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
42 /** The parent class for anything that goes on the canvas.
44 * Items have a position, which is expressed in the coordinates of the parent.
45 * They also have a bounding box, which describes the area in which they have
46 * drawable content, which is expressed in their own coordinates (whose origin
47 * is at the item position).
49 * Any item that is being displayed on a canvas has a pointer to that canvas,
50 * and all except the `root group' have a pointer to their parent group.
53 class LIBCANVAS_API Item
58 Item (Group *, Duple);
63 /** Render this item to a Cairo context.
64 * @param area Area to draw, in **window** coordinates
66 * Items must convert their own coordinates into window coordinates
67 * because Cairo is limited to a fixed point coordinate space that
68 * does not extend as far as the Ardour timeline. All rendering must
69 * be done using coordinates that do not exceed the (rough) limits
70 * of the canvas' window, to avoid odd errors within Cairo as it
71 * converts doubles into its fixed point format and then tesselates
74 virtual void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const = 0;
76 /** Adds one or more items to the vector @param items based on their
77 * covering @param point which is in **window** coordinates
79 * Note that Item::add_items_at_window_point() is only intended to be
80 * called on items already looked up in a LookupTable (i.e. by a
81 * parent group) and thus known to cover @param point already.
83 * Derived classes may add more items than themselves (e.g. Group).
85 virtual void add_items_at_point (Duple /*point*/, std::vector<Item const *>& items) const {
86 items.push_back (this);
89 virtual bool covers (Duple const &) const;
91 /** Update _bounding_box and _bounding_box_dirty */
92 virtual void compute_bounding_box () const = 0;
98 void reparent (Group *);
100 /** @return Parent group, or 0 if this is the root group */
101 Group* parent () const {
105 uint32_t depth() const;
106 const Item* closest_ancestor_with (const Item& other) const;
107 bool common_ancestor_within (uint32_t, const Item& other) const;
109 /** returns true if this item is an ancestor of @param candidate,
110 * and false otherwise.
112 bool is_ancestor_of (const Item& candidate) const {
113 return candidate.is_descendant_of (*this);
115 /** returns true if this Item is a descendant of @param candidate,
116 * and false otherwise.
118 bool is_descendant_of (const Item& candidate) const;
120 void set_position (Duple);
121 void set_x_position (Coord);
122 void set_y_position (Coord);
125 virtual void scroll_to (Duple const&) {}
127 /** @return Position of this item in the parent's coordinates */
128 Duple position () const {
132 Duple window_origin() const;
133 Duple canvas_origin() const;
135 ScrollGroup* scroll_parent() const { return _scroll_parent; }
137 boost::optional<Rect> bounding_box () const;
138 Coord height() const;
141 Duple item_to_parent (Duple const &) const;
142 Rect item_to_parent (Rect const &) const;
143 Duple parent_to_item (Duple const &) const;
144 Rect parent_to_item (Rect const &) const;
146 /* XXX: it's a pity these two aren't the same form as item_to_parent etc.,
147 but it makes a bit of a mess in the rest of the code if they are not.
149 void canvas_to_item (Coord &, Coord &) const;
150 void item_to_canvas (Coord &, Coord &) const;
152 Duple canvas_to_item (Duple const&) const;
153 Rect item_to_canvas (Rect const&) const;
154 Duple item_to_canvas (Duple const&) const;
155 Rect canvas_to_item (Rect const&) const;
157 Duple item_to_window (Duple const&, bool rounded = true) const;
158 Duple window_to_item (Duple const&) const;
159 Rect item_to_window (Rect const&) const;
160 Rect window_to_item (Rect const&) const;
162 void raise_to_top ();
164 void lower_to_bottom ();
169 /** @return true if this item is visible (ie it will be rendered),
172 bool visible () const {
176 /** @return Our canvas, or 0 if we are not attached to one */
177 Canvas* canvas () const {
181 void set_ignore_events (bool);
182 bool ignore_events () const {
183 return _ignore_events;
186 void set_data (std::string const &, void *);
187 void* get_data (std::string const &) const;
189 /* This is a sigc++ signal because it is solely
190 concerned with GUI stuff and is thus single-threaded
194 struct EventAccumulator {
195 typedef T result_type;
197 result_type operator () (U first, U last) {
198 while (first != last) {
208 sigc::signal1<bool, GdkEvent*, EventAccumulator<bool> > Event;
214 #ifdef CANVAS_COMPATIBILITY
218 virtual void dump (std::ostream&) const;
219 std::string whatami() const;
223 /** To be called at the beginning of any property change that
224 * may alter the bounding box of this item
226 void begin_change ();
227 /** To be called at the endof any property change that
228 * may alter the bounding box of this item
231 /** To be called at the beginning of any property change that
232 * does NOT alter the bounding box of this item
234 void begin_visual_change ();
235 /** To be called at the endof any property change that
236 * does NOT alter the bounding box of this item
238 void end_visual_change ();
241 /** parent group; may be 0 if we are the root group or if we have been unparent()ed */
243 /** scroll parent group; may be 0 if we are the root group or if we have been unparent()ed */
244 ScrollGroup* _scroll_parent;
245 /** position of this item in parent coordinates */
247 /** true if this item is visible (ie to be drawn), otherwise false */
249 /** our bounding box before any change that is currently in progress */
250 boost::optional<Rect> _pre_change_bounding_box;
252 /** our bounding box; may be out of date if _bounding_box_dirty is true */
253 mutable boost::optional<Rect> _bounding_box;
254 /** true if _bounding_box might be out of date, false if its definitely not */
255 mutable bool _bounding_box_dirty;
257 /* XXX: this is a bit grubby */
258 std::map<std::string, void *> _data;
265 Duple scroll_offset() const;
266 Duple position_offset() const;
268 void find_scroll_parent ();
271 extern LIBCANVAS_API std::ostream& operator<< (std::ostream&, const ArdourCanvas::Item&);