1------------------------------------------------------------------------------
2--                  GtkAda - Ada95 binding for Gtk+/Gnome                   --
3--                                                                          --
4--                     Copyright (C) 1998-2015, AdaCore                     --
5--                                                                          --
6-- This library is free software;  you can redistribute it and/or modify it --
7-- under terms of the  GNU General Public License  as published by the Free --
8-- Software  Foundation;  either version 3,  or (at your  option) any later --
9-- version. This library is distributed in the hope that it will be useful, --
10-- but WITHOUT ANY WARRANTY;  without even the implied warranty of MERCHAN- --
11-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE.                            --
12--                                                                          --
13-- As a special exception under Section 7 of GPL version 3, you are granted --
14-- additional permissions described in the GCC Runtime Library Exception,   --
15-- version 3.1, as published by the Free Software Foundation.               --
16--                                                                          --
17-- You should have received a copy of the GNU General Public License and    --
18-- a copy of the GCC Runtime Library Exception along with this program;     --
19-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
20-- <http://www.gnu.org/licenses/>.                                          --
21--                                                                          --
22------------------------------------------------------------------------------
23
24--  Various support utilities for the models
25
26with Gtkada.Canvas_View.Rtrees;   use Gtkada.Canvas_View.Rtrees;
27
28package Gtkada.Canvas_View.Models is
29
30   ------------
31   -- Rtrees --
32   ------------
33   --  A wrapper around another model, which provides efficient geospatial
34   --  queries, like finding the smaller enclosing rectangle for all the
35   --  items, or all the items within a given region.
36   --  The items are stored in the base model, and the Rtree model adds
37   --  an extra data structure on top of it to speed up the queries.
38   --  When new items are added to the model, Refresh_Layout *must* be
39   --  called to refresh the internal cache (but this should always be done
40   --  in any case to refresh the display of links for instance).
41   --
42   --  Wrapping a model in a Rtree means that the speed of displaying the
43   --  canvas (and more importantly scrolling it) now depends on the number
44   --  of items on the screen, not the total number of items in the model).
45   --  As a result, it is possible to have models with hundreds of
46   --  thousands of items.
47
48   generic
49      type Base_Model_Record is new Canvas_Model_Record with private;
50      --  The underlying implementation of the model (which for instance
51      --  provides support for Add and Remove), and for which the Rtree
52      --  is used as a wrapper.
53
54   package Rtree_Models is
55      type Rtree_Model_Record is new Base_Model_Record with private;
56      type Rtree_Model is access all Rtree_Model_Record'Class;
57
58      procedure Gtk_New (Self : out Rtree_Model);
59      procedure Initialize
60         (Self : not null access Rtree_Model_Record'Class);
61      --  Create a new Rtree model.
62
63      overriding procedure For_Each_Item
64        (Self     : not null access Rtree_Model_Record;
65         Callback : not null access procedure
66           (Item : not null access Abstract_Item_Record'Class);
67         Selected_Only : Boolean := False;
68         Filter        : Item_Kind_Filter := Kind_Any;
69         In_Area       : Model_Rectangle := No_Rectangle);
70      overriding function Bounding_Box
71        (Self   : not null access Rtree_Model_Record;
72         Margin : Model_Coordinate := 0.0)
73         return Model_Rectangle;
74      overriding function Toplevel_Item_At
75        (Self    : not null access Rtree_Model_Record;
76         Point   : Model_Point;
77         Context : Draw_Context) return Abstract_Item;
78      overriding procedure Refresh_Layout
79         (Self        : not null access Rtree_Model_Record;
80          Send_Signal : Boolean := True);
81
82   private
83      type Rtree_Model_Record is new Base_Model_Record with record
84         Items_Tree, Links_Tree : Rtree
85           (Min_Children => Default_Min_Children,
86            Max_Children => Default_Max_Children);
87      end record;
88   end Rtree_Models;
89
90end Gtkada.Canvas_View.Models;
91