fltk/FL/Fl_Tree.H

//
// "$Id$"
//

#ifndef FL_TREE_H
#define FL_TREE_H

#include <FL/Fl.H>
#include <FL/Fl_Group.H>
#include <FL/Fl_Scrollbar.H>
#include <FL/fl_draw.H>

#include <FL/Fl_Tree_Item.H>
#include <FL/Fl_Tree_Prefs.H>

//////////////////////
// FL/Fl_Tree.H
//////////////////////
//
// Fl_Tree -- This file is part of the Fl_Tree widget for FLTK
// Copyright (C) 2009-2010 by Greg Ercolano.
//
// This library 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 library 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 library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//

///
/// \file
/// \brief This file contains the definitions of the Fl_Tree class
///

/// \class Fl_Tree
///
/// \brief Tree widget.
///
/// \code
///     Fl_Tree                                         // Top level widget
///        |--- Fl_Tree_Item                            // Items in the tree
///        |--- Fl_Tree_Prefs                           // Preferences for the tree
///                  |--- Fl_Tree_Connector (enum)      // Connection modes
///                  |--- Fl_Tree_Select (enum)         // Selection modes
///                  |--- Fl_Tree_Sort (enum)           // Sort behavior
/// \endcode
///
///     An expandable tree widget.
///
///     Similar to Fl_Browser, Fl_Tree is browser of Fl_Tree_Item's, which can be
///     in a parented hierarchy. Subtrees can be expanded or closed. Items can be
///     added, deleted, inserted, sorted and re-ordered.
///
///     The tree items may also contain other FLTK widgets, like buttons, input fields,
///     or even "custom" widgets.
///
///     The callback() is invoked depending on the value of when():
///
///         - FL_WHEN_RELEASE -- callback invoked when left mouse button is released on an item
///         - FL_WHEN_CHANGED -- callback invoked when left mouse changes selection state
///
///     The simple way to define a tree:
/// \code
///    #include <FL/Fl_Tree.H>
///    [..]
///    Fl_Tree tree(X,Y,W,H);
///    tree.begin();
///      tree.add("Flintstones/Fred");
///      tree.add("Flintstones/Wilma");
///      tree.add("Flintstones/Pebbles");
///      tree.add("Simpsons/Homer");
///      tree.add("Simpsons/Marge");
///      tree.add("Simpsons/Bart");
///      tree.add("Simpsons/Lisa");
///    tree.end();
/// \endcode
///     
///     Items can be added with add(),
///     removed with remove(),
///     completely cleared with clear(),
///     inserted with insert() and insert_above(),
///     selected/deselected with select() and deselect(),
///     open/closed with open() and closed().
///     Children of an item can be swapped around with Fl_Tree_Item::swap_children(),
///     sorting can be controlled when items are add()ed via sortorder().
///     You can walk the entire tree with first() and next().
///     You can walk selected items with first_selected_item() and
///     next_selected_item().
///     Items can be found by their pathname using find_item(const char*),
///     and an item's pathname can be found with item_pathname().
///
///     The tree can have different selection behaviors controlled by selectmode().
///
///     FLTK widgets (including custom widgets) can be assigned to tree items via
///     Fl_Tree_Item::widget().
///
///     Icons for individual items can be changed with
///     Fl_Tree_Item::openicon(), 
///     Fl_Tree_Item::closeicon(),
///     Fl_Tree_Item::usericon().
///
///     Various default preferences can be globally manipulated via Fl_Tree_Prefs, 
///     including colors, margins, icons, connection lines. 
///
///     The tree's callback() will be invoked when items change state or are open/closed.
///     when() controls when mouse/keyboard events invoke the callback.
///     callback_item() and callback_reason() can be used to determine the cause of the callback.
///
///     \image html tree-elements.png
///     \image latex tree-elements.png "Fl_Tree dimensions" width=6cm
///

/// \enum Fl_Tree_Reason
/// The reason the callback was invoked.
///
enum Fl_Tree_Reason {
  FL_TREE_REASON_NONE=0,	///< unknown reason
  FL_TREE_REASON_SELECTED,	///< an item was selected
  FL_TREE_REASON_DESELECTED,	///< an item was de-selected
  FL_TREE_REASON_OPENED,	///< an item was opened
  FL_TREE_REASON_CLOSED		///< an item was closed
};


class FL_EXPORT Fl_Tree : public Fl_Group {
  Fl_Tree_Item  *_root;				// can be null!
  Fl_Tree_Item  *_item_focus;			// item that has focus box
  Fl_Tree_Item  *_callback_item;		// item invoked during callback (can be NULL)
  Fl_Tree_Reason _callback_reason;		// reason for the callback
  Fl_Tree_Prefs  _prefs;			// all the tree's settings
  int            _scrollbar_size;		// size of scrollbar trough

protected:
  /// Vertical scrollbar
  Fl_Scrollbar *_vscroll;
  
protected:
  void item_clicked(Fl_Tree_Item* val);
  /// Do the callback for the item, setting the item and reason
  void do_callback_for_item(Fl_Tree_Item* item, Fl_Tree_Reason reason) {
    callback_reason(reason);
    callback_item(item);
    do_callback((Fl_Widget*)this, user_data());
  }
  Fl_Tree_Item *next_visible_item(Fl_Tree_Item *start, int dir);

public:
  Fl_Tree(int X, int Y, int W, int H, const char *L=0);
  ~Fl_Tree();
  int handle(int e);
  void draw();
  
  ///////////////////////
  // root methods
  ///////////////////////
  
  /// Set the label for the root item. 
  ///
  /// Makes an internally managed copy of 'new_label'.
  ///
  void root_label(const char *new_label) {
    if ( ! _root ) return;
    _root->label(new_label);
  }
  /// Returns the root item.
  Fl_Tree_Item* root() {
    return(_root);
  }
  
  ////////////////////////////////
  // Item creation/removal methods
  ////////////////////////////////
  Fl_Tree_Item *add(const char *path);
  Fl_Tree_Item* add(Fl_Tree_Item *item, const char *name);
  Fl_Tree_Item *insert_above(Fl_Tree_Item *above, const char *name);
  Fl_Tree_Item* insert(Fl_Tree_Item *item, const char *name, int pos);
  
  /// Remove the specified \p item from the tree.
  /// If it has children, all those are removed too.
  /// \returns 0 if done, -1 if 'item' not found.
  ///
  int remove(Fl_Tree_Item *item) {
    if ( !item ) return(0);
    if ( item == _root ) {
      clear();
    } else {
      Fl_Tree_Item *parent = item->parent();		// find item's parent
      if ( ! parent ) return(-1);
      parent->remove_child(item);			// remove child + children
    }
    return(0);
  } 
  /// Clear all children from the tree.
  /// The tree will be left completely empty.
  ///
  void clear() {
    if ( ! _root ) return;
    _root->clear_children();
    delete _root; _root = 0;
  } 
  /// Clear all the children of a particular node in the tree specified by \p item.
  void clear_children(Fl_Tree_Item *item) {
    if ( item->has_children() ) {
      item->clear_children();
      redraw();				// redraw only if there were children to clear
    }
  } 
  
  ////////////////////////
  // Item lookup methods
  ////////////////////////
  Fl_Tree_Item *find_item(const char *path);
  const Fl_Tree_Item *find_item(const char *path) const;
  int item_pathname(char *pathname, int pathnamelen, const Fl_Tree_Item *item) const;

  const Fl_Tree_Item *find_clicked() const;
  
  /// Return the item that was last clicked.
  ///
  /// Valid only from within the callback().
  ///
  /// Deprecated: use callback_item() instead.
  ///
  /// \returns the item clicked, or 0 if none.
  ///          0 may also be used to indicate several items were clicked/changed.
  ///
  Fl_Tree_Item *item_clicked() {
    return(_callback_item);
  }
  Fl_Tree_Item *first();
  Fl_Tree_Item *next(Fl_Tree_Item *item=0);
  Fl_Tree_Item *prev(Fl_Tree_Item *item=0);
  Fl_Tree_Item *last();
  Fl_Tree_Item *first_selected_item();
  Fl_Tree_Item *next_selected_item(Fl_Tree_Item *item=0);

  //////////////////////////
  // Item open/close methods
  //////////////////////////
  
  /// Open the specified 'item'.
  /// This causes the item's children (if any) to be shown.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] item -- the item to be opened
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - callback() is not invoked
  ///     -   1 - callback() is invoked if item changed,
  ///             callback_reason() will be FL_TREE_REASON_OPENED
  ///
  /// \returns
  ///     -   1 -- item was opened
  ///     -   0 -- item was already open, no change
  ///
  /// \see open(), close(), is_open(), is_close(), callback_item(), callback_reason()
  ///
  int open(Fl_Tree_Item *item, int docallback=1) {
    if ( item->is_open() ) return(0);
    item->open();
    redraw();
    if ( docallback ) {
      do_callback_for_item(item, FL_TREE_REASON_OPENED);
    }
    return(1);
  }
  /// Opens the item specified by \p path (eg: "Parent/child/item").
  /// This causes the item's children (if any) to be shown.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - callback() is not invoked
  ///     -   1 - callback() is invoked if item changed,
  ///             callback_reason() will be FL_TREE_REASON_OPENED
  ///
  /// \returns
  ///     -   1 -- OK: item opened
  ///     -   0 -- OK: item was already open, no change
  ///     -  -1 -- ERROR: item was not found
  ///
  /// \see open(), close(), is_open(), is_close(), callback_item(), callback_reason()
  ///         
  int open(const char *path, int docallback=1) {
    Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(open(item, docallback));
  }
  /// Toggle the open state of \p item.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] item -- the item to be opened
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - callback() is not invoked
  ///     -   1 - callback() is invoked, callback_reason() will be either
  ///             FL_TREE_REASON_OPENED or FL_TREE_REASON_CLOSED
  ///
  /// \see open(), close(), is_open(), is_close(), callback_item(), callback_reason()
  ///
  void open_toggle(Fl_Tree_Item *item, int docallback=1) {
    if ( item->is_open() ) {
      close(item, docallback);
    } else {
      open(item, docallback);
    }
  }
  /// Closes the specified \p item.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] item -- the item to be closed
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - callback() is not invoked
  ///     -   1 - callback() is invoked if item changed,
  ///             callback_reason() will be FL_TREE_REASON_CLOSED
  ///
  /// \returns
  ///     -   1 -- item was closed
  ///     -   0 -- item was already closed, no change
  ///
  /// \see open(), close(), is_open(), is_close(), callback_item(), callback_reason()
  ///
  int close(Fl_Tree_Item *item, int docallback=1) {
    if ( item->is_close() ) return(0);
    item->close();
    redraw();
    if ( docallback ) {
      do_callback_for_item(item, FL_TREE_REASON_CLOSED);
    }
    return(1);
  }
  /// Closes the item specified by \p path, eg: "Parent/child/item".
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - callback() is not invoked
  ///     -   1 - callback() is invoked if item changed,
  ///             callback_reason() will be FL_TREE_REASON_CLOSED
  ///
  /// \returns
  ///     -   1 -- OK: item closed
  ///     -   0 -- OK: item was already closed, no change
  ///     -  -1 -- ERROR: item was not found
  ///
  /// \see open(), close(), is_open(), is_close(), callback_item(), callback_reason()
  ///         
  int close(const char *path, int docallback=1) {
    Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(close(item, docallback));
  }
  /// See if \p item is open.
  ///
  /// Items that are 'open' are themselves not necessarily visible;
  /// one of the item's parents might be closed.
  ///
  /// \param[in] item -- the item to be tested
  ///
  /// \returns
  ///     -  1 : item is open
  ///     -  0 : item is closed
  ///
  int is_open(Fl_Tree_Item *item) const {
    return(item->is_open()?1:0);
  }
  /// See if item specified by \p path (eg: "Parent/child/item") is open.
  ///
  /// Items that are 'open' are themselves not necessarily visible;
  /// one of the item's parents might be closed.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  ///
  /// \returns
  ///     -    1 - OK: item is open
  ///     -    0 - OK: item is closed
  ///     -   -1 - ERROR: item was not found
  ///
  int is_open(const char *path) const {
    const Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(item->is_open()?1:0);
  }
  /// See if the specified \p item is closed.
  ///
  /// \param[in] item -- the item to be tested
  ///
  /// \returns
  ///     -   1 : item is open
  ///     -   0 : item is closed
  ///
  int is_close(Fl_Tree_Item *item) const {
    return(item->is_close());
  }
  /// See if item specified by \p path (eg: "Parent/child/item") is closed.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  ///
  /// \returns
  ///     -   1 - OK: item is closed
  ///     -   0 - OK: item is open
  ///     -  -1 - ERROR: item was not found
  ///
  int is_close(const char *path) const {
    const Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(item->is_close()?1:0);
  }
  
  /// Select the specified \p item. Use 'deselect()' to de-select it.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] item -- the item to be selected
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - the callback() is not invoked
  ///     -   1 - the callback() is invoked if item changed state,
  ///             callback_reason() will be FL_TREE_REASON_SELECTED
  ///
  /// \returns
  ///     -   1 - item's state was changed
  ///     -   0 - item was already selected, no change was made
  ///
  int select(Fl_Tree_Item *item, int docallback=1) {
    if ( ! item->is_selected() ) {
      item->select();
      set_changed();
      if ( docallback ) {
        do_callback_for_item(item, FL_TREE_REASON_SELECTED);
      }
      redraw();
      return(1);
    }
    return(0);
  }
  /// Select the item specified by \p path (eg: "Parent/child/item").
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - the callback() is not invoked
  ///     -   1 - the callback() is invoked if item changed state,
  ///             callback_reason() will be FL_TREE_REASON_SELECTED
  ///
  /// \returns
  ///     -   1 : OK: item's state was changed
  ///     -   0 : OK: item was already selected, no change was made
  ///     -  -1 : ERROR: item was not found
  ///
  int select(const char *path, int docallback=1) {
    Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(select(item, docallback));
  }
  /// Toggle the select state of the specified \p item.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] item -- the item to be selected
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - the callback() is not invoked
  ///     -   1 - the callback() is invoked, callback_reason() will be
  ///             either FL_TREE_REASON_SELECTED or FL_TREE_REASON_DESELECTED
  ///
  void select_toggle(Fl_Tree_Item *item, int docallback=1) {
    item->select_toggle();
    set_changed();
    if ( docallback ) {
      do_callback_for_item(item, item->is_selected() ? FL_TREE_REASON_SELECTED
                                                     : FL_TREE_REASON_DESELECTED);
    }
    redraw();
  }
  /// De-select the specified \p item.
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] item -- the item to be selected
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - the callback() is not invoked
  ///     -   1 - the callback() is invoked if item changed state,
  ///             callback_reason() will be FL_TREE_REASON_DESELECTED
  ///
  /// \returns
  ///     - 0 - item was already deselected, no change was made
  ///     - 1 - item's state was changed
  ///
  int deselect(Fl_Tree_Item *item, int docallback=1) {
    if ( item->is_selected() ) {
      item->deselect();
      set_changed();
      if ( docallback ) {
        do_callback_for_item(item, FL_TREE_REASON_DESELECTED);
      }
      redraw();
      return(1);
    }
    return(0);
  }
  /// Deselect an item specified by \p path (eg: "Parent/child/item").
  /// Handles redrawing if anything was actually changed.
  /// Invokes the callback depending on the value of optional parameter \p docallback.
  ///
  /// The callback can use callback_item() and callback_reason() respectively to determine 
  /// the item changed and the reason the callback was called.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  /// \param[in] docallback -- A flag that determines if the callback() is invoked or not:
  ///     -   0 - the callback() is not invoked
  ///     -   1 - the callback() is invoked if item changed state,
  ///             callback_reason() will be FL_TREE_REASON_DESELECTED
  ///
  ///  \returns
  ///     -   1 - OK: item's state was changed
  ///     -   0 - OK: item was already deselected, no change was made
  ///     -  -1 - ERROR: item was not found
  ///
  int deselect(const char *path, int docallback=1) {
    Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(deselect(item, docallback));
  }
  
  int deselect_all(Fl_Tree_Item *item=0, int docallback=1);
  int select_only(Fl_Tree_Item *selitem, int docallback=1);
  int select_all(Fl_Tree_Item *item=0, int docallback=1);
  void set_item_focus(Fl_Tree_Item *o);
  
  /// See if the specified \p item is selected.
  ///
  /// \param[in] item -- the item to be tested
  ///
  /// \return
  ///     -   1 : item selected
  ///     -   0 : item deselected
  ///
  int is_selected(Fl_Tree_Item *item) const {
    return(item->is_selected()?1:0);
  }
  /// See if item specified by \p path (eg: "Parent/child/item") is selected.
  ///
  /// \param[in] path -- the tree item's pathname (eg. "Flintstones/Fred")
  ///
  /// \returns
  ///     -   1 : item selected
  ///     -   0 : item deselected
  ///     -  -1 : item was not found
  ///
  int is_selected(const char *path) {
    Fl_Tree_Item *item = find_item(path);
    if ( ! item ) return(-1);
    return(is_selected(item));
  }
  /// Print the tree as 'ascii art' to stdout.
  /// Used mainly for debugging.
  ///
  void show_self() {
    if ( ! _root ) return;
    _root->show_self();
  }
  
  /////////////////////////////////
  // Item attribute related methods
  /////////////////////////////////
  
  /// Get the default label fontsize used for creating new items.
  int labelsize() const {
    return(_prefs.labelsize());
  }
  /// Set the default label font size used for creating new items.
  /// To change the font size on a per-item basis, use Fl_Tree_Item::labelsize(int)
  ///
  void labelsize(int val) {
    _prefs.labelsize(val);
  }
  
  /// Get the default font face used for item's labels when new items are created.
  ///
  /// Don't use this if you want to change an existing label() size; use
  /// item->labelfont() instead.
  ///
  int labelfont() const {
    return(_prefs.labelfont());
  }
  /// Set the default font face used for item's labels when new items are created.
  ///
  /// Don't use this if you want to change an existing label() size; use
  /// item->labelfont(int) instead.
  ///
  void labelfont(int val) {
    _prefs.labelfont(val);
  }
  /// Get the amount of white space (in pixels) that should appear
  /// between the widget's left border and the tree's contents.
  ///
  int  marginleft() const {
    return(_prefs.marginleft());
  }
  /// Set the amount of white space (in pixels) that should appear
  /// between the widget's left border and the left side of the tree's contents.
  ///
  void marginleft(int val) {
    _prefs.marginleft(val);
    redraw();
  }
  /// Get the amount of white space (in pixels) that should appear
  /// between the widget's top border and the top of the tree's contents.
  ///
  int  margintop() const {
    return(_prefs.margintop());
  }
  /// Sets the amount of white space (in pixels) that should appear
  /// between the widget's top border and the top of the tree's contents.
  ///
  void margintop(int val) {
    _prefs.margintop(val);
    redraw();
  }
  /// Get the amount of white space (in pixels) that should appear
  /// below an open child tree's contents.
  ///
  int  openchild_marginbottom() const {
    return(_prefs.openchild_marginbottom());
  }
  /// Set the amount of white space (in pixels) that should appear
  /// below an open child tree's contents.
  ///
  void openchild_marginbottom(int val) {
    _prefs.openchild_marginbottom(val);
    redraw();
  }
  /// Gets the width of the horizontal connection lines (in pixels) 
  /// that appear to the left of each tree item's label.
  ///
  int  connectorwidth() const {
    return(_prefs.connectorwidth());
  }
  /// Sets the width of the horizontal connection lines (in pixels) 
  /// that appear to the left of each tree item's label.
  ///
  void connectorwidth(int val) {
    _prefs.connectorwidth(val);
    redraw();
  }
  /// Returns the Fl_Image being used as the default user icon for newly created items.
  /// Returns zero if no icon has been set, which is the default.
  ///
  Fl_Image *usericon() const {
    return(_prefs.usericon());
  }
  /// Sets the Fl_Image to be used as the default user icon for all
  /// newly created items.
  ///
  /// If you want to specify user icons on a per-item basis,
  /// use Fl_Tree_Item::usericon() instead.
  ///
  /// \param[in] val -- The new image to be used, or
  ///                   zero to disable user icons.
  ///
  void usericon(Fl_Image *val) {
    _prefs.usericon(val);
    redraw();
  }
  /// Returns the icon to be used as the 'open' icon.
  /// If none was set, the internal default is returned,
  /// a simple '[+]' icon.
  ///
  Fl_Image *openicon() const {
    return(_prefs.openicon());
  }
  /// Sets the icon to be used as the 'open' icon.
  /// This overrides the built in default '[+]' icon.
  ///
  /// \param[in] val -- The new image, or zero to use the default [+] icon.
  ///
  void openicon(Fl_Image *val) {
    _prefs.openicon(val);
    redraw();
  }
  /// Returns the icon to be used as the 'close' icon.
  /// If none was set, the internal default is returned,
  /// a simple '[-]' icon.
  ///
  Fl_Image *closeicon() const {
    return(_prefs.closeicon());
  }
  /// Sets the icon to be used as the 'close' icon.
  /// This overrides the built in default '[-]' icon.
  ///
  /// \param[in] val -- The new image, or zero to use the default [-] icon.
  ///
  void closeicon(Fl_Image *val) {
    _prefs.closeicon(val);
    redraw();
  }
  /// Returns 1 if the collapse icon is enabled, 0 if not.
  int showcollapse() const {
    return(_prefs.showcollapse());
  }
  /// Set if we should show the collapse icon or not.
  /// If collapse icons are disabled, the user will not be able
  /// to interactively collapse items in the tree, unless the application
  /// provides some other means via open() and close().
  ///
  /// \param[in] val 1: shows collapse icons (default),\n
  ///                0: hides collapse icons.
  ///
  void showcollapse(int val) {
    _prefs.showcollapse(val);
    redraw();
  }
  /// Returns 1 if the root item is to be shown, or 0 if not.
  int showroot() const {
    return(_prefs.showroot());
  }
  /// Set if the root item should be shown or not.
  /// \param[in] val 1 -- show the root item (default)\n
  ///                0 -- hide the root item.
  ///
  void showroot(int val) {
    _prefs.showroot(val);
    redraw();
  }
  /// Returns the line drawing style for inter-connecting items.
  Fl_Tree_Connector connectorstyle() const {
    return(_prefs.connectorstyle());
  }
  /// Sets the line drawing style for inter-connecting items.
  void connectorstyle(Fl_Tree_Connector val) {
    _prefs.connectorstyle(val);
    redraw();
  }
  /// Set the default sort order used when items are added to the tree.
  ///     See Fl_Tree_Sort for possible values.
  ///
  Fl_Tree_Sort sortorder() const {
    return(_prefs.sortorder());
  }
  /// Gets the sort order used to add items to the tree.
  void sortorder(Fl_Tree_Sort val) {
    _prefs.sortorder(val);
    // no redraw().. only affects new add()itions
  }
  /// Sets the style of box used to draw selected items.
  /// This is an fltk Fl_Boxtype.
  /// The default is influenced by FLTK's current Fl::scheme()
  ///
  Fl_Boxtype selectbox() const {
    return(_prefs.selectbox());
  }
  /// Gets the style of box used to draw selected items.
  /// This is an fltk Fl_Boxtype.
  /// The default is influenced by FLTK's current Fl::scheme()
  ///
  void selectbox(Fl_Boxtype val) {
    _prefs.selectbox(val);
    redraw();
  }
  /// Gets the tree's current selection mode.
  Fl_Tree_Select selectmode() const {
    return(_prefs.selectmode());
  }
  /// Sets the tree's selection mode.
  void selectmode(Fl_Tree_Select val) {
    _prefs.selectmode(val);
  }
  int displayed(Fl_Tree_Item *item);
  void show_item(Fl_Tree_Item *item, int yoff);
  void show_item(Fl_Tree_Item *item);
  void show_item_bottom(Fl_Tree_Item *item);
  void show_item_middle(Fl_Tree_Item *item);
  void show_item_top(Fl_Tree_Item *item);
  void display(Fl_Tree_Item *item);
  int  vposition() const;
  void vposition(int ypos);

  /// See if widget \p w is one of the Fl_Tree widget's scrollbars.
  /// Use this to skip over the scrollbars when walking the child() array. Example:
  /// \code
  /// for ( int i=0; i<tree->children(); i++ ) {    // walk children
  ///     Fl_Widget *w= tree->child(i);
  ///     if ( brow->is_scrollbar(w) ) continue;    // skip scrollbars
  ///     ..do work here..
  /// }
  /// \endcode
  /// \param[in] w Widget to test
  /// \returns 1 if \p w is a scrollbar, 0 if not.
  ///
  int is_scrollbar(Fl_Widget *w) {
      return( ( w == _vscroll ) ? 1 : 0 );
  }
  /// Gets the current size of the scrollbars' troughs, in pixels.
  ///
  /// If this value is zero (default), this widget will use the global
  /// Fl::scrollbar_size() value as the scrollbar's width.
  /// 
  /// \returns Scrollbar size in pixels, or 0 if the global Fl::scrollsize() is being used.
  /// \see Fl::scrollbar_size(int)
  ///
  int scrollbar_size() const {
      return(_scrollbar_size);
  }
  /// Sets the pixel size of the scrollbars' troughs to the \p size, in pixels.
  ///
  /// Normally you should not need this method, and should use the global
  /// Fl::scrollbar_size(int) instead to manage the size of ALL 
  /// your widgets' scrollbars. This ensures your application 
  /// has a consistent UI, is the default behavior, and is normally
  /// what you want.
  ///
  /// Only use THIS method if you really need to override the global
  /// scrollbar size. The need for this should be rare.
  ///   
  /// Setting \p size to the special value of 0 causes the widget to
  /// track the global Fl::scrollbar_size(), which is the default.
  ///   
  /// \param[in] size Sets the scrollbar size in pixels.\n
  ///                 If 0 (default), scrollbar size tracks the global Fl::scrollbar_size()
  /// \see Fl::scrollbar_size()
  ///
  void scrollbar_size(int size) {
      _scrollbar_size = size;
      int scrollsize = _scrollbar_size ? _scrollbar_size : Fl::scrollbar_size();
      if ( _vscroll->w() != scrollsize ) {
        _vscroll->resize(x()+w()-scrollsize, h(), scrollsize, _vscroll->h());
      }
  }   

  ///////////////////////
  // callback related
  ///////////////////////

  /// Sets the item that was changed for this callback.
  ///    Used internally to pass the item that invoked the callback.
  ///
  void callback_item(Fl_Tree_Item* item) {
    _callback_item = item;
  }
  /// Gets the item that caused the callback.
  /// The callback() can use this value to see which item changed.
  ///
  Fl_Tree_Item* callback_item() {
    return(_callback_item);
  }
  /// Sets the reason for this callback.
  ///    Used internally to pass the reason the callback was invoked.
  ///
  void callback_reason(Fl_Tree_Reason reason) {
    _callback_reason = reason;
  }
  /// Gets the reason for this callback.
  ///
  /// The callback() can use this value to see why it was called. Example:
  /// \code
  ///     void MyTreeCallback(Fl_Widget *w, void *userdata) {
  ///         Fl_Tree *tree = (Fl_Tree*)w;
  ///         Fl_Tree_Item *item = tree->callback_item();    // the item changed (can be NULL if more than one item was changed!)
  ///         switch ( tree->callback_reason() ) {           // reason callback was invoked
  ///             case     FL_TREE_REASON_OPENED: ..item was opened..
  ///             case     FL_TREE_REASON_CLOSED: ..item was closed..
  ///             case   FL_TREE_REASON_SELECTED: ..item was selected..
  ///             case FL_TREE_REASON_DESELECTED: ..item was deselected..
  ///         }
  ///     }
  /// \endcode
  ///
  Fl_Tree_Reason callback_reason() const {
    return(_callback_reason);
  }

  /// Load FLTK preferences
  void load(class Fl_Preferences&);
};

#endif /*FL_TREE_H*/

//
// End of "$Id$".
//