2 Copyright (C) 2011-2013 Paul Davis
3 Original Author: Carl Hetherington <cth@carlh.net>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #ifndef __CANVAS_ITEM_H__
21 #define __CANVAS_ITEM_H__
27 #include <cairomm/context.h>
29 #include "pbd/signals.h"
31 #include "canvas/types.h"
33 namespace ArdourCanvas
40 /** The parent class for anything that goes on the canvas.
42 * Items have a position, which is expressed in the coordinates of the parent.
43 * They also have a bounding box, which describes the area in which they have
44 * drawable content, which is expressed in their own coordinates (whose origin
45 * is at the item position).
47 * Any item that is being displayed on a canvas has a pointer to that canvas,
48 * and all except the `root group' have a pointer to their parent group.
56 Item (Group *, Duple);
61 /** Render this item to a Cairo context.
62 * @param area Area to draw, in **window** coordinates
64 * Items must convert their own coordinates into window coordinates
65 * because Cairo is limited to a fixed point coordinate space that
66 * does not extend as far as the Ardour timeline. All rendering must
67 * be done using coordinates that do not exceed the (rough) limits
68 * of the canvas' window, to avoid odd errors within Cairo as it
69 * converts doubles into its fixed point format and then tesselates
72 virtual void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const = 0;
74 virtual void add_items_at_point (Duple, std::vector<Item const *>& items) const {
75 items.push_back (this);
78 virtual bool covers (Duple const &) const;
80 /** Update _bounding_box and _bounding_box_dirty */
81 virtual void compute_bounding_box () const = 0;
87 void reparent (Group *);
89 /** @return Parent group, or 0 if this is the root group */
90 Group* parent () const {
94 uint32_t depth() const;
95 const Item* closest_ancestor_with (const Item& other) const;
96 bool common_ancestor_within (uint32_t, const Item& other) const;
98 /** returns true if this item is an ancestor of @param candidate,
99 * and false otherwise.
101 bool is_ancestor_of (const Item& candidate) const {
102 return candidate.is_descendant_of (*this);
104 /** returns true if this Item is a descendant of @param candidate,
105 * and false otherwise.
107 bool is_descendant_of (const Item& candidate) const;
109 void set_position (Duple);
110 void set_x_position (Coord);
111 void set_y_position (Coord);
114 /** @return Position of this item in the parent's coordinates */
115 Duple position () const {
119 boost::optional<Rect> bounding_box () const;
120 Coord height() const;
123 Duple item_to_parent (Duple const &) const;
124 Rect item_to_parent (Rect const &) const;
125 Duple parent_to_item (Duple const &) const;
126 Rect parent_to_item (Rect const &) const;
127 /* XXX: it's a pity these aren't the same form as item_to_parent etc.,
128 but it makes a bit of a mess in the rest of the code if they are not.
131 void canvas_to_item (Coord &, Coord &) const;
132 Duple canvas_to_item (Duple const &) const;
133 void item_to_canvas (Coord &, Coord &) const;
134 Rect item_to_canvas (Rect const &) const;
135 Rect canvas_to_item (Rect const &) const;
136 Duple item_to_canvas (Duple const &) const;
138 Duple item_to_window (Duple const&) const;
139 Duple window_to_item (Duple const&) const;
140 Rect item_to_window (Rect const&) const;
142 void raise_to_top ();
144 void lower_to_bottom ();
149 /** @return true if this item is visible (ie it will be rendered),
152 bool visible () const {
156 /** @return Our canvas, or 0 if we are not attached to one */
157 Canvas* canvas () const {
161 void set_ignore_events (bool);
162 bool ignore_events () const {
163 return _ignore_events;
166 void set_data (std::string const &, void *);
167 void* get_data (std::string const &) const;
169 /* This is a sigc++ signal because it is solely
170 concerned with GUI stuff and is thus single-threaded
174 struct EventAccumulator {
175 typedef T result_type;
177 result_type operator () (U first, U last) {
178 while (first != last) {
188 sigc::signal1<bool, GdkEvent*, EventAccumulator<bool> > Event;
194 #ifdef CANVAS_COMPATIBILITY
198 virtual void dump (std::ostream&) const;
199 std::string whatami() const;
203 /** To be called at the beginning of any property change that
204 * may alter the bounding box of this item
206 void begin_change ();
207 /** To be called at the endof any property change that
208 * may alter the bounding box of this item
211 /** To be called at the beginning of any property change that
212 * does NOT alter the bounding box of this item
214 void begin_visual_change ();
215 /** To be called at the endof any property change that
216 * does NOT alter the bounding box of this item
218 void end_visual_change ();
221 /** parent group; may be 0 if we are the root group or if we have been unparent()ed */
223 /** position of this item in parent coordinates */
225 /** true if this item is visible (ie to be drawn), otherwise false */
227 /** our bounding box before any change that is currently in progress */
228 boost::optional<Rect> _pre_change_bounding_box;
230 /** our bounding box; may be out of date if _bounding_box_dirty is true */
231 mutable boost::optional<Rect> _bounding_box;
232 /** true if _bounding_box might be out of date, false if its definitely not */
233 mutable bool _bounding_box_dirty;
235 /* XXX: this is a bit grubby */
236 std::map<std::string, void *> _data;
244 extern std::ostream& operator<< (std::ostream&, const ArdourCanvas::Item&);