
+static void sp_group_release(SPObject *object) {
+	if ( SP_GROUP(object)->_layer_mode == SPGroup::LAYER ) {
+		sp_document_remove_resource(SP_OBJECT_DOCUMENT(object), "layer", object);
+	}
+	if (((SPObjectClass *)parent_class)->release) {
+		((SPObjectClass *)parent_class)->release(object);
+	}
+}
+
+static void
+sp_group_dispose(GObject *object)
+{
+	SP_GROUP(object)->_display_modes.~map();
+}
+
+static void
+sp_group_child_added (SPObject *object, Inkscape::XML::Node *child, Inkscape::XML::Node *ref)
+{
+	SPItem *item;
+
+	item = SP_ITEM (object);
+
+	if (((SPObjectClass *) (parent_class))->child_added)
+		(* ((SPObjectClass *) (parent_class))->child_added) (object, child, ref);
+
+    SPObject *last_child = object->lastChild();
+    if (last_child && SP_OBJECT_REPR(last_child) == child) {
+        // optimization for the common special case where the child is being added at the end
+	    SPObject *ochild = last_child;
+	    if ( SP_IS_ITEM(ochild) ) {
+		    /* TODO: this should be moved into SPItem somehow */
+		    SPItemView *v;
+		    NRArenaItem *ac;
+
+		    for (v = item->display; v != NULL; v = v->next) {
+			    ac = sp_item_invoke_show (SP_ITEM (ochild), NR_ARENA_ITEM_ARENA (v->arenaitem), v->key, v->flags);
+
+			    if (ac) {
+				    nr_arena_item_append_child (v->arenaitem, ac);
+				    nr_arena_item_unref (ac);
+			    }
+		    }
+	    }
+    } else {    // general case
+	    SPObject *ochild = sp_object_get_child_by_repr(object, child);
+	    if ( ochild && SP_IS_ITEM(ochild) ) {
+		    /* TODO: this should be moved into SPItem somehow */
+		    SPItemView *v;
+		    NRArenaItem *ac;
+
+		    unsigned position = sp_item_pos_in_parent(SP_ITEM(ochild));
+
+		    for (v = item->display; v != NULL; v = v->next) {
+			    ac = sp_item_invoke_show (SP_ITEM (ochild), NR_ARENA_ITEM_ARENA (v->arenaitem), v->key, v->flags);
+
+			    if (ac) {
+				    nr_arena_item_add_child (v->arenaitem, ac, NULL);
+				    nr_arena_item_set_order (ac, position);
+				    nr_arena_item_unref (ac);
+			    }
+		    }
+	    }
+    }
+
+	object->requestModified(SP_OBJECT_MODIFIED_FLAG);
+}
+
+/* fixme: hide (Lauris) */
+
+static void
+sp_group_remove_child (SPObject * object, Inkscape::XML::Node * child)
+{
+	if (((SPObjectClass *) (parent_class))->remove_child)
+		(* ((SPObjectClass *) (parent_class))->remove_child) (object, child);
+
+	object->requestModified(SP_OBJECT_MODIFIED_FLAG);
+}
+
+static void
+sp_group_order_changed (SPObject *object, Inkscape::XML::Node *child, Inkscape::XML::Node *old_ref, Inkscape::XML::Node *new_ref)
+{
+	if (((SPObjectClass *) (parent_class))->order_changed)
+		(* ((SPObjectClass *) (parent_class))->order_changed) (object, child, old_ref, new_ref);
+
+	SPObject *ochild = sp_object_get_child_by_repr(object, child);
+	if ( ochild && SP_IS_ITEM(ochild) ) {
+		/* TODO: this should be moved into SPItem somehow */
+		SPItemView *v;
+		unsigned position = sp_item_pos_in_parent(SP_ITEM(ochild));
+		for ( v = SP_ITEM (ochild)->display ; v != NULL ; v = v->next ) {
+			nr_arena_item_set_order (v->arenaitem, position);
+		}
+	}
+
+	object->requestModified(SP_OBJECT_MODIFIED_FLAG);
+}
+
+static void
+sp_group_update (SPObject *object, SPCtx *ctx, unsigned int flags)
+{
+	SPGroup *group;
+	SPObject *child;
+	SPItemCtx *ictx, cctx;
+	GSList *l;
+
+	group = SP_GROUP (object);
+	ictx = (SPItemCtx *) ctx;
+	cctx = *ictx;
+
+	if (((SPObjectClass *) (parent_class))->update)
+		((SPObjectClass *) (parent_class))->update (object, ctx, flags);
+
+	if (flags & SP_OBJECT_MODIFIED_FLAG) flags |= SP_OBJECT_PARENT_MODIFIED_FLAG;
+	flags &= SP_OBJECT_MODIFIED_CASCADE;
+
+	l = NULL;
+	for (child = sp_object_first_child(object) ; child != NULL ; child = SP_OBJECT_NEXT(child) ) {
+		g_object_ref (G_OBJECT (child));
+		l = g_slist_prepend (l, child);
+	}
+	l = g_slist_reverse (l);
+	while (l) {
+		child = SP_OBJECT (l->data);
+		l = g_slist_remove (l, child);
+		if (flags || (child->uflags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_CHILD_MODIFIED_FLAG))) {
+			if (SP_IS_ITEM (child)) {
+				SPItem const &chi = *SP_ITEM(child);
+				cctx.i2doc = chi.transform * ictx->i2doc;
+				cctx.i2vp = chi.transform * ictx->i2vp;
+				child->updateDisplay((SPCtx *)&cctx, flags);
+			} else {
+				child->updateDisplay(ctx, flags);
+			}
+		}
+		g_object_unref (G_OBJECT (child));
+	}
+}
+
+static void
+sp_group_modified (SPObject *object, guint flags)
+{
+	SPGroup *group;
+	SPObject *child;
+	GSList *l;
+
+	group = SP_GROUP (object);
+
+	if (flags & SP_OBJECT_MODIFIED_FLAG) flags |= SP_OBJECT_PARENT_MODIFIED_FLAG;
+	flags &= SP_OBJECT_MODIFIED_CASCADE;
+
+	l = NULL;
+	for (child = sp_object_first_child(object) ; child != NULL ; child = SP_OBJECT_NEXT(child) ) {
+		g_object_ref (G_OBJECT (child));
+		l = g_slist_prepend (l, child);
+	}
+	l = g_slist_reverse (l);
+	while (l) {
+		child = SP_OBJECT (l->data);
+		l = g_slist_remove (l, child);
+		if (flags || (child->mflags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_CHILD_MODIFIED_FLAG))) {
+			child->emitModified(flags);
+		}
+		g_object_unref (G_OBJECT (child));
+	}
+}
+
+static Inkscape::XML::Node *
+sp_group_write (SPObject *object, Inkscape::XML::Node *repr, guint flags)
+{
+	SPGroup *group;
+	SPObject *child;
+	Inkscape::XML::Node *crepr;
+
+	group = SP_GROUP (object);
+
+	if (flags & SP_OBJECT_WRITE_BUILD) {
+		GSList *l;
+		if (!repr) repr = sp_repr_new ("svg:g");
+		l = NULL;
+		for (child = sp_object_first_child(object); child != NULL; child = SP_OBJECT_NEXT(child) ) {
+			crepr = child->updateRepr(NULL, flags);
+			if (crepr) l = g_slist_prepend (l, crepr);
+		}
+		while (l) {
+			repr->addChild((Inkscape::XML::Node *) l->data, NULL);
+			Inkscape::GC::release((Inkscape::XML::Node *) l->data);
+			l = g_slist_remove (l, l->data);
+		}
+	} else {
+		for (child = sp_object_first_child(object) ; child != NULL; child = SP_OBJECT_NEXT(child) ) {
+			child->updateRepr(flags);
+		}
+	}
+
+	if ( flags & SP_OBJECT_WRITE_EXT ) {
+		const char *value;
+		if ( group->_layer_mode == SPGroup::LAYER ) {
+			value = "layer";
+		} else if ( flags & SP_OBJECT_WRITE_ALL ) {
+			value = "group";
+		} else {
+			value = NULL;
+		}
+		repr->setAttribute("inkscape:groupmode", value);
+	}
+
+	if (((SPObjectClass *) (parent_class))->write)
+		((SPObjectClass *) (parent_class))->write (object, repr, flags);
+
+	return repr;
+}
+
+static void
+sp_group_bbox(SPItem const *item, NRRect *bbox, NR::Matrix const &transform, unsigned const flags)
+{
+	for (SPObject *o = sp_object_first_child(SP_OBJECT(item)); o != NULL; o = SP_OBJECT_NEXT(o)) {
+		if (SP_IS_ITEM(o)) {
+			SPItem *child = SP_ITEM(o);
+			NR::Matrix const ct(child->transform * transform);
+			sp_item_invoke_bbox_full(child, bbox, ct, flags, FALSE);
+		}
+	}
+}
+
+static void
+sp_group_print (SPItem * item, SPPrintContext *ctx)
+{
+	SPGroup * group;
+	SPItem * child;
+	SPObject * o;
+
+	group = SP_GROUP (item);
+
+	for (o = sp_object_first_child(SP_OBJECT(item)) ; o != NULL ; o = SP_OBJECT_NEXT(o) ) {
+		if (SP_IS_ITEM (o)) {
+			child = SP_ITEM (o);
+			sp_item_invoke_print (SP_ITEM (o), ctx);
+		}
+	}
+}
+
+static gchar * sp_group_description (SPItem * item)
+{
+	SPGroup * group;
+	SPObject * o;
+	gint len;
+
+	group = SP_GROUP (item);
+
+	len = 0;
+	for ( o = sp_object_first_child(SP_OBJECT(item)) ; o != NULL ; o = SP_OBJECT_NEXT(o) ) {
+		if (SP_IS_ITEM(o)) {
+			len += 1;
+		}
+	}
+
+	return g_strdup_printf(
+			ngettext("<b>Group</b> of <b>%d</b> object",
+				 "<b>Group</b> of <b>%d</b> objects",
+				 len), len);
+}
+
+static void sp_group_set(SPObject *object, unsigned key, char const *value) {
+	SPGroup *group=SP_GROUP(object);
+
+	switch (key) {
+		case SP_ATTR_INKSCAPE_GROUPMODE: {
+			if ( value && !strcmp(value, "layer") ) {
+				group->setLayerMode(SPGroup::LAYER);
+			} else {
+				group->setLayerMode(SPGroup::GROUP);
+			}
+		} break;
+		default: {
+			if (((SPObjectClass *) (parent_class))->set) {
+				(* ((SPObjectClass *) (parent_class))->set)(object, key, value);
+			}
+		}
+	}
+}
+
+static NRArenaItem *
+sp_group_show (SPItem *item, NRArena *arena, unsigned int key, unsigned int flags)
+{
+	SPGroup *group;
+	NRArenaItem *ai, *ac, *ar;
+	SPItem * child;
+	SPObject * o;
+
+	group = (SPGroup *) item;
+
+	ai = NRArenaGroup::create(arena);
+	nr_arena_group_set_transparent(NR_ARENA_GROUP (ai),
+	                               group->effectiveLayerMode(key) ==
+				         SPGroup::LAYER);
+
+	ar = NULL;
+
+	for (o = sp_object_first_child(SP_OBJECT(item)) ; o != NULL; o = SP_OBJECT_NEXT(o) ) {
+		if (SP_IS_ITEM (o)) {
+			child = SP_ITEM (o);
+			ac = sp_item_invoke_show (child, arena, key, flags);
+			if (ac) {
+				nr_arena_item_add_child (ai, ac, ar);
+				ar = ac;
+				nr_arena_item_unref (ac);
+			}
+		}
+	}
+
+	return ai;
+}
+
+static void
+sp_group_hide (SPItem *item, unsigned int key)
+{
+	SPGroup * group;
+	SPItem * child;
+	SPObject * o;
+
+	group = (SPGroup *) item;
+
+	for (o = sp_object_first_child(SP_OBJECT(item)) ; o != NULL; o = SP_OBJECT_NEXT(o) ) {
+		if (SP_IS_ITEM (o)) {
+			child = SP_ITEM (o);
+			sp_item_invoke_hide (child, key);
+		}
+	}
+
+	if (((SPItemClass *) parent_class)->hide)
+		((SPItemClass *) parent_class)->hide (item, key);
+}
+
+static void sp_group_snappoints (SPItem const *item, SnapPointsIter p)
+{
+	for (SPObject const *o = sp_object_first_child(SP_OBJECT(item));
+	     o != NULL;
+	     o = SP_OBJECT_NEXT(o))
+	{
+		if (SP_IS_ITEM(o)) {
+			sp_item_snappoints(SP_ITEM(o), p);
+		}
+	}
+}
+
+
+void
+sp_item_group_ungroup (SPGroup *group, GSList **children, bool do_done)
+{
+	g_return_if_fail (group != NULL);
+	g_return_if_fail (SP_IS_GROUP (group));
+
+	SPDocument *doc = SP_OBJECT_DOCUMENT (group);
+	SPObject *root = SP_DOCUMENT_ROOT (doc);
+	SPObject *defs = SP_OBJECT (SP_ROOT (root)->defs);
+
+	SPItem *gitem = SP_ITEM (group);
+	Inkscape::XML::Node *grepr = SP_OBJECT_REPR (gitem);
+
+	g_return_if_fail (!strcmp (grepr->name(), "svg:g") || !strcmp (grepr->name(), "svg:a") || !strcmp (grepr->name(), "svg:switch"));
+
+      // this converts the gradient/pattern fill/stroke on the group, if any, to userSpaceOnUse
+      sp_item_adjust_paint_recursive (gitem, NR::identity(), NR::identity(), false);
+
+	SPItem *pitem = SP_ITEM (SP_OBJECT_PARENT (gitem));
+	Inkscape::XML::Node *prepr = SP_OBJECT_REPR (pitem);
+
+	/* Step 1 - generate lists of children objects */
+	GSList *items = NULL;
+	GSList *objects = NULL;
+	for (SPObject *child = sp_object_first_child(SP_OBJECT(group)) ; child != NULL; child = SP_OBJECT_NEXT(child) ) {
+
+		if (SP_IS_ITEM (child)) {
+
+			SPItem *citem = SP_ITEM (child);
+
+			/* Merging of style */
+			// this converts the gradient/pattern fill/stroke, if any, to userSpaceOnUse; we need to do
+			// it here _before_ the new transform is set, so as to use the pre-transform bbox
+			sp_item_adjust_paint_recursive (citem, NR::identity(), NR::identity(), false);
+
+			sp_style_merge_from_dying_parent(SP_OBJECT_STYLE(child), SP_OBJECT_STYLE(gitem));
+			/*
+			 * fixme: We currently make no allowance for the case where child is cloned
+			 * and the group has any style settings.
+			 *
+			 * (This should never occur with documents created solely with the current
+			 * version of inkscape without using the XML editor: we usually apply group
+			 * style changes to children rather than to the group itself.)
+			 *
+			 * If the group has no style settings, then
+			 * sp_style_merge_from_dying_parent should be a no-op.  Otherwise (i.e. if
+			 * we change the child's style to compensate for its parent going away)
+			 * then those changes will typically be reflected in any clones of child,
+			 * whereas we'd prefer for Ungroup not to affect the visual appearance.
+			 *
+			 * The only way of preserving styling appearance in general is for child to
+			 * be put into a new group -- a somewhat surprising response to an Ungroup
+			 * command.  We could add a new groupmode:transparent that would mostly
+			 * hide the existence of such groups from the user (i.e. editing behaves as
+			 * if the transparent group's children weren't in a group), though that's
+			 * extra complication & maintenance burden and this case is rare.
+			 */
+
+			child->updateRepr();
+
+			Inkscape::XML::Node *nrepr = SP_OBJECT_REPR (child)->duplicate();
+
+			// Merging transform
+			NR::Matrix ctrans;
+			NR::Matrix const g(gitem->transform);
+			if (SP_IS_USE(citem) && sp_use_get_original (SP_USE(citem)) && 
+					SP_OBJECT_PARENT (sp_use_get_original (SP_USE(citem))) == SP_OBJECT(group)) {
+				// make sure a clone's effective transform is the same as was under group
+				ctrans = g.inverse() * citem->transform * g;
+			} else {
+				ctrans = citem->transform * g;
+			}
+
+			// FIXME: constructing a transform that would fully preserve the appearance of a
+			// textpath if it is ungrouped with its path seems to be impossible in general
+			// case. E.g. if the group was squeezed, to keep the ungrouped textpath squeezed
+			// as well, we'll need to relink it to some "virtual" path which is inversely
+			// stretched relative to the actual path, and then squeeze the textpath back so it
+			// would both fit the actual path _and_ be squeezed as before. It's a bummer.
+
+			// This is just a way to temporarily remember the transform in repr. When repr is
+			// reattached outside of the group, the transform will be written more properly
+			// (i.e. optimized into the object if the corresponding preference is set)
+			gchar affinestr[80];
+			if (sp_svg_transform_write(affinestr, 79, ctrans)) {
+				nrepr->setAttribute("transform", affinestr);
+			} else {
+				nrepr->setAttribute("transform", NULL);
+			}
+
+			items = g_slist_prepend (items, nrepr);
+
+		} else {
+			Inkscape::XML::Node *nrepr = SP_OBJECT_REPR (child)->duplicate();
+			objects = g_slist_prepend (objects, nrepr);
+		}
+	}
+
+	/* Step 2 - clear group */
+	// remember the position of the group
+	gint pos = SP_OBJECT_REPR(group)->position();
+
+	// the group is leaving forever, no heir, clones should take note; its children however are going to reemerge
+	SP_OBJECT (group)->deleteObject(true, false);
+
+	/* Step 3 - add nonitems */
+	if (objects) {
+	    Inkscape::XML::Node *last_def = SP_OBJECT_REPR(defs)->lastChild();
+	    while (objects) {
+		SP_OBJECT_REPR(defs)->addChild((Inkscape::XML::Node *) objects->data, last_def);
+		Inkscape::GC::release((Inkscape::XML::Node *) objects->data);
+		objects = g_slist_remove (objects, objects->data);
+	    }
+	}
+
+	/* Step 4 - add items */
+	gint const preserve = prefs_get_int_attribute("options.preservetransform", "value", 0);
+	while (items) {
+		Inkscape::XML::Node *repr = (Inkscape::XML::Node *) items->data;
+		// add item
+		prepr->appendChild(repr);
+		// restore position; since the items list was prepended (i.e. reverse), we now add
+		// all children at the same pos, which inverts the order once again
+		repr->setPosition(pos > 0 ? pos : 0);
+
+		// fill in the children list if non-null
+		SPItem *nitem = (SPItem *) doc->getObjectByRepr(repr);
+
+		/* Optimize the transform matrix if requested. */
+		// No compensations are required because this is supposed to be a non-transformation visually.
+		if (!preserve) {
+			NR::Matrix (*set_transform)(SPItem *, NR::Matrix const &) = ((SPItemClass *) G_OBJECT_GET_CLASS(nitem))->set_transform;
+			if (set_transform) {
+				sp_item_set_item_transform(nitem, set_transform(nitem, nitem->transform));
+				nitem->updateRepr();
+			}
+		}
+
+		Inkscape::GC::release(repr);
+		if (children && SP_IS_ITEM (nitem)) 
+			*children = g_slist_prepend (*children, nitem);
+
+		items = g_slist_remove (items, items->data);
+	}
+
+	if (do_done) sp_document_done (doc);
+}
+
+/*
+ * some API for list aspect of SPGroup
+ */
+
+GSList * 
+sp_item_group_item_list (SPGroup * group)
+{
+        GSList *s;
+	SPObject *o;
+
+	g_return_val_if_fail (group != NULL, NULL);
+	g_return_val_if_fail (SP_IS_GROUP (group), NULL);
+
+	s = NULL;
+
+	for ( o = sp_object_first_child(SP_OBJECT(group)) ; o != NULL ; o = SP_OBJECT_NEXT(o) ) {
+		if (SP_IS_ITEM (o)) {
+			s = g_slist_prepend (s, o);
+		}
+	}
+
+	return g_slist_reverse (s);
+}
+
+SPObject *
+sp_item_group_get_child_by_name (SPGroup *group, SPObject *ref, const gchar *name)
+{
+	SPObject *child;
+	child = (ref) ? SP_OBJECT_NEXT(ref) : sp_object_first_child(SP_OBJECT(group));
+	while ( child && strcmp (SP_OBJECT_REPR(child)->name(), name) ) {
+		child = SP_OBJECT_NEXT(child);
+	}
+	return child;
+}
+
+void SPGroup::setLayerMode(LayerMode mode) {
+	if ( _layer_mode != mode ) {
+		if ( mode == LAYER ) {
+			sp_document_add_resource(SP_OBJECT_DOCUMENT(this), "layer", this);
+		} else {
+			sp_document_remove_resource(SP_OBJECT_DOCUMENT(this), "layer", this);
+		}
+		_layer_mode = mode;
+		_updateLayerMode();
+	}
+}
+
+SPGroup::LayerMode SPGroup::layerDisplayMode(unsigned int dkey) const {
+	std::map<unsigned int, LayerMode>::const_iterator iter;
+	iter = _display_modes.find(dkey);
+	if ( iter != _display_modes.end() ) {
+		return (*iter).second;
+	} else {
+		return GROUP;
+	}
+}
+
+void SPGroup::setLayerDisplayMode(unsigned int dkey, SPGroup::LayerMode mode) {
+	if ( layerDisplayMode(dkey) != mode ) {
+		_display_modes[dkey] = mode;
+		_updateLayerMode(dkey);
+	}
+}
+
+void SPGroup::_updateLayerMode(unsigned int display_key) {
+	SPItemView *view;
+	for ( view = this->display ; view ; view = view->next ) {
+		if ( !display_key || view->key == display_key ) {
+			NRArenaGroup *arena_group=NR_ARENA_GROUP(view->arenaitem);
+			if (arena_group) {
+				nr_arena_group_set_transparent(arena_group, effectiveLayerMode(view->key) == SPGroup::LAYER);
+			}
+		}
+	}
+}