src/object-snapper.cpp

   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  */
  12
  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"
  23
  24
  25 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
  26     : Snapper(nv, d), _snap_to_nodes(true), _snap_to_paths(true)
  27 {
  28
  29 }
  30
  31
  32 /**
  33  *  \param p Point we are trying to snap (desktop coordinates)
  34  */
  35
  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))) {
  44
  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             }
  50
  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::Maybe<NR::Rect> b = sp_item_bbox_desktop(SP_ITEM(o));
  57                     if ( b && NR::expand(*b, -getDistance()).contains(p) ) {
  58                         c.push_back(SP_ITEM(o));
  59                     }
  60                 }
  61             }
  62
  63         }
  64     }
  65 }
  66
  67
  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;
  76
  77     for (std::list<SPItem*>::const_iterator i = cand.begin(); i != cand.end(); i++) {
  78         if (SP_IS_SHAPE(*i)) {
  79
  80             SPShape const *sh = SP_SHAPE(*i);
  81             if (sh->curve) {
  82
  83                 int j = 0;
  84                 NR::Matrix const i2doc = sp_item_i2doc_affine(*i);
  85
  86                 while (SP_CURVE_BPATH(sh->curve)[j].code != NR_END) {
  87
  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);
  91
  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                     }
  97
  98                     j++;
  99                 }
 100             }
 101         }
 102     }
 103 }
 104
 105
 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;
 114
 115     NR::Point const p_doc = desktop->dt2doc(p);
 116
 117     for (std::list<SPItem*>::const_iterator i = cand.begin(); i != cand.end(); i++) {
 118
 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();
 122
 123         Path *livarot_path = Path_for_item(*i, true, true);
 124         if (!livarot_path)
 125             continue;
 126
 127         livarot_path->ConvertWithBackData(0.01);
 128
 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 && o->t >= 0 && o->t <= 1) {
 132
 133             /* Convert the nearest point back to desktop coordinates */
 134             NR::Point const o_it = get_point_on_Path(livarot_path, o->piece, o->t);
 135             NR::Point const o_dt = desktop->doc2dt(o_it * i2doc);
 136
 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         }
 142
 143         delete livarot_path;
 144     }
 145
 146 }
 147
 148
 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     }
 155
 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);
 159
 160     SnappedPoint s(p, NR_HUGE);
 161
 162     if (_snap_to_nodes) {
 163         _snapNodes(s, p, cand);
 164     }
 165     if (_snap_to_paths) {
 166         _snapPaths(s, p, cand);
 167     }
 168
 169     return s;
 170 }
 171
 172
 173
 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 }
 183
 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 :