Changes to solve STR#2426;

	1) Hitting ENTER to select an item should make sure the item is
	   displayed if off-screen (Mayank Malik, pointing out similar behavior in Fl_Browser_)

        2) show_item() without a positional argument will invoke show_item_top()
	   if the item is off-screen.

	3) Added new method displayed() (to match Fl_Browser_'s)



git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@7893 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 22 insertions, 0 deletions

diff --git a/src/Fl_Tree.cxx b/src/Fl_Tree.cxx
index 7704de04d..7b8ffdc75 100644
--- a/src/Fl_Tree.cxx
+++ b/src/Fl_Tree.cxx
@@ -520,6 +520,7 @@ int Fl_Tree::handle(int e) {
 	    case FL_KP_Enter:
 	      if ( when() & ~FL_WHEN_ENTER_KEY) {
 		select_only(_item_focus);
+		show_item(_item_focus);		// STR #2426
 		return(1);
 	      }
 	      break;
@@ -789,6 +790,27 @@ void Fl_Tree::show_item(Fl_Tree_Item *item, int yoff) {
   redraw();
 }
 
+/// See if \p item is currently displayed on-screen (visible within the widget).
+/// This can be used to detect if the item is scrolled off-screen.
+/// Checks to see if the item's vertical position is within the top and bottom
+/// edges of the display window. This does NOT take into account the hide()/show()
+/// status of the item.
+///
+int Fl_Tree::displayed(Fl_Tree_Item *item) {
+  return( (item->y() >= y() && item->y() <= (y()+h()-item->h())) ? 1 : 0);
+}
+
+/// Adjust the vertical scroll bar to show \p item at the top
+/// of the display IF it is currently off-screen (eg. show_item_top()).
+/// If it is already on-screen, no change is made.
+///
+/// \see show_item_top(), show_item_middle(), show_item_bottom()
+///
+void Fl_Tree::show_item(Fl_Tree_Item *item) {
+  if ( displayed(item) ) return;
+  show_item_top(item);
+}
+
 /// Adjust the vertical scrollbar so that \p item is at the top of the display.
 void Fl_Tree::show_item_top(Fl_Tree_Item *item) {
   item = item ? item : first();