/* Dia -- an diagram creation/manipulation program
 * Copyright (C) 1999 Alexander Larsson
 *
 * BezierConn  Copyright (C) 1999 James Henstridge
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

 /** \file bezier_conn.c Allows to construct object consisting of bezier lines */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h> /* memcpy() */

#include "bezier_conn.h"
#include "diarenderer.h"


#define HANDLE_BEZMAJOR  (HANDLE_CUSTOM1)
#define HANDLE_LEFTCTRL  (HANDLE_CUSTOM2)
#define HANDLE_RIGHTCTRL (HANDLE_CUSTOM3)

enum change_type {
  TYPE_ADD_POINT,
  TYPE_REMOVE_POINT
};


static DiaObjectChange *dia_bezier_conn_point_object_change_new  (BezierConn       *bezier,
                                                                  enum change_type  type,
                                                                  BezPoint         *point,
                                                                  BezCornerType     corner_type,
                                                                  int               pos,
                                                                  Handle           *handle1,
                                                                  ConnectionPoint  *connected_to1,
                                                                  Handle           *handle2,
                                                                  ConnectionPoint  *connected_to2,
                                                                  Handle           *handle3,
                                                                  ConnectionPoint  *connected_to3);
static DiaObjectChange *dia_bezier_conn_corner_object_change_new (BezierConn       *bezier,
                                                                  Handle           *handle,
                                                                  Point            *point_left,
                                                                  Point            *point_right,
                                                                  BezCornerType     old_corner_type,
                                                                  BezCornerType     new_corner_type);


/**
 * setup_handle:
 * @handle: A handle to set up.
 * @id: Handle id (%HANDLE_BEZMAJOR or %HANDLE_RIGHTCTRL or %HANDLE_LEFTCTRL)
 *
 * Set up a handle for any part of a bezier
 */
static void
setup_handle (Handle *handle, HandleId id)
{
  handle->id = id;
  handle->type = HANDLE_MINOR_CONTROL;
  handle->connect_type = (id == HANDLE_BEZMAJOR) ?
      HANDLE_CONNECTABLE : HANDLE_NONCONNECTABLE;
  handle->connected_to = NULL;
}


/**
 * get_handle_nr:
 * @bezier: A bezier object with handles set up.
 * @handle: A handle object.
 *
 * Get the number in the array of handles that a given handle has.
 *
 * Returns: The index in bezier->object.handles of the handle object, or -1 if
 *          `handle' is not in the array.
 *
 * Since: dawn-of-time
 */
static int
get_handle_nr (BezierConn *bezier, Handle *handle)
{
  int i = 0;
  for (i = 0; i < bezier->object.num_handles; i++) {
    if (bezier->object.handles[i] == handle)
      return i;
  }
  return -1;
}

#define get_comp_nr(hnum) (((int)(hnum)+2)/3)
#define get_major_nr(hnum) (((int)(hnum)+1)/3)

void new_handles (BezierConn *bezier, int num_points);


/**
 * bezierconn_move_handle:
 * @bezier: The object whose handle is being moved.
 * @handle: The handle being moved.
 * @to: The position it has been moved to (corrected for
 *   vertical/horizontal only movement).
 * @cp: If non-%NULL, the connectionpoint found at this position.
 *   If @cp is %NULL, there may or may not be a connectionpoint.
 * @reason: ignored
 * @modifiers: ignored
 *
 * Move one of the handles associated with the BezierConn
 *
 * Returns: %NULL
 */
DiaObjectChange *
bezierconn_move_handle (BezierConn       *bezier,
                        Handle           *handle,
                        Point            *to,
                        ConnectionPoint  *cp,
                        HandleMoveReason  reason,
                        ModifierKeys      modifiers)
{
  int handle_nr, comp_nr;
  Point delta, pt;

  delta = *to;
  point_sub (&delta, &handle->pos);

  handle_nr = get_handle_nr (bezier, handle);
  comp_nr = get_comp_nr (handle_nr);

  switch (handle->id) {
    case HANDLE_MOVE_STARTPOINT:
      bezier->bezier.points[0].p1 = *to;
      /* shift adjacent point */
      point_add (&bezier->bezier.points[1].p1, &delta);
      break;
    case HANDLE_MOVE_ENDPOINT:
      bezier->bezier.points[bezier->bezier.num_points-1].p3 = *to;
      /* shift adjacent point */
      point_add (&bezier->bezier.points[bezier->bezier.num_points-1].p2,
                 &delta);
      break;
    case HANDLE_BEZMAJOR:
      bezier->bezier.points[comp_nr].p3 = *to;
      /* shift adjacent point */
      point_add (&bezier->bezier.points[comp_nr].p2, &delta);
      point_add (&bezier->bezier.points[comp_nr+1].p1, &delta);
      break;
    case HANDLE_LEFTCTRL:
      bezier->bezier.points[comp_nr].p2 = *to;
      if (comp_nr < bezier->bezier.num_points - 1) {
        switch (bezier->bezier.corner_types[comp_nr]) {
          case BEZ_CORNER_SYMMETRIC:
            pt = bezier->bezier.points[comp_nr].p3;
            point_sub (&pt, &bezier->bezier.points[comp_nr].p2);
            point_add (&pt, &bezier->bezier.points[comp_nr].p3);
            bezier->bezier.points[comp_nr+1].p1 = pt;
            break;
          case BEZ_CORNER_SMOOTH: {
              real len;
              pt = bezier->bezier.points[comp_nr+1].p1;
              point_sub (&pt, &bezier->bezier.points[comp_nr].p3);
              len = point_len (&pt);
              pt = bezier->bezier.points[comp_nr].p2;
              point_sub (&pt, &bezier->bezier.points[comp_nr].p3);
              if (point_len (&pt) > 0) {
                point_normalize (&pt);
              } else {
                pt.x = 1.0;
                pt.y = 0.0;
              }
              point_scale (&pt, -len);
              point_add (&pt, &bezier->bezier.points[comp_nr].p3);
              bezier->bezier.points[comp_nr+1].p1 = pt;
              break;
            }
          case BEZ_CORNER_CUSP:
          default:
            /* Do nothing to the other guy */
            break;
        }
      }
      break;
    case HANDLE_RIGHTCTRL:
      bezier->bezier.points[comp_nr].p1 = *to;
      if (comp_nr > 1) {
        switch (bezier->bezier.corner_types[comp_nr-1]) {
          case BEZ_CORNER_SYMMETRIC:
            pt = bezier->bezier.points[comp_nr - 1].p3;
            point_sub (&pt, &bezier->bezier.points[comp_nr].p1);
            point_add (&pt, &bezier->bezier.points[comp_nr - 1].p3);
            bezier->bezier.points[comp_nr-1].p2 = pt;
            break;
          case BEZ_CORNER_SMOOTH: {
            real len;
            pt = bezier->bezier.points[comp_nr-1].p2;
            point_sub (&pt, &bezier->bezier.points[comp_nr-1].p3);
            len = point_len (&pt);
            pt = bezier->bezier.points[comp_nr].p1;
            point_sub (&pt, &bezier->bezier.points[comp_nr-1].p3);
            if (point_len (&pt) > 0) {
              point_normalize (&pt);
            } else {
              pt.x = 1.0;
              pt.y = 0.0;
            }
            point_scale (&pt, -len);
            point_add (&pt, &bezier->bezier.points[comp_nr-1].p3);
            bezier->bezier.points[comp_nr-1].p2 = pt;
            break;
          }
          case BEZ_CORNER_CUSP:
            /* Do nothing to the other guy */
            break;
          default:
            g_return_val_if_reached (NULL);
        }
      }
      break;
    case HANDLE_RESIZE_N:
    case HANDLE_RESIZE_NE:
    case HANDLE_RESIZE_E:
    case HANDLE_RESIZE_SE:
    case HANDLE_RESIZE_S:
    case HANDLE_RESIZE_SW:
    case HANDLE_RESIZE_W:
    case HANDLE_RESIZE_NW:
    case HANDLE_CUSTOM4:
    case HANDLE_CUSTOM5:
    case HANDLE_CUSTOM6:
    case HANDLE_CUSTOM7:
    case HANDLE_CUSTOM8:
    case HANDLE_CUSTOM9:
    default:
      g_warning ("Internal error in bezierconn_move_handle.\n");
      break;
  }

  return NULL;
}


/**
 * bezierconn_move:
 * @param bezier The object being moved.
 * @param to Where the object is being moved to.  This is the first point
 * of the points array.
 *
 * Move the entire object.
 *
 * Returns: %NULL
 */
DiaObjectChange *
bezierconn_move (BezierConn *bezier, Point *to)
{
  Point p;
  int i;

  p = *to;
  point_sub (&p, &bezier->bezier.points[0].p1);

  bezier->bezier.points[0].p1 = *to;
  for (i = 1; i < bezier->bezier.num_points; i++) {
    point_add (&bezier->bezier.points[i].p1, &p);
    point_add (&bezier->bezier.points[i].p2, &p);
    point_add (&bezier->bezier.points[i].p3, &p);
  }

  return NULL;
}


/**
 * bezierconn_closest_handle:
 * @bezier: A bezier object
 * @point: A point to find distances from
 *
 * Return the handle closest to a given point.
 *
 * Returns: The handle on `bezier' closest to `point'.
 */
Handle *
bezierconn_closest_handle (BezierConn *bezier,
                           Point      *point)
{
  int i, hn;
  real dist;
  Handle *closest;

  closest = bezier->object.handles[0];
  dist = distance_point_point (point, &closest->pos);
  for (i = 1, hn = 1; i < bezier->bezier.num_points; i++, hn++) {
    real new_dist;

    new_dist = distance_point_point (point, &bezier->bezier.points[i].p1);
    if (new_dist < dist) {
      dist = new_dist;
      closest = bezier->object.handles[hn];
    }
    hn++;

    new_dist = distance_point_point (point, &bezier->bezier.points[i].p2);
    if (new_dist < dist) {
      dist = new_dist;
      closest = bezier->object.handles[hn];
    }
    hn++;

    new_dist = distance_point_point (point, &bezier->bezier.points[i].p3);
    if (new_dist < dist) {
      dist = new_dist;
      closest = bezier->object.handles[hn];
    }
  }
  return closest;
}


/**
 * bezierconn_closest_major_handle:
 * @bezier: A bezier connection
 * @point: A point
 *
 * Return the major handle for the control point with the handle closest to
 * a given point.
 *
 * @bug Don't we really want the major handle that's actually closest to
 * the point?  This is used in connection with object menus and could cause
 * some unexpected selection of handles if a different segment has a control
 * point close to the major handle.
 *
 * Returns: The major (middle) handle of the bezier control that has the
 *          handle closest to point.
 *
 * Since: dawn-of-time
 */
Handle *
bezierconn_closest_major_handle (BezierConn *bezier, Point *point)
{
  Handle *closest = bezierconn_closest_handle (bezier, point);

  return bezier->object.handles[3 * get_major_nr (get_handle_nr (bezier,
                                                                 closest))];
}


/**
 * bezierconn_distance_from:
 * @bezier: A bezier object.
 * @point: A point to compare with.
 * @line_width: The line width of the bezier line.
 *
 * Return the distance from a bezier to a point.
 *
 * Returns: The shortest distance from the point to any part of the bezier.
 *
 * Since: dawn-of-time
 */
double
bezierconn_distance_from (BezierConn *bezier, Point *point, double line_width)
{
  return distance_bez_line_point (bezier->bezier.points,
                                  bezier->bezier.num_points,
                                  line_width,
                                  point);
}


/**
 * add_handles:
 * @bezier: The bezierconn having handles added.
 * @pos: Where in the list of segments to add the handle
 * @point: The bezier point to add. This should already be initialized
 *          with sensible positions.
 * @corner_type: What kind of corner this bezpoint should be.
 * @handle1: The handle that will be put on the bezier line.
 * @handle2: The handle that will be put before handle1
 * @handle3: The handle that will be put after handle1
 *
 * Add a trio of handles to a bezier.
 *
 * Since: dawn-of-time
 */
static void
add_handles (BezierConn    *bezier,
             int            pos,
             BezPoint      *point,
             BezCornerType  corner_type,
             Handle        *handle1,
             Handle        *handle2,
             Handle        *handle3)
{
  int i, next;
  DiaObject *obj = &bezier->object;

  g_return_if_fail (pos > 0);

  bezier->bezier.num_points++;
  next = pos + 1;
  bezier->bezier.points = g_renew (BezPoint,
                                   bezier->bezier.points,
                                   bezier->bezier.num_points);
  bezier->bezier.corner_types = g_renew (BezCornerType,
                                         bezier->bezier.corner_types,
                                         bezier->bezier.num_points);

  for (i = bezier->bezier.num_points - 1; i > pos; i--) {
    bezier->bezier.points[i] = bezier->bezier.points[i - 1];
    bezier->bezier.corner_types[i] = bezier->bezier.corner_types[i - 1];
  }
  bezier->bezier.points[pos] = *point;
  bezier->bezier.points[pos].p1 = bezier->bezier.points[next].p1;
  bezier->bezier.points[next].p1 = point->p1;
  bezier->bezier.corner_types[pos] = corner_type;
  object_add_handle_at (obj, handle1, 3 * pos - 2);
  object_add_handle_at (obj, handle2, 3 * pos - 1);
  object_add_handle_at (obj, handle3, 3 * pos);

  if (pos==bezier->bezier.num_points - 1) {
    obj->handles[obj->num_handles - 4]->type = HANDLE_MINOR_CONTROL;
    obj->handles[obj->num_handles - 4]->id = HANDLE_BEZMAJOR;
  }
}


/**
 * remove_handles:
 * @bezier: The bezierconn to remove handles from.
 * @pos: The position in the bezierpoint array to remove handles and
 *       bezpoint at.
 *
 * Remove a trio of handles from a bezierconn.
 *
 * Since: dawn-of-time
 */
static void
remove_handles (BezierConn *bezier, int pos)
{
  int i;
  DiaObject *obj;
  Handle *old_handle1, *old_handle2, *old_handle3;
  Point tmppoint;

  g_return_if_fail (pos > 0);

  obj = (DiaObject *) bezier;

  if (pos==obj->num_handles - 1) {
    obj->handles[obj->num_handles - 4]->type = HANDLE_MAJOR_CONTROL;
    obj->handles[obj->num_handles - 4]->id = HANDLE_MOVE_ENDPOINT;
  }

  /* delete the points */
  bezier->bezier.num_points--;
  tmppoint = bezier->bezier.points[pos].p1;
  for (i = pos; i < bezier->bezier.num_points; i++) {
    bezier->bezier.points[i] = bezier->bezier.points[i + 1];
    bezier->bezier.corner_types[i] = bezier->bezier.corner_types[i + 1];
  }
  bezier->bezier.points[pos].p1 = tmppoint;
  bezier->bezier.points = g_renew (BezPoint,
                                   bezier->bezier.points,
                                   bezier->bezier.num_points);
  bezier->bezier.corner_types = g_renew (BezCornerType,
                                         bezier->bezier.corner_types,
                                         bezier->bezier.num_points);

  old_handle1 = obj->handles[3 * pos - 2];
  old_handle2 = obj->handles[3 * pos - 1];
  old_handle3 = obj->handles[3 * pos];
  object_remove_handle (&bezier->object, old_handle1);
  object_remove_handle (&bezier->object, old_handle2);
  object_remove_handle (&bezier->object, old_handle3);
}


/**
 * bezierconn_add_segment:
 * @bezier: The bezierconn to add the segment to.
 * @segment: Which segment to split.
 * @point: Where to put the new corner, or %NULL if undetermined.
 *
 * Add a point by splitting segment into two, putting the new point at
 * 'point' or, if NULL, in the middle. This function will attempt to come
 * up with reasonable placements for the control points.
 *
 * Returns: An #DiaObjectChange object with undo information for the split.
 *
 * Since: dawn-of-time
 */
DiaObjectChange *
bezierconn_add_segment (BezierConn *bezier,
                        int         segment,
                        Point      *point)
{
  BezPoint realpoint;
  BezCornerType corner_type = BEZ_CORNER_SYMMETRIC;
  Handle *new_handle1, *new_handle2, *new_handle3;
  Point startpoint;
  Point other;

  if (segment == 0) {
    startpoint = bezier->bezier.points[0].p1;
  } else {
    startpoint = bezier->bezier.points[segment].p3;
  }
  other = bezier->bezier.points[segment + 1].p3;

  if (point == NULL) {
    realpoint.p1.x = (startpoint.x + other.x) / 6;
    realpoint.p1.y = (startpoint.y + other.y) / 6;
    realpoint.p2.x = (startpoint.x + other.x) / 3;
    realpoint.p2.y = (startpoint.y + other.y) / 3;
    realpoint.p3.x = (startpoint.x + other.x) / 2;
    realpoint.p3.y = (startpoint.y + other.y) / 2;
  } else {
    realpoint.p2.x = point->x + (startpoint.x - other.x) / 6;
    realpoint.p2.y = point->y + (startpoint.y - other.y) / 6;

    realpoint.p3 = *point;
    /* this really goes into the next segment ... */
    realpoint.p1.x = point->x - (startpoint.x - other.x) / 6;
    realpoint.p1.y = point->y - (startpoint.y - other.y) / 6;
  }
  realpoint.type = BEZ_CURVE_TO;

  new_handle1 = g_new0 (Handle, 1);
  new_handle2 = g_new0 (Handle, 1);
  new_handle3 = g_new0 (Handle, 1);
  setup_handle (new_handle1, HANDLE_RIGHTCTRL);
  setup_handle (new_handle2, HANDLE_LEFTCTRL);
  setup_handle (new_handle3, HANDLE_BEZMAJOR);
  add_handles (bezier,
               segment + 1,
               &realpoint,
               corner_type,
               new_handle1,
               new_handle2,
               new_handle3);

  return dia_bezier_conn_point_object_change_new (bezier,
                                                  TYPE_ADD_POINT,
                                                  &realpoint,
                                                  corner_type,
                                                  segment + 1,
                                                  new_handle1,
                                                  NULL,
                                                  new_handle2,
                                                  NULL,
                                                  new_handle3,
                                                  NULL);
}


/**
 * bezierconn_remove_segment:
 * @bezier The bezier to remove a segment from.
 * @pos The index of the segment to remove.
 *
 * Remove a segment from a bezier.
 *
 * Returns: Undo information for the segment removal.
 *
 * Since: dawn-of-time
 */
DiaObjectChange *
bezierconn_remove_segment (BezierConn *bezier, int pos)
{
  Handle *old_handle1, *old_handle2, *old_handle3;
  ConnectionPoint *cpt1, *cpt2, *cpt3;
  BezPoint old_point;
  BezCornerType old_ctype;
  int next;

  g_return_val_if_fail (pos > 0, NULL);
  g_return_val_if_fail (bezier->bezier.num_points > 2, NULL);

  if (pos == bezier->bezier.num_points-1) {
    pos--;
  }
  next = pos+1;

  old_handle1 = bezier->object.handles[3 * pos - 2];
  old_handle2 = bezier->object.handles[3 * pos - 1];
  old_handle3 = bezier->object.handles[3 * pos];
  old_point = bezier->bezier.points[pos];
  /* remember the old control point of following bezpoint */
  old_point.p1 = bezier->bezier.points[next].p1;
  old_ctype = bezier->bezier.corner_types[pos];

  cpt1 = old_handle1->connected_to;
  cpt2 = old_handle2->connected_to;
  cpt3 = old_handle3->connected_to;

  object_unconnect ((DiaObject *) bezier, old_handle1);
  object_unconnect ((DiaObject *) bezier, old_handle2);
  object_unconnect ((DiaObject *) bezier, old_handle3);

  remove_handles (bezier, pos);

  bezierconn_update_data (bezier);

  return dia_bezier_conn_point_object_change_new (bezier,
                                                  TYPE_REMOVE_POINT,
                                                  &old_point,
                                                  old_ctype,
                                                  pos,
                                                  old_handle1,
                                                  cpt1,
                                                  old_handle2,
                                                  cpt2,
                                                  old_handle3,
                                                  cpt3);
}


/**
 * bezierconn_straighten_corner:
 * @bezier: A bezierconn to straighten a corner of
 * @comp_nr: The index into the corner_types array of the corner to
 *           straighten.
 *
 * Limit movability of control handles
 *
 * Update a corner to have less freedom in its control handles, arranging
 * the control points at some reasonable places.
 */
static void
bezierconn_straighten_corner (BezierConn *bezier, int comp_nr)
{
  int next_nr = comp_nr+1;

  /* Neat thing would be to have the kind of straigthening depend on
     which handle was chosen:  Mid-handle does average, other leaves that
     handle where it is. */
  switch (bezier->bezier.corner_types[comp_nr]) {
    case BEZ_CORNER_SYMMETRIC: {
        Point pt1, pt2;

        pt1 = bezier->bezier.points[comp_nr].p3;
        point_sub (&pt1, &bezier->bezier.points[comp_nr].p2);
        pt2 = bezier->bezier.points[comp_nr].p3;
        point_sub (&pt2, &bezier->bezier.points[next_nr].p1);
        point_scale (&pt2, -1.0);
        point_add (&pt1, &pt2);
        point_scale (&pt1, 0.5);
        pt2 = pt1;
        point_scale (&pt1, -1.0);
        point_add (&pt1, &bezier->bezier.points[comp_nr].p3);
        point_add (&pt2, &bezier->bezier.points[comp_nr].p3);
        bezier->bezier.points[comp_nr].p2 = pt1;
        bezier->bezier.points[next_nr].p1 = pt2;
        bezierconn_update_data (bezier);
      }
      break;
    case BEZ_CORNER_SMOOTH: {
        Point pt1, pt2;
        real len1, len2;
        pt1 = bezier->bezier.points[comp_nr].p3;
        point_sub (&pt1, &bezier->bezier.points[comp_nr].p2);
        pt2 = bezier->bezier.points[comp_nr].p3;
        point_sub (&pt2, &bezier->bezier.points[next_nr].p1);
        len1 = point_len (&pt1);
        len2 = point_len (&pt2);
        point_scale (&pt2, -1.0);
        if (len1 > 0)
          point_normalize (&pt1);
        if (len2 > 0)
          point_normalize (&pt2);
        point_add (&pt1, &pt2);
        point_scale (&pt1, 0.5);
        pt2 = pt1;
        point_scale (&pt1, -len1);
        point_add (&pt1, &bezier->bezier.points[comp_nr].p3);
        point_scale (&pt2, len2);
        point_add (&pt2, &bezier->bezier.points[comp_nr].p3);
        bezier->bezier.points[comp_nr].p2 = pt1;
        bezier->bezier.points[next_nr].p1 = pt2;
        bezierconn_update_data (bezier);
      }
      break;
    case BEZ_CORNER_CUSP:
      break;
    default:
      g_return_if_reached ();
  }
}


/**
 * bezierconn_set_corner_type:
 * @bezier: The bezierconn that has the corner
 * @handle: The handle whose corner should be set.
 * @corner_type: What type of corner the handle should have.
 *
 * Change the corner type of a bezier line.
 *
 * Returns: Undo information about the corner change.
 */
DiaObjectChange *
bezierconn_set_corner_type (BezierConn    *bezier,
                            Handle        *handle,
                            BezCornerType  corner_type)
{
  Handle *mid_handle;
  Point old_left, old_right;
  int old_type;
  int handle_nr, comp_nr;

  handle_nr = get_handle_nr (bezier, handle);

  switch (handle->id) {
    case HANDLE_BEZMAJOR:
      mid_handle = handle;
      break;
    case HANDLE_LEFTCTRL:
      handle_nr++;
      mid_handle = bezier->object.handles[handle_nr];
      break;
    case HANDLE_RIGHTCTRL:
      handle_nr--;
      mid_handle = bezier->object.handles[handle_nr];
      break;
    case HANDLE_MOVE_STARTPOINT:
    case HANDLE_MOVE_ENDPOINT:
    case HANDLE_RESIZE_N:
    case HANDLE_RESIZE_NE:
    case HANDLE_RESIZE_E:
    case HANDLE_RESIZE_SE:
    case HANDLE_RESIZE_S:
    case HANDLE_RESIZE_SW:
    case HANDLE_RESIZE_W:
    case HANDLE_RESIZE_NW:
    case HANDLE_CUSTOM4:
    case HANDLE_CUSTOM5:
    case HANDLE_CUSTOM6:
    case HANDLE_CUSTOM7:
    case HANDLE_CUSTOM8:
    case HANDLE_CUSTOM9:
    default:
      g_warning ("Internal error: Setting corner type of endpoint of bezier");
      return NULL;
  }

  comp_nr = get_major_nr (handle_nr);

  old_type = bezier->bezier.corner_types[comp_nr];
  old_left = bezier->bezier.points[comp_nr].p2;
  old_right = bezier->bezier.points[comp_nr + 1].p1;

  bezier->bezier.corner_types[comp_nr] = corner_type;

  bezierconn_straighten_corner (bezier, comp_nr);

  return dia_bezier_conn_corner_object_change_new (bezier,
                                                   mid_handle,
                                                   &old_left,
                                                   &old_right,
                                                   old_type,
                                                   corner_type);
}


/**
 * bezierconn_update_data:
 * @bezier: A bezierconn to update.
 *
 * Update handle array and handle positions after changes.
 *
 * Since: dawn-of-time
 */
void
bezierconn_update_data (BezierConn *bezier)
{
  int i;
  DiaObject *obj = &bezier->object;

  /* handle the case of whole points array update (via set_prop) */
  if (3*bezier->bezier.num_points - 2 != obj->num_handles) {
    /* also maintain potential connections */
    ConnectionPoint *cps = bezier->object.handles[0]->connected_to;
    ConnectionPoint *cpe =
          bezier->object.handles[obj->num_handles - 1]->connected_to;

    g_assert(0 == obj->num_connections);

    if (cps) {
      object_unconnect (&bezier->object, bezier->object.handles[0]);
    }

    if (cpe) {
      object_unconnect (&bezier->object,
                        bezier->object.handles[obj->num_handles - 1]);
    }

    /* delete the old ones */
    for (i = 0; i < obj->num_handles; i++) {
      g_clear_pointer (&obj->handles[i], g_free);
    }
    g_clear_pointer (&obj->handles, g_free);

    obj->num_handles = 3 * bezier->bezier.num_points - 2;
    obj->handles = g_new (Handle *, obj->num_handles);

    new_handles (bezier, bezier->bezier.num_points);

    /* we may assign NULL once more here */
    if (cps) {
      object_connect (&bezier->object, bezier->object.handles[0], cps);
    }

    if (cpe) {
      object_connect (&bezier->object,
                      bezier->object.handles[obj->num_handles - 1], cpe);
    }
  }

  /* Update handles: */
  bezier->object.handles[0]->pos = bezier->bezier.points[0].p1;
  for (i = 1; i < bezier->bezier.num_points; i++) {
    bezier->object.handles[3 * i - 2]->pos = bezier->bezier.points[i].p1;
    bezier->object.handles[3 * i - 1]->pos = bezier->bezier.points[i].p2;
    bezier->object.handles[3 * i]->pos   = bezier->bezier.points[i].p3;
  }
}


/**
 * bezierconn_update_boundingbox:
 * @bezier: A bezier line to update bounding box for.
 *
 * Update the boundingbox of the connection.
 *
 * Since: dawn-of-time
 */
void
bezierconn_update_boundingbox (BezierConn *bezier)
{
  g_return_if_fail (bezier != NULL);

  polybezier_bbox (&bezier->bezier.points[0],
                   bezier->bezier.num_points,
                   &bezier->extra_spacing, FALSE,
                   &bezier->object.bounding_box);
}


/**
 * new_handles:
 * @bezier: A bezierconn object initialized with room for 3*num_points-2
 * handles.
 * @num_points: The number of points of the bezierconn.
 *
 * Create all handles used by a bezier conn.
 *
 * Since: dawn-of-time
 */
void
new_handles (BezierConn *bezier, int num_points)
{
  DiaObject *obj;
  int i;

  obj = &bezier->object;

  obj->handles[0] = g_new0 (Handle, 1);
  obj->handles[0]->connect_type = HANDLE_CONNECTABLE;
  obj->handles[0]->connected_to = NULL;
  obj->handles[0]->type = HANDLE_MAJOR_CONTROL;
  obj->handles[0]->id = HANDLE_MOVE_STARTPOINT;

  for (i = 1; i < num_points; i++) {
    obj->handles[3 * i - 2] = g_new0 (Handle, 1);
    obj->handles[3 * i - 1] = g_new0 (Handle, 1);
    obj->handles[3 * i] = g_new0 (Handle, 1);

    setup_handle (obj->handles[3 * i - 2], HANDLE_RIGHTCTRL);
    setup_handle (obj->handles[3 * i - 1], HANDLE_LEFTCTRL);

    obj->handles[3 * i]->connect_type = HANDLE_CONNECTABLE;
    obj->handles[3 * i]->connected_to = NULL;
    obj->handles[3 * i]->type = HANDLE_MAJOR_CONTROL;
    obj->handles[3 * i]->id = HANDLE_MOVE_ENDPOINT;
  }
}


/**
 * bezierconn_init:
 * @bezier: A newly allocated bezierconn object.
 * @num_points: The initial number of points on the curve.
 *
 * Initialize a bezier object with the given amount of points.
 * The points array of the bezier object might not be previously
 * initialized with appropriate positions.
 * This will set up handles and make all corners symmetric.
 *
 * Since: dawn-of-time
 */
void
bezierconn_init (BezierConn *bezier, int num_points)
{
  DiaObject *obj;
  int i;

  obj = &bezier->object;

  object_init (obj, 3 * num_points - 2, 0);

  bezier->bezier.num_points = num_points;

  bezier->bezier.points = g_new (BezPoint, num_points);
  bezier->bezier.corner_types = g_new (BezCornerType, num_points);
  bezier->bezier.points[0].type = BEZ_MOVE_TO;
  bezier->bezier.corner_types[0] = BEZ_CORNER_SYMMETRIC;
  for (i = 1; i < num_points; i++) {
    bezier->bezier.points[i].type = BEZ_CURVE_TO;
    bezier->bezier.corner_types[i] = BEZ_CORNER_SYMMETRIC;
  }

  new_handles (bezier, num_points);

  /* The points might not be assigned at this point,
   * so don't try to use them */
  /* bezierconn_update_data(bezier); */
}


/**
 * bezierconn_copy:
 * @from: The object to copy from.
 * @to: The object to copy to.
 *
 * Copy a bezierconn objects. This function in turn invokes object_copy().
 *
 * Since: dawn-of-time
 */
void
bezierconn_copy (BezierConn *from, BezierConn *to)
{
  int i;
  DiaObject *toobj, *fromobj;

  toobj = &to->object;
  fromobj = &from->object;

  object_copy (fromobj, toobj);

  beziercommon_copy (&from->bezier, &to->bezier);

  to->object.handles[0] = g_new0 (Handle, 1);
  *to->object.handles[0] = *from->object.handles[0];
  for (i = 1; i < to->object.num_handles - 1; i++) {
    to->object.handles[i] = g_new0 (Handle, 1);
    setup_handle (to->object.handles[i], from->object.handles[i]->id);
  }
  to->object.handles[to->object.num_handles - 1] = g_new0 (Handle, 1);
  *to->object.handles[to->object.num_handles - 1] =
    *from->object.handles[to->object.num_handles - 1];

  memcpy (&to->extra_spacing, &from->extra_spacing, sizeof (to->extra_spacing));
  bezierconn_update_data (to);
}


/**
 * bezierconn_destroy:
 * @bezier: An object to destroy.
 *
 * Destroy a bezierconn object.
 *
 * This function in turn calls object_destroy() and frees structures
 * allocated by this bezierconn, but not the object itself
 *
 * Since: dawn-of-time
 */
void
bezierconn_destroy (BezierConn *bezier)
{
  int i, nh;
  Handle **temp_handles;

  /* Need to store these temporary since object.handles is
     freed by object_destroy() */
  nh = bezier->object.num_handles;
  temp_handles = g_new (Handle *, nh);
  for (i = 0; i < nh; i++) {
    temp_handles[i] = bezier->object.handles[i];
  }

  object_destroy (&bezier->object);

  for (i = 0; i < nh; i++) {
    g_clear_pointer (&temp_handles[i], g_free);
  }
  g_clear_pointer (&temp_handles, g_free);

  g_clear_pointer (&bezier->bezier.points, g_free);
  g_clear_pointer (&bezier->bezier.corner_types, g_free);
}


/**
 * bezierconn_save:
 * @bezier: The object to save.
 * @obj_node: The XML node to save it into
 * @ctx: The context to transport error information.
 *
 * Save the data defined by a bezierconn object to XML.
 *
 * Since: dawn-of-time
 */
void
bezierconn_save (BezierConn *bezier,
                 ObjectNode  obj_node,
                 DiaContext *ctx)
{
  int i;
  AttributeNode attr;

  object_save (&bezier->object, obj_node, ctx);

  attr = new_attribute (obj_node, "bez_points");

  data_add_point (attr, &bezier->bezier.points[0].p1, ctx);
  for (i = 1; i < bezier->bezier.num_points; i++) {
    if (BEZ_MOVE_TO == bezier->bezier.points[i].type) {
      g_warning ("only first BezPoint can be a BEZ_MOVE_TO");
    }
    data_add_point (attr, &bezier->bezier.points[i].p1, ctx);
    data_add_point (attr, &bezier->bezier.points[i].p2, ctx);
    data_add_point (attr, &bezier->bezier.points[i].p3, ctx);
  }

  attr = new_attribute (obj_node, "corner_types");
  for (i = 0; i < bezier->bezier.num_points; i++) {
    data_add_enum (attr, bezier->bezier.corner_types[i], ctx);
  }
}


/**
 * bezierconn_load:
 * @bezier: A newly allocated bezierconn object to load into.
 * @obj_node: The XML node to load from.
 * @ctx: The context in which this function is called
 *
 * Load a bezierconn object from XML.
 *
 * Does object_init() on the bezierconn object.
 *
 * Since: dawn-of-time
 */
void
bezierconn_load (BezierConn *bezier,
                 ObjectNode  obj_node,
                 DiaContext *ctx)
{
  int i;
  AttributeNode attr;
  DataNode data;

  DiaObject *obj = &bezier->object;

  object_load (obj, obj_node, ctx);

  attr = object_find_attribute (obj_node, "bez_points");

  if (attr != NULL) {
    bezier->bezier.num_points = (attribute_num_data (attr) + 2) / 3;
  } else {
    bezier->bezier.num_points = 0;
  }

  object_init (obj, 3 * bezier->bezier.num_points - 2, 0);

  data = attribute_first_data (attr);
  if (bezier->bezier.num_points != 0) {
    bezier->bezier.points = g_new (BezPoint, bezier->bezier.num_points);
    bezier->bezier.points[0].type = BEZ_MOVE_TO;
    data_point (data, &bezier->bezier.points[0].p1, ctx);
    data = data_next (data);

    for (i = 1; i < bezier->bezier.num_points; i++) {
      bezier->bezier.points[i].type = BEZ_CURVE_TO;
      data_point (data, &bezier->bezier.points[i].p1, ctx);
      data = data_next (data);
      data_point (data, &bezier->bezier.points[i].p2, ctx);
      data = data_next (data);
      data_point (data, &bezier->bezier.points[i].p3, ctx);
      data = data_next (data);
    }
  }

  bezier->bezier.corner_types = g_new (BezCornerType, bezier->bezier.num_points);
  attr = object_find_attribute (obj_node, "corner_types");
  /* if corner_types is missing or corrupt */
  if (!attr || attribute_num_data (attr) != bezier->bezier.num_points) {
    for (i = 0; i < bezier->bezier.num_points; i++) {
      bezier->bezier.corner_types[i] = BEZ_CORNER_SYMMETRIC;
    }
  } else {
    data = attribute_first_data (attr);
    for (i = 0; i < bezier->bezier.num_points; i++) {
      bezier->bezier.corner_types[i] = data_enum (data, ctx);
      data = data_next (data);
    }
  }

  obj->handles[0] = g_new0 (Handle,1);
  obj->handles[0]->connect_type = HANDLE_CONNECTABLE;
  obj->handles[0]->connected_to = NULL;
  obj->handles[0]->type = HANDLE_MAJOR_CONTROL;
  obj->handles[0]->id = HANDLE_MOVE_STARTPOINT;

  for (i = 1; i < bezier->bezier.num_points; i++) {
    obj->handles[3 * i - 2] = g_new0 (Handle, 1);
    setup_handle (obj->handles[3 * i - 2], HANDLE_RIGHTCTRL);
    obj->handles[3 * i - 1] = g_new0 (Handle, 1);
    setup_handle (obj->handles[3 * i - 1], HANDLE_LEFTCTRL);
    obj->handles[3 * i]     = g_new0 (Handle, 1);
    setup_handle (obj->handles[3 * i],   HANDLE_BEZMAJOR);
  }

  obj->handles[obj->num_handles - 1]->connect_type = HANDLE_CONNECTABLE;
  obj->handles[obj->num_handles - 1]->connected_to = NULL;
  obj->handles[obj->num_handles - 1]->type = HANDLE_MAJOR_CONTROL;
  obj->handles[obj->num_handles - 1]->id = HANDLE_MOVE_ENDPOINT;

  bezierconn_update_data (bezier);
}


struct _DiaBezierConnPointObjectChange {
  DiaObjectChange obj_change;

  enum change_type type;
  int applied;

  BezPoint point;
  BezCornerType corner_type;
  int pos;

  /* owning ref when not applied for ADD_POINT
   * owning ref when applied for REMOVE_POINT */
  Handle *handle1, *handle2, *handle3;
  /* NULL if not connected */
  ConnectionPoint *connected_to1, *connected_to2, *connected_to3;
};


DIA_DEFINE_OBJECT_CHANGE (DiaBezierConnPointObjectChange,
                          dia_bezier_conn_point_object_change)


/**
 * dia_bezier_point_object_change_free:
 * @change: The undo information to free.
 *
 * Free undo information about adding or removing points.
 *
 * Since: 0.98
 */
static void
dia_bezier_conn_point_object_change_free (DiaObjectChange *self)
{
  DiaBezierConnPointObjectChange *change = DIA_BEZIER_CONN_POINT_OBJECT_CHANGE (self);

  if ((change->type == TYPE_ADD_POINT && !change->applied) ||
      (change->type == TYPE_REMOVE_POINT && change->applied) ){
    g_clear_pointer (&change->handle1, g_free);
    g_clear_pointer (&change->handle2, g_free);
    g_clear_pointer (&change->handle3, g_free);
  }
}


/**
 * dia_bezier_point_object_change_apply:
 * @change: The change to apply.
 * @obj: The object (must be a BezierConn) to apply the change to.
 *
 * Apply a point addition/removal.
 *
 * Since: 0.98
 */
static void
dia_bezier_conn_point_object_change_apply (DiaObjectChange *self, DiaObject *obj)
{
  DiaBezierConnPointObjectChange *change = DIA_BEZIER_CONN_POINT_OBJECT_CHANGE (self);

  change->applied = 1;
  switch (change->type) {
    case TYPE_ADD_POINT:
      add_handles ((BezierConn *) obj, change->pos, &change->point,
                   change->corner_type,
                   change->handle1, change->handle2, change->handle3);
      break;
    case TYPE_REMOVE_POINT:
      object_unconnect (obj, change->handle1);
      object_unconnect (obj, change->handle2);
      object_unconnect (obj, change->handle3);
      remove_handles ((BezierConn *) obj, change->pos);
      break;
    default:
      g_return_if_reached ();
  }
}


/**
 * dia_bezier_conn_point_object_change_revert:
 * @change: The change to revert.
 * @obj: The object (must be a BezierConn) to revert the change of.
 *
 * Revert (unapply) a point addition/removal.
 *
 * Since: 0.98
 */
static void
dia_bezier_conn_point_object_change_revert (DiaObjectChange *self, DiaObject *obj)
{
  DiaBezierConnPointObjectChange *change = DIA_BEZIER_CONN_POINT_OBJECT_CHANGE (self);

  switch (change->type) {
    case TYPE_ADD_POINT:
      remove_handles ((BezierConn *) obj, change->pos);
      break;
    case TYPE_REMOVE_POINT:
      add_handles ((BezierConn *) obj, change->pos, &change->point,
                   change->corner_type,
                   change->handle1, change->handle2, change->handle3);

      if (change->connected_to1) {
        object_connect (obj, change->handle1, change->connected_to1);
      }

      if (change->connected_to2) {
        object_connect (obj, change->handle2, change->connected_to2);
      }

      if (change->connected_to3) {
        object_connect (obj, change->handle3, change->connected_to3);
      }

      break;
    default:
      g_return_if_reached ();
  }
  change->applied = 0;
}


/**
 * dia_bezier_conn_point_object_change_new:
 * @bezier: The object that the change applies to (ignored)
 * @type: The type of change (either TYPE_ADD_POINT or TYPE_REMOVE_POINT)
 * @point: The point being added or removed.
 * @corner_type: Which type of corner is at the point.
 * @pos: The position of the point.
 * @handle1: The first (central) handle.
 * @connected_to1: What the first handle is connected to.
 * @handle2: The second (left-hand) handle.
 * @connected_to2: What the second handle is connected to.
 * @handle3: The third (right-hand) handle.
 * @connected_to3: What the third handle is connected to.
 *
 * Create undo information about a point being added or removed.
 *
 * Returns: Newly created undo information.
 *
 * Since: 0.98
 */
static DiaObjectChange *
dia_bezier_conn_point_object_change_new (BezierConn       *bezier,
                                         enum change_type  type,
                                         BezPoint         *point,
                                         BezCornerType     corner_type,
                                         int               pos,
                                         Handle           *handle1,
                                         ConnectionPoint  *connected_to1,
                                         Handle           *handle2,
                                         ConnectionPoint  *connected_to2,
                                         Handle           *handle3,
                                    ConnectionPoint  *connected_to3)
{
  DiaBezierConnPointObjectChange *change;

  change = dia_object_change_new (DIA_TYPE_BEZIER_CONN_POINT_OBJECT_CHANGE);

  change->type = type;
  change->applied = 1;
  change->point = *point;
  change->corner_type = corner_type;
  change->pos = pos;
  change->handle1 = handle1;
  change->connected_to1 = connected_to1;
  change->handle2 = handle2;
  change->connected_to2 = connected_to2;
  change->handle3 = handle3;
  change->connected_to3 = connected_to3;

  return DIA_OBJECT_CHANGE (change);
}


struct _DiaBezierConnCornerObjectChange {
  DiaObjectChange obj_change;
  /* Only one kind of corner_change */
  int applied;

  Handle *handle;
  /* Old places when SET_CORNER_TYPE is applied */
  Point point_left, point_right;
  BezCornerType old_type, new_type;
};


DIA_DEFINE_OBJECT_CHANGE (DiaBezierConnCornerObjectChange,
                          dia_bezier_conn_corner_object_change)


static void
dia_bezier_conn_corner_object_change_free (DiaObjectChange *self)
{
}


/**
 * dia_bezier_corner_object_change_apply:
 * @change: The undo information to apply.
 * @obj: The object to apply the undo information too.
 *
 * Apply a change of corner type. This may change the position of the
 * control handles by calling bezierconn_straighten_corner.
 *
 * Since: 0.98
 */
static void
dia_bezier_conn_corner_object_change_apply (DiaObjectChange *self, DiaObject *obj)
{
  DiaBezierConnCornerObjectChange *change = DIA_BEZIER_CONN_CORNER_OBJECT_CHANGE (self);
  BezierConn *bezier = (BezierConn *) obj;
  int handle_nr = get_handle_nr (bezier, change->handle);
  int comp_nr = get_major_nr (handle_nr);

  bezierconn_straighten_corner (bezier, comp_nr);

  bezier->bezier.corner_types[comp_nr] = change->new_type;

  change->applied = 1;
}


/**
 * dia_bezier_conn_corner_object_change_revert:
 * @self: Undo information to apply.
 * @obj: The bezierconn object to apply the change to.
 *
 * Revert (unapply) a change of corner type. This may move the position
 * of the control handles to what they were before applying.
 *
 * Since: 0.98
 */
static void
dia_bezier_conn_corner_object_change_revert (DiaObjectChange *self, DiaObject *obj)
{
  DiaBezierConnCornerObjectChange *change = DIA_BEZIER_CONN_CORNER_OBJECT_CHANGE (self);
  BezierConn *bezier = (BezierConn *) obj;
  int handle_nr = get_handle_nr (bezier, change->handle);
  int comp_nr = get_major_nr (handle_nr);

  bezier->bezier.points[comp_nr].p2 = change->point_left;
  bezier->bezier.points[comp_nr + 1].p1 = change->point_right;
  bezier->bezier.corner_types[comp_nr] = change->old_type;

  change->applied = 0;
}


/**
 * dia_bezier_conn_corner_object_change_new:
 * @bezier: The bezier object this applies to.
 * @handle: The handle of the corner being changed.
 * @point_left: The position of the left control handle.
 * @point_right: The position of the right control handle.
 * @old_corner_type: The corner type before applying.
 * @new_corner_type: The corner type being changed to.
 *
 * Create new undo information about a changing the type of a corner.
 * Note that the created #DiaObjectChange object has nothing in it that needs
 * freeing.
 *
 * Returns: Newly allocated undo information.
 *
 * Since: 0.98
 */
static DiaObjectChange *
dia_bezier_conn_corner_object_change_new (BezierConn    *bezier,
                                          Handle        *handle,
                                          Point         *point_left,
                                          Point         *point_right,
                                          BezCornerType  old_corner_type,
                                          BezCornerType  new_corner_type)
{
  DiaBezierConnCornerObjectChange *change;

  change = dia_object_change_new (DIA_TYPE_BEZIER_CONN_CORNER_OBJECT_CHANGE);

  change->old_type = old_corner_type;
  change->new_type = new_corner_type;
  change->applied = 1;

  change->handle = handle;
  change->point_left = *point_left;
  change->point_right = *point_right;

  return DIA_OBJECT_CHANGE (change);
}
