[dia] [substitute] implement object_substitute() for object replacement

[Hans Breuer <hans src gnome org>]

commit 8aefc202b6e91c5ca4ed5a0079d9d75b124e80eb
Author: Hans Breuer <hans breuer org>
Date:   Sun Sep 16 13:18:20 2012 +0200

    [substitute] implement object_substitute() for object replacement
    
    The type of an object can not change dynamically. To substitute one
    object with another this function helps. It does it's best to transfer
    all the existing object relations, e.g. connections, parent_layer
    and parenting information.

 lib/libdia.def |    2 +
 lib/object.c   |  154 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 lib/object.h   |    8 +--
 3 files changed, 157 insertions(+), 7 deletions(-)
---
diff --git a/lib/libdia.def b/lib/libdia.def
index 5613c0e..02117c6 100644
--- a/lib/libdia.def
+++ b/lib/libdia.def
@@ -540,6 +540,7 @@ EXPORTS
  object_save_props
  object_save_using_properties
  object_set_props_from_offsets
+ object_substitute
  object_toggle_prop
  object_unconnect
 
@@ -556,6 +557,7 @@ EXPORTS
  orthconn_move
  orthconn_move_handle
  orthconn_save
+ orthconn_set_points
  orthconn_toggle_autorouting_callback
  orthconn_update_boundingbox
  orthconn_update_data
diff --git a/lib/object.c b/lib/object.c
index b33b0c5..158d33d 100644
--- a/lib/object.c
+++ b/lib/object.c
@@ -290,7 +290,7 @@ object_list_move_delta_r(GList *objects, Point *delta, gboolean affected)
  * @param objects The list ob objects to move.
  * @param delta The amount to move them.
  */
-extern ObjectChange*
+ObjectChange*
 object_list_move_delta(GList *objects, Point *delta)
 {
   GList *list;
@@ -316,6 +316,158 @@ object_list_move_delta(GList *objects, Point *delta)
   return objchange;
 }
 
+typedef struct _ObjectChangeExchange
+{
+  ObjectChange change;
+  DiaObject    *orig;
+  DiaObject    *subst;
+  gboolean      applied;
+} ObjectChangeExchange;
+
+Handle *
+_find_connectable (DiaObject *obj, int *num)
+{
+  int n = *num;
+  for (; n < obj->num_handles; ++n) {
+    if (obj->handles[n]->connect_type!=HANDLE_NONCONNECTABLE) {
+      *num = n;
+      return obj->handles[n];
+    }
+  }
+  return NULL;
+}
+
+static PropDescription _style_prop_descs[] = {
+  PROP_STD_LINE_WIDTH,
+  PROP_STD_LINE_COLOUR,
+  PROP_STD_LINE_STYLE,
+  PROP_STD_LINE_JOIN,
+  PROP_STD_LINE_CAPS,
+  PROP_STD_FILL_COLOUR,
+  PROP_STD_TEXT,
+  PROP_DESC_END
+};
+
+static void
+_object_exchange (ObjectChange *change, DiaObject *obj)
+{
+  ObjectChangeExchange *c = (ObjectChangeExchange *)change;
+  Layer *layer = dia_object_get_parent_layer (obj);
+  DiagramData *dia = layer ? layer_get_parent_diagram(layer) : NULL;
+  DiaObject *subst = (obj == c->orig) ? c->subst : c->orig;
+  DiaObject *parent_object = obj->parent;
+  Handle *h1, *h2;
+  int n1 = 0, n2 = 0;
+  GPtrArray *props;
+  int obj_index = 0;
+
+  props = prop_list_from_descs (_style_prop_descs, pdtpp_true);
+  /* removing from the diagram first, to have the right update areas */
+  if (layer) {
+    obj_index = layer_object_get_index (layer, obj);
+    layer_remove_object (layer, obj);
+    if (dia)
+      data_unselect(dia, obj);
+  }
+  if (obj->ops->get_props)
+    obj->ops->get_props(obj, props);
+  /* transfer connections where possible - first find the right handles */
+  h1 = _find_connectable (obj, &n1);
+  h2 = _find_connectable (subst, &n2);
+  while (h1 && h2) {
+    /* The connection point of the other object - beware self connections */
+    ConnectionPoint *cp = h1->connected_to;
+
+    if (cp) {
+      h2->pos = h1->pos;
+      object_unconnect (obj, h1);
+      object_connect (subst, h2, cp);
+      /* make the object update it's data - e.g. autorouting */
+      subst->ops->move_handle(subst, h2, &h2->pos, cp, HANDLE_MOVE_CONNECTED, 0);
+    }
+    ++n1;
+    ++n2;
+    h1 = _find_connectable (obj, &n1);
+    h2 = _find_connectable (subst, &n2);
+  }
+  /* disconnect the rest - sorry: no undo for that */
+  object_unconnect_all (obj);
+  /* transfer parenting information */
+  if (parent_object) {
+    GList *sibling = g_list_find (parent_object->children, obj);
+    parent_object->children = g_list_insert_before (parent_object->children, sibling, subst);
+    parent_object->children = g_list_remove (parent_object->children, obj);
+  }
+  /* apply style properties */
+  if (subst->ops->get_props)
+    subst->ops->set_props(subst, props);
+  prop_list_free(props);
+  /* adding to the diagram last, to have the right update areas */
+  if (layer) {
+    layer_add_object_at (layer, subst, obj_index);
+    if (dia)
+      data_select(dia, subst);
+  }
+}
+/* It is adviced to not use the passed in object at all */
+static void
+_object_exchange_apply (ObjectChange *change, DiaObject *obj)
+{
+  ObjectChangeExchange *c = (ObjectChangeExchange *)change;
+
+  g_return_if_fail (c->applied == 0);
+  _object_exchange (change, c->orig);
+  c->applied = 1;
+}
+/* It is adviced to not use the passed in object at all */
+static void
+_object_exchange_revert (ObjectChange *change, DiaObject *obj)
+{
+  ObjectChangeExchange *c = (ObjectChangeExchange *)change;
+
+  g_return_if_fail (c->applied != 0);
+  _object_exchange (change, c->subst);
+  c->applied = 0;
+}
+static void
+_object_exchange_free (ObjectChange *change)
+{
+  ObjectChangeExchange *c = (ObjectChangeExchange *)change;
+  DiaObject *obj = c->applied ? c->orig : c->subst;
+
+  if (obj) {
+    obj->ops->destroy(obj);
+    g_free(obj);
+  }
+}
+/*!
+ * \brief Replace an object with another one
+ *
+ * The type of an object can not change dynamically. To substitute one
+ * object with another this function help. It does it's best to transfer
+ * all the existing object relations, e.g. connections, parent_layer 
+ * and parenting information.
+ *
+ * @param obj   the original object which will be replace
+ * @param subst the sunstitute object
+ * @return      _ObjectChange containing undo/redo information
+ */
+ObjectChange *
+object_substitute (DiaObject *obj, DiaObject *subst)
+{
+  ObjectChangeExchange *change = g_new0(ObjectChangeExchange, 1);
+
+  change->change.apply  = _object_exchange_apply;
+  change->change.revert = _object_exchange_revert;
+  change->change.free   = _object_exchange_free;
+  change->orig  = obj;
+  change->subst = subst;
+
+  _object_exchange_apply ((ObjectChange*)change, obj);
+
+  return (ObjectChange*)change;
+}
+
 /** Destroy a list of objects by calling ops->destroy on each in turn.
  * @param list_to_be_destroyed A of objects list to destroy.  The list itself
  *                             will also be freed.
diff --git a/lib/object.h b/lib/object.h
index d66ffe0..7f57df7 100644
--- a/lib/object.h
+++ b/lib/object.h
@@ -376,12 +376,8 @@ void object_load(DiaObject *obj, ObjectNode obj_node, DiaContext *ctx);
 GList *object_copy_list(GList *list);
 ObjectChange* object_list_move_delta_r(GList *objects, Point *delta, gboolean affected);
 ObjectChange* object_list_move_delta(GList *objects, Point *delta);
-/** Rotate an object around a point.  If center is NULL, the position of
- * the object is used. */
-ObjectChange* object_list_rotate(GList *objects, Point *center, real angle);
-/** Scale an object around a point.  If center is NULL, the position of
- * the object is used. */
-ObjectChange* object_list_scale(GList *objects, Point *center, real factor);
+ObjectChange *object_substitute (DiaObject *obj, DiaObject *subst);
+
 void destroy_object_list(GList *list);
 void object_add_handle(DiaObject *obj, Handle *handle);
 void object_add_handle_at(DiaObject *obj, Handle *handle, int pos);