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 // if the existing type is also NODE_CUSP, retract handles
572 if (_type == NODE_CUSP) {
573 _front.retract();
574 _back.retract();
575 }
576 break;
577 case NODE_AUTO:
578 // auto handles make no sense for endnodes
579 if (isEndNode()) return;
580 _updateAutoHandles();
581 break;
582 case NODE_SMOOTH: {
583 // rotate handles to be colinear
584 // for degenerate nodes set positions like auto handles
585 bool prev_line = _is_line_segment(_prev(), this);
586 bool next_line = _is_line_segment(this, _next());
587 if (_type == NODE_SMOOTH) {
588 // for a node that is already smooth and has a degenerate handle,
589 // drag out the second handle to 1/3 the length of the linear segment
590 if (_front.isDegenerate()) {
591 double dist = Geom::distance(_next()->position(), position());
592 _front.setRelativePos(Geom::unit_vector(-_back.relativePos()) * dist / 3);
593 }
594 if (_back.isDegenerate()) {
595 double dist = Geom::distance(_prev()->position(), position());
596 _back.setRelativePos(Geom::unit_vector(-_front.relativePos()) * dist / 3);
597 }
598 } else if (isDegenerate()) {
599 _updateAutoHandles();
600 } else if (_front.isDegenerate()) {
601 // if the front handle is degenerate and this...next is a line segment,
602 // make back colinear; otherwise pull out the other handle
603 // to 1/3 of distance to prev
604 if (next_line) {
605 _back.setDirection(*_next(), *this);
606 } else if (_prev()) {
607 Geom::Point dir = direction(_back, *this);
608 _front.setRelativePos(Geom::distance(_prev()->position(), position()) / 3 * dir);
609 }
610 } else if (_back.isDegenerate()) {
611 if (prev_line) {
612 _front.setDirection(*_prev(), *this);
613 } else if (_next()) {
614 Geom::Point dir = direction(_front, *this);
615 _back.setRelativePos(Geom::distance(_next()->position(), position()) / 3 * dir);
616 }
617 } else {
618 // both handles are extended. make colinear while keeping length
619 // first make back colinear with the vector front ---> back,
620 // then make front colinear with back ---> node
621 // (not back ---> front because back's position was changed in the first call)
622 _back.setDirection(_front, _back);
623 _front.setDirection(_back, *this);
624 }
625 } break;
626 case NODE_SYMMETRIC:
627 if (isEndNode()) return; // symmetric handles make no sense for endnodes
628 if (isDegenerate()) {
629 // similar to auto handles but set the same length for both
630 Geom::Point vec_next = _next()->position() - position();
631 Geom::Point vec_prev = _prev()->position() - position();
632 double len_next = vec_next.length(), len_prev = vec_prev.length();
633 double len = (len_next + len_prev) / 6; // take 1/3 of average
634 if (len == 0) return;
636 Geom::Point dir = Geom::unit_vector((len_prev / len_next) * vec_next - vec_prev);
637 _back.setRelativePos(-dir * len);
638 _front.setRelativePos(dir * len);
639 } else {
640 // Both handles are extended. Compute average length, use direction from
641 // back handle to front handle. This also works correctly for degenerates
642 double len = (_front.length() + _back.length()) / 2;
643 Geom::Point dir = direction(_back, _front);
644 _front.setRelativePos(dir * len);
645 _back.setRelativePos(-dir * len);
646 }
647 break;
648 default: break;
649 }
650 }
651 _type = type;
652 _setShape(_node_type_to_shape(type));
653 updateState();
654 }
656 /** Pick the best type for this node, based on the position of its handles.
657 * This is what assigns types to nodes created using the pen tool. */
658 void Node::pickBestType()
659 {
660 _type = NODE_CUSP;
661 bool front_degen = _front.isDegenerate();
662 bool back_degen = _back.isDegenerate();
663 bool both_degen = front_degen && back_degen;
664 bool neither_degen = !front_degen && !back_degen;
665 do {
666 // if both handles are degenerate, do nothing
667 if (both_degen) break;
668 // if neither are degenerate, check their respective positions
669 if (neither_degen) {
670 Geom::Point front_delta = _front.position() - position();
671 Geom::Point back_delta = _back.position() - position();
672 // for now do not automatically make nodes symmetric, it can be annoying
673 /*if (Geom::are_near(front_delta, -back_delta)) {
674 _type = NODE_SYMMETRIC;
675 break;
676 }*/
677 if (Geom::are_near(Geom::unit_vector(front_delta),
678 Geom::unit_vector(-back_delta)))
679 {
680 _type = NODE_SMOOTH;
681 break;
682 }
683 }
684 // check whether the handle aligns with the previous line segment.
685 // we know that if front is degenerate, back isn't, because
686 // both_degen was false
687 if (front_degen && _next() && _next()->_back.isDegenerate()) {
688 Geom::Point segment_delta = Geom::unit_vector(_next()->position() - position());
689 Geom::Point handle_delta = Geom::unit_vector(_back.position() - position());
690 if (Geom::are_near(segment_delta, -handle_delta)) {
691 _type = NODE_SMOOTH;
692 break;
693 }
694 } else if (back_degen && _prev() && _prev()->_front.isDegenerate()) {
695 Geom::Point segment_delta = Geom::unit_vector(_prev()->position() - position());
696 Geom::Point handle_delta = Geom::unit_vector(_front.position() - position());
697 if (Geom::are_near(segment_delta, -handle_delta)) {
698 _type = NODE_SMOOTH;
699 break;
700 }
701 }
702 } while (false);
703 _setShape(_node_type_to_shape(_type));
704 updateState();
705 }
707 bool Node::isEndNode()
708 {
709 return !_prev() || !_next();
710 }
712 /** Move the node to the bottom of its canvas group. Useful for node break, to ensure that
713 * the selected nodes are above the unselected ones. */
714 void Node::sink()
715 {
716 sp_canvas_item_move_to_z(_canvas_item, 0);
717 }
719 NodeType Node::parse_nodetype(char x)
720 {
721 switch (x) {
722 case 'a': return NODE_AUTO;
723 case 'c': return NODE_CUSP;
724 case 's': return NODE_SMOOTH;
725 case 'z': return NODE_SYMMETRIC;
726 default: return NODE_PICK_BEST;
727 }
728 }
730 /** Customized event handler to catch scroll events needed for selection grow/shrink. */
731 bool Node::_eventHandler(GdkEvent *event)
732 {
733 static NodeList::iterator origin;
734 static int dir;
736 switch (event->type)
737 {
738 case GDK_SCROLL:
739 if (event->scroll.direction == GDK_SCROLL_UP) {
740 dir = 1;
741 } else if (event->scroll.direction == GDK_SCROLL_DOWN) {
742 dir = -1;
743 } else break;
744 if (held_control(event->scroll)) {
745 _selection.spatialGrow(this, dir);
746 } else {
747 _linearGrow(dir);
748 }
749 return true;
750 default:
751 break;
752 }
753 return ControlPoint::_eventHandler(event);
754 }
756 // TODO Move this to 2Geom!
757 static double bezier_length (Geom::Point a0, Geom::Point a1, Geom::Point a2, Geom::Point a3)
758 {
759 double lower = Geom::distance(a0, a3);
760 double upper = Geom::distance(a0, a1) + Geom::distance(a1, a2) + Geom::distance(a2, a3);
762 if (upper - lower < Geom::EPSILON) return (lower + upper)/2;
764 Geom::Point // Casteljau subdivision
765 b0 = a0,
766 c0 = a3,
767 b1 = 0.5*(a0 + a1),
768 t0 = 0.5*(a1 + a2),
769 c1 = 0.5*(a2 + a3),
770 b2 = 0.5*(b1 + t0),
771 c2 = 0.5*(t0 + c1),
772 b3 = 0.5*(b2 + c2); // == c3
773 return bezier_length(b0, b1, b2, b3) + bezier_length(b3, c2, c1, c0);
774 }
776 /** Select or deselect a node in this node's subpath based on its path distance from this node.
777 * @param dir If negative, shrink selection by one node; if positive, grow by one node */
778 void Node::_linearGrow(int dir)
779 {
780 // Interestingly, we do not need any help from PathManipulator when doing linear grow.
781 // First handle the trivial case of growing over an unselected node.
782 if (!selected() && dir > 0) {
783 _selection.insert(this);
784 return;
785 }
787 NodeList::iterator this_iter = NodeList::get_iterator(this);
788 NodeList::iterator fwd = this_iter, rev = this_iter;
789 double distance_back = 0, distance_front = 0;
791 // Linear grow is simple. We find the first unselected nodes in each direction
792 // and compare the linear distances to them.
793 if (dir > 0) {
794 if (!selected()) {
795 _selection.insert(this);
796 return;
797 }
799 // find first unselected nodes on both sides
800 while (fwd && fwd->selected()) {
801 NodeList::iterator n = fwd.next();
802 distance_front += bezier_length(*fwd, fwd->_front, n->_back, *n);
803 fwd = n;
804 if (fwd == this_iter)
805 // there is no unselected node in this cyclic subpath
806 return;
807 }
808 // do the same for the second direction. Do not check for equality with
809 // this node, because there is at least one unselected node in the subpath,
810 // so we are guaranteed to stop.
811 while (rev && rev->selected()) {
812 NodeList::iterator p = rev.prev();
813 distance_back += bezier_length(*rev, rev->_back, p->_front, *p);
814 rev = p;
815 }
817 NodeList::iterator t; // node to select
818 if (fwd && rev) {
819 if (distance_front <= distance_back) t = fwd;
820 else t = rev;
821 } else {
822 if (fwd) t = fwd;
823 if (rev) t = rev;
824 }
825 if (t) _selection.insert(t.ptr());
827 // Linear shrink is more complicated. We need to find the farthest selected node.
828 // This means we have to check the entire subpath. We go in the direction in which
829 // the distance we traveled is lower. We do this until we run out of nodes (ends of path)
830 // or the two iterators meet. On the way, we store the last selected node and its distance
831 // in each direction (if any). At the end, we choose the one that is farther and deselect it.
832 } else {
833 // both iterators that store last selected nodes are initially empty
834 NodeList::iterator last_fwd, last_rev;
835 double last_distance_back = 0, last_distance_front = 0;
837 while (rev || fwd) {
838 if (fwd && (!rev || distance_front <= distance_back)) {
839 if (fwd->selected()) {
840 last_fwd = fwd;
841 last_distance_front = distance_front;
842 }
843 NodeList::iterator n = fwd.next();
844 if (n) distance_front += bezier_length(*fwd, fwd->_front, n->_back, *n);
845 fwd = n;
846 } else if (rev && (!fwd || distance_front > distance_back)) {
847 if (rev->selected()) {
848 last_rev = rev;
849 last_distance_back = distance_back;
850 }
851 NodeList::iterator p = rev.prev();
852 if (p) distance_back += bezier_length(*rev, rev->_back, p->_front, *p);
853 rev = p;
854 }
855 // Check whether we walked the entire cyclic subpath.
856 // This is initially true because both iterators start from this node,
857 // so this check cannot go in the while condition.
858 // When this happens, we need to check the last node, pointed to by the iterators.
859 if (fwd && fwd == rev) {
860 if (!fwd->selected()) break;
861 NodeList::iterator fwdp = fwd.prev(), revn = rev.next();
862 double df = distance_front + bezier_length(*fwdp, fwdp->_front, fwd->_back, *fwd);
863 double db = distance_back + bezier_length(*revn, revn->_back, rev->_front, *rev);
864 if (df > db) {
865 last_fwd = fwd;
866 last_distance_front = df;
867 } else {
868 last_rev = rev;
869 last_distance_back = db;
870 }
871 break;
872 }
873 }
875 NodeList::iterator t;
876 if (last_fwd && last_rev) {
877 if (last_distance_front >= last_distance_back) t = last_fwd;
878 else t = last_rev;
879 } else {
880 if (last_fwd) t = last_fwd;
881 if (last_rev) t = last_rev;
882 }
883 if (t) _selection.erase(t.ptr());
884 }
885 }
887 void Node::_setState(State state)
888 {
889 // change node size to match type and selection state
890 switch (_type) {
891 case NODE_AUTO:
892 case NODE_CUSP:
893 if (selected()) _setSize(11);
894 else _setSize(9);
895 break;
896 default:
897 if(selected()) _setSize(9);
898 else _setSize(7);
899 break;
900 }
901 SelectableControlPoint::_setState(state);
902 }
904 bool Node::grabbed(GdkEventMotion *event)
905 {
906 if (SelectableControlPoint::grabbed(event))
907 return true;
909 // Dragging out handles with Shift + drag on a node.
910 if (!held_shift(*event)) return false;
912 Handle *h;
913 Geom::Point evp = event_point(*event);
914 Geom::Point rel_evp = evp - _last_click_event_point();
916 // This should work even if dragtolerance is zero and evp coincides with node position.
917 double angle_next = HUGE_VAL;
918 double angle_prev = HUGE_VAL;
919 bool has_degenerate = false;
920 // determine which handle to drag out based on degeneration and the direction of drag
921 if (_front.isDegenerate() && _next()) {
922 Geom::Point next_relpos = _desktop->d2w(_next()->position())
923 - _desktop->d2w(position());
924 angle_next = fabs(Geom::angle_between(rel_evp, next_relpos));
925 has_degenerate = true;
926 }
927 if (_back.isDegenerate() && _prev()) {
928 Geom::Point prev_relpos = _desktop->d2w(_prev()->position())
929 - _desktop->d2w(position());
930 angle_prev = fabs(Geom::angle_between(rel_evp, prev_relpos));
931 has_degenerate = true;
932 }
933 if (!has_degenerate) return false;
934 h = angle_next < angle_prev ? &_front : &_back;
936 h->setPosition(_desktop->w2d(evp));
937 h->setVisible(true);
938 h->transferGrab(this, event);
939 Handle::_drag_out = true;
940 return true;
941 }
943 void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event)
944 {
945 // For a note on how snapping is implemented in Inkscape, see snap.h.
946 SnapManager &sm = _desktop->namedview->snap_manager;
947 bool snap = sm.someSnapperMightSnap();
948 Inkscape::SnappedPoint sp;
949 if (snap) {
950 /* setup
951 * TODO We are doing this every time a snap happens. It should once be done only once
952 * per drag - maybe in the grabbed handler?
953 * TODO Unselected nodes vector must be valid during the snap run, because it is not
954 * copied. Fix this in snap.h and snap.cpp, then the above.
955 * TODO Snapping to unselected segments of selected paths doesn't work yet. */
957 // Build the list of unselected nodes.
958 std::vector<Inkscape::SnapCandidatePoint> unselected;
959 typedef ControlPointSelection::Set Set;
960 Set &nodes = _selection.allPoints();
961 for (Set::iterator i = nodes.begin(); i != nodes.end(); ++i) {
962 if (!(*i)->selected()) {
963 Node *n = static_cast<Node*>(*i);
964 Inkscape::SnapCandidatePoint p(n->position(), n->_snapSourceType(), n->_snapTargetType());
965 unselected.push_back(p);
966 }
967 }
968 sm.setupIgnoreSelection(_desktop, true, &unselected);
969 }
971 if (held_control(*event)) {
972 Geom::Point origin = _last_drag_origin();
973 std::vector<Inkscape::Snapper::SnapConstraint> constraints;
974 if (held_alt(*event)) {
975 // with Ctrl+Alt, constrain to handle lines
976 // project the new position onto a handle line that is closer;
977 // also snap to perpendiculars of handle lines
979 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
980 int snaps = prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
981 double min_angle = M_PI / snaps;
983 boost::optional<Geom::Point> front_point, back_point, fperp_point, bperp_point;
984 if (_front.isDegenerate()) {
985 if (_is_line_segment(this, _next()))
986 front_point = _next()->position() - origin;
987 } else {
988 front_point = _front.relativePos();
989 }
990 if (_back.isDegenerate()) {
991 if (_is_line_segment(_prev(), this))
992 back_point = _prev()->position() - origin;
993 } else {
994 back_point = _back.relativePos();
995 }
996 if (front_point) {
997 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *front_point));
998 fperp_point = Geom::rot90(*front_point);
999 }
1000 if (back_point) {
1001 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *back_point));
1002 bperp_point = Geom::rot90(*back_point);
1003 }
1004 // perpendiculars only snap when they are further than snap increment away
1005 // from the second handle constraint
1006 if (fperp_point && (!back_point ||
1007 (fabs(Geom::angle_between(*fperp_point, *back_point)) > min_angle &&
1008 fabs(Geom::angle_between(*fperp_point, *back_point)) < M_PI - min_angle)))
1009 {
1010 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *fperp_point));
1011 }
1012 if (bperp_point && (!front_point ||
1013 (fabs(Geom::angle_between(*bperp_point, *front_point)) > min_angle &&
1014 fabs(Geom::angle_between(*bperp_point, *front_point)) < M_PI - min_angle)))
1015 {
1016 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, *bperp_point));
1017 }
1019 sp = sm.multipleConstrainedSnaps(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), constraints);
1020 } else {
1021 // with Ctrl, constrain to axes
1022 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, Geom::Point(1, 0)));
1023 constraints.push_back(Inkscape::Snapper::SnapConstraint(origin, Geom::Point(0, 1)));
1024 sp = sm.multipleConstrainedSnaps(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()), constraints);
1025 }
1026 new_pos = sp.getPoint();
1027 } else if (snap) {
1028 sp = sm.freeSnap(Inkscape::SnapCandidatePoint(new_pos, _snapSourceType()));
1029 new_pos = sp.getPoint();
1030 }
1032 SelectableControlPoint::dragged(new_pos, event);
1033 }
1035 bool Node::clicked(GdkEventButton *event)
1036 {
1037 if(_pm()._nodeClicked(this, event))
1038 return true;
1039 return SelectableControlPoint::clicked(event);
1040 }
1042 Inkscape::SnapSourceType Node::_snapSourceType()
1043 {
1044 if (_type == NODE_SMOOTH || _type == NODE_AUTO)
1045 return SNAPSOURCE_NODE_SMOOTH;
1046 return SNAPSOURCE_NODE_CUSP;
1047 }
1048 Inkscape::SnapTargetType Node::_snapTargetType()
1049 {
1050 if (_type == NODE_SMOOTH || _type == NODE_AUTO)
1051 return SNAPTARGET_NODE_SMOOTH;
1052 return SNAPTARGET_NODE_CUSP;
1053 }
1055 /** @brief Gets the handle that faces the given adjacent node.
1056 * Will abort with error if the given node is not adjacent. */
1057 Handle *Node::handleToward(Node *to)
1058 {
1059 if (_next() == to) {
1060 return front();
1061 }
1062 if (_prev() == to) {
1063 return back();
1064 }
1065 g_error("Node::handleToward(): second node is not adjacent!");
1066 }
1068 /** @brief Gets the node in the direction of the given handle.
1069 * Will abort with error if the handle doesn't belong to this node. */
1070 Node *Node::nodeToward(Handle *dir)
1071 {
1072 if (front() == dir) {
1073 return _next();
1074 }
1075 if (back() == dir) {
1076 return _prev();
1077 }
1078 g_error("Node::nodeToward(): handle is not a child of this node!");
1079 }
1081 /** @brief Gets the handle that goes in the direction opposite to the given adjacent node.
1082 * Will abort with error if the given node is not adjacent. */
1083 Handle *Node::handleAwayFrom(Node *to)
1084 {
1085 if (_next() == to) {
1086 return back();
1087 }
1088 if (_prev() == to) {
1089 return front();
1090 }
1091 g_error("Node::handleAwayFrom(): second node is not adjacent!");
1092 }
1094 /** @brief Gets the node in the direction opposite to the given handle.
1095 * Will abort with error if the handle doesn't belong to this node. */
1096 Node *Node::nodeAwayFrom(Handle *h)
1097 {
1098 if (front() == h) {
1099 return _prev();
1100 }
1101 if (back() == h) {
1102 return _next();
1103 }
1104 g_error("Node::nodeAwayFrom(): handle is not a child of this node!");
1105 }
1107 Glib::ustring Node::_getTip(unsigned state)
1108 {
1109 if (state_held_shift(state)) {
1110 bool can_drag_out = (_next() && _front.isDegenerate()) || (_prev() && _back.isDegenerate());
1111 if (can_drag_out) {
1112 /*if (state_held_control(state)) {
1113 return format_tip(C_("Path node tip",
1114 "<b>Shift+Ctrl:</b> drag out a handle and snap its angle "
1115 "to %f° increments"), snap_increment_degrees());
1116 }*/
1117 return C_("Path node tip",
1118 "<b>Shift</b>: drag out a handle, click to toggle selection");
1119 }
1120 return C_("Path node tip", "<b>Shift</b>: click to toggle selection");
1121 }
1123 if (state_held_control(state)) {
1124 if (state_held_alt(state)) {
1125 return C_("Path node tip", "<b>Ctrl+Alt</b>: move along handle lines, click to delete node");
1126 }
1127 return C_("Path node tip",
1128 "<b>Ctrl</b>: move along axes, click to change node type");
1129 }
1131 if (state_held_alt(state)) {
1132 return C_("Path node tip", "<b>Alt</b>: sculpt nodes");
1133 }
1135 // No modifiers: assemble tip from node type
1136 char const *nodetype = node_type_to_localized_string(_type);
1137 if (_selection.transformHandlesEnabled() && selected()) {
1138 if (_selection.size() == 1) {
1139 return format_tip(C_("Path node tip",
1140 "<b>%s</b>: drag to shape the path (more: Shift, Ctrl, Alt)"), nodetype);
1141 }
1142 return format_tip(C_("Path node tip",
1143 "<b>%s</b>: drag to shape the path, click to toggle scale/rotation handles (more: Shift, Ctrl, Alt)"), nodetype);
1144 }
1145 return format_tip(C_("Path node tip",
1146 "<b>%s</b>: drag to shape the path, click to select only this node (more: Shift, Ctrl, Alt)"), nodetype);
1147 }
1149 Glib::ustring Node::_getDragTip(GdkEventMotion */*event*/)
1150 {
1151 Geom::Point dist = position() - _last_drag_origin();
1152 GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
1153 GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
1154 Glib::ustring ret = format_tip(C_("Path node tip", "Move node by %s, %s"),
1155 x->str, y->str);
1156 g_string_free(x, TRUE);
1157 g_string_free(y, TRUE);
1158 return ret;
1159 }
1161 char const *Node::node_type_to_localized_string(NodeType type)
1162 {
1163 switch (type) {
1164 case NODE_CUSP: return _("Cusp node");
1165 case NODE_SMOOTH: return _("Smooth node");
1166 case NODE_SYMMETRIC: return _("Symmetric node");
1167 case NODE_AUTO: return _("Auto-smooth node");
1168 default: return "";
1169 }
1170 }
1172 /** Determine whether two nodes are joined by a linear segment. */
1173 bool Node::_is_line_segment(Node *first, Node *second)
1174 {
1175 if (!first || !second) return false;
1176 if (first->_next() == second)
1177 return first->_front.isDegenerate() && second->_back.isDegenerate();
1178 if (second->_next() == first)
1179 return second->_front.isDegenerate() && first->_back.isDegenerate();
1180 return false;
1181 }
1183 SPCtrlShapeType Node::_node_type_to_shape(NodeType type)
1184 {
1185 switch(type) {
1186 case NODE_CUSP: return SP_CTRL_SHAPE_DIAMOND;
1187 case NODE_SMOOTH: return SP_CTRL_SHAPE_SQUARE;
1188 case NODE_AUTO: return SP_CTRL_SHAPE_CIRCLE;
1189 case NODE_SYMMETRIC: return SP_CTRL_SHAPE_SQUARE;
1190 default: return SP_CTRL_SHAPE_DIAMOND;
1191 }
1192 }
1195 /**
1196 * @class NodeList
1197 * @brief An editable list of nodes representing a subpath.
1198 *
1199 * It can optionally be cyclic to represent a closed path.
1200 * The list has iterators that act like plain node iterators, but can also be used
1201 * to obtain shared pointers to nodes.
1202 */
1204 NodeList::NodeList(SubpathList &splist)
1205 : _list(splist)
1206 , _closed(false)
1207 {
1208 this->ln_list = this;
1209 this->ln_next = this;
1210 this->ln_prev = this;
1211 }
1213 NodeList::~NodeList()
1214 {
1215 clear();
1216 }
1218 bool NodeList::empty()
1219 {
1220 return ln_next == this;
1221 }
1223 NodeList::size_type NodeList::size()
1224 {
1225 size_type sz = 0;
1226 for (ListNode *ln = ln_next; ln != this; ln = ln->ln_next) ++sz;
1227 return sz;
1228 }
1230 bool NodeList::closed()
1231 {
1232 return _closed;
1233 }
1235 /** A subpath is degenerate if it has no segments - either one node in an open path
1236 * or no nodes in a closed path */
1237 bool NodeList::degenerate()
1238 {
1239 return closed() ? empty() : ++begin() == end();
1240 }
1242 NodeList::iterator NodeList::before(double t, double *fracpart)
1243 {
1244 double intpart;
1245 *fracpart = std::modf(t, &intpart);
1246 int index = intpart;
1248 iterator ret = begin();
1249 std::advance(ret, index);
1250 return ret;
1251 }
1253 // insert a node before i
1254 NodeList::iterator NodeList::insert(iterator i, Node *x)
1255 {
1256 ListNode *ins = i._node;
1257 x->ln_next = ins;
1258 x->ln_prev = ins->ln_prev;
1259 ins->ln_prev->ln_next = x;
1260 ins->ln_prev = x;
1261 x->ln_list = this;
1262 return iterator(x);
1263 }
1265 void NodeList::splice(iterator pos, NodeList &list)
1266 {
1267 splice(pos, list, list.begin(), list.end());
1268 }
1270 void NodeList::splice(iterator pos, NodeList &list, iterator i)
1271 {
1272 NodeList::iterator j = i;
1273 ++j;
1274 splice(pos, list, i, j);
1275 }
1277 void NodeList::splice(iterator pos, NodeList &/*list*/, iterator first, iterator last)
1278 {
1279 ListNode *ins_beg = first._node, *ins_end = last._node, *at = pos._node;
1280 for (ListNode *ln = ins_beg; ln != ins_end; ln = ln->ln_next) {
1281 ln->ln_list = this;
1282 }
1283 ins_beg->ln_prev->ln_next = ins_end;
1284 ins_end->ln_prev->ln_next = at;
1285 at->ln_prev->ln_next = ins_beg;
1287 ListNode *atprev = at->ln_prev;
1288 at->ln_prev = ins_end->ln_prev;
1289 ins_end->ln_prev = ins_beg->ln_prev;
1290 ins_beg->ln_prev = atprev;
1291 }
1293 void NodeList::shift(int n)
1294 {
1295 // 1. make the list perfectly cyclic
1296 ln_next->ln_prev = ln_prev;
1297 ln_prev->ln_next = ln_next;
1298 // 2. find new begin
1299 ListNode *new_begin = ln_next;
1300 if (n > 0) {
1301 for (; n > 0; --n) new_begin = new_begin->ln_next;
1302 } else {
1303 for (; n < 0; ++n) new_begin = new_begin->ln_prev;
1304 }
1305 // 3. relink begin to list
1306 ln_next = new_begin;
1307 ln_prev = new_begin->ln_prev;
1308 new_begin->ln_prev->ln_next = this;
1309 new_begin->ln_prev = this;
1310 }
1312 void NodeList::reverse()
1313 {
1314 for (ListNode *ln = ln_next; ln != this; ln = ln->ln_prev) {
1315 std::swap(ln->ln_next, ln->ln_prev);
1316 Node *node = static_cast<Node*>(ln);
1317 Geom::Point save_pos = node->front()->position();
1318 node->front()->setPosition(node->back()->position());
1319 node->back()->setPosition(save_pos);
1320 }
1321 std::swap(ln_next, ln_prev);
1322 }
1324 void NodeList::clear()
1325 {
1326 for (iterator i = begin(); i != end();) erase (i++);
1327 }
1329 NodeList::iterator NodeList::erase(iterator i)
1330 {
1331 // some gymnastics are required to ensure that the node is valid when deleted;
1332 // otherwise the code that updates handle visibility will break
1333 Node *rm = static_cast<Node*>(i._node);
1334 ListNode *rmnext = rm->ln_next, *rmprev = rm->ln_prev;
1335 ++i;
1336 delete rm;
1337 rmprev->ln_next = rmnext;
1338 rmnext->ln_prev = rmprev;
1339 return i;
1340 }
1342 // TODO this method is very ugly!
1343 // converting SubpathList to an intrusive list might allow us to get rid of it
1344 void NodeList::kill()
1345 {
1346 for (SubpathList::iterator i = _list.begin(); i != _list.end(); ++i) {
1347 if (i->get() == this) {
1348 _list.erase(i);
1349 return;
1350 }
1351 }
1352 }
1354 NodeList &NodeList::get(Node *n) {
1355 return n->nodeList();
1356 }
1357 NodeList &NodeList::get(iterator const &i) {
1358 return *(i._node->ln_list);
1359 }
1362 /**
1363 * @class SubpathList
1364 * @brief Editable path composed of one or more subpaths
1365 */
1367 } // namespace UI
1368 } // namespace Inkscape
1370 /*
1371 Local Variables:
1372 mode:c++
1373 c-file-style:"stroustrup"
1374 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1375 indent-tabs-mode:nil
1376 fill-column:99
1377 End:
1378 */
1379 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :