1 /** @file
2 * Editable node - implementation
3 */
4 /* Authors:
5 * Krzysztof Kosiński <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, *towards, *towards_second;
110 Node *node_towards; // node in direction of this handle
111 Node *node_away; // node in the opposite direction
112 if (this == &_parent->_front) {
113 other = &_parent->_back;
114 node_towards = _parent->_next();
115 node_away = _parent->_prev();
116 towards = node_towards ? &node_towards->_back : 0;
117 towards_second = node_towards ? &node_towards->_front : 0;
118 } else {
119 other = &_parent->_front;
120 node_towards = _parent->_prev();
121 node_away = _parent->_next();
122 towards = node_towards ? &node_towards->_front : 0;
123 towards_second = node_towards ? &node_towards->_back : 0;
124 }
126 if (Geom::are_near(new_pos, _parent->position())) {
127 // The handle becomes degenerate. If the segment between it and the node
128 // in its direction becomes linear and there are smooth nodes
129 // at its ends, make their handles colinear with the segment
130 if (towards && towards->isDegenerate()) {
131 if (node_towards->type() == NODE_SMOOTH) {
132 towards_second->setDirection(*_parent, *node_towards);
133 }
134 if (_parent->type() == NODE_SMOOTH) {
135 other->setDirection(*node_towards, *_parent);
136 }
137 }
138 setPosition(new_pos);
139 return;
140 }
142 if (_parent->type() == NODE_SMOOTH && Node::_is_line_segment(_parent, node_away)) {
143 // restrict movement to the line joining the nodes
144 Geom::Point direction = _parent->position() - node_away->position();
145 Geom::Point delta = new_pos - _parent->position();
146 // project the relative position on the direction line
147 Geom::Point new_delta = (Geom::dot(delta, direction)
148 / Geom::L2sq(direction)) * direction;
149 setRelativePos(new_delta);
150 return;
151 }
153 switch (_parent->type()) {
154 case NODE_AUTO:
155 _parent->setType(NODE_SMOOTH, false);
156 // fall through - auto nodes degrade into smooth nodes
157 case NODE_SMOOTH: {
158 /* for smooth nodes, we need to rotate the other handle so that it's colinear
159 * with the dragged one while conserving length. */
160 other->setDirection(new_pos, *_parent);
161 } break;
162 case NODE_SYMMETRIC:
163 // for symmetric nodes, place the other handle on the opposite side
164 other->setRelativePos(-(new_pos - _parent->position()));
165 break;
166 default: break;
167 }
169 setPosition(new_pos);
170 }
172 void Handle::setPosition(Geom::Point const &p)
173 {
174 ControlPoint::setPosition(p);
175 sp_ctrlline_set_coords(SP_CTRLLINE(_handle_line), _parent->position(), position());
177 // update degeneration info and visibility
178 if (Geom::are_near(position(), _parent->position()))
179 _degenerate = true;
180 else _degenerate = false;
181 if (_parent->_handles_shown && _parent->visible() && !_degenerate) {
182 setVisible(true);
183 } else {
184 setVisible(false);
185 }
186 // If both handles become degenerate, convert to parent cusp node
187 if (_parent->isDegenerate()) {
188 _parent->setType(NODE_CUSP, false);
189 }
190 }
192 void Handle::setLength(double len)
193 {
194 if (isDegenerate()) return;
195 Geom::Point dir = Geom::unit_vector(relativePos());
196 setRelativePos(dir * len);
197 }
199 void Handle::retract()
200 {
201 setPosition(_parent->position());
202 }
204 void Handle::setDirection(Geom::Point const &from, Geom::Point const &to)
205 {
206 setDirection(to - from);
207 }
209 void Handle::setDirection(Geom::Point const &dir)
210 {
211 Geom::Point unitdir = Geom::unit_vector(dir);
212 setRelativePos(unitdir * length());
213 }
215 char const *Handle::handle_type_to_localized_string(NodeType type)
216 {
217 switch(type) {
218 case NODE_CUSP: return _("Cusp node handle");
219 case NODE_SMOOTH: return _("Smooth node handle");
220 case NODE_SYMMETRIC: return _("Symmetric node handle");
221 case NODE_AUTO: return _("Auto-smooth node handle");
222 default: return "";
223 }
224 }
226 bool Handle::grabbed(GdkEventMotion *)
227 {
228 _saved_other_pos = other().position();
229 _saved_length = _drag_out ? 0 : length();
230 _pm()._handleGrabbed();
231 return false;
232 }
234 void Handle::dragged(Geom::Point &new_pos, GdkEventMotion *event)
235 {
236 Geom::Point parent_pos = _parent->position();
237 Geom::Point origin = _last_drag_origin();
238 // with Alt, preserve length
239 if (held_alt(*event)) {
240 new_pos = parent_pos + Geom::unit_vector(new_pos - parent_pos) * _saved_length;
241 }
242 // with Ctrl, constrain to M_PI/rotationsnapsperpi increments from vertical
243 // and the original position.
244 if (held_control(*event)) {
245 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
246 int snaps = 2 * prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
248 // note: if snapping to the original position is only desired in the original
249 // direction of the handle, change 2nd line below to Ray instead of Line
250 Geom::Line original_line(parent_pos, origin);
251 Geom::Point snap_pos = parent_pos + Geom::constrain_angle(
252 Geom::Point(0,0), new_pos - parent_pos, snaps, Geom::Point(1,0));
253 Geom::Point orig_pos = original_line.pointAt(original_line.nearestPoint(new_pos));
255 if (Geom::distance(snap_pos, new_pos) < Geom::distance(orig_pos, new_pos)) {
256 new_pos = snap_pos;
257 } else {
258 new_pos = orig_pos;
259 }
260 }
261 // with Shift, if the node is cusp, rotate the other handle as well
262 if (_parent->type() == NODE_CUSP && !_drag_out) {
263 if (held_shift(*event)) {
264 Geom::Point other_relpos = _saved_other_pos - parent_pos;
265 other_relpos *= Geom::Rotate(Geom::angle_between(origin - parent_pos, new_pos - parent_pos));
266 other().setRelativePos(other_relpos);
267 } else {
268 // restore the position
269 other().setPosition(_saved_other_pos);
270 }
271 }
272 _pm().update();
273 }
275 void Handle::ungrabbed(GdkEventButton *event)
276 {
277 // hide the handle if it's less than dragtolerance away from the node
278 // TODO is this actually desired?
279 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
280 int drag_tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
282 Geom::Point dist = _desktop->d2w(_parent->position()) - _desktop->d2w(position());
283 if (dist.length() <= drag_tolerance) {
284 move(_parent->position());
285 }
287 // HACK: If the handle was dragged out, call parent's ungrabbed handler,
288 // so that transform handles reappear
289 if (_drag_out) {
290 _parent->ungrabbed(event);
291 }
292 _drag_out = false;
294 _pm()._handleUngrabbed();
295 }
297 bool Handle::clicked(GdkEventButton *event)
298 {
299 _pm()._handleClicked(this, event);
300 return true;
301 }
303 Handle &Handle::other()
304 {
305 if (this == &_parent->_front) return _parent->_back;
306 return _parent->_front;
307 }
309 static double snap_increment_degrees() {
310 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
311 int snaps = prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
312 return 180.0 / snaps;
313 }
315 Glib::ustring Handle::_getTip(unsigned state)
316 {
317 char const *more;
318 bool can_shift_rotate = _parent->type() == NODE_CUSP && !other().isDegenerate();
319 if (can_shift_rotate) {
320 more = C_("Path handle tip", "more: Ctrl, Alt, Ctrl+Alt, Shift");
321 } else {
322 more = C_("Path handle tip", "more: Ctrl, Alt, Ctrl+Alt");
323 }
324 if (state_held_alt(state)) {
325 if (state_held_control(state)) {
326 if (state_held_shift(state) && can_shift_rotate) {
327 return format_tip(C_("Path handle tip",
328 "<b>Shift+Ctrl+Alt</b>: preserve length and snap rotation angle to %f° "
329 "increments while rotating both handles"),
330 snap_increment_degrees());
331 } else {
332 return format_tip(C_("Path handle tip",
333 "<b>Ctrl+Alt</b>: preserve length and snap rotation angle to %f° increments"),
334 snap_increment_degrees());
335 }
336 } else {
337 if (state_held_shift(state) && can_shift_rotate) {
338 return C_("Path handle tip",
339 "<b>Shift+Alt:</b> preserve handle length and rotate both handles");
340 } else {
341 return C_("Path handle tip",
342 "<b>Alt:</b> preserve handle length while dragging");
343 }
344 }
345 } else {
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>Ctrl:</b> snap rotation angle to %f° increments, click to retract"),
350 snap_increment_degrees());
351 } else {
352 return format_tip(C_("Path handle tip",
353 "<b>Shift+Ctrl:</b> snap rotation angle to %f° increments and rotate both handles"),
354 snap_increment_degrees());
355 }
356 } else if (state_held_shift(state) && can_shift_rotate) {
357 return C_("Path hande tip",
358 "<b>Shift</b>: rotate both handles by the same angle");
359 }
360 }
362 switch (_parent->type()) {
363 case NODE_AUTO:
364 return format_tip(C_("Path handle tip",
365 "<b>Auto node handle:</b> drag to convert to smooth node (%s)"), more);
366 default:
367 return format_tip(C_("Path handle tip",
368 "<b>%s:</b> drag to shape the segment (%s)"),
369 handle_type_to_localized_string(_parent->type()), more);
370 }
371 }
373 Glib::ustring Handle::_getDragTip(GdkEventMotion */*event*/)
374 {
375 Geom::Point dist = position() - _last_drag_origin();
376 // report angle in mathematical convention
377 double angle = Geom::angle_between(Geom::Point(-1,0), position() - _parent->position());
378 angle += M_PI; // angle is (-M_PI...M_PI] - offset by +pi and scale to 0...360
379 angle *= 360.0 / (2 * M_PI);
380 GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
381 GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
382 GString *len = SP_PX_TO_METRIC_STRING(length(), _desktop->namedview->getDefaultMetric());
383 Glib::ustring ret = format_tip(C_("Path handle tip",
384 "Move by %s, %s; angle %.2f°, length %s"), x->str, y->str, angle, len->str);
385 g_string_free(x, TRUE);
386 g_string_free(y, TRUE);
387 g_string_free(len, TRUE);
388 return ret;
389 }
391 /**
392 * @class Node
393 * @brief Curve endpoint in an editable path.
394 *
395 * The method move() keeps node type invariants during translations.
396 */
398 Node::Node(NodeSharedData const &data, Geom::Point const &initial_pos)
399 : SelectableControlPoint(data.desktop, initial_pos, Gtk::ANCHOR_CENTER,
400 SP_CTRL_SHAPE_DIAMOND, 9.0, *data.selection, &node_colors, data.node_group)
401 , _front(data, initial_pos, this)
402 , _back(data, initial_pos, this)
403 , _type(NODE_CUSP)
404 , _handles_shown(false)
405 {
406 // NOTE we do not set type here, because the handles are still degenerate
407 }
409 // NOTE: not using iterators won't make this much quicker because iterators can be 100% inlined.
410 Node *Node::_next()
411 {
412 NodeList::iterator n = NodeList::get_iterator(this).next();
413 if (n) return n.ptr();
414 return NULL;
415 }
416 Node *Node::_prev()
417 {
418 NodeList::iterator p = NodeList::get_iterator(this).prev();
419 if (p) return p.ptr();
420 return NULL;
421 }
423 void Node::move(Geom::Point const &new_pos)
424 {
425 // move handles when the node moves.
426 Geom::Point old_pos = position();
427 Geom::Point delta = new_pos - position();
428 setPosition(new_pos);
429 _front.setPosition(_front.position() + delta);
430 _back.setPosition(_back.position() + delta);
432 // if the node has a smooth handle after a line segment, it should be kept colinear
433 // with the segment
434 _fixNeighbors(old_pos, new_pos);
435 }
437 void Node::transform(Geom::Matrix const &m)
438 {
439 Geom::Point old_pos = position();
440 setPosition(position() * m);
441 _front.setPosition(_front.position() * m);
442 _back.setPosition(_back.position() * m);
444 /* Affine transforms keep handle invariants for smooth and symmetric nodes,
445 * but smooth nodes at ends of linear segments and auto nodes need special treatment */
446 _fixNeighbors(old_pos, position());
447 }
449 Geom::Rect Node::bounds()
450 {
451 Geom::Rect b(position(), position());
452 b.expandTo(_front.position());
453 b.expandTo(_back.position());
454 return b;
455 }
457 void Node::_fixNeighbors(Geom::Point const &old_pos, Geom::Point const &new_pos)
458 {
459 /* This method restores handle invariants for neighboring nodes,
460 * and invariants that are based on positions of those nodes for this one. */
462 /* Fix auto handles */
463 if (_type == NODE_AUTO) _updateAutoHandles();
464 if (old_pos != new_pos) {
465 if (_next() && _next()->_type == NODE_AUTO) _next()->_updateAutoHandles();
466 if (_prev() && _prev()->_type == NODE_AUTO) _prev()->_updateAutoHandles();
467 }
469 /* Fix smooth handles at the ends of linear segments.
470 * Rotate the appropriate handle to be colinear with the segment.
471 * If there is a smooth node at the other end of the segment, rotate it too. */
472 Handle *handle, *other_handle;
473 Node *other;
474 if (_is_line_segment(this, _next())) {
475 handle = &_back;
476 other = _next();
477 other_handle = &_next()->_front;
478 } else if (_is_line_segment(_prev(), this)) {
479 handle = &_front;
480 other = _prev();
481 other_handle = &_prev()->_back;
482 } else return;
484 if (_type == NODE_SMOOTH && !handle->isDegenerate()) {
485 handle->setDirection(other->position(), new_pos);
486 }
487 // also update the handle on the other end of the segment
488 if (other->_type == NODE_SMOOTH && !other_handle->isDegenerate()) {
489 other_handle->setDirection(new_pos, other->position());
490 }
491 }
493 void Node::_updateAutoHandles()
494 {
495 // Recompute the position of automatic handles.
496 // For endnodes, retract both handles. (It's only possible to create an end auto node
497 // through the XML editor.)
498 if (isEndNode()) {
499 _front.retract();
500 _back.retract();
501 return;
502 }
504 // Auto nodes automaticaly adjust their handles to give an appearance of smoothness,
505 // no matter what their surroundings are.
506 Geom::Point vec_next = _next()->position() - position();
507 Geom::Point vec_prev = _prev()->position() - position();
508 double len_next = vec_next.length(), len_prev = vec_prev.length();
509 if (len_next > 0 && len_prev > 0) {
510 // "dir" is an unit vector perpendicular to the bisector of the angle created
511 // by the previous node, this auto node and the next node.
512 Geom::Point dir = Geom::unit_vector((len_prev / len_next) * vec_next - vec_prev);
513 // Handle lengths are equal to 1/3 of the distance from the adjacent node.
514 _back.setRelativePos(-dir * (len_prev / 3));
515 _front.setRelativePos(dir * (len_next / 3));
516 } else {
517 // If any of the adjacent nodes coincides, retract both handles.
518 _front.retract();
519 _back.retract();
520 }
521 }
523 void Node::showHandles(bool v)
524 {
525 _handles_shown = v;
526 if (!_front.isDegenerate()) _front.setVisible(v);
527 if (!_back.isDegenerate()) _back.setVisible(v);
528 }
530 /** Sets the node type and optionally restores the invariants associated with the given type.
531 * @param type The type to set
532 * @param update_handles Whether to restore invariants associated with the given type.
533 * Passing false is useful e.g. wen initially creating the path,
534 * and when making cusp nodes during some node algorithms.
535 * Pass true when used in response to an UI node type button.
536 */
537 void Node::setType(NodeType type, bool update_handles)
538 {
539 if (type == NODE_PICK_BEST) {
540 pickBestType();
541 updateState(); // The size of the control might have changed
542 return;
543 }
545 // if update_handles is true, adjust handle positions to match the node type
546 // handle degenerate handles appropriately
547 if (update_handles) {
548 switch (type) {
549 case NODE_CUSP:
550 // if the existing type is also NODE_CUSP, retract handles
551 if (_type == NODE_CUSP) {
552 _front.retract();
553 _back.retract();
554 }
555 break;
556 case NODE_AUTO:
557 // auto handles make no sense for endnodes
558 if (isEndNode()) return;
559 _updateAutoHandles();
560 break;
561 case NODE_SMOOTH: {
562 // rotate handles to be colinear
563 // for degenerate nodes set positions like auto handles
564 bool prev_line = _is_line_segment(_prev(), this);
565 bool next_line = _is_line_segment(this, _next());
566 if (_type == NODE_SMOOTH) {
567 // for a node that is already smooth and at the end of a linear segment,
568 // drag out the second handle to 1/3 the length of the linear segment
569 if (next_line) {
570 _front.setRelativePos((_prev()->position() - position()) / 3);
571 }
572 if (prev_line) {
573 _back.setRelativePos((_next()->position() - position()) / 3);
574 }
575 } else if (isDegenerate()) {
576 _updateAutoHandles();
577 } else if (_front.isDegenerate()) {
578 // if the front handle is degenerate and this...next is a line segment,
579 // make back colinear; otherwise pull out the other handle
580 // to 1/3 of distance to prev
581 if (next_line) {
582 _back.setDirection(*_next(), *this);
583 } else if (_prev()) {
584 Geom::Point dir = direction(_back, *this);
585 _front.setRelativePos(Geom::distance(_prev()->position(), position()) / 3 * dir);
586 }
587 } else if (_back.isDegenerate()) {
588 if (prev_line) {
589 _front.setDirection(*_prev(), *this);
590 } else if (_next()) {
591 Geom::Point dir = direction(_front, *this);
592 _back.setRelativePos(Geom::distance(_next()->position(), position()) / 3 * dir);
593 }
594 } else {
595 // both handles are extended. make colinear while keeping length
596 // first make back colinear with the vector front ---> back,
597 // then make front colinear with back ---> node
598 // (not back ---> front because back's position was changed in the first call)
599 _back.setDirection(_front, _back);
600 _front.setDirection(_back, *this);
601 }
602 } break;
603 case NODE_SYMMETRIC:
604 if (isEndNode()) return; // symmetric handles make no sense for endnodes
605 if (isDegenerate()) {
606 // similar to auto handles but set the same length for both
607 Geom::Point vec_next = _next()->position() - position();
608 Geom::Point vec_prev = _prev()->position() - position();
609 double len_next = vec_next.length(), len_prev = vec_prev.length();
610 double len = (len_next + len_prev) / 6; // take 1/3 of average
611 if (len == 0) return;
613 Geom::Point dir = Geom::unit_vector((len_prev / len_next) * vec_next - vec_prev);
614 _back.setRelativePos(-dir * len);
615 _front.setRelativePos(dir * len);
616 } else {
617 // Both handles are extended. Compute average length, use direction from
618 // back handle to front handle. This also works correctly for degenerates
619 double len = (_front.length() + _back.length()) / 2;
620 Geom::Point dir = direction(_back, _front);
621 _front.setRelativePos(dir * len);
622 _back.setRelativePos(-dir * len);
623 }
624 break;
625 default: break;
626 }
627 }
628 _type = type;
629 _setShape(_node_type_to_shape(type));
630 updateState();
631 }
633 /** Pick the best type for this node, based on the position of its handles.
634 * This is what assigns types to nodes created using the pen tool. */
635 void Node::pickBestType()
636 {
637 _type = NODE_CUSP;
638 bool front_degen = _front.isDegenerate();
639 bool back_degen = _back.isDegenerate();
640 bool both_degen = front_degen && back_degen;
641 bool neither_degen = !front_degen && !back_degen;
642 do {
643 // if both handles are degenerate, do nothing
644 if (both_degen) break;
645 // if neither are degenerate, check their respective positions
646 if (neither_degen) {
647 Geom::Point front_delta = _front.position() - position();
648 Geom::Point back_delta = _back.position() - position();
649 // for now do not automatically make nodes symmetric, it can be annoying
650 /*if (Geom::are_near(front_delta, -back_delta)) {
651 _type = NODE_SYMMETRIC;
652 break;
653 }*/
654 if (Geom::are_near(Geom::unit_vector(front_delta),
655 Geom::unit_vector(-back_delta)))
656 {
657 _type = NODE_SMOOTH;
658 break;
659 }
660 }
661 // check whether the handle aligns with the previous line segment.
662 // we know that if front is degenerate, back isn't, because
663 // both_degen was false
664 if (front_degen && _next() && _next()->_back.isDegenerate()) {
665 Geom::Point segment_delta = Geom::unit_vector(_next()->position() - position());
666 Geom::Point handle_delta = Geom::unit_vector(_back.position() - position());
667 if (Geom::are_near(segment_delta, -handle_delta)) {
668 _type = NODE_SMOOTH;
669 break;
670 }
671 } else if (back_degen && _prev() && _prev()->_front.isDegenerate()) {
672 Geom::Point segment_delta = Geom::unit_vector(_prev()->position() - position());
673 Geom::Point handle_delta = Geom::unit_vector(_front.position() - position());
674 if (Geom::are_near(segment_delta, -handle_delta)) {
675 _type = NODE_SMOOTH;
676 break;
677 }
678 }
679 } while (false);
680 _setShape(_node_type_to_shape(_type));
681 updateState();
682 }
684 bool Node::isEndNode()
685 {
686 return !_prev() || !_next();
687 }
689 /** Move the node to the bottom of its canvas group. Useful for node break, to ensure that
690 * the selected nodes are above the unselected ones. */
691 void Node::sink()
692 {
693 sp_canvas_item_move_to_z(_canvas_item, 0);
694 }
696 NodeType Node::parse_nodetype(char x)
697 {
698 switch (x) {
699 case 'a': return NODE_AUTO;
700 case 'c': return NODE_CUSP;
701 case 's': return NODE_SMOOTH;
702 case 'z': return NODE_SYMMETRIC;
703 default: return NODE_PICK_BEST;
704 }
705 }
707 /** Customized event handler to catch scroll events needed for selection grow/shrink. */
708 bool Node::_eventHandler(GdkEvent *event)
709 {
710 static NodeList::iterator origin;
711 static int dir;
713 switch (event->type)
714 {
715 case GDK_SCROLL:
716 if (event->scroll.direction == GDK_SCROLL_UP) {
717 dir = 1;
718 } else if (event->scroll.direction == GDK_SCROLL_DOWN) {
719 dir = -1;
720 } else break;
721 if (held_control(event->scroll)) {
722 _selection.spatialGrow(this, dir);
723 } else {
724 _linearGrow(dir);
725 }
726 return true;
727 default:
728 break;
729 }
730 return ControlPoint::_eventHandler(event);
731 }
733 // TODO Move this to 2Geom!
734 static double bezier_length (Geom::Point a0, Geom::Point a1, Geom::Point a2, Geom::Point a3)
735 {
736 double lower = Geom::distance(a0, a3);
737 double upper = Geom::distance(a0, a1) + Geom::distance(a1, a2) + Geom::distance(a2, a3);
739 if (upper - lower < Geom::EPSILON) return (lower + upper)/2;
741 Geom::Point // Casteljau subdivision
742 b0 = a0,
743 c0 = a3,
744 b1 = 0.5*(a0 + a1),
745 t0 = 0.5*(a1 + a2),
746 c1 = 0.5*(a2 + a3),
747 b2 = 0.5*(b1 + t0),
748 c2 = 0.5*(t0 + c1),
749 b3 = 0.5*(b2 + c2); // == c3
750 return bezier_length(b0, b1, b2, b3) + bezier_length(b3, c2, c1, c0);
751 }
753 /** Select or deselect a node in this node's subpath based on its path distance from this node.
754 * @param dir If negative, shrink selection by one node; if positive, grow by one node */
755 void Node::_linearGrow(int dir)
756 {
757 // Interestingly, we do not need any help from PathManipulator when doing linear grow.
758 // First handle the trivial case of growing over an unselected node.
759 if (!selected() && dir > 0) {
760 _selection.insert(this);
761 return;
762 }
764 NodeList::iterator this_iter = NodeList::get_iterator(this);
765 NodeList::iterator fwd = this_iter, rev = this_iter;
766 double distance_back = 0, distance_front = 0;
768 // Linear grow is simple. We find the first unselected nodes in each direction
769 // and compare the linear distances to them.
770 if (dir > 0) {
771 if (!selected()) {
772 _selection.insert(this);
773 return;
774 }
776 // find first unselected nodes on both sides
777 while (fwd && fwd->selected()) {
778 NodeList::iterator n = fwd.next();
779 distance_front += bezier_length(*fwd, fwd->_front, n->_back, *n);
780 fwd = n;
781 if (fwd == this_iter)
782 // there is no unselected node in this cyclic subpath
783 return;
784 }
785 // do the same for the second direction. Do not check for equality with
786 // this node, because there is at least one unselected node in the subpath,
787 // so we are guaranteed to stop.
788 while (rev && rev->selected()) {
789 NodeList::iterator p = rev.prev();
790 distance_back += bezier_length(*rev, rev->_back, p->_front, *p);
791 rev = p;
792 }
794 NodeList::iterator t; // node to select
795 if (fwd && rev) {
796 if (distance_front <= distance_back) t = fwd;
797 else t = rev;
798 } else {
799 if (fwd) t = fwd;
800 if (rev) t = rev;
801 }
802 if (t) _selection.insert(t.ptr());
804 // Linear shrink is more complicated. We need to find the farthest selected node.
805 // This means we have to check the entire subpath. We go in the direction in which
806 // the distance we traveled is lower. We do this until we run out of nodes (ends of path)
807 // or the two iterators meet. On the way, we store the last selected node and its distance
808 // in each direction (if any). At the end, we choose the one that is farther and deselect it.
809 } else {
810 // both iterators that store last selected nodes are initially empty
811 NodeList::iterator last_fwd, last_rev;
812 double last_distance_back = 0, last_distance_front = 0;
814 while (rev || fwd) {
815 if (fwd && (!rev || distance_front <= distance_back)) {
816 if (fwd->selected()) {
817 last_fwd = fwd;
818 last_distance_front = distance_front;
819 }
820 NodeList::iterator n = fwd.next();
821 if (n) distance_front += bezier_length(*fwd, fwd->_front, n->_back, *n);
822 fwd = n;
823 } else if (rev && (!fwd || distance_front > distance_back)) {
824 if (rev->selected()) {
825 last_rev = rev;
826 last_distance_back = distance_back;
827 }
828 NodeList::iterator p = rev.prev();
829 if (p) distance_back += bezier_length(*rev, rev->_back, p->_front, *p);
830 rev = p;
831 }
832 // Check whether we walked the entire cyclic subpath.
833 // This is initially true because both iterators start from this node,
834 // so this check cannot go in the while condition.
835 // When this happens, we need to check the last node, pointed to by the iterators.
836 if (fwd && fwd == rev) {
837 if (!fwd->selected()) break;
838 NodeList::iterator fwdp = fwd.prev(), revn = rev.next();
839 double df = distance_front + bezier_length(*fwdp, fwdp->_front, fwd->_back, *fwd);
840 double db = distance_back + bezier_length(*revn, revn->_back, rev->_front, *rev);
841 if (df > db) {
842 last_fwd = fwd;
843 last_distance_front = df;
844 } else {
845 last_rev = rev;
846 last_distance_back = db;
847 }
848 break;
849 }
850 }
852 NodeList::iterator t;
853 if (last_fwd && last_rev) {
854 if (last_distance_front >= last_distance_back) t = last_fwd;
855 else t = last_rev;
856 } else {
857 if (last_fwd) t = last_fwd;
858 if (last_rev) t = last_rev;
859 }
860 if (t) _selection.erase(t.ptr());
861 }
862 }
864 void Node::_setState(State state)
865 {
866 // change node size to match type and selection state
867 switch (_type) {
868 case NODE_AUTO:
869 case NODE_CUSP:
870 if (selected()) _setSize(11);
871 else _setSize(9);
872 break;
873 default:
874 if(selected()) _setSize(9);
875 else _setSize(7);
876 break;
877 }
878 SelectableControlPoint::_setState(state);
879 }
881 bool Node::grabbed(GdkEventMotion *event)
882 {
883 if (SelectableControlPoint::grabbed(event))
884 return true;
886 // Dragging out handles with Shift + drag on a node.
887 if (!held_shift(*event)) return false;
889 Handle *h;
890 Geom::Point evp = event_point(*event);
891 Geom::Point rel_evp = evp - _last_click_event_point();
893 // This should work even if dragtolerance is zero and evp coincides with node position.
894 double angle_next = HUGE_VAL;
895 double angle_prev = HUGE_VAL;
896 bool has_degenerate = false;
897 // determine which handle to drag out based on degeneration and the direction of drag
898 if (_front.isDegenerate() && _next()) {
899 Geom::Point next_relpos = _desktop->d2w(_next()->position())
900 - _desktop->d2w(position());
901 angle_next = fabs(Geom::angle_between(rel_evp, next_relpos));
902 has_degenerate = true;
903 }
904 if (_back.isDegenerate() && _prev()) {
905 Geom::Point prev_relpos = _desktop->d2w(_prev()->position())
906 - _desktop->d2w(position());
907 angle_prev = fabs(Geom::angle_between(rel_evp, prev_relpos));
908 has_degenerate = true;
909 }
910 if (!has_degenerate) return false;
911 h = angle_next < angle_prev ? &_front : &_back;
913 h->setPosition(_desktop->w2d(evp));
914 h->setVisible(true);
915 h->transferGrab(this, event);
916 Handle::_drag_out = true;
917 return true;
918 }
920 void Node::dragged(Geom::Point &new_pos, GdkEventMotion *event)
921 {
922 // For a note on how snapping is implemented in Inkscape, see snap.h.
923 SnapManager &sm = _desktop->namedview->snap_manager;
924 bool snap = sm.someSnapperMightSnap();
925 std::vector<Inkscape::SnapCandidatePoint> unselected;
926 if (snap) {
927 /* setup
928 * TODO We are doing this every time a snap happens. It should once be done only once
929 * per drag - maybe in the grabbed handler?
930 * TODO Unselected nodes vector must be valid during the snap run, because it is not
931 * copied. Fix this in snap.h and snap.cpp, then the above.
932 * TODO Snapping to unselected segments of selected paths doesn't work yet. */
934 // Build the list of unselected nodes.
935 typedef ControlPointSelection::Set Set;
936 Set &nodes = _selection.allPoints();
937 for (Set::iterator i = nodes.begin(); i != nodes.end(); ++i) {
938 if (!(*i)->selected()) {
939 Node *n = static_cast<Node*>(*i);
940 Inkscape::SnapCandidatePoint p(n->position(), n->_snapSourceType(), n->_snapTargetType());
941 unselected.push_back(p);
942 }
943 }
944 sm.setupIgnoreSelection(_desktop, true, &unselected);
945 }
947 if (held_control(*event)) {
948 Geom::Point origin = _last_drag_origin();
949 Inkscape::SnappedPoint fp, bp;
950 if (held_alt(*event)) {
951 // with Ctrl+Alt, constrain to handle lines
952 // project the new position onto a handle line that is closer
953 boost::optional<Geom::Point> front_point, back_point;
954 boost::optional<Inkscape::Snapper::ConstraintLine> line_front, line_back;
955 if (_front.isDegenerate()) {
956 if (_is_line_segment(this, _next()))
957 front_point = _next()->position() - origin;
958 } else {
959 front_point = _front.relativePos();
960 }
961 if (_back.isDegenerate()) {
962 if (_is_line_segment(_prev(), this))
963 back_point = _prev()->position() - origin;
964 } else {
965 back_point = _back.relativePos();
966 }
967 if (front_point)
968 line_front = Inkscape::Snapper::ConstraintLine(origin, *front_point);
969 if (back_point)
970 line_back = Inkscape::Snapper::ConstraintLine(origin, *back_point);
972 // TODO: combine the snap and non-snap branches by modifying snap.h / snap.cpp
973 if (snap) {
974 if (line_front) {
975 fp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(position(),
976 _snapSourceType()), *line_front);
977 }
978 if (line_back) {
979 bp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(position(),
980 _snapSourceType()), *line_back);
981 }
982 }
983 if (fp.getSnapped() || bp.getSnapped()) {
984 if (fp.isOtherSnapBetter(bp, false)) {
985 bp.getPoint(new_pos);
986 } else {
987 fp.getPoint(new_pos);
988 }
989 } else {
990 boost::optional<Geom::Point> pos;
991 if (line_front) {
992 pos = line_front->projection(new_pos);
993 }
994 if (line_back) {
995 Geom::Point pos2 = line_back->projection(new_pos);
996 if (!pos || (pos && Geom::distance(new_pos, *pos) > Geom::distance(new_pos, pos2)))
997 pos = pos2;
998 }
999 if (pos) {
1000 new_pos = *pos;
1001 } else {
1002 new_pos = origin;
1003 }
1004 }
1005 } else {
1006 // with Ctrl, constrain to axes
1007 // TODO combine the two branches
1008 if (snap) {
1009 Inkscape::Snapper::ConstraintLine line_x(origin, Geom::Point(1, 0));
1010 Inkscape::Snapper::ConstraintLine line_y(origin, Geom::Point(0, 1));
1011 fp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(position(), _snapSourceType()), line_x);
1012 bp = sm.constrainedSnap(Inkscape::SnapCandidatePoint(position(), _snapSourceType()), line_y);
1013 }
1014 if (fp.getSnapped() || bp.getSnapped()) {
1015 if (fp.isOtherSnapBetter(bp, false)) {
1016 fp = bp;
1017 }
1018 fp.getPoint(new_pos);
1019 } else {
1020 Geom::Point origin = _last_drag_origin();
1021 Geom::Point delta = new_pos - origin;
1022 Geom::Dim2 d = (fabs(delta[Geom::X]) < fabs(delta[Geom::Y])) ? Geom::X : Geom::Y;
1023 new_pos[d] = origin[d];
1024 }
1025 }
1026 } else if (snap) {
1027 sm.freeSnapReturnByRef(new_pos, _snapSourceType());
1028 }
1030 SelectableControlPoint::dragged(new_pos, event);
1031 }
1033 bool Node::clicked(GdkEventButton *event)
1034 {
1035 if(_pm()._nodeClicked(this, event))
1036 return true;
1037 return SelectableControlPoint::clicked(event);
1038 }
1040 Inkscape::SnapSourceType Node::_snapSourceType()
1041 {
1042 if (_type == NODE_SMOOTH || _type == NODE_AUTO)
1043 return SNAPSOURCE_NODE_SMOOTH;
1044 return SNAPSOURCE_NODE_CUSP;
1045 }
1046 Inkscape::SnapTargetType Node::_snapTargetType()
1047 {
1048 if (_type == NODE_SMOOTH || _type == NODE_AUTO)
1049 return SNAPTARGET_NODE_SMOOTH;
1050 return SNAPTARGET_NODE_CUSP;
1051 }
1053 Glib::ustring Node::_getTip(unsigned state)
1054 {
1055 if (state_held_shift(state)) {
1056 bool can_drag_out = (_next() && _front.isDegenerate()) || (_prev() && _back.isDegenerate());
1057 if (can_drag_out) {
1058 /*if (state_held_control(state)) {
1059 return format_tip(C_("Path node tip",
1060 "<b>Shift+Ctrl:</b> drag out a handle and snap its angle "
1061 "to %f° increments"), snap_increment_degrees());
1062 }*/
1063 return C_("Path node tip",
1064 "<b>Shift:</b> drag out a handle, click to toggle selection");
1065 }
1066 return C_("Path node tip", "<b>Shift:</b> click to toggle selection");
1067 }
1069 if (state_held_control(state)) {
1070 if (state_held_alt(state)) {
1071 return C_("Path node tip", "<b>Ctrl+Alt:</b> move along handle lines, click to delete node");
1072 }
1073 return C_("Path node tip",
1074 "<b>Ctrl:</b> move along axes, click to change node type");
1075 }
1077 // assemble tip from node name
1078 char const *nodetype = node_type_to_localized_string(_type);
1079 if (_selection.transformHandlesEnabled() && selected()) {
1080 if (_selection.size() == 1) {
1081 return format_tip(C_("Path node tip",
1082 "<b>%s:</b> drag to shape the path (more: Shift, Ctrl, Ctrl+Alt)"), nodetype);
1083 }
1084 return format_tip(C_("Path node tip",
1085 "<b>%s:</b> drag to shape the path, click to toggle scale/rotation handles (more: Shift, Ctrl, Ctrl+Alt)"), nodetype);
1086 }
1087 return format_tip(C_("Path node tip",
1088 "<b>%s:</b> drag to shape the path, click to select only this node (more: Shift, Ctrl, Ctrl+Alt)"), nodetype);
1089 }
1091 Glib::ustring Node::_getDragTip(GdkEventMotion */*event*/)
1092 {
1093 Geom::Point dist = position() - _last_drag_origin();
1094 GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
1095 GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
1096 Glib::ustring ret = format_tip(C_("Path node tip", "Move by %s, %s"),
1097 x->str, y->str);
1098 g_string_free(x, TRUE);
1099 g_string_free(y, TRUE);
1100 return ret;
1101 }
1103 char const *Node::node_type_to_localized_string(NodeType type)
1104 {
1105 switch (type) {
1106 case NODE_CUSP: return _("Cusp node");
1107 case NODE_SMOOTH: return _("Smooth node");
1108 case NODE_SYMMETRIC: return _("Symmetric node");
1109 case NODE_AUTO: return _("Auto-smooth node");
1110 default: return "";
1111 }
1112 }
1114 /** Determine whether two nodes are joined by a linear segment. */
1115 bool Node::_is_line_segment(Node *first, Node *second)
1116 {
1117 if (!first || !second) return false;
1118 if (first->_next() == second)
1119 return first->_front.isDegenerate() && second->_back.isDegenerate();
1120 if (second->_next() == first)
1121 return second->_front.isDegenerate() && first->_back.isDegenerate();
1122 return false;
1123 }
1125 SPCtrlShapeType Node::_node_type_to_shape(NodeType type)
1126 {
1127 switch(type) {
1128 case NODE_CUSP: return SP_CTRL_SHAPE_DIAMOND;
1129 case NODE_SMOOTH: return SP_CTRL_SHAPE_SQUARE;
1130 case NODE_AUTO: return SP_CTRL_SHAPE_CIRCLE;
1131 case NODE_SYMMETRIC: return SP_CTRL_SHAPE_SQUARE;
1132 default: return SP_CTRL_SHAPE_DIAMOND;
1133 }
1134 }
1137 /**
1138 * @class NodeList
1139 * @brief An editable list of nodes representing a subpath.
1140 *
1141 * It can optionally be cyclic to represent a closed path.
1142 * The list has iterators that act like plain node iterators, but can also be used
1143 * to obtain shared pointers to nodes.
1144 */
1146 NodeList::NodeList(SubpathList &splist)
1147 : _list(splist)
1148 , _closed(false)
1149 {
1150 this->list = this;
1151 this->next = this;
1152 this->prev = this;
1153 }
1155 NodeList::~NodeList()
1156 {
1157 clear();
1158 }
1160 bool NodeList::empty()
1161 {
1162 return next == this;
1163 }
1165 NodeList::size_type NodeList::size()
1166 {
1167 size_type sz = 0;
1168 for (ListNode *ln = next; ln != this; ln = ln->next) ++sz;
1169 return sz;
1170 }
1172 bool NodeList::closed()
1173 {
1174 return _closed;
1175 }
1177 /** A subpath is degenerate if it has no segments - either one node in an open path
1178 * or no nodes in a closed path */
1179 bool NodeList::degenerate()
1180 {
1181 return closed() ? empty() : ++begin() == end();
1182 }
1184 NodeList::iterator NodeList::before(double t, double *fracpart)
1185 {
1186 double intpart;
1187 *fracpart = std::modf(t, &intpart);
1188 int index = intpart;
1190 iterator ret = begin();
1191 std::advance(ret, index);
1192 return ret;
1193 }
1195 // insert a node before i
1196 NodeList::iterator NodeList::insert(iterator i, Node *x)
1197 {
1198 ListNode *ins = i._node;
1199 x->next = ins;
1200 x->prev = ins->prev;
1201 ins->prev->next = x;
1202 ins->prev = x;
1203 x->ListNode::list = this;
1204 return iterator(x);
1205 }
1207 void NodeList::splice(iterator pos, NodeList &list)
1208 {
1209 splice(pos, list, list.begin(), list.end());
1210 }
1212 void NodeList::splice(iterator pos, NodeList &list, iterator i)
1213 {
1214 NodeList::iterator j = i;
1215 ++j;
1216 splice(pos, list, i, j);
1217 }
1219 void NodeList::splice(iterator pos, NodeList &list, iterator first, iterator last)
1220 {
1221 ListNode *ins_beg = first._node, *ins_end = last._node, *at = pos._node;
1222 for (ListNode *ln = ins_beg; ln != ins_end; ln = ln->next) {
1223 ln->list = this;
1224 }
1225 ins_beg->prev->next = ins_end;
1226 ins_end->prev->next = at;
1227 at->prev->next = ins_beg;
1229 ListNode *atprev = at->prev;
1230 at->prev = ins_end->prev;
1231 ins_end->prev = ins_beg->prev;
1232 ins_beg->prev = atprev;
1233 }
1235 void NodeList::shift(int n)
1236 {
1237 // 1. make the list perfectly cyclic
1238 next->prev = prev;
1239 prev->next = next;
1240 // 2. find new begin
1241 ListNode *new_begin = next;
1242 if (n > 0) {
1243 for (; n > 0; --n) new_begin = new_begin->next;
1244 } else {
1245 for (; n < 0; ++n) new_begin = new_begin->prev;
1246 }
1247 // 3. relink begin to list
1248 next = new_begin;
1249 prev = new_begin->prev;
1250 new_begin->prev->next = this;
1251 new_begin->prev = this;
1252 }
1254 void NodeList::reverse()
1255 {
1256 for (ListNode *ln = next; ln != this; ln = ln->prev) {
1257 std::swap(ln->next, ln->prev);
1258 Node *node = static_cast<Node*>(ln);
1259 Geom::Point save_pos = node->front()->position();
1260 node->front()->setPosition(node->back()->position());
1261 node->back()->setPosition(save_pos);
1262 }
1263 std::swap(next, prev);
1264 }
1266 void NodeList::clear()
1267 {
1268 for (iterator i = begin(); i != end();) erase (i++);
1269 }
1271 NodeList::iterator NodeList::erase(iterator i)
1272 {
1273 // some gymnastics are required to ensure that the node is valid when deleted;
1274 // otherwise the code that updates handle visibility will break
1275 Node *rm = static_cast<Node*>(i._node);
1276 ListNode *rmnext = rm->next, *rmprev = rm->prev;
1277 ++i;
1278 delete rm;
1279 rmprev->next = rmnext;
1280 rmnext->prev = rmprev;
1281 return i;
1282 }
1284 // TODO this method is very ugly!
1285 // converting SubpathList to an intrusive list might allow us to get rid of it
1286 void NodeList::kill()
1287 {
1288 for (SubpathList::iterator i = _list.begin(); i != _list.end(); ++i) {
1289 if (i->get() == this) {
1290 _list.erase(i);
1291 return;
1292 }
1293 }
1294 }
1296 NodeList &NodeList::get(Node *n) {
1297 return *(n->list());
1298 }
1299 NodeList &NodeList::get(iterator const &i) {
1300 return *(i._node->list);
1301 }
1304 /**
1305 * @class SubpathList
1306 * @brief Editable path composed of one or more subpaths
1307 */
1309 } // namespace UI
1310 } // namespace Inkscape
1312 /*
1313 Local Variables:
1314 mode:c++
1315 c-file-style:"stroustrup"
1316 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1317 indent-tabs-mode:nil
1318 fill-column:99
1319 End:
1320 */
1321 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :