class Fl_Browser_ : public Fl_Widget

This is the base class for browsers. To be useful it must be subclassed and several virtual functions defined. The Forms-compatable browser and the file chooser's browser are subclassed off of this.

Yes, I know this should be a template...

This has been designed so that the subclass has complete control over the storage of the data, although because next() and prev() functions are used to index, it works best as a linked list or as a large block of characters in which the line breaks must be searched for.

A great deal of work has been done so that the "height" of a data object does not need to be determined until it is drawn. Very useful if actually figuring out the size of an object requires accessing image data or doing stat() on a file or doing some other slow operation.

#define FL_NORMAL_BROWSER	0
#define FL_SELECT_BROWSER	1
#define FL_HOLD_BROWSER		2
#define FL_MULTI_BROWSER	3

class Fl_Browser_ : public Fl_Group {
  int position_;	// where user wants it scrolled to
  int real_position_;	// the current vertical scrolling position
  int hposition_;	// where user wants it panned to
  int real_hposition_;	// the current horizontal scrolling position
  void *top_;		// which item scrolling position is in
  int offset_;		// and how far down that item it is
  void *selection_;	// which is selected (except for FL_MULTI_BROWSER)
  void update_top();
  void *redraw1,*redraw2; // minimal update pointers

protected:

  // All of the following must be supplied by the subclass:
  virtual void *item_first() const = 0;
  virtual void *item_next(void *) const = 0;
  virtual void *item_prev(void *) const = 0;
  virtual int item_height(void *) const = 0;
  virtual int item_width(void *) const = 0;
  virtual int item_quick_height(void *) const ;
  virtual void item_draw(void *,int,int,int,int) const = 0;
  // you don't have to provide these but it may help speed it up:
  virtual int full_width() const ;	// current width of all items
  virtual int full_height() const ;	// current height of all items
  virtual int incr_height() const ;	// average height of an item
  // These only need to be done by subclass if you want a multi-browser:
  virtual void item_select(void *,int=1);
  virtual int item_selected(void *) const ;

  // things the subclass may want to call:
  void *top() const {return top_;}
  void *selection() const {return selection_;}
  void new_list(); // completely clobber all data, as though list replaced
  void deleting(void *a); // get rid of any pointers to a
  void replacing(void *a,void *b); // change a pointers to b
  void inserting(void *a,void *b); // insert a before b
  int displayed(void *) const ; // true if this line is visible
  void redraw_line(void *); // minimal update, no change in size
  void redraw_lines() {damage(1);} // redraw all of them
  void bbox(int&,int&,int&,int&) const;
  int leftedge() const;	// x position after scrollbar & border
  void *find_item(int my); // item under mouse
  void draw(int,int,int,int);
  int handle(int,int,int,int,int);

  void draw();
  int handle(int);
  Fl_Browser_(int,int,int,int,const char * = 0);

public:

  Fl_Scrollbar scrollbar;		// Vertical scrollbar
  Fl_Scrollbar hscrollbar;		// Horizontal scrollbar

  void resize(int,int,int,int);

  int select(void *,int=1,int docallbacks=0);
  int select_only(void *,int docallbacks=0);
  int deselect(int docallbacks=0);
  int position() const {return position_;}
  int hposition() const {return hposition_;}
  void position(int); // scroll to here
  void hposition(int); // pan to here
  void display(void*); // scroll so this item is shown

  void scrollbar_right() {scrollbar.align(FL_ALIGN_RIGHT);}
  void scrollbar_left() {scrollbar.align(FL_ALIGN_LEFT);}

};