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"
33 #include "canvas/fill.h"
34 #include "canvas/outline.h"
35 #include "canvas/lookup_table.h"
37 namespace ArdourCanvas
44 /** The parent class for anything that goes on the canvas.
46 * Items have a position, which is expressed in the coordinates of the parent.
47 * They also have a bounding box, which describes the area in which they have
48 * drawable content, which is expressed in their own coordinates (whose origin
49 * is at the item position).
51 * Any item that is being displayed on a canvas has a pointer to that canvas,
52 * and all except the `root group' have a pointer to their parent group.
55 class LIBCANVAS_API Item : public Fill, public Outline
60 Item (Item *, Duple const& p);
65 /** Render this item to a Cairo context.
66 * @param area Area to draw, in **window** coordinates
68 * Items must convert their own coordinates into window coordinates
69 * because Cairo is limited to a fixed point coordinate space that
70 * does not extend as far as the Ardour timeline. All rendering must
71 * be done using coordinates that do not exceed the (rough) limits
72 * of the canvas' window, to avoid odd errors within Cairo as it
73 * converts doubles into its fixed point format and then tesselates
76 virtual void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const = 0;
78 /** Adds one or more items to the vector @param items based on their
79 * covering @param point which is in **window** coordinates
81 * Note that Item::add_items_at_window_point() is only intended to be
82 * called on items already looked up in a LookupTable (i.e. by a
83 * parent) and thus known to cover @param point already.
85 * Derived classes may add more items than themselves (e.g. containers).
87 virtual void add_items_at_point (Duple /*point*/, std::vector<Item const *>& items) const;
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 (Item *);
100 /** @return Parent group, or 0 if this is the root group */
101 Item* 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 /** @return Position of this item in the parent's coordinates */
126 Duple position () const {
130 Duple window_origin() const;
131 Duple canvas_origin() const;
133 ScrollGroup* scroll_parent() const { return _scroll_parent; }
135 boost::optional<Rect> bounding_box () const;
136 Coord height() const;
139 Duple item_to_parent (Duple const &) const;
140 Rect item_to_parent (Rect const &) const;
141 Duple parent_to_item (Duple const &) const;
142 Rect parent_to_item (Rect const &) const;
144 /* XXX: it's a pity these two aren't the same form as item_to_parent etc.,
145 but it makes a bit of a mess in the rest of the code if they are not.
147 void canvas_to_item (Coord &, Coord &) const;
148 void item_to_canvas (Coord &, Coord &) const;
150 Duple canvas_to_item (Duple const&) const;
151 Rect item_to_canvas (Rect const&) const;
152 Duple item_to_canvas (Duple const&) const;
153 Rect canvas_to_item (Rect const&) const;
155 Duple item_to_window (Duple const&, bool rounded = true) const;
156 Duple window_to_item (Duple const&) const;
157 Rect item_to_window (Rect const&) const;
158 Rect window_to_item (Rect const&) const;
160 void raise_to_top ();
162 void lower_to_bottom ();
167 /** @return true if this item is visible (ie it will be rendered),
170 bool visible () const {
174 /** @return Our canvas, or 0 if we are not attached to one */
175 Canvas* canvas () const {
179 void set_ignore_events (bool);
180 bool ignore_events () const {
181 return _ignore_events;
184 void set_data (std::string const &, void *);
185 void* get_data (std::string const &) const;
187 /* nested item ("grouping") API */
189 void remove (Item *);
190 void clear (bool with_delete = false);
191 std::list<Item*> const & items () const {
194 void raise_child_to_top (Item *);
195 void raise_child (Item *, int);
196 void lower_child_to_bottom (Item *);
197 void child_changed ();
199 static int default_items_per_cell;
202 /* This is a sigc++ signal because it is solely
203 concerned with GUI stuff and is thus single-threaded
207 struct EventAccumulator {
208 typedef T result_type;
210 result_type operator () (U first, U last) {
211 while (first != last) {
221 sigc::signal1<bool, GdkEvent*, EventAccumulator<bool> > Event;
227 #ifdef CANVAS_COMPATIBILITY
231 virtual void dump (std::ostream&) const;
232 std::string whatami() const;
236 friend class Outline;
238 /** To be called at the beginning of any property change that
239 * may alter the bounding box of this item
241 void begin_change ();
242 /** To be called at the endof any property change that
243 * may alter the bounding box of this item
246 /** To be called at the beginning of any property change that
247 * does NOT alter the bounding box of this item
249 void begin_visual_change ();
250 /** To be called at the endof any property change that
251 * does NOT alter the bounding box of this item
253 void end_visual_change ();
256 /** parent group; may be 0 if we are the root group or if we have been unparent()ed */
258 /** scroll parent group; may be 0 if we are the root group or if we have been unparent()ed */
259 ScrollGroup* _scroll_parent;
260 /** position of this item in parent coordinates */
262 /** true if this item is visible (ie to be drawn), otherwise false */
264 /** our bounding box before any change that is currently in progress */
265 boost::optional<Rect> _pre_change_bounding_box;
267 /** our bounding box; may be out of date if _bounding_box_dirty is true */
268 mutable boost::optional<Rect> _bounding_box;
269 /** true if _bounding_box might be out of date, false if its definitely not */
270 mutable bool _bounding_box_dirty;
272 /* XXX: this is a bit grubby */
273 std::map<std::string, void *> _data;
275 /* nesting ("grouping") API */
277 void invalidate_lut () const;
278 void clear_items (bool with_delete);
280 void ensure_lut () const;
281 mutable LookupTable* _lut;
282 /* our items, from lowest to highest in the stack */
283 std::list<Item*> _items;
285 void add_child_bounding_boxes() const;
286 void render_children (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const;
293 Duple scroll_offset() const;
294 Duple position_offset() const;
296 void find_scroll_parent ();
299 extern LIBCANVAS_API std::ostream& operator<< (std::ostream&, const ArdourCanvas::Item&);