[dia] [substitute] Upgradeable Standard - ZigZagLine to Bezier

[Hans Breuer <hans src gnome org>]

commit a99e44dbececfdf9af9048d42f7a566324b54981
Author: Hans Breuer <hans breuer org>
Date:   Sun Sep 16 15:12:20 2012 +0200

    [substitute] Upgradeable Standard - ZigZagLine to Bezier
    
    Accessible through the object's context menu this function substitutes
    the _Zigzagline with a _Bezierline. The function creates a favorable
    representation of the original _OrthConn data of the given object.
    
    Also a small adaption of object_substitute() algorithm:
    Bezierlines don't have just two connectable handles, but
    every major handle is connectable. So if the 'input obj' is
    at the end we should search subst from the end, too.

 lib/object.c                  |   30 ++++++++++++--
 objects/standard/zigzagline.c |   84 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 105 insertions(+), 9 deletions(-)
---
diff --git a/lib/object.c b/lib/object.c
index 158d33d..a1c97c6 100644
--- a/lib/object.c
+++ b/lib/object.c
@@ -324,11 +324,12 @@ typedef struct _ObjectChangeExchange
   gboolean      applied;
 } ObjectChangeExchange;
 
-Handle *
+static Handle *
 _find_connectable (DiaObject *obj, int *num)
 {
-  int n = *num;
-  for (; n < obj->num_handles; ++n) {
+  int dir = *num >= 0 ? 1 : -1;
+  int n = (*num >= 0 ? *num : -*num);
+  for (; n < obj->num_handles && n >= 0; n+=dir) {
     if (obj->handles[n]->connect_type!=HANDLE_NONCONNECTABLE) {
       *num = n;
       return obj->handles[n];
@@ -336,7 +337,22 @@ _find_connectable (DiaObject *obj, int *num)
   }
   return NULL;
 }
-
+/*!
+ * Bezierlines don't have just two connectable handles, but every 
+ * major handle is connectable. To let us find the correct handles
+ * for connection transfer this function checks if there is
+ * a higher handle index connectable.
+ */
+static int
+_more_connectable (DiaObject *obj, int num)
+{
+  int n;
+  for (n = num+1; n < obj->num_handles; ++n) {
+    if (obj->handles[n]->connect_type!=HANDLE_NONCONNECTABLE)
+      return TRUE;
+  }
+  return FALSE;
+}
 static PropDescription _style_prop_descs[] = {
   PROP_STD_LINE_WIDTH,
   PROP_STD_LINE_COLOUR,
@@ -386,8 +402,12 @@ _object_exchange (ObjectChange *change, DiaObject *obj)
       subst->ops->move_handle(subst, h2, &h2->pos, cp, HANDLE_MOVE_CONNECTED, 0);
     }
     ++n1;
-    ++n2;
     h1 = _find_connectable (obj, &n1);
+    /* if we are at the end of the input line change search direction to backward */
+    if (h1 && !_more_connectable(obj, n1))
+      n2 = -(subst->num_handles-1);
+    else
+      ++n2;
     h2 = _find_connectable (subst, &n2);
   }
   /* disconnect the rest - sorry: no undo for that */
diff --git a/objects/standard/zigzagline.c b/objects/standard/zigzagline.c
index e0119e4..f683759 100644
--- a/objects/standard/zigzagline.c
+++ b/objects/standard/zigzagline.c
@@ -31,6 +31,7 @@
 #include "attributes.h"
 #include "properties.h"
 #include "autoroute.h"
+#include "create.h"
 
 #include "tool-icons.h"
 
@@ -254,6 +255,7 @@ zigzagline_create(Point *startpoint,
   Zigzagline *zigzagline;
   OrthConn *orth;
   DiaObject *obj;
+  Point dummy = {0, 0};
 
   /*zigzagline_init_defaults();*/
   zigzagline = g_malloc0(sizeof(Zigzagline));
@@ -262,8 +264,16 @@ zigzagline_create(Point *startpoint,
   
   obj->type = &zigzagline_type;
   obj->ops = &zigzagline_ops;
-  
-  orthconn_init(orth, startpoint);
+
+  if (startpoint)
+    orthconn_init(orth, startpoint);
+  else
+    orthconn_init(orth, &dummy);
+
+  if (user_data) {
+    MultipointCreateData *pcd = (MultipointCreateData *)user_data;
+    orthconn_set_points (orth, pcd->num_points, pcd->points);
+  }
 
   zigzagline->line_width =  attributes_get_default_linewidth();
   zigzagline->line_color = attributes_get_foreground();
@@ -274,7 +284,7 @@ zigzagline_create(Point *startpoint,
   zigzagline->start_arrow = attributes_get_default_start_arrow();
   zigzagline->end_arrow = attributes_get_default_end_arrow();
   zigzagline->corner_radius = 0.0;
-  
+
   *handle1 = orth->handles[0];
   *handle2 = orth->handles[orth->numpoints-2];
 
@@ -383,9 +393,74 @@ zigzagline_delete_segment_callback(DiaObject *obj, Point *clicked, gpointer data
   return change;
 }
 
+/*!
+ * \brief Upgrade the _Zigzagline to a _Bezierline
+ *
+ * Accessible through the object's context menu this function substitutes 
+ * the _Zigzagline with a _Bezierline. The function creates a favorable
+ * representation of the original _OrthConn data of the given object.
+ *
+ * @param obj  explicit this pointer
+ * @param clicked  last clicked point on the canvas or NULL
+ * @param data a pointer to extra data, unused here
+ * @return  undo/redo information as _ObjectChange
+ *
+ * \memberof _Zigzagline
+ */
+static ObjectChange *
+_convert_to_bezierline_callback (DiaObject *obj, Point *clicked, gpointer data)
+{
+  DiaObject *poly;
+  Zigzagline *zigzagline = (Zigzagline *)obj;
+  OrthConn *orth = &zigzagline->orth;
+  BezPoint *bp;
+  int i, j, num_points;
+  DiaObject *bezier;
+
+  num_points = (orth->numpoints + 1) / 2;
+  bp = g_new(BezPoint, num_points);
+  bp[0].type = BEZ_MOVE_TO;
+  bp[0].p1 = orth->points[0];
+
+  for (i = 1, j = 1; i < num_points && j < orth->numpoints; ++i) {
+    bp[i].type = BEZ_CURVE_TO;
+    bp[i].p1 = orth->points[j++];
+    bp[i].p2 = orth->points[j++];
+    if (j + 2 < orth->numpoints) {
+      /* if we have more than two points left, use the middle of the segment */
+      Point p = { (orth->points[j-1].x + orth->points[j].x) / 2.0,
+		  (orth->points[j-1].y + orth->points[j].y) / 2.0 };
+      bp[i].p3 = p;
+    } else if (j + 2 == orth->numpoints) {
+      /* if we one extra point left, use the middle of two segments */
+      Point p1 = { (orth->points[j-2].x + orth->points[j-1].x) / 2.0,
+		   (orth->points[j-2].y + orth->points[j-1].y) / 2.0 };
+      Point p2 = { (orth->points[j-1].x + orth->points[j].x) / 2.0,
+		   (orth->points[j-1].y + orth->points[j].y) / 2.0 };
+      Point p =  { (p1.x + p2.x) / 2.0, (p1.y + p2.y) / 2.0 };
+      bp[i].p3 = p;
+      /* also adapt the previous control point */
+      bp[i].p2 = p1;
+      /* and do the final bezpoint */
+      bp[i+1].type = BEZ_CURVE_TO;
+      bp[i+1].p1 = p2;
+      bp[i+1].p2 = orth->points[j];
+      bp[i+1].p3 = orth->points[j+1];
+      break;
+    } else {
+      bp[i].p3 = orth->points[j++];
+    }
+  }
+  bezier = create_standard_bezierline(num_points, bp, &zigzagline->end_arrow, &zigzagline->start_arrow);
+  g_free(bp);
+
+  return object_substitute (obj, bezier);
+}
+
 static DiaMenuItem object_menu_items[] = {
   { N_("Add segment"), zigzagline_add_segment_callback, NULL, 1 },
   { N_("Delete segment"), zigzagline_delete_segment_callback, NULL, 1 },
+  { N_("Upgrade to Bezierline"), _convert_to_bezierline_callback, NULL, 1 },
   ORTHCONN_COMMON_MENUS,
 };
 
@@ -405,7 +480,8 @@ zigzagline_get_object_menu(Zigzagline *zigzagline, Point *clickedpoint)
   /* Set entries sensitive/selected etc here */
   object_menu_items[0].active = orthconn_can_add_segment(orth, clickedpoint);
   object_menu_items[1].active = orthconn_can_delete_segment(orth, clickedpoint);
-  orthconn_update_object_menu(orth, clickedpoint, &object_menu_items[2]);
+  object_menu_items[2].active = TRUE;
+  orthconn_update_object_menu(orth, clickedpoint, &object_menu_items[3]);
 
   return &object_menu;
 }