1 /**
2 * \file object-snapper.cpp
3 * \brief Snapping things to objects.
4 *
5 * Authors:
6 * Carl Hetherington <inkscape@carlh.net>
7 *
8 * Copyright (C) 2005 Authors
9 *
10 * Released under GNU GPL, read the file 'COPYING' for more information
11 */
13 #include "libnr/n-art-bpath.h"
14 #include "libnr/nr-rect-ops.h"
15 #include "document.h"
16 #include "sp-namedview.h"
17 #include "sp-path.h"
18 #include "sp-item-group.h"
19 #include "display/curve.h"
20 #include "desktop.h"
21 #include "inkscape.h"
22 #include "splivarot.h"
25 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
26 : Snapper(nv, d), _snap_to_nodes(true), _snap_to_paths(true)
27 {
29 }
32 /**
33 * \param p Point we are trying to snap (desktop coordinates)
34 */
36 void Inkscape::ObjectSnapper::_findCandidates(std::list<SPItem*>& c,
37 SPObject* r,
38 std::list<SPItem const *> const &it,
39 NR::Point const &p) const
40 {
41 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
42 for (SPObject* o = sp_object_first_child(r); o != NULL; o = SP_OBJECT_NEXT(o)) {
43 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !desktop->itemIsHidden(SP_ITEM(o))) {
45 /* See if this item is on the ignore list */
46 std::list<SPItem const *>::const_iterator i = it.begin();
47 while (i != it.end() && *i != o) {
48 i++;
49 }
51 if (i == it.end()) {
52 /* See if the item is within range */
53 if (SP_IS_GROUP(o)) {
54 _findCandidates(c, o, it, p);
55 } else {
56 NR::Rect const b = NR::expand(sp_item_bbox_desktop(SP_ITEM(o)), -getDistance());
57 if (b.contains(p)) {
58 c.push_back(SP_ITEM(o));
59 }
60 }
61 }
63 }
64 }
65 }
68 void Inkscape::ObjectSnapper::_snapNodes(Inkscape::SnappedPoint &s,
69 NR::Point const &p,
70 std::list<SPItem*> const &cand) const
71 {
72 /* FIXME: this seems like a hack. Perhaps Snappers should be
73 ** in SPDesktop rather than SPNamedView?
74 */
75 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
77 for (std::list<SPItem*>::const_iterator i = cand.begin(); i != cand.end(); i++) {
78 if (SP_IS_SHAPE(*i)) {
80 SPShape const *sh = SP_SHAPE(*i);
81 if (sh->curve) {
83 int j = 0;
84 NR::Matrix const i2doc = sp_item_i2doc_affine(*i);
86 while (SP_CURVE_BPATH(sh->curve)[j].code != NR_END) {
88 /* Get this node in desktop coordinates */
89 NArtBpath const &bp = SP_CURVE_BPATH(sh->curve)[j];
90 NR::Point const n = desktop->doc2dt(bp.c(3) * i2doc);
92 /* Try to snap to this node of the path */
93 NR::Coord const dist = NR::L2(n - p);
94 if (dist < getDistance() && dist < s.getDistance()) {
95 s = SnappedPoint(n, dist);
96 }
98 j++;
99 }
100 }
101 }
102 }
103 }
106 void Inkscape::ObjectSnapper::_snapPaths(Inkscape::SnappedPoint &s,
107 NR::Point const &p,
108 std::list<SPItem*> const &cand) const
109 {
110 /* FIXME: this seems like a hack. Perhaps Snappers should be
111 ** in SPDesktop rather than SPNamedView?
112 */
113 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
115 NR::Point const p_doc = desktop->dt2doc(p);
117 for (std::list<SPItem*>::const_iterator i = cand.begin(); i != cand.end(); i++) {
119 /* Transform the requested snap point to this item's coordinates */
120 NR::Matrix const i2doc = sp_item_i2doc_affine(*i);
121 NR::Point const p_it = p_doc * i2doc.inverse();
123 Path *livarot_path = Path_for_item(*i, true, true);
124 if (!livarot_path)
125 continue;
127 livarot_path->ConvertWithBackData(0.01);
129 /* Look for the nearest position on this SPItem to our snap point */
130 NR::Maybe<Path::cut_position> const o = get_nearest_position_on_Path(livarot_path, p_it);
131 if (o != NR::Nothing() && o.assume().t >= 0 && o.assume().t <= 1) {
133 /* Convert the nearest point back to desktop coordinates */
134 NR::Point const o_it = get_point_on_Path(livarot_path, o.assume().piece, o.assume().t);
135 NR::Point const o_dt = desktop->doc2dt(o_it * i2doc);
137 NR::Coord const dist = NR::L2(o_dt - p);
138 if (dist < getDistance() && dist < s.getDistance()) {
139 s = SnappedPoint(o_dt, dist);
140 }
141 }
143 delete livarot_path;
144 }
146 }
149 Inkscape::SnappedPoint Inkscape::ObjectSnapper::_doFreeSnap(NR::Point const &p,
150 std::list<SPItem const *> const &it) const
151 {
152 if ( NULL == _named_view ) {
153 return SnappedPoint(p, NR_HUGE);
154 }
156 /* Get a list of all the SPItems that we will try to snap to */
157 std::list<SPItem*> cand;
158 _findCandidates(cand, sp_document_root(_named_view->document), it, p);
160 SnappedPoint s(p, NR_HUGE);
162 if (_snap_to_nodes) {
163 _snapNodes(s, p, cand);
164 }
165 if (_snap_to_paths) {
166 _snapPaths(s, p, cand);
167 }
169 return s;
170 }
174 Inkscape::SnappedPoint Inkscape::ObjectSnapper::_doConstrainedSnap(NR::Point const &p,
175 ConstraintLine const &c,
176 std::list<SPItem const *> const &it) const
177 {
178 /* FIXME: this needs implementing properly; I think we have to do the
179 ** intersection of c with the objects.
180 */
181 return _doFreeSnap(p, it);
182 }
184 /*
185 Local Variables:
186 mode:c++
187 c-file-style:"stroustrup"
188 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
189 indent-tabs-mode:nil
190 fill-column:99
191 End:
192 */
193 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :