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/visibility.h"
32 #include "canvas/types.h"
34 namespace ArdourCanvas
41 /** The parent class for anything that goes on the canvas.
43 * Items have a position, which is expressed in the coordinates of the parent.
44 * They also have a bounding box, which describes the area in which they have
45 * drawable content, which is expressed in their own coordinates (whose origin
46 * is at the item position).
48 * Any item that is being displayed on a canvas has a pointer to that canvas,
49 * and all except the `root group' have a pointer to their parent group.
52 class LIBCANVAS_API Item
57 Item (Group *, Duple);
62 /** Render this item to a Cairo context.
63 * @param area Area to draw, in **window** coordinates
65 * Items must convert their own coordinates into window coordinates
66 * because Cairo is limited to a fixed point coordinate space that
67 * does not extend as far as the Ardour timeline. All rendering must
68 * be done using coordinates that do not exceed the (rough) limits
69 * of the canvas' window, to avoid odd errors within Cairo as it
70 * converts doubles into its fixed point format and then tesselates
73 virtual void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const = 0;
75 virtual void add_items_at_point (Duple, std::vector<Item const *>& items) const {
76 items.push_back (this);
79 virtual bool covers (Duple const &) const;
81 /** Update _bounding_box and _bounding_box_dirty */
82 virtual void compute_bounding_box () const = 0;
88 void reparent (Group *);
90 /** @return Parent group, or 0 if this is the root group */
91 Group* parent () const {
95 uint32_t depth() const;
96 const Item* closest_ancestor_with (const Item& other) const;
97 bool common_ancestor_within (uint32_t, const Item& other) const;
99 /** returns true if this item is an ancestor of @param candidate,
100 * and false otherwise.
102 bool is_ancestor_of (const Item& candidate) const {
103 return candidate.is_descendant_of (*this);
105 /** returns true if this Item is a descendant of @param candidate,
106 * and false otherwise.
108 bool is_descendant_of (const Item& candidate) const;
110 void set_position (Duple);
111 void set_x_position (Coord);
112 void set_y_position (Coord);
115 enum ScrollSensitivity {
116 ScrollsVertically = 0x1,
117 ScrollsHorizontally = 0x2
120 void set_scroll_sensitivity (ScrollSensitivity s);
121 ScrollSensitivity scroll_sensitivity () const { return _scroll_sensitivity; }
123 virtual void scroll_to (Duple const& d);
124 Duple scroll_offset() const { return _scroll_offset; }
126 /** @return Position of this item in the parent's coordinates */
127 Duple position () const {
131 boost::optional<Rect> bounding_box () const;
132 Coord height() const;
135 Duple item_to_parent (Duple const &) const;
136 Rect item_to_parent (Rect const &) const;
137 Duple parent_to_item (Duple const &) const;
138 Rect parent_to_item (Rect const &) const;
140 /* XXX: it's a pity these two aren't the same form as item_to_parent etc.,
141 but it makes a bit of a mess in the rest of the code if they are not.
143 void canvas_to_item (Coord &, Coord &) const;
144 void item_to_canvas (Coord &, Coord &) const;
146 Duple item_to_window (Duple const&, bool rounded = true) const;
147 Duple window_to_item (Duple const&) const;
148 Rect item_to_window (Rect const&) const;
149 Rect window_to_item (Rect const&) const;
151 void raise_to_top ();
153 void lower_to_bottom ();
158 /** @return true if this item is visible (ie it will be rendered),
161 bool visible () const {
165 /** @return Our canvas, or 0 if we are not attached to one */
166 Canvas* canvas () const {
170 void set_ignore_events (bool);
171 bool ignore_events () const {
172 return _ignore_events;
175 void set_data (std::string const &, void *);
176 void* get_data (std::string const &) const;
178 /* This is a sigc++ signal because it is solely
179 concerned with GUI stuff and is thus single-threaded
183 struct EventAccumulator {
184 typedef T result_type;
186 result_type operator () (U first, U last) {
187 while (first != last) {
197 sigc::signal1<bool, GdkEvent*, EventAccumulator<bool> > Event;
203 #ifdef CANVAS_COMPATIBILITY
207 virtual void dump (std::ostream&) const;
208 std::string whatami() const;
212 /** To be called at the beginning of any property change that
213 * may alter the bounding box of this item
215 void begin_change ();
216 /** To be called at the endof any property change that
217 * may alter the bounding box of this item
220 /** To be called at the beginning of any property change that
221 * does NOT alter the bounding box of this item
223 void begin_visual_change ();
224 /** To be called at the endof any property change that
225 * does NOT alter the bounding box of this item
227 void end_visual_change ();
230 /** parent group; may be 0 if we are the root group or if we have been unparent()ed */
232 /** position of this item in parent coordinates */
234 /** true if this item is visible (ie to be drawn), otherwise false */
236 /** our bounding box before any change that is currently in progress */
237 boost::optional<Rect> _pre_change_bounding_box;
239 /** our bounding box; may be out of date if _bounding_box_dirty is true */
240 mutable boost::optional<Rect> _bounding_box;
241 /** true if _bounding_box might be out of date, false if its definitely not */
242 mutable bool _bounding_box_dirty;
244 /* XXX: this is a bit grubby */
245 std::map<std::string, void *> _data;
251 ScrollSensitivity _scroll_sensitivity;
252 Duple _scroll_offset;
255 extern LIBCANVAS_API std::ostream& operator<< (std::ostream&, const ArdourCanvas::Item&);