path: root/generic/Group.c

/*
 * Group.c -- Implementation of Group item.
 *
 * Authors		: Patrick Lecoanet.
 * Creation date	: Wed Jun 23 10:09:20 1999
 *
 * $Id$
 */

/*
 *  Copyright (c) 1999 - 1999 CENA, Patrick Lecoanet --
 *
 * This code is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This code 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this code; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */


#include "Types.h"
#include "WidgetInfo.h"
#include "Item.h"
#include "Geo.h"
#include "tkZinc.h"

#include <malloc.h>
#include <X11/extensions/shape.h>

static const char rcsid[] = "$Id$";
static const char compile_id[]="$Compile: " __FILE__ " " __DATE__ " " __TIME__ " $";


/*
 **********************************************************************************
 *
 * Specific Group item record
 *
 **********************************************************************************
 */
static ZnAttrConfig	group_attrs[] = {
  { ZN_CONFIG_BOOL, "-atomic", NULL,
    Tk_Offset(GroupItemStruct, header.flags), ATOMIC_BIT,
    ZN_REPICK_FLAG, False },
  { ZN_CONFIG_ITEM, "-clip", NULL,
    Tk_Offset(GroupItemStruct, clip), 0,
    ZN_COORDS_FLAG|ZN_ITEM_FLAG, False },
  { ZN_CONFIG_BOOL, "-composerotation", NULL,
    Tk_Offset(GroupItemStruct, header.flags), COMPOSE_ROTATION_BIT,
    ZN_TRANSFO_FLAG, False },
  { ZN_CONFIG_BOOL, "-composescale", NULL,
    Tk_Offset(GroupItemStruct, header.flags), COMPOSE_SCALE_BIT,
    ZN_TRANSFO_FLAG, False },
  { ZN_CONFIG_PRI, "-priority", NULL,
    Tk_Offset(GroupItemStruct, header.priority), 0,
    ZN_DRAW_FLAG|ZN_REPICK_FLAG, False },
  { ZN_CONFIG_BOOL, "-sensitive", NULL,
    Tk_Offset(GroupItemStruct, header.flags), SENSITIVE_BIT,
    ZN_REPICK_FLAG, False },
  { ZN_CONFIG_TAGS, "-tags", NULL,
    Tk_Offset(GroupItemStruct, header.tags), 0, 0, False },
  { ZN_CONFIG_BOOL, "-visible", NULL,
    Tk_Offset(GroupItemStruct, header.flags), VISIBLE_BIT,
    ZN_DRAW_FLAG|ZN_REPICK_FLAG|ZN_VIS_FLAG, False },
  
  { ZN_CONFIG_END, NULL, NULL, 0, 0, 0 }
};


/*
 **********************************************************************************
 *
 * Init --
 *
 **********************************************************************************
 */
static int
Init(Item		item,
     int		*argc,
     Tcl_Obj *CONST	*args[])
{
  GroupItem	group = (GroupItem) item;
  
  group->head = ZN_NO_ITEM;
  group->tail = ZN_NO_ITEM;
  group->clip = ZN_NO_ITEM;
  group->dependents = NULL;
  SET(item->flags, VISIBLE_BIT);
  SET(item->flags, SENSITIVE_BIT);
  SET(item->flags, COMPOSE_ROTATION_BIT);
  SET(item->flags, COMPOSE_SCALE_BIT);
  CLEAR(item->flags, ATOMIC_BIT);
  item->priority = DEFAULT_GROUP_PRIORITY;
#ifdef OM
  group->call_om = False;
#endif
  
  return ZN_OK;
}


/*
 **********************************************************************************
 *
 * Clone --
 *
 **********************************************************************************
 */
static void
Clone(Item	item)
{
  GroupItem	group = (GroupItem) item;  
  ZnList	dependents;
  Item		connected, current_item, new_item;
  Item		*items;
  Tcl_HashTable	mapping;
  Tcl_HashEntry	*entry;
  int		new, num_items, i;

  current_item = group->head;
  group->head = group->tail = ZN_NO_ITEM;
#ifdef OM
  group->call_om = False;
#endif
  dependents = group->dependents;
  if (dependents) {
    Tcl_InitHashTable(&mapping, TCL_ONE_WORD_KEYS);
  }

  /*
   * First clone all the children, and build a mapping
   * table if there is some attachments to relink.
   */
  while (current_item != ZN_NO_ITEM) {
    connected = current_item->connected_item;
    new_item = ITEM.CloneItem(current_item);
    new_item->connected_item = connected;
    ITEM.InsertItem(new_item, item, ZN_NO_ITEM, True);
    
    if (dependents) {
      entry = Tcl_CreateHashEntry(&mapping, (char *) current_item, &new);
      Tcl_SetHashValue(entry, (ClientData) new_item);
    }
    if (current_item == group->clip) {
      group->clip = new_item;
    }
    current_item = current_item->next;
  }
  
  /*
   * Then rebuild the dependency list with
   * the new items.
   */
  if (dependents) {
    /*printf("rebuilding dependents\n");*/
    group->dependents = NULL;
    items = (Item *) ZnListArray(dependents);
    num_items = ZnListSize(dependents);
    for (i = 0; i < num_items; i++, items++) {
      entry = Tcl_FindHashEntry(&mapping, (char *) *items);
      if (entry == NULL) {
	ZnWarning("Can't find item correspondance in Group Clone");
	abort();
      }
      else {
	current_item = (Item) Tcl_GetHashValue(entry);
      }
      entry = Tcl_FindHashEntry(&mapping, (char *) current_item->connected_item);
      if (entry == NULL) {
	ZnWarning("Can't found item correspondance in Group Clone");
	abort();
      }
      else {
	/*printf("item %d correspond to ", current_item->connected_item->id);*/
	current_item->connected_item = (Item) Tcl_GetHashValue(entry);
	/*printf("%d\n", current_item->connected_item->id);*/
	ITEM.InsertDependentItem(current_item);
      }
    }
    Tcl_DeleteHashTable(&mapping);
  }
}


/*
 **********************************************************************************
 *
 * Destroy --
 *
 **********************************************************************************
 */
static void
Destroy(Item	item)
{
  GroupItem	group = (GroupItem) item;
  Item		current_item, next_item;

  current_item = group->head;
  while (current_item != ZN_NO_ITEM) {
    next_item = current_item->next;
    ITEM.DestroyItem(current_item);
    current_item = next_item;
  }
  if (group->dependents) {
    ZnListFree(group->dependents);
  }
}


/*
 **********************************************************************************
 *
 * SetXShape --
 *
 **********************************************************************************
 */
static void
SetXShape(Item	grp)
{
#ifdef SHAPE
  WidgetInfo	*wi = grp->wi;
  Item		clip = ((GroupItem) grp)->clip;
  int		i, j, num_pts, max_num_pts;
  ZnPos		min_x, min_y, max_x, max_y;
  ZnPoly	poly;
  ZnPoint	*p;
  ZnBool	simple;
  ZnDim		width, height;
  XPoint	*xpts, *xp;
  Region	reg;
  
  if (!wi->has_x_shape) {
    return;
  }

  if ((clip == ZN_NO_ITEM) || !wi->reshape) {
    /*
     * Reset both clip just to be sure (the application can have
     * changed wi->full_reshape while resetting wi->reshape).
     */
    XShapeCombineMask(wi->dpy, ZnWindowId(wi->win), ShapeBounding,
		      0, 0, None, ShapeSet);
    XShapeCombineMask(wi->dpy, wi->real_top, ShapeBounding,
		      0, 0, None, ShapeSet);
  }
  else {
    /*
     * Get the clip shape.
     */
    simple = clip->class->GetClipVertices(clip, &poly);
    if (simple || (poly.num_contours == 0)) {
      /*
       * Nothing to do: after normalisation the rectangular shape will
       * fit exactly the window. We may test here if a shape is currently
       * active and reset the mask only in this case (need a flag in wi).
       */
      XShapeCombineMask(wi->dpy, ZnWindowId(wi->win), ShapeBounding,
			0, 0, None, ShapeSet);
      XShapeCombineMask(wi->dpy, wi->real_top, ShapeBounding,
			0, 0, None, ShapeSet);
    }
    else {
      /*
       * First make the vertices start at zero.
       */
      max_x = min_x = poly.contours[0].points[0].x;
      max_y = min_y = poly.contours[0].points[0].y;
      max_num_pts = poly.contours[0].num_points;
      for (j = 0; j < poly.num_contours; j++) {
	p = poly.contours[j].points;
	num_pts = poly.contours[j].num_points;
	if (num_pts > max_num_pts) {
	  max_num_pts = num_pts;
	}
	for (i = 0; i < num_pts; p++, i++) {
	  if (p->x < min_x) {
	    min_x = p->x;
	  }
	  if (p->y < min_y) {
	    min_y = p->y;
	  }
	  if (p->x > max_x) {
	    max_x = p->x;
	  }
	  if (p->y > max_y) {
	    max_y = p->y;
	  }
	}
      }
      for (j = 0; j < poly.num_contours; j++) {
	p = poly.contours[j].points;
	num_pts = poly.contours[j].num_points;
	for (i = 0; i < num_pts; i++, p++) {
	  p->x -= min_x;
	  p->y -= min_y;
	}
      }
      max_x -= min_x;
      max_y -= min_y;
      
      /*
       * Now normalize the shape and map it to the window size.
       */
      width = wi->width + 2*wi->inset;
      height = wi->height + 2*wi->inset;
      xpts = (XPoint *) ZnMalloc(max_num_pts * sizeof(XPoint));
      XShapeCombineMask(wi->dpy, wi->full_reshape?ZnWindowId(wi->win):wi->real_top,
			ShapeBounding, 0, 0, None, ShapeSet);
      XShapeCombineRegion(wi->dpy,  wi->full_reshape?wi->real_top:ZnWindowId(wi->win),
			  ShapeBounding, 0, 0, None, ShapeSet);
      for (j = 0; j < poly.num_contours; j++) {
	p = poly.contours[j].points;
	num_pts = poly.contours[j].num_points;
	for (xp = xpts, i = 0; i < num_pts; i++, p++, xp++) {
	  xp->x = (short) (p->x * width / max_x);
	  xp->y = (short) (p->y * height / max_y);
	}
	/*
	 * Translate it in a region and apply this region to the window.
	 */
	reg = XPolygonRegion(xpts, num_pts, EvenOddRule);
	XShapeCombineRegion(wi->dpy,  wi->full_reshape?wi->real_top:ZnWindowId(wi->win),
			    ShapeBounding, 0, 0, reg,
			    poly.holes[j]?ShapeSubtract:ShapeUnion);
	XDestroyRegion(reg);
      }
      ZnFree(xpts);
    }
  }
#endif
}


/*
 **********************************************************************************
 *
 * Configure --
 *
 **********************************************************************************
 */
static int
Configure(Item		item,
	  int		argc,
	  Tcl_Obj *CONST argv[],
	  int		*flags)
{
  GroupItem	group = (GroupItem) item;
  WidgetInfo	*wi = item->wi;
  
  if (ITEM_P.ConfigureAttributes((char *) item, -1, argc, argv, flags) == ZN_ERROR) {
    return ZN_ERROR;
  }

  /*
   * If the clip item changed, check if it is a legal
   * item type that is inside this group.
   */
  if (ISSET(*flags, ZN_ITEM_FLAG)) {
    if (group->clip &&
	(!group->clip->class->GetClipVertices || (group->clip->parent != item))) {
      group->clip = ZN_NO_ITEM;
      Tcl_AppendResult(wi->interp,
		       " clip item must be a child of the group", NULL);
      return ZN_ERROR;
    }
    if (!group->clip && (item == wi->top_group)) {
      SetXShape(item);
    }
  }
  
  return ZN_OK;
}


/*
 **********************************************************************************
 *
 * Query --
 *
 **********************************************************************************
 */
static int
Query(Item		item,
      int		argc,
      Tcl_Obj *CONST	argv[])
{
  if (ITEM_P.QueryAttribute((char *) item, -1, argv[0]) == ZN_ERROR) {
    return ZN_ERROR;
  }

  return ZN_OK;
}


/*
 **********************************************************************************
 *
 * PushClip --
 *	Save the current clip shape and current clipbox if needed.
 *	Intersect the previous shape and the local to obtain the
 *	new current shape. Use this shape to compute the current
 *	clipbox and if set_gc is True compute the current region.
 *
 **********************************************************************************
 */
static void
PushClip(GroupItem	group,
	 ZnBool		set_gc)
{
  WidgetInfo	*wi = ((Item) group)->wi;
  ZnPoly	poly;
  ZnBool	simple;

  if ((group->clip != ZN_NO_ITEM) &&
      ((((Item) group) != wi->top_group) || !wi->reshape)) {
    simple = group->clip->class->GetClipVertices(group->clip, &poly);
    /*printf("Group: PushClip group %d\n", ((Item) group)->id);*/
    ITEM_P.PushClip(wi, &poly, simple, set_gc);
  }
}


/*
 **********************************************************************************
 *
 * PopClip --
 *	Re-install the previous clip shape if any (stack can be empty).
 *
 **********************************************************************************
 */
static void
PopClip(GroupItem	group,
	ZnBool		set_gc)
{
  WidgetInfo	*wi = ((Item) group)->wi;

  if ((group->clip != ZN_NO_ITEM) &&
      ((((Item) group) != wi->top_group) || !wi->reshape)) {
    /*printf("Group: PopClip group %d\n", ((Item) group)->id);*/
    ITEM_P.PopClip(wi, set_gc);
  }
}


/*
 **********************************************************************************
 *
 * PushTransform --
 *	Save the current transform then concatenate the item transform to
 *	form the new current transform.
 *
 **********************************************************************************
 */
static void
PushTransform(Item	item)
{
  if (!item->transfo &&
      ISSET(item->flags, COMPOSE_SCALE_BIT) &&
      ISSET(item->flags, COMPOSE_ROTATION_BIT)) {
    return;
  }

  ITEM_P.PushTransform(item->wi, item->transfo,
		       ISSET(item->flags, COMPOSE_SCALE_BIT),
		       ISSET(item->flags, COMPOSE_ROTATION_BIT));
  /*printf("Pushing transfo for item: %d\n;", item->id);
    ZnPrintTransfo(wi->current_transfo);*/
}


/*
 **********************************************************************************
 *
 * PopTransform --
 *	Restore the previously saved transform from the stack.
 *
 **********************************************************************************
 */
static void
PopTransform(Item	item)
{
  if (!item->transfo &&
      ISSET(item->flags, COMPOSE_SCALE_BIT) &&
      ISSET(item->flags, COMPOSE_ROTATION_BIT)) {
    return;
  }

  ITEM_P.PopTransform(item->wi);
  /*printf("Popping transfo for item: %d\n", item->id);
  ZnPrintTransfo(wi->current_transfo);*/
}


/*
 **********************************************************************************
 *
 * ComputeCoordinates --
 *	Compute the geometrical elements of a group. First of all save the current
 *	transform and combine it with the item transform. Then call the item
 *	ComputeCoordinates method.
 *	For regular child items (not groups) some of the code of the item
 *	itself is factored out in CallRegularCC.
 *
 **********************************************************************************
 */
static void
CallRegularCC(Item	item)
{
  WidgetInfo	*wi = item->wi;
  ZnBBox	*clip_box;
  
  /*
   * Do some generic pre-work in behalf of the (regular) children.
   */
  if (ISSET(item->flags, VISIBLE_BIT)) {
    ITEM_P.Damage(wi, &item->item_bounding_box);
  }
  PushTransform(item);
  
  /*printf("calling cc on regular item %d\n", item->id);*/
  /*ZnPrintTransfo(wi->current_transfo);*/
  item->class->ComputeCoordinates(item, False);
  /*
   * If a current clipbox exists adjust the item
   * bounding box accordingly. When computing coordinates
   * the damaged area is not pushed onto the clipstack,
   * the following predicate is thus valid for testing
   * a clipbox. 
   */
  if (ITEM_P.CurrentClip(wi, NULL, &clip_box, NULL)) {
    ZnBBox inter;
    
    IntersectBBox(&item->item_bounding_box, clip_box, &inter);
    item->item_bounding_box = inter;
  }
  /*
   * Do some generic post-work in behalf of the (regular) children.
   */
  if (ISSET(item->inv_flags, ZN_REPICK_FLAG)) {
    SET(wi->events_flags, INTERNAL_NEED_REPICK);
  }
  if (ISSET(item->inv_flags, ZN_COORDS_FLAG) &&
      (ISSET(item->flags, SENSITIVE_BIT) ||
       ISSET(item->flags, VISIBLE_BIT))) {
    SET(wi->events_flags, INTERNAL_NEED_REPICK);
  }
  /*
   * Damage if the item is visible or if it is
   * a group clipper.
   */
  if (ISSET(item->flags, VISIBLE_BIT) ||
      (item == ((GroupItem) item->parent)->clip)) {
    ITEM_P.Damage(wi, &item->item_bounding_box);
  }
  PopTransform(item);
  item->inv_flags = 0;
  /*printf("Done cc on regular item %d\n", item->id);*/
}

static void
ComputeCoordinates(Item		item,
		   ZnBool	force)
{
  GroupItem	group = (GroupItem) item;
  Item		current_item;
  Item		*deps;
  int		num_deps, i;

  PushTransform(item);
  /*  printf("Group.c\n");
    ZnPrintTransfo(item->wi->current_transfo);    
    printf("\n");*/

  force |= ISSET(item->inv_flags, ZN_TRANSFO_FLAG);
  
  /*
   * Clip shape is computed in the group's local
   * coordinates.
   */
  if (group->clip != ZN_NO_ITEM) {
    /*
     * Update the geometry of the clip item if needed.
     * Its bounding box will be clipped by the current
     * clipbox (i.e the clipbox of the group's parent).
     */
    if (force ||
	ISSET(group->clip->inv_flags, ZN_COORDS_FLAG) ||
	ISSET(group->clip->inv_flags, ZN_TRANSFO_FLAG)) {
      /*printf("calling cc on clip item %d for group %d\n",
	group->clip->id, item->id);*/
      CallRegularCC(group->clip);
      if (item == item->wi->top_group) {
	SetXShape(item);
      }
      /*
       * If the clip item has changed we need to compute
       * new clipped bounding boxes for all the children.
       */
      force = True;
    }
  }
  
  PushClip(group, False);
  
  for (current_item = group->head; current_item != ZN_NO_ITEM;
       current_item = current_item->next) {
    /*
     * Skip the clip item, it has been already updated.
     * Skip as well items with a dependency, they will
     * be updated later.
     */
    if ((current_item == group->clip) ||
	(current_item->connected_item != ZN_NO_ITEM)) {
      continue;
    }
    if (force ||
	ISSET(current_item->inv_flags, ZN_COORDS_FLAG) ||
	ISSET(current_item->inv_flags, ZN_TRANSFO_FLAG)) {
      if (current_item->class != ZnGroup) {
	/*printf("calling cc on item %d\n", current_item->id);*/
	CallRegularCC(current_item);
      }
      else {
	/*printf("calling cc on group %d\n", current_item->id);*/
	current_item->class->ComputeCoordinates(current_item, force);
      }
    }
  }
  /*
   * Update coordinates and bounding boxes following
   * a possible change in connected items. Only regular
   * items can be concerned.
   */
  if (group->dependents) {
    num_deps = ZnListSize(group->dependents);
    deps = (Item *) ZnListArray(group->dependents);
    for (i = 0; i < num_deps; i++) {
      current_item = deps[i];
      if (force ||
	  ISSET(current_item->inv_flags, ZN_COORDS_FLAG) ||
	  ISSET(current_item->inv_flags, ZN_TRANSFO_FLAG) ||
	  ISSET(current_item->connected_item->flags, UPDATE_DEPENDENT_BIT)) {	
        /*printf("Updating dependent: %d\n", current_item->id);*/	
	CallRegularCC(current_item);
      }
    }
    /*
     * Now, we must reset the update_dependent flag
     */
    for (i = 0; i < num_deps; i++) {
      CLEAR(deps[i]->connected_item->flags, UPDATE_DEPENDENT_BIT);
    }
    /*printf("... done\n");*/
  }
  /*
   * Compute the bounding box.
   */
  ResetBBox(&item->item_bounding_box);
  current_item = group->head;
  while (current_item != ZN_NO_ITEM) {
    AddBBoxToBBox(&item->item_bounding_box, &current_item->item_bounding_box);
    current_item = current_item->next;    
  }
  item->inv_flags = 0;

  PopClip(group, False);
  PopTransform(item);
}


/*
 **********************************************************************************
 *
 * ToArea --
 *	Tell if the object is entirely outside (-1),
 *	entirely inside (1) or in between (0).
 *
 **********************************************************************************
 */
static int
ToArea(Item	item,
       ZnBBox	*area,
       Tk_Uid	tag_uid,
       int	enclosed,
       ZnBool	report)
{
  GroupItem	group = (GroupItem) item;
  Item		current_item;
  ZnBBox	enclosing, inter;
  int		result;
  ZnBool	outside = True;
  ZnBool	atomic = ISSET(item->flags, ATOMIC_BIT);
  
  PushTransform(item);

  enclosing.orig.x = area->orig.x - 1;
  enclosing.orig.y = area->orig.y - 1;
  enclosing.corner.x = area->corner.x + 1;
  enclosing.corner.y = area->corner.y + 1;
  
  current_item = group->head;
  while (current_item != ZN_NO_ITEM) {
    if (ISCLEAR(current_item->flags, VISIBLE_BIT) &&
	ISCLEAR(current_item->flags, SENSITIVE_BIT)) {
      goto cont_ta;
    }
    IntersectBBox(&enclosing, &current_item->item_bounding_box, &inter);
    if (IsEmptyBBox(&inter)) {
      goto cont_ta;
    }
    if (current_item->class != ZnGroup) {
      PushTransform(current_item);
    }

    /*
     * If this group is ATOMIC, ask the child groups to report
     * instead of adding their children to the result.
     */
    result = current_item->class->ToArea(current_item, area, tag_uid,
					 enclosed, atomic);
    outside &= (result == -1);
    /*
     * If this group is ATOMIC, it must report itself as matching
     * if a/ the request is 'enclosed' and all the children are
     * enclosed or b/ the request is 'overlapping' and at least one
     * child overlaps (or is enclosed). If not ATOMIC, the group
     * never match the area.
     * So here we can do early tests to shortcut the search when
     * the most stringent conditions are met.
     */
    if (atomic) {
      if (!enclosed && (result >= 0)) {
	result = 0;
	goto out;
      } else if (enclosed && (result == 0)) {
	goto out;
      }
    }
    if (!atomic && (result >= enclosed)) {
      DoItem(item->wi->interp, current_item, ZN_NO_PART, tag_uid);
    }
    
    if (current_item->class != ZnGroup) {
      PopTransform(current_item);
    }
  cont_ta:
    current_item = current_item->next;
  }

  if (!atomic) {
    result = -1;
  }
  else if (outside) {
    result = -1;
  }
  else {
    result = 1;
  }
  
 out:  
  PopTransform(item);
  return result;
}


/*
 **********************************************************************************
 *
 * Draw --
 *
 **********************************************************************************
 */
static void
Draw(Item 	item)
{
  GroupItem	group = (GroupItem) item;
  WidgetInfo	*wi = item->wi;
  Item		current_item;
  ZnBBox	bbox, old_damaged_area, *clip_box;
  
  PushTransform(item);
  PushClip(group, True);
  if (group->clip != ZN_NO_ITEM) {
    ITEM_P.CurrentClip(wi, NULL, &clip_box, NULL);
    old_damaged_area = wi->damaged_area;
    IntersectBBox(&wi->damaged_area, clip_box, &bbox);
    wi->damaged_area = bbox;
  }
  
  current_item = group->tail;
  while (current_item != ZN_NO_ITEM) {
    if (ISSET(current_item->flags, VISIBLE_BIT)) {
      IntersectBBox(&wi->damaged_area, &current_item->item_bounding_box, &bbox);
      if (!IsEmptyBBox(&bbox)) {
	if (current_item->class != ZnGroup) {
	  PushTransform(current_item);
	}
	current_item->class->Draw(current_item);
	if (wi->draw_bboxes) {
	  XGCValues  	values;
	  values.foreground = ZnPixel(wi->bbox_color);
	  values.fill_style = FillSolid;
	  values.line_width = 1;
	  values.line_style = (current_item->class==ZnGroup)?LineOnOffDash:LineSolid;
	  XChangeGC(wi->dpy, wi->gc, GCForeground|GCLineStyle|GCLineWidth|GCFillStyle,
		    &values);
	  XDrawRectangle(wi->dpy, wi->draw_buffer, wi->gc,
			 current_item->item_bounding_box.orig.x,
			 current_item->item_bounding_box.orig.y,
			 current_item->item_bounding_box.corner.x -
			 current_item->item_bounding_box.orig.x,
			 current_item->item_bounding_box.corner.y -
			 current_item->item_bounding_box.orig.y);
	}
	if (current_item->class != ZnGroup) {
	  PopTransform(current_item);
	}
      }
    }
    current_item = current_item->previous;
  }

  if (group->clip != ZN_NO_ITEM) {
    wi->damaged_area = old_damaged_area;
  }
  PopClip(group, True);
  PopTransform(item);
}


/*
 **********************************************************************************
 *
 * IsSensitive --
 *
 **********************************************************************************
 */
static ZnBool
IsSensitive(Item	item,
	    int		item_part)
{
  ZnBool	sensitive = ISSET(item->flags, SENSITIVE_BIT);
  Item		parent = item->parent;
  
  while (sensitive && (parent != ZN_NO_ITEM)) {
    sensitive &= ISSET(item->flags, SENSITIVE_BIT);
    parent = parent->parent;
  }
  return sensitive;
}


/*
 **********************************************************************************
 *
 * Pick --
 *	Given a point an an aperture, find the topmost group item/part
 *	that is (a) within the pick_aperture
 *		(b) the top most
 *		(c) has either its sensibility or its visibility set.
 *
 * Results:
 *	The return value is the distance of the picked item/part if one
 *	has been found or a really big distance if not. a_item and a_part
 *	are set to point the picked item/part or to ZN_NO_ITEM/ZN_NO_PART.
 *	If the group is ATOMIC, a_item points the group instead of the
 *	actual item.
 *
 * Side effects:
 *	None.
 *
 **********************************************************************************
 */
static double
Pick(Item	item,
     ZnPoint	*p,
     Item	start_item,
     int	aperture,
     Item	*a_item,
     int	*a_part)
{
  GroupItem	group = (GroupItem) item;
  Item		p_item, current_item;
  WidgetInfo	*wi = item->wi;
  int		p_part;
  double	dist, best = 1e10;
  ZnBBox	bbox, inter, *clip_box;
  ZnBool	in_depth;
  
  *a_item= ZN_NO_ITEM;
  *a_part = ZN_NO_PART;

  if (group->head == ZN_NO_ITEM) {
    return best;
  }
  
  PushTransform(item);
  PushClip(group, False);
  
  bbox.orig.x = p->x - aperture;
  bbox.orig.y = p->y - aperture;
  bbox.corner.x = p->x + (aperture?aperture:1);
  bbox.corner.y = p->y + (aperture?aperture:1);

  if (ITEM_P.CurrentClip(wi, NULL, &clip_box, NULL)) {
    IntersectBBox(&bbox, clip_box, &inter);
    if (IsEmptyBBox(&inter)) {
      goto out;
    }
  }
  
  if ((start_item == ZN_NO_ITEM) || (start_item->parent == item)) {
    in_depth = False;
  }
  else {
    in_depth = True;
  }
  if ((start_item == ZN_NO_ITEM) || (start_item->parent != item)) {
    current_item = group->head;
  }
  else {
    current_item = start_item;
  }
  
  do {
    if (ISCLEAR(current_item->flags, SENSITIVE_BIT) &&
	ISCLEAR(current_item->flags, VISIBLE_BIT)) {
      goto cont;
    }
    IntersectBBox(&bbox, &current_item->item_bounding_box, &inter);
    if (IsEmptyBBox(&inter)) {
      goto cont;
    }
    if (current_item->class != ZnGroup) {
      if (in_depth) {
	goto cont;
      }
      PushTransform(current_item);
      p_item = current_item;
      p_part = ZN_NO_PART;
      dist = current_item->class->Pick(current_item, p, NULL, aperture,
				       &p_item, &p_part);
      PopTransform(current_item);
    }
    else {
      dist = current_item->class->Pick(current_item, p,
				       in_depth ? start_item : NULL,
				       aperture, &p_item, &p_part);
    }
    if ((dist > aperture) || (dist >= best)) {
      goto cont;
    }
    if (ISSET(item->flags, ATOMIC_BIT)) {
      *a_item = item;
    }
    else {
      *a_item = p_item;
      *a_part = p_part;
    }
    best = dist;
    /*printf("found %d:%d, at %g\n", (*a_item)->id, *a_part, dist);*/
    if (dist <= 0.0) {
      break;
    }
  cont:
    current_item = current_item->next;
  } while  (current_item != ZN_NO_ITEM);

 out:
  PopClip(group, False);
  PopTransform(item);
  
  return best;
}


/*
 **********************************************************************************
 *
 * Coords --
 *	Return or edit the group translation (can be also interpreted as the
 *	position of the group origin in the group's parent).
 *
 **********************************************************************************
 */
static int
Coords(Item	item,
       int	contour,
       int	index,
       int	cmd,
       ZnPoint	**pts,
       int	*num_pts)
{
  if ((cmd == COORDS_ADD) || (cmd == COORDS_ADD_LAST) || (cmd == COORDS_REMOVE)) {
    Tcl_AppendResult(item->wi->interp,
		     " groups can't add or remove vertices", NULL);
    return ZN_ERROR;
  }
  else if ((cmd == COORDS_REPLACE) || (cmd == COORDS_REPLACE_ALL)) {
    if (*num_pts == 0) {
      Tcl_AppendResult(item->wi->interp,
		       " coords command need 1 point on groups", NULL);
      return ZN_ERROR;
    }
    if (!item->transfo) {
      item->transfo = ZnTransfoNew();
    }
    ZnSetTranslation(item->transfo, (*pts)[0].x, (*pts)[0].y);
    ITEM.Invalidate(item, ZN_TRANSFO_FLAG);
  }
  else if ((cmd == COORDS_READ) || (cmd == COORDS_READ_ALL)) {
    ZnPoint	*p;
    
    ZnListAssertSize(item->wi->work_pts, 1);
    p = (ZnPoint *) ZnListArray(item->wi->work_pts);
    ZnTransfoDecompose(item->transfo, NULL, p, NULL, NULL);
    *num_pts = 1;
    *pts = p;
  }
  return ZN_OK;
}


/*
 **********************************************************************************
 *
 * PostScript --
 *
 **********************************************************************************
 */
static void
PostScript(Item			item,
	   PostScriptInfo	ps_info)
{
}


/*
 **********************************************************************************
 *
 * Exported functions struct --
 *
 **********************************************************************************
 */
static ItemClassStruct GROUP_ITEM_CLASS = {
  sizeof(GroupItemStruct),
  False,		/* has_fields */
  False,		/* has_parts */
  False,		/* has_anchors */
  "group",
  group_attrs,
  Init,
  Clone,
  Destroy,
  Configure,
  Query,
  NULL,			/* GetFieldSet */
  NULL,			/* GetAnchor */
  NULL,			/* GetClipVertices */
  Coords,
  NULL,			/* InsertChars */
  NULL,			/* DeleteChars */
  NULL,			/* Cursor */
  NULL,			/* Index */
  NULL,			/* Selection */
  NULL,			/* Contour */
  ComputeCoordinates,
  ToArea,
  Draw,
  IsSensitive,
  Pick,
  NULL,			/* PickVertex */
  PostScript
};

ZnItemClassId ZnGroup = (ZnItemClassId) &GROUP_ITEM_CLASS;