1 /** @file
2 * Editable node - implementation
3 */
4 /* Authors:
5 * Krzysztof KosiĆski <tweenk.pl@gmail.com>
6 *
7 * Copyright (C) 2009 Authors
8 * Released under GNU GPL, read the file 'COPYING' for more information
9 */
11 #include <iostream>
12 #include <stdexcept>
13 #include <boost/utility.hpp>
14 #include <glib.h>
15 #include <glib/gi18n.h>
16 #include <2geom/bezier-utils.h>
17 #include <2geom/transforms.h>
19 #include "display/sp-ctrlline.h"
20 #include "display/sp-canvas.h"
21 #include "display/sp-canvas-util.h"
22 #include "desktop.h"
23 #include "desktop-handles.h"
24 #include "preferences.h"
25 #include "snap.h"
26 #include "snap-preferences.h"
27 #include "sp-metrics.h"
28 #include "sp-namedview.h"
29 #include "ui/tool/control-point-selection.h"
30 #include "ui/tool/event-utils.h"
31 #include "ui/tool/multi-path-manipulator.h"
32 #include "ui/tool/node.h"
33 #include "ui/tool/path-manipulator.h"
35 namespace Inkscape {
36 namespace UI {
38 static SelectableControlPoint::ColorSet node_colors = {
39 {
40 {0xbfbfbf00, 0x000000ff}, // normal fill, stroke
41 {0xff000000, 0x000000ff}, // mouseover fill, stroke
42 {0xff000000, 0x000000ff} // clicked fill, stroke
43 },
44 {0x0000ffff, 0x000000ff}, // normal fill, stroke when selected
45 {0xff000000, 0x000000ff}, // mouseover fill, stroke when selected
46 {0xff000000, 0x000000ff} // clicked fill, stroke when selected
47 };
49 static ControlPoint::ColorSet handle_colors = {
50 {0xffffffff, 0x000000ff}, // normal fill, stroke
51 {0xff000000, 0x000000ff}, // mouseover fill, stroke
52 {0xff000000, 0x000000ff} // clicked fill, stroke
53 };
55 std::ostream &operator<<(std::ostream &out, NodeType type)
56 {
57 switch(type) {
58 case NODE_CUSP: out << 'c'; break;
59 case NODE_SMOOTH: out << 's'; break;
60 case NODE_AUTO: out << 'a'; break;
61 case NODE_SYMMETRIC: out << 'z'; break;
62 default: out << 'b'; break;
63 }
64 return out;
65 }
67 /** Computes an unit vector of the direction from first to second control point */
68 static Geom::Point direction(Geom::Point const &first, Geom::Point const &second) {
69 return Geom::unit_vector(second - first);
70 }
72 /**
73 * @class Handle
74 * @brief Control point of a cubic Bezier curve in a path.
75 *
76 * Handle keeps the node type invariant only for the opposite handle of the same node.
77 * Keeping the invariant on node moves is left to the %Node class.
78 */
80 Geom::Point Handle::_saved_other_pos(0, 0);
81 double Handle::_saved_length = 0.0;
82 bool Handle::_drag_out = false;
84 Handle::Handle(NodeSharedData const &data, Geom::Point const &initial_pos, Node *parent)
85 : ControlPoint(data.desktop, initial_pos, Gtk::ANCHOR_CENTER, SP_CTRL_SHAPE_CIRCLE, 7.0,
86 &handle_colors, data.handle_group)
87 , _parent(parent)
88 , _degenerate(true)
89 {
90 _cset = &handle_colors;
91 _handle_line = sp_canvas_item_new(data.handle_line_group, SP_TYPE_CTRLLINE, NULL);
92 setVisible(false);
93 }
94 Handle::~Handle()
95 {
96 //sp_canvas_item_hide(_handle_line);
97 gtk_object_destroy(GTK_OBJECT(_handle_line));
98 }
100 void Handle::setVisible(bool v)
101 {
102 ControlPoint::setVisible(v);
103 if (v) sp_canvas_item_show(_handle_line);
104 else sp_canvas_item_hide(_handle_line);
105 }
107 void Handle::move(Geom::Point const &new_pos)
108 {
109 Handle *other = this->other();
110 Node *node_towards = _parent->nodeToward(this); // node in direction of this handle
111 Node *node_away = _parent->nodeAwayFrom(this); // node in the opposite direction
112 Handle *towards = node_towards ? node_towards->handleAwayFrom(_parent) : NULL;
113 Handle *towards_second = node_towards ? node_towards->handleToward(_parent) : NULL;
115 if (Geom::are_near(new_pos, _parent->position())) {
116 // The handle becomes degenerate. If the segment between it and the node
117 // in its direction becomes linear and there are smooth nodes
118 // at its ends, make their handles colinear with the segment
119 if (towards && towards->isDegenerate()) {
120 if (node_towards->type() == NODE_SMOOTH) {
121 towards_second->setDirection(*_parent, *node_towards);
122 }
123 if (_parent->type() == NODE_SMOOTH) {
124 other->setDirection(*node_towards, *_parent);
125 }
126 }
127 setPosition(new_pos);
128 return;
129 }
131 if (_parent->type() == NODE_SMOOTH && Node::_is_line_segment(_parent, node_away)) {
132 // restrict movement to the line joining the nodes
133 Geom::Point direction = _parent->position() - node_away->position();
134 Geom::Point delta = new_pos - _parent->position();
135 // project the relative position on the direction line
136 Geom::Point new_delta = (Geom::dot(delta, direction)
137 / Geom::L2sq(direction)) * direction;
138 setRelativePos(new_delta);
139 return;
140 }
142 switch (_parent->type()) {
143 case NODE_AUTO:
144 _parent->setType(NODE_SMOOTH, false);
145 // fall through - auto nodes degrade into smooth nodes
146 case NODE_SMOOTH: {
147 /* for smooth nodes, we need to rotate the other handle so that it's colinear
148 * with the dragged one while conserving length. */
149 other->setDirection(new_pos, *_parent);
150 } break;
151 case NODE_SYMMETRIC:
152 // for symmetric nodes, place the other handle on the opposite side
153 other->setRelativePos(-(new_pos - _parent->position()));
154 break;
155 default: break;
156 }
158 setPosition(new_pos);
159 }
161 void Handle::setPosition(Geom::Point const &p)
162 {
163 ControlPoint::setPosition(p);
164 sp_ctrlline_set_coords(SP_CTRLLINE(_handle_line), _parent->position(), position());
166 // update degeneration info and visibility
167 if (Geom::are_near(position(), _parent->position()))
168 _degenerate = true;
169 else _degenerate = false;
170 if (_parent->_handles_shown && _parent->visible() && !_degenerate) {
171 setVisible(true);
172 } else {
173 setVisible(false);
174 }
175 // If both handles become degenerate, convert to parent cusp node
176 if (_parent->isDegenerate()) {
177 _parent->setType(NODE_CUSP, false);
178 }
179 }
181 void Handle::setLength(double len)
182 {
183 if (isDegenerate()) return;
184 Geom::Point dir = Geom::unit_vector(relativePos());
185 setRelativePos(dir * len);
186 }
188 void Handle::retract()
189 {
190 setPosition(_parent->position());
191 }
193 void Handle::setDirection(Geom::Point const &from, Geom::Point const &to)
194 {
195 setDirection(to - from);
196 }
198 void Handle::setDirection(Geom::Point const &dir)
199 {
200 Geom::Point unitdir = Geom::unit_vector(dir);
201 setRelativePos(unitdir * length());
202 }
204 char const *Handle::handle_type_to_localized_string(NodeType type)
205 {
206 switch(type) {
207 case NODE_CUSP: return _("Cusp node handle");
208 case NODE_SMOOTH: return _("Smooth node handle");
209 case NODE_SYMMETRIC: return _("Symmetric node handle");
210 case NODE_AUTO: return _("Auto-smooth node handle");
211 default: return "";
212 }
213 }
215 bool Handle::grabbed(GdkEventMotion *)
216 {
217 _saved_other_pos = other()->position();
218 _saved_length = _drag_out ? 0 : length();
219 _pm()._handleGrabbed();
220 return false;
221 }
223 void Handle::dragged(Geom::Point &new_pos, GdkEventMotion *event)
224 {
225 Geom::Point parent_pos = _parent->position();
226 Geom::Point origin = _last_drag_origin();
227 SnapManager &sm = _desktop->namedview->snap_manager;
228 bool snap = sm.someSnapperMightSnap();
230 // with Alt, preserve length
231 if (held_alt(*event)) {
232 new_pos = parent_pos + Geom::unit_vector(new_pos - parent_pos) * _saved_length;
233 snap = false;
234 }
235 // with Ctrl, constrain to M_PI/rotationsnapsperpi increments from vertical
236 // and the original position.
237 if (held_control(*event)) {
238 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
239 int snaps = 2 * prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
241 // note: if snapping to the original position is only desired in the original
242 // direction of the handle, change to Ray instead of Line
243 Geom::Line original_line(parent_pos, origin);
244 Geom::Point snap_pos = parent_pos + Geom::constrain_angle(
245 Geom::Point(0,0), new_pos - parent_pos, snaps, Geom::Point(1,0));
246 Geom::Point orig_pos = original_line.pointAt(original_line.nearestPoint(new_pos));
248 if (Geom::distance(snap_pos, new_pos) < Geom::distance(orig_pos, new_pos)) {
249 new_pos = snap_pos;
250 } else {
251 new_pos = orig_pos;
252 }
253 snap = false;
254 }
256 std::vector<Inkscape::SnapCandidatePoint> unselected;
257 if (snap) {
258 typedef ControlPointSelection::Set Set;
259 Set &nodes = _parent->_selection.allPoints();
260 for (Set::iterator i = nodes.begin(); i != nodes.end(); ++i) {
261 Node *n = static_cast<Node*>(*i);
262 Inkscape::SnapCandidatePoint p(n->position(), n->_snapSourceType(), n->_snapTargetType());
263 unselected.push_back(p);
264 }
265 sm.setupIgnoreSelection(_desktop, true, &unselected);
267 Node *node_away = (this == &_parent->_front ? _parent->_prev() : _parent->_next());
268 if (_parent->type() == NODE_SMOOTH && Node::_is_line_segment(_parent, node_away)) {
269 Inkscape::Snapper::SnapConstraint cl(_parent->position(),
270 _parent->position() - node_away->position());
271 Inkscape::SnappedPoint p;
272 p = sm.constrainedSnap(Inkscape::SnapCandidatePoint(new_pos, SNAPSOURCE_NODE_HANDLE), cl);
273 new_pos = p.getPoint();
274 } else {
275 sm.freeSnapReturnByRef(new_pos, SNAPSOURCE_NODE_HANDLE);
276 }
277 sm.unSetup();
278 }
281 // with Shift, if the node is cusp, rotate the other handle as well
282 if (_parent->type() == NODE_CUSP && !_drag_out) {
283 if (held_shift(*event)) {
284 Geom::Point other_relpos = _saved_other_pos - parent_pos;
285 other_relpos *= Geom::Rotate(Geom::angle_between(origin - parent_pos, new_pos - parent_pos));
286 other()->setRelativePos(other_relpos);
287 } else {
288 // restore the position
289 other()->setPosition(_saved_other_pos);
290 }
291 }
292 move(new_pos); // needed for correct update, even though it's redundant
293 _pm().update();
294 }
296 void Handle::ungrabbed(GdkEventButton *event)
297 {
298 // hide the handle if it's less than dragtolerance away from the node
299 // TODO is this actually desired?
300 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
301 int drag_tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
303 Geom::Point dist = _desktop->d2w(_parent->position()) - _desktop->d2w(position());
304 if (dist.length() <= drag_tolerance) {
305 move(_parent->position());
306 }
308 // HACK: If the handle was dragged out, call parent's ungrabbed handler,
309 // so that transform handles reappear
310 if (_drag_out) {
311 _parent->ungrabbed(event);
312 }
313 _drag_out = false;
315 _pm()._handleUngrabbed();
316 }
318 bool Handle::clicked(GdkEventButton *event)
319 {
320 _pm()._handleClicked(this, event);
321 return true;
322 }
324 Handle *Handle::other()
325 {
326 if (this == &_parent->_front) return &_parent->_back;
327 return &_parent->_front;
328 }
330 static double snap_increment_degrees() {
331 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
332 int snaps = prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
333 return 180.0 / snaps;
334 }
336 Glib::ustring Handle::_getTip(unsigned state)
337 {
338 char const *more;
339 bool can_shift_rotate = _parent->type() == NODE_CUSP && !other()->isDegenerate();
340 if (can_shift_rotate) {
341 more = C_("Path handle tip", "more: Shift, Ctrl, Alt");
342 } else {
343 more = C_("Path handle tip", "more: Ctrl, Alt");
344 }
345 if (state_held_alt(state)) {
346 if (state_held_control(state)) {
347 if (state_held_shift(state) && can_shift_rotate) {
348 return format_tip(C_("Path handle tip",
349 "<b>Shift+Ctrl+Alt</b>: preserve length and snap rotation angle to %g° "
350 "increments while rotating both handles"),
351 snap_increment_degrees());
352 } else {
353 return format_tip(C_("Path handle tip",
354 "<b>Ctrl+Alt</b>: preserve length and snap rotation angle to %g° increments"),
355 snap_increment_degrees());
356 }
357 } else {
358 if (state_held_shift(state) && can_shift_rotate) {
359 return C_("Path handle tip",
360 "<b>Shift+Alt</b>: preserve handle length and rotate both handles");
361 } else {
362 return C_("Path handle tip",
363 "<b>Alt</b>: preserve handle length while dragging");
364 }
365 }
366 } else {
367 if (state_held_control(state)) {
368 if (state_held_shift(state) && can_shift_rotate) {
369 return format_tip(C_("Path handle tip",
370 "<b>Shift+Ctrl</b>: snap rotation angle to %g° increments and rotate both handles"),
371 snap_increment_degrees());
372 } else {
373 return format_tip(C_("Path handle tip",
374 "<b>Ctrl</b>: snap rotation angle to %g° increments, click to retract"),
375 snap_increment_degrees());
376 }
377 } else if (state_held_shift(state) && can_shift_rotate) {
378 return C_("Path hande tip",
379 "<b>Shift</b>: rotate both handles by the same angle");
380 }
381 }
383 switch (_parent->type()) {
384 case NODE_AUTO:
385 return format_tip(C_("Path handle tip",
386 "<b>Auto node handle</b>: drag to convert to smooth node (%s)"), more);
387 default:
388 return format_tip(C_("Path handle tip",
389 "<b>%s</b>: drag to shape the segment (%s)"),
390 handle_type_to_localized_string(_parent->type()), more);
391 }
392 }
394 Glib::ustring Handle::_getDragTip(GdkEventMotion */*event*/)
395 {
396 Geom::Point dist = position() - _last_drag_origin();
397 // report angle in mathematical convention
398 double angle = Geom::angle_between(Geom::Point(-1,0), position() - _parent->position());
399 angle += M_PI; // angle is (-M_PI...M_PI] - offset by +pi and scale to 0...360
400 angle *= 360.0 / (2 * M_PI);
401 GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
402 GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
403 GString *len = SP_PX_TO_METRIC_STRING(length(), _desktop->namedview->getDefaultMetric());
404 Glib::ustring ret = format_tip(C_("Path handle tip",
405 "Move handle by %s, %s; angle %.2f°, length %s"), x->str, y->str, angle, len->str);
406 g_string_free(x, TRUE);
407 g_string_free(y, TRUE);
408 g_string_free(len, TRUE);
409 return ret;
410 }
412 /**
413 * @class Node
414 * @brief Curve endpoint in an editable path.
415 *
416 * The method move() keeps node type invariants during translations.
417 */
419 Node::Node(NodeSharedData const &data, Geom::Point const &initial_pos)
420 : SelectableControlPoint(data.desktop, initial_pos, Gtk::ANCHOR_CENTER,
421 SP_CTRL_SHAPE_DIAMOND, 9.0, *data.selection, &node_colors, data.node_group)
422 , _front(data, initial_pos, this)
423 , _back(data, initial_pos, this)
424 , _type(NODE_CUSP)
425 , _handles_shown(false)
426 {
427 // NOTE we do not set type here, because the handles are still degenerate
428 }
430 // NOTE: not using iterators won't make this much quicker because iterators can be 100% inlined.
431 Node *Node::_next()
432 {
433 NodeList::iterator n = NodeList::get_iterator(this).next();
434 if (n) return n.ptr();
435 return NULL;
436 }
437 Node *Node::_prev()
438 {
439 NodeList::iterator p = NodeList::get_iterator(this).prev();
440 if (p) return p.ptr();
441 return NULL;
442 }
444 void Node::move(Geom::Point const &new_pos)
445 {
446 // move handles when the node moves.
447 Geom::Point old_pos = position();
448 Geom::Point delta = new_pos - position();
449 setPosition(new_pos);
450 _front.setPosition(_front.position() + delta);
451 _back.setPosition(_back.position() + delta);
453 // if the node has a smooth handle after a line segment, it should be kept colinear
454 // with the segment
455 _fixNeighbors(old_pos, new_pos);
456 }
458 void Node::transform(Geom::Matrix const &m)
459 {
460 Geom::Point old_pos = position();
461 setPosition(position() * m);
462 _front.setPosition(_front.position() * m);
463 _back.setPosition(_back.position() * m);
465 /* Affine transforms keep handle invariants for smooth and symmetric nodes,
466 * but smooth nodes at ends of linear segments and auto nodes need special treatment */
467 _fixNeighbors(old_pos, position());
468 }
470 Geom::Rect Node::bounds()
471 {
472 Geom::Rect b(position(), position());
473 b.expandTo(_front.position());
474 b.expandTo(_back.position());
475 return b;
476 }
478 void Node::_fixNeighbors(Geom::Point const &old_pos, Geom::Point const &new_pos)
479 {
480 /* This method restores handle invariants for neighboring nodes,
481 * and invariants that are based on positions of those nodes for this one. */
483 /* Fix auto handles */
484 if (_type == NODE_AUTO) _updateAutoHandles();
485 if (old_pos != new_pos) {
486 if (_next() && _next()->_type == NODE_AUTO) _next()->_updateAutoHandles();
487 if (_prev() && _prev()->_type == NODE_AUTO) _prev()->_updateAutoHandles();
488 }
490 /* Fix smooth handles at the ends of linear segments.
491 * Rotate the appropriate handle to be colinear with the segment.
492 * If there is a smooth node at the other end of the segment, rotate it too. */
493 Handle *handle, *other_handle;
494 Node *other;
495 if (_is_line_segment(this, _next())) {
496 handle = &_back;
497 other = _next();
498 other_handle = &_next()->_front;
499 } else if (_is_line_segment(_prev(), this)) {
500 handle = &_front;
501 other = _prev();
502 other_handle = &_prev()->_back;
503 } else return;
505 if (_type == NODE_SMOOTH && !handle->isDegenerate()) {
506 handle->setDirection(other->position(), new_pos);
507 }
508 // also update the handle on the other end of the segment
509 if (other->_type == NODE_SMOOTH && !other_handle->isDegenerate()) {
510 other_handle->setDirection(new_pos, other->position());
511 }
512 }
514 void Node::_updateAutoHandles()
515 {
516 // Recompute the position of automatic handles.
517 // For endnodes, retract both handles. (It's only possible to create an end auto node
518 // through the XML editor.)
519 if (isEndNode()) {
520 _front.retract();
521 _back.retract();
522 return;
523 }
525 // Auto nodes automaticaly adjust their handles to give an appearance of smoothness,
526 // no matter what their surroundings are.
527 Geom::Point vec_next = _next()->position() - position();
528 Geom::Point vec_prev = _prev()->position() - position();
529 double len_next = vec_next.length(), len_prev = vec_prev.length();
530 if (len_next > 0 && len_prev > 0) {
531 // "dir" is an unit vector perpendicular to the bisector of the angle created
532 // by the previous node, this auto node and the next node.
533 Geom::Point dir = Geom::unit_vector((len_prev / len_next) * vec_next - vec_prev);
534 // Handle lengths are equal to 1/3 of the distance from the adjacent node.
535 _back.setRelativePos(-dir * (len_prev / 3));
536 _front.setRelativePos(dir * (len_next / 3));
537 } else {
538 // If any of the adjacent nodes coincides, retract both handles.
539 _front.retract();
540 _back.retract();
541 }
542 }
544 void Node::showHandles(bool v)
545 {
546 _handles_shown = v;
547 if (!_front.isDegenerate()) _front.setVisible(v);
548 if (!_back.isDegenerate()) _back.setVisible(v);
549 }
551 /** Sets the node type and optionally restores the invariants associated with the given type.
552 * @param type The type to set
553 * @param update_handles Whether to restore invariants associated with the given type.
554 * Passing false is useful e.g. wen initially creating the path,
555 * and when making cusp nodes during some node algorithms.
556 * Pass true when used in response to an UI node type button.
557 */
558 void Node::setType(NodeType type, bool update_handles)
559 {
560 if (type == NODE_PICK_BEST) {
561 pickBestType();
562 updateState(); // The size of the control might have changed
563 return;
564 }
566 // if update_handles is true, adjust handle positions to match the node type
567 // handle degenerate handles appropriately
568 if (update_handles) {
569 switch (type) {
570 case NODE_CUSP:
571 // nothing to do
572 break;
573 case NODE_AUTO:
574 // auto handles make no sense for endnodes
575 if (isEndNode()) return;
576 _updateAutoHandles();
577 break;
578 case NODE_SMOOTH: {
579 // ignore attempts to make smooth endnodes.
580 if (isEndNode()) return;
581 // rotate handles to be colinear
582 // for degenerate nodes set positions like auto handles
583 bool prev_line = _is_line_segment(_prev(), this);
584 bool next_line = _is_line_segment(this, _next());
585 if (_type == NODE_SMOOTH) {
586 // For a node that is already smooth and has a degenerate handle,
587 // drag out the second handle without changing the direction of the first one.
588 if (_front.isDegenerate()) {
589 double dist = Geom::distance(_next()->position(), position());
590 _front.setRelativePos(Geom::unit_vector(-_back.relativePos()) * dist / 3);
591 }
592 if (_back.isDegenerate()) {
593 double dist = Geom::distance(_prev()->position(), position());
594 _back.setRelativePos(Geom::unit_vector(-_front.relativePos()) * dist / 3);
595 }
596 } else if (isDegenerate()) {
597 _updateAutoHandles();
598 } else if (_front.isDegenerate()) {
599 // if the front handle is degenerate and this...next is a line segment,
600 // make back colinear; otherwise pull out the other handle
601 // to 1/3 of distance to prev
602 if (next_line) {
603 _back.setDirection(*_next(), *this);
604 } else if (_prev()) {
605 Geom::Point dir = direction(_back, *this);
606 _front.setRelativePos(Geom::distance(_prev()->position(), position()) / 3 * dir);
607 }
608 } else if (_back.isDegenerate()) {
609 if (prev_line) {
610 _front.setDirection(*_prev(), *this);
611 } else if (_next()) {
612 Geom::Point dir = direction(_front, *this);
613 _back.setRelativePos(Geom::distance(_next()->position(), position()) / 3 * dir);
614 }
615 } else {
616 // both handles are extended. make colinear while keeping length
617 // first make back colinear with the vector front ---> back,
618 // then make front colinear with back ---> node
619 // (not back ---> front because back's position was changed in the first call)
620 _back.setDirection(_front, _back);
621 _front.setDirection(_back, *this);
622 }
623 } break;
624 case NODE_SYMMETRIC:
625 if (isEndNode()) return; // symmetric handles make no sense for endnodes
626 if (isDegenerate()) {
627 // similar to auto handles but set the same length for both
628 Geom::Point vec_next = _next()->position() - position();
629 Geom::Point vec_prev = _prev()->position() - position();
630 double len_next = vec_next.length(), len_prev = vec_prev.length();
631 double len = (len_next + len_prev) / 6; // take 1/3 of average
632 if (len == 0) return;
634 Geom::Point dir = Geom::unit_vector((len_prev / len_next) * vec_next - vec_prev);
635 _back.setRelativePos(-dir * len);
636 _front.setRelativePos(dir * len);
637 } else {
638 // Both handles are extended. Compute average length, use direction from
639 // back handle to front handle. This also works correctly for degenerates
640 double len = (_front.length() + _back.length()) / 2;
641 Geom::Point dir = direction(_back, _front);
642 _front.setRelativePos(dir * len);
643 _back.setRelativePos(-dir * len);
644 }
645 break;
646 default: break;
647 }
648 }
649 _type = type;
650 _setShape(_node_type_to_shape(type));
651 updateState();
652 }
654 /** Pick the best type for this node, based on the position of its handles.
655 * This is what assigns types to nodes created using the pen tool. */
656 void Node::pickBestType()
657 {
658 _type = NODE_CUSP;
659 bool front_degen = _front.isDegenerate();
660 bool back_degen = _back.isDegenerate();
661 bool both_degen = front_degen && back_degen;
662 bool neither_degen = !front_degen && !back_degen;
663 do {
664 // if both handles are degenerate, do nothing
665 if (both_degen) break;
666 // if neither are degenerate, check their respective positions
667 if (neither_degen) {
668 Geom::Point front_delta = _front.position() - position();
669 Geom::Point back_delta = _back.position() - position();
670 // for now do not automatically make nodes symmetric, it can be annoying
671 /*if (Geom::are_near(front_delta, -back_delta)) {
672 _type = NODE_SYMMETRIC;
673 break;
674 }*/
675 if (Geom::are_near(Geom::unit_vector(front_delta),
676 Geom::unit_vector(-back_delta)))
677 {
678 _type = NODE_SMOOTH;
679 break;
680 }
681 }
682 // check whether the handle aligns with the previous line segment.
683 // we know that if front is degenerate, back isn't, because
684 // both_degen was false
685 if (front_degen && _next() && _next()->_back.isDegenerate()) {
686 Geom::Point segment_delta = Geom::unit_vector(_next()->position() - position());
687 Geom::Point handle_delta = Geom::unit_vector(_back.position() - position());
688 if (Geom::are_near(segment_delta, -handle_delta)) {
689 _type = NODE_SMOOTH;
690 break;
691 }
692 } else if (back_degen && _prev() && _prev()->_front.isDegenerate()) {
693 Geom::Point segment_delta = Geom::unit_vector(_prev()->position() - position());
694 Geom::Point handle_delta = Geom::unit_vector(_front.position() - position());
695 if (Geom::are_near(segment_delta, -handle_delta)) {
696 _type = NODE_SMOOTH;
697 break;
698 }
699 }
700 } while (false);
701 _setShape(_node_type_to_shape(_type));
702 updateState();
703 }
705 bool Node::isEndNode()
706 {
707 return !_prev() || !_next();
708 }
710 /** Move the node to the bottom of its canvas group. Useful for node break, to ensure that
711 * the selected nodes are above the unselected ones. */
712 void Node::sink()
713 {
714 sp_canvas_item_move_to_z(_canvas_item, 0);
715 }
717 NodeType Node::parse_nodetype(char x)
718 {
719 switch (x) {
720 case 'a': return NODE_AUTO;
721 case 'c': return NODE_CUSP;
722 case 's': return NODE_SMOOTH;
723 case 'z': return NODE_SYMMETRIC;
724 default: return NODE_PICK_BEST;
725 }
726 }
728 /** Customized event handler to catch scroll events needed for selection grow/shrink. */
729 bool Node::_eventHandler(GdkEvent *event)
730 {
731 int dir = 0;
733 switch (event->type)
734 {
735 case GDK_SCROLL:
736 if (event->scroll.direction == GDK_SCROLL_UP) {
737 dir = 1;
738 } else if (event->scroll.direction == GDK_SCROLL_DOWN) {
739 dir = -1;
740 } else break;
741 if (held_control(event->scroll)) {
742 _linearGrow(dir);
743 } else {
744 _selection.spatialGrow(this, dir);
745 }
746 return true;
747 case GDK_KEY_PRESS:
748 switch (shortcut_key(event->key))
749 {
750 case GDK_Page_Up:
751 dir = 1;
752 break;
753 case GDK_Page_Down:
754 dir = -1;
755 break;
756 default: goto bail_out;
757 }
759 if (held_control(event->key)) {
760 _linearGrow(dir);
761 } else {
762 _selection.spatialGrow(this, dir);
763 }
764 return true;
765 default:
766 break;
767 }
769 bail_out:
770 return ControlPoint::_eventHandler(event);
771 }
773 // TODO Move this to 2Geom!
774 static double bezier_length (Geom::Point a0, Geom::Point a1, Geom::Point a2, Geom::Point a3)
775 {
776 double lower = Geom::distance(a0, a3);
777 double upper = Geom::distance(a0, a1) + Geom::distance(a1, a2) + Geom::distance(a2, a3);
779 if (upper - lower < Geom::EPSILON) return (lower + upper)/2;
781 Geom::Point // Casteljau subdivision
782 b0 = a0,
783 c0 = a3,
784 b1 = 0.5*(a0 + a1),
785 t0 = 0.5*(a1 + a2),
786 c1 = 0.5*(a2 + a3),
787 b2 = 0.5*(b1 + t0),
788 c2 = 0.5*(t0 + c1),
789 b3 = 0.5*(b2 + c2); // == c3
790 return bezier_length(b0, b1, b2, b3) + bezier_length(b3, c2, c1, c0);
791 }
793 /** Select or deselect a node in this node's subpath based on its path distance from this node.
794 * @param dir If negative, shrink selection by one node; if positive, grow by one node */
795 void Node::_linearGrow(int dir)
796 {
797 // Interestingly, we do not need any help from PathManipulator when doing linear grow.
798 // First handle the trivial case of growing over an unselected node.
799 if (!selected() && dir > 0) {
800 _selection.insert(this);
801 return;
802 }
804 NodeList::iterator this_iter = NodeList::get_iterator(this);
805 NodeList::iterator fwd = this_iter, rev = this_iter;
806 double distance_back = 0, distance_front = 0;
808 // Linear grow is simple. We find the first unselected nodes in each direction
809 // and compare the linear distances to them.
810 if (dir > 0) {
811 if (!selected()) {
812 _selection.insert(this);
813 return;
814 }
816 // find first unselected nodes on both sides
817 while (fwd && fwd->selected()) {
818 NodeList::iterator n = fwd.next();
819 distance_front += bezier_length(*fwd, fwd->_front, n->_back, *n);
820 fwd = n;
821 if (fwd == this_iter)
822 // there is no unselected node in this cyclic subpath
823 return;
824 }
825 // do the same for the second direction. Do not check for equality with
826 // this node, because there is at least one unselected node in the subpath,
827 // so we are guaranteed to stop.
828 while (rev && rev->selected()) {
829 NodeList::iterator p = rev.prev();
830 distance_back += bezier_length(*rev, rev->_back, p->_front, *p);
831 rev = p;
832 }
834 NodeList::iterator t; // node to select
835 if (fwd && rev) {
836 if (distance_front <= distance_back) t = fwd;
837 else t = rev;
838 } else {
839 if (fwd) t = fwd;
840 if (rev) t = rev;
841 }
842 if (t) _selection.insert(t.ptr());
844 // Linear shrink is more complicated. We need to find the farthest selected node.
845 // This means we have to check the entire subpath. We go in the direction in which
846 // the distance we traveled is lower. We do this until we run out of nodes (ends of path)
847 // or the two iterators meet. On the way, we store the last selected node and its distance
848 // in each direction (if any). At the end, we choose the one that is farther and deselect it.
849 } else {
850 // both iterators that store last selected nodes are initially empty
851 NodeList::iterator last_fwd, last_rev;
852 double last_distance_back = 0, last_distance_front = 0;
854 while (rev || fwd) {
855 if (fwd && (!rev || distance_front <= distance_back)) {
856 if (fwd->selected()) {
857 last_fwd = fwd;
858 last_distance_front = distance_front;
859 }
860 NodeList::iterator n = fwd.next();
861 if (n) distance_front += bezier_length(*fwd, fwd->_front, n->_back, *n);
862 fwd = n;
863 } else if (rev && (!fwd || distance_front > distance_back)) {
864 if (rev->selected()) {
865 last_rev = rev;
866 last_distance_back = distance_back;
867 }
868 NodeList::iterator p = rev.prev();
869 if (p) distance_back += bezier_length(*rev, rev->_back, p->_front, *p);
870 rev = p;
871 }
872 // Check whether we walked the entire cyclic subpath.
873 // This is initially true because both iterators start from this node,
874 // so this check cannot go in the while condition.
875 // When this happens, we need to check the last node, pointed to by the iterators.
876 if (fwd && fwd == rev) {
877 if (!fwd->selected()) break;
878 NodeList::iterator fwdp = fwd.prev(), revn = rev.next();
879 double df = distance_front + bezier_length(*fwdp, fwdp->_front, fwd->_back, *fwd);
880 double db = distance_back + bezier_length(*revn, revn->_back, rev->_front, *rev);
881 if (df > db) {
882 last_fwd = fwd;
883 last_distance_front = df;
884 } else {
885 last_rev = rev;
886 last_distance_back = db;
887 }
888 break;
889 }
890 }
892 NodeList::iterator t;
893 if (last_fwd && last_rev) {
894 if (last_distance_front >= last_distance_back) t = last_fwd;
895 else t = last_rev;
896 } else {
897 if (last_fwd) t = last_fwd;
898 if (last_rev) t = last_rev;
899 }
900 if (t) _selection.erase(t.ptr());
901 }
902 }
904 void Node::_setState(State state)
905 {
906 // change node size to match type and selection state
907 switch (_type) {
908 case NODE_AUTO:
909 case NODE_CUSP:
910 if (selected()) _setSize(11);
911 else _setSize(9);
912 break;
913 default:
914 if(selected()) _setSize(9);
915 else _setSize(7);
916 break;
917 }
918 SelectableControlPoint::_setState(state);
919 }
921 bool Node::grabbed(GdkEventMotion *event)
922 {
923 if (SelectableControlPoint::grabbed(event))
924 return true;
926 // Dragging out handles with Shift + drag on a node.
927 if (!held_shift(*event)) return false;
929 Handle *h;
930 Geom::Point evp = event_point(*event);
931 Geom::Point rel_evp = evp - _last_click_event_point();
933 // This should work even if dragtolerance is zero and evp coincides with node position.
934 double angle_next = HUGE_VAL;
935 double angle_prev = HUGE_VAL;
936 bool has_degenerate = false;
937 // determine which handle to drag out based on degeneration and the direction of drag
938 if (_front.isDegenerate() && _next()) {
939 Geom::Point next_relpos = _desktop->d2w(_next()->position())
940 - _desktop->d2w(position());
941 angle_next = fabs(Geom::angle_between(rel_evp, next_relpos));
942 has_degenerate = true;
943 }
944 if (_back.isDegenerate() && _prev()) {
945 Geom::Point prev_relpos = _desktop->d2w(_prev()->position())
946 - _desktop->d2w(position());
947 angle_prev = fabs(Geom::angle_between(rel_evp, prev_relpos));
948 has_degenerate = true;
949 }
950 if (!has_degenerate) return false;
951 h = angle_next < angle_prev ? &_front : &_back;
953 h->setPosition(_desktop->w2d(evp));
954 h->setVisible(true);
955 h->transferGrab(this, event);
956 Handle::_drag_out = true;
957 return true;
958 }
960 void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event)
961 {
962 // For a note on how snapping is implemented in Inkscape, see snap.h.
963 SnapManager &sm = _desktop->namedview->snap_manager;
964 // even if we won't really snap, we might still call the one of the
965 // constrainedSnap() methods to enforce the constraints, so we need
966 // to setup the snapmanager anyway; this is also required for someSnapperMightSnap()
967 sm.setup(_desktop);
969 // do not snap when Shift is pressed
970 bool snap = !held_shift(*event) && sm.someSnapperMightSnap();
972 Inkscape::SnappedPoint sp;
973 std::vector<Inkscape::SnapCandidatePoint> unselected;
974 if (snap) {
975 /* setup
976 * TODO We are doing this every time a snap happens. It should once be done only once
977 * per drag - maybe in the grabbed handler?
978 * TODO Unselected nodes vector must be valid during the snap run, because it is not
979 * copied. Fix this in snap.h and snap.cpp, then the above.
980 * TODO Snapping to unselected segments of selected paths doesn't work yet. */
982 // Build the list of unselected nodes.
983 typedef ControlPointSelection::Set Set;
984 Set &nodes = _selection.allPoints();
985 for (Set::iterator i = nodes.begin(); i != nodes.end(); ++i) {
986 if (!(*i)->selected()) {
987 Node *n = static_cast<Node*>(*i);
988 Inkscape::SnapCandidatePoint p(n->position(), n->_snapSourceType(), n->_snapTargetType());
989 unselected.push_back(p);
990 }
991 }
992 sm.unSetup();
993 sm.setupIgnoreSelection(_desktop, true, &unselected);
994 }
996 if (held_control(*event)) {
997 Geom::Point origin = _last_drag_origin();
998 std::vector<Inkscape::Snapper::SnapConstraint> constraints;
999 if (held_alt(*event)) {
1000 // with Ctrl+Alt, constrain to handle lines
1001 // project the new position onto a handle line that is closer;
1002 // also snap to perpendiculars of handle lines
1004 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1005 int snaps = prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
1006 double min_angle = M_PI / snaps;
1008 boost::optional<Geom::Point> front_point, back_point, fperp_point, bperp_point;
1009 if (_front.isDegenerate()) {
1010 if (_is_line_segment(this, _next()))
1011 front_point = _next()->position() - origin;
1012 } else {
1013 front_point = _front.relativePos();
1014 }
1015 if (_back.isDegenerate()) {
1016 if (_is_line_segment(_prev(), this))
1017 back_point = _prev()->position() - origin;
1018 } else {
1019 back_point = _back.relativePos();
1020 }
1021 if (front_point) {
1022 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *front_point));
1023 fperp_point = Geom::rot90(*front_point);
1024 }
1025 if (back_point) {
1026 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *back_point));
1027 bperp_point = Geom::rot90(*back_point);
1028 }
1029 // perpendiculars only snap when they are further than snap increment away
1030 // from the second handle constraint
1031 if (fperp_point && (!back_point ||
1032 (fabs(Geom::angle_between(*fperp_point, *back_point)) > min_angle &&
1033 fabs(Geom::angle_between(*fperp_point, *back_point)) < M_PI - min_angle)))
1034 {
1035 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *fperp_point));
1036 }
1037 if (bperp_point && (!front_point ||
1038 (fabs(Geom::angle_between(*bperp_point, *front_point)) > min_angle &&
1039 fabs(Geom::angle_between(*bperp_point, *front_point)) < M_PI - min_angle)))
1040 {
1041 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *bperp_point));
1042 }
1044 sp = sm.multipleConstrainedSnaps(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), constraints, held_shift(*event));
1045 } else {
1046 // with Ctrl, constrain to axes
1047 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, Geom::Point(1, 0)));
1048 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, Geom::Point(0, 1)));
1049 sp = sm.multipleConstrainedSnaps(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), constraints, held_shift(*event));
1050 }
1051 new_pos = sp.getPoint();
1052 } else if (snap) {
1053 sp = sm.freeSnap(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()));
1054 new_pos = sp.getPoint();
1055 }
1057 sm.unSetup();
1059 SelectableControlPoint::dragged(new_pos, event);
1060 }
1062 bool Node::clicked(GdkEventButton *event)
1063 {
1064 if(_pm()._nodeClicked(this, event))
1065 return true;
1066 return SelectableControlPoint::clicked(event);
1067 }
1069 Inkscape::SnapSourceType Node::_snapSourceType()
1070 {
1071 if (_type == NODE_SMOOTH || _type == NODE_AUTO)
1072 return SNAPSOURCE_NODE_SMOOTH;
1073 return SNAPSOURCE_NODE_CUSP;
1074 }
1075 Inkscape::SnapTargetType Node::_snapTargetType()
1076 {
1077 if (_type == NODE_SMOOTH || _type == NODE_AUTO)
1078 return SNAPTARGET_NODE_SMOOTH;
1079 return SNAPTARGET_NODE_CUSP;
1080 }
1082 /** @brief Gets the handle that faces the given adjacent node.
1083 * Will abort with error if the given node is not adjacent. */
1084 Handle *Node::handleToward(Node *to)
1085 {
1086 if (_next() == to) {
1087 return front();
1088 }
1089 if (_prev() == to) {
1090 return back();
1091 }
1092 g_error("Node::handleToward(): second node is not adjacent!");
1093 }
1095 /** @brief Gets the node in the direction of the given handle.
1096 * Will abort with error if the handle doesn't belong to this node. */
1097 Node *Node::nodeToward(Handle *dir)
1098 {
1099 if (front() == dir) {
1100 return _next();
1101 }
1102 if (back() == dir) {
1103 return _prev();
1104 }
1105 g_error("Node::nodeToward(): handle is not a child of this node!");
1106 }
1108 /** @brief Gets the handle that goes in the direction opposite to the given adjacent node.
1109 * Will abort with error if the given node is not adjacent. */
1110 Handle *Node::handleAwayFrom(Node *to)
1111 {
1112 if (_next() == to) {
1113 return back();
1114 }
1115 if (_prev() == to) {
1116 return front();
1117 }
1118 g_error("Node::handleAwayFrom(): second node is not adjacent!");
1119 }
1121 /** @brief Gets the node in the direction opposite to the given handle.
1122 * Will abort with error if the handle doesn't belong to this node. */
1123 Node *Node::nodeAwayFrom(Handle *h)
1124 {
1125 if (front() == h) {
1126 return _prev();
1127 }
1128 if (back() == h) {
1129 return _next();
1130 }
1131 g_error("Node::nodeAwayFrom(): handle is not a child of this node!");
1132 }
1134 Glib::ustring Node::_getTip(unsigned state)
1135 {
1136 if (state_held_shift(state)) {
1137 bool can_drag_out = (_next() && _front.isDegenerate()) || (_prev() && _back.isDegenerate());
1138 if (can_drag_out) {
1139 /*if (state_held_control(state)) {
1140 return format_tip(C_("Path node tip",
1141 "<b>Shift+Ctrl:</b> drag out a handle and snap its angle "
1142 "to %f° increments"), snap_increment_degrees());
1143 }*/
1144 return C_("Path node tip",
1145 "<b>Shift</b>: drag out a handle, click to toggle selection");
1146 }
1147 return C_("Path node tip", "<b>Shift</b>: click to toggle selection");
1148 }
1150 if (state_held_control(state)) {
1151 if (state_held_alt(state)) {
1152 return C_("Path node tip", "<b>Ctrl+Alt</b>: move along handle lines, click to delete node");
1153 }
1154 return C_("Path node tip",
1155 "<b>Ctrl</b>: move along axes, click to change node type");
1156 }
1158 if (state_held_alt(state)) {
1159 return C_("Path node tip", "<b>Alt</b>: sculpt nodes");
1160 }
1162 // No modifiers: assemble tip from node type
1163 char const *nodetype = node_type_to_localized_string(_type);
1164 if (_selection.transformHandlesEnabled() && selected()) {
1165 if (_selection.size() == 1) {
1166 return format_tip(C_("Path node tip",
1167 "<b>%s</b>: drag to shape the path (more: Shift, Ctrl, Alt)"), nodetype);
1168 }
1169 return format_tip(C_("Path node tip",
1170 "<b>%s</b>: drag to shape the path, click to toggle scale/rotation handles (more: Shift, Ctrl, Alt)"), nodetype);
1171 }
1172 return format_tip(C_("Path node tip",
1173 "<b>%s</b>: drag to shape the path, click to select only this node (more: Shift, Ctrl, Alt)"), nodetype);
1174 }
1176 Glib::ustring Node::_getDragTip(GdkEventMotion */*event*/)
1177 {
1178 Geom::Point dist = position() - _last_drag_origin();
1179 GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
1180 GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
1181 Glib::ustring ret = format_tip(C_("Path node tip", "Move node by %s, %s"),
1182 x->str, y->str);
1183 g_string_free(x, TRUE);
1184 g_string_free(y, TRUE);
1185 return ret;
1186 }
1188 char const *Node::node_type_to_localized_string(NodeType type)
1189 {
1190 switch (type) {
1191 case NODE_CUSP: return _("Cusp node");
1192 case NODE_SMOOTH: return _("Smooth node");
1193 case NODE_SYMMETRIC: return _("Symmetric node");
1194 case NODE_AUTO: return _("Auto-smooth node");
1195 default: return "";
1196 }
1197 }
1199 /** Determine whether two nodes are joined by a linear segment. */
1200 bool Node::_is_line_segment(Node *first, Node *second)
1201 {
1202 if (!first || !second) return false;
1203 if (first->_next() == second)
1204 return first->_front.isDegenerate() && second->_back.isDegenerate();
1205 if (second->_next() == first)
1206 return second->_front.isDegenerate() && first->_back.isDegenerate();
1207 return false;
1208 }
1210 SPCtrlShapeType Node::_node_type_to_shape(NodeType type)
1211 {
1212 switch(type) {
1213 case NODE_CUSP: return SP_CTRL_SHAPE_DIAMOND;
1214 case NODE_SMOOTH: return SP_CTRL_SHAPE_SQUARE;
1215 case NODE_AUTO: return SP_CTRL_SHAPE_CIRCLE;
1216 case NODE_SYMMETRIC: return SP_CTRL_SHAPE_SQUARE;
1217 default: return SP_CTRL_SHAPE_DIAMOND;
1218 }
1219 }
1222 /**
1223 * @class NodeList
1224 * @brief An editable list of nodes representing a subpath.
1225 *
1226 * It can optionally be cyclic to represent a closed path.
1227 * The list has iterators that act like plain node iterators, but can also be used
1228 * to obtain shared pointers to nodes.
1229 */
1231 NodeList::NodeList(SubpathList &splist)
1232 : _list(splist)
1233 , _closed(false)
1234 {
1235 this->ln_list = this;
1236 this->ln_next = this;
1237 this->ln_prev = this;
1238 }
1240 NodeList::~NodeList()
1241 {
1242 clear();
1243 }
1245 bool NodeList::empty()
1246 {
1247 return ln_next == this;
1248 }
1250 NodeList::size_type NodeList::size()
1251 {
1252 size_type sz = 0;
1253 for (ListNode *ln = ln_next; ln != this; ln = ln->ln_next) ++sz;
1254 return sz;
1255 }
1257 bool NodeList::closed()
1258 {
1259 return _closed;
1260 }
1262 /** A subpath is degenerate if it has no segments - either one node in an open path
1263 * or no nodes in a closed path */
1264 bool NodeList::degenerate()
1265 {
1266 return closed() ? empty() : ++begin() == end();
1267 }
1269 NodeList::iterator NodeList::before(double t, double *fracpart)
1270 {
1271 double intpart;
1272 *fracpart = std::modf(t, &intpart);
1273 int index = intpart;
1275 iterator ret = begin();
1276 std::advance(ret, index);
1277 return ret;
1278 }
1280 // insert a node before i
1281 NodeList::iterator NodeList::insert(iterator i, Node *x)
1282 {
1283 ListNode *ins = i._node;
1284 x->ln_next = ins;
1285 x->ln_prev = ins->ln_prev;
1286 ins->ln_prev->ln_next = x;
1287 ins->ln_prev = x;
1288 x->ln_list = this;
1289 return iterator(x);
1290 }
1292 void NodeList::splice(iterator pos, NodeList &list)
1293 {
1294 splice(pos, list, list.begin(), list.end());
1295 }
1297 void NodeList::splice(iterator pos, NodeList &list, iterator i)
1298 {
1299 NodeList::iterator j = i;
1300 ++j;
1301 splice(pos, list, i, j);
1302 }
1304 void NodeList::splice(iterator pos, NodeList &/*list*/, iterator first, iterator last)
1305 {
1306 ListNode *ins_beg = first._node, *ins_end = last._node, *at = pos._node;
1307 for (ListNode *ln = ins_beg; ln != ins_end; ln = ln->ln_next) {
1308 ln->ln_list = this;
1309 }
1310 ins_beg->ln_prev->ln_next = ins_end;
1311 ins_end->ln_prev->ln_next = at;
1312 at->ln_prev->ln_next = ins_beg;
1314 ListNode *atprev = at->ln_prev;
1315 at->ln_prev = ins_end->ln_prev;
1316 ins_end->ln_prev = ins_beg->ln_prev;
1317 ins_beg->ln_prev = atprev;
1318 }
1320 void NodeList::shift(int n)
1321 {
1322 // 1. make the list perfectly cyclic
1323 ln_next->ln_prev = ln_prev;
1324 ln_prev->ln_next = ln_next;
1325 // 2. find new begin
1326 ListNode *new_begin = ln_next;
1327 if (n > 0) {
1328 for (; n > 0; --n) new_begin = new_begin->ln_next;
1329 } else {
1330 for (; n < 0; ++n) new_begin = new_begin->ln_prev;
1331 }
1332 // 3. relink begin to list
1333 ln_next = new_begin;
1334 ln_prev = new_begin->ln_prev;
1335 new_begin->ln_prev->ln_next = this;
1336 new_begin->ln_prev = this;
1337 }
1339 void NodeList::reverse()
1340 {
1341 for (ListNode *ln = ln_next; ln != this; ln = ln->ln_prev) {
1342 std::swap(ln->ln_next, ln->ln_prev);
1343 Node *node = static_cast<Node*>(ln);
1344 Geom::Point save_pos = node->front()->position();
1345 node->front()->setPosition(node->back()->position());
1346 node->back()->setPosition(save_pos);
1347 }
1348 std::swap(ln_next, ln_prev);
1349 }
1351 void NodeList::clear()
1352 {
1353 for (iterator i = begin(); i != end();) erase (i++);
1354 }
1356 NodeList::iterator NodeList::erase(iterator i)
1357 {
1358 // some gymnastics are required to ensure that the node is valid when deleted;
1359 // otherwise the code that updates handle visibility will break
1360 Node *rm = static_cast<Node*>(i._node);
1361 ListNode *rmnext = rm->ln_next, *rmprev = rm->ln_prev;
1362 ++i;
1363 delete rm;
1364 rmprev->ln_next = rmnext;
1365 rmnext->ln_prev = rmprev;
1366 return i;
1367 }
1369 // TODO this method is very ugly!
1370 // converting SubpathList to an intrusive list might allow us to get rid of it
1371 void NodeList::kill()
1372 {
1373 for (SubpathList::iterator i = _list.begin(); i != _list.end(); ++i) {
1374 if (i->get() == this) {
1375 _list.erase(i);
1376 return;
1377 }
1378 }
1379 }
1381 NodeList &NodeList::get(Node *n) {
1382 return n->nodeList();
1383 }
1384 NodeList &NodeList::get(iterator const &i) {
1385 return *(i._node->ln_list);
1386 }
1389 /**
1390 * @class SubpathList
1391 * @brief Editable path composed of one or more subpaths
1392 */
1394 } // namespace UI
1395 } // namespace Inkscape
1397 /*
1398 Local Variables:
1399 mode:c++
1400 c-file-style:"stroustrup"
1401 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1402 indent-tabs-mode:nil
1403 fill-column:99
1404 End:
1405 */
1406 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :