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-image.h"
  19 #include "sp-item-group.h"
  20 #include "sp-item.h"
  21 #include "sp-use.h"
  22 #include "display/curve.h"
  23 #include "desktop.h"
  24 #include "inkscape.h"
  25 #include "splivarot.h"
  26 #include "prefs-utils.h"
  27
  28
  29 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
  30     : Snapper(nv, d), _snap_to_nodes(true), _snap_to_paths(true)
  31 {
  32
  33 }
  34
  35
  36 /**
  37  *  \param p Point we are trying to snap (desktop coordinates)
  38  */
  39
  40 void Inkscape::ObjectSnapper::_findCandidates(std::list<SPItem*>& c,
  41                                               SPObject* r,
  42                                               std::list<SPItem const *> const &it,
  43                                               NR::Point const &p) const
  44 {
  45     if (ThisSnapperMightSnap()) {
  46         SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
  47         for (SPObject* o = sp_object_first_child(r); o != NULL; o = SP_OBJECT_NEXT(o)) {
  48             if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !desktop->itemIsHidden(SP_ITEM(o))) {
  49
  50                 /* See if this item is on the ignore list */
  51                 std::list<SPItem const *>::const_iterator i = it.begin();
  52                 while (i != it.end() && *i != o) {
  53                     i++;
  54                 }
  55
  56                 if (i == it.end()) {
  57                     /* See if the item is within range */
  58                     if (SP_IS_GROUP(o)) {
  59                         _findCandidates(c, o, it, p);
  60                     } else {
  61                         NR::Maybe<NR::Rect> b = sp_item_bbox_desktop(SP_ITEM(o));
  62                         if ( b && NR::expand(*b, -getDistance()).contains(p) ) {
  63                             c.push_back(SP_ITEM(o));
  64                         }
  65                     }
  66                 }
  67
  68             }
  69         }
  70     }
  71 }
  72
  73
  74 void Inkscape::ObjectSnapper::_snapNodes(Inkscape::SnappedPoint &s,
  75                                          NR::Point const &p,
  76                                          std::list<SPItem*> const &cand) const
  77 {
  78     /* FIXME: this seems like a hack.  Perhaps Snappers should be
  79     ** in SPDesktop rather than SPNamedView?
  80     */
  81     SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
  82
  83     // Determine the type of bounding box we should snap to
  84     //TODO if (_snap_to_bbox) ???? -> will save some cpu time
  85         gchar const *prefs_bbox = prefs_get_string_attribute("tools.select", "bounding_box");
  86         SPItem::BBoxType bbox_type = (prefs_bbox != NULL && strcmp(prefs_bbox, "geometric")==0)? SPItem::GEOMETRIC_BBOX : SPItem::APPROXIMATE_BBOX;
  87
  88     for (std::list<SPItem*>::const_iterator i = cand.begin(); i != cand.end(); i++) {
  89
  90         NR::Matrix i2doc(NR::identity());
  91         SPItem *root_item = NULL;
  92         if (SP_IS_USE(*i)) {
  93             i2doc = sp_use_get_root_transform(SP_USE(*i));
  94             root_item = sp_use_root(SP_USE(*i));
  95         } else {
  96             i2doc = sp_item_i2doc_affine(*i);
  97             root_item = *i;
  98         }
  99
 100         SPCurve *curve = NULL;
 101
 102         if (SP_IS_SHAPE(root_item)) {
 103             SPShape const *sh = SP_SHAPE(root_item);
 104             curve = sh->curve;
 105         } else if (SP_IS_IMAGE(root_item)) {
 106             SPImage const *im = SP_IMAGE(root_item);
 107             curve = im->curve;
 108         }
 109
 110                 std::list<NR::Point> points_to_snap_to;
 111
 112         //Collect all nodes so we can snap to them
 113         if (curve) {
 114             int j = 0;
 115             while (SP_CURVE_BPATH(curve)[j].code != NR_END) {
 116                 /* Get this node in desktop coordinates */
 117                 NArtBpath const &bp = SP_CURVE_BPATH(curve)[j];
 118                 points_to_snap_to.push_back(desktop->doc2dt(bp.c(3) * i2doc));
 119                 j++;
 120             }
 121         }
 122
 123         //Collect the bounding box's corners so we can snap to them
 124         NR::Maybe<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
 125         if (b) {
 126                 for ( unsigned k = 0 ; k < 4 ; k++ ) {
 127                     points_to_snap_to.push_back(b->corner(k));
 128                 }
 129         }
 130
 131         //Do the snapping, using all the nodes and corners collected above
 132         for (std::list<NR::Point>::const_iterator k = points_to_snap_to.begin(); k != points_to_snap_to.end(); k++) {
 133             /* Try to snap to this node of the path */
 134             NR::Coord const dist = NR::L2(*k - p);
 135             if (dist < getDistance() && dist < s.getDistance()) {
 136                 s = SnappedPoint(*k, dist);
 137             }
 138         }
 139     }
 140 }
 141
 142
 143 void Inkscape::ObjectSnapper::_snapPaths(Inkscape::SnappedPoint &s,
 144                                          NR::Point const &p,
 145                                          std::list<SPItem*> const &cand) const
 146 {
 147     /* FIXME: this seems like a hack.  Perhaps Snappers should be
 148     ** in SPDesktop rather than SPNamedView?
 149     */
 150     SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
 151
 152     NR::Point const p_doc = desktop->dt2doc(p);
 153
 154     // Determine the type of bounding box we should snap to
 155     //TODO if (_snap_to_bbox) ???? -> will save some cpu time
 156         gchar const *prefs_bbox = prefs_get_string_attribute("tools.select", "bounding_box");
 157         SPItem::BBoxType bbox_type = (prefs_bbox != NULL && strcmp(prefs_bbox, "geometric")==0)? SPItem::GEOMETRIC_BBOX : SPItem::APPROXIMATE_BBOX;
 158
 159     for (std::list<SPItem*>::const_iterator i = cand.begin(); i != cand.end(); i++) {
 160
 161         /* Transform the requested snap point to this item's coordinates */
 162         NR::Matrix i2doc(NR::identity());
 163         SPItem *root_item = NULL;
 164         /* We might have a clone at hand, so make sure we get the root item */
 165         if (SP_IS_USE(*i)) {
 166             i2doc = sp_use_get_root_transform(SP_USE(*i));
 167             root_item = sp_use_root(SP_USE(*i));
 168         } else {
 169             i2doc = sp_item_i2doc_affine(*i);
 170             root_item = *i;
 171         }
 172
 173         //Build a list of all paths considered for snapping to
 174         std::list<Path*> paths_to_snap_to;
 175
 176         //Add the item's path to snap to
 177         paths_to_snap_to.push_back(Path_for_item(root_item, true, true));
 178
 179         //Add the item's bounding box to snap to
 180         //This will get ugly... rect -> curve -> bpath
 181         NRRect rect;
 182         sp_item_invoke_bbox(root_item, &rect, i2doc, TRUE, bbox_type);
 183         NR::Maybe<NR::Rect> bbox = rect.upgrade();
 184         SPCurve *curve = sp_curve_new_from_rect(bbox);
 185         NArtBpath *bpath = SP_CURVE_BPATH(curve);
 186         Path *path = bpath_to_Path(bpath);
 187         paths_to_snap_to.push_back(path);
 188         delete curve;
 189         delete bpath;
 190
 191         //Now we can finally do the real snapping, using the paths collected above
 192         for (std::list<Path*>::const_iterator k = paths_to_snap_to.begin(); k != paths_to_snap_to.end(); k++) {
 193                 if (*k) {
 194                     (*k)->ConvertWithBackData(0.01);
 195
 196                         /* Look for the nearest position on this SPItem to our snap point */
 197                         NR::Maybe<Path::cut_position> const o = get_nearest_position_on_Path(*k, p_doc);
 198                         if (o && o->t >= 0 && o->t <= 1) {
 199
 200                             /* Convert the nearest point back to desktop coordinates */
 201                             NR::Point const o_it = get_point_on_Path(*k, o->piece, o->t);
 202                             NR::Point const o_dt = desktop->doc2dt(o_it);
 203
 204                             NR::Coord const dist = NR::L2(o_dt - p);
 205                             if (dist < getDistance() && dist < s.getDistance()) {
 206                                 s = SnappedPoint(o_dt, dist);
 207                             }
 208                         }
 209
 210                         delete *k;
 211                 }
 212             }
 213     }
 214 }
 215
 216
 217 Inkscape::SnappedPoint Inkscape::ObjectSnapper::_doFreeSnap(NR::Point const &p,
 218                                                             std::list<SPItem const *> const &it) const
 219 {
 220     if ( NULL == _named_view ) {
 221         return SnappedPoint(p, NR_HUGE);
 222     }
 223
 224     /* Get a list of all the SPItems that we will try to snap to */
 225     std::list<SPItem*> cand;
 226     _findCandidates(cand, sp_document_root(_named_view->document), it, p);
 227
 228     SnappedPoint s(p, NR_HUGE);
 229
 230     if (_snap_to_nodes) {
 231         _snapNodes(s, p, cand);
 232     }
 233     if (_snap_to_paths) {
 234         _snapPaths(s, p, cand);
 235     }
 236
 237     return s;
 238 }
 239
 240
 241
 242 Inkscape::SnappedPoint Inkscape::ObjectSnapper::_doConstrainedSnap(NR::Point const &p,
 243                                                                    ConstraintLine const &c,
 244                                                                    std::list<SPItem const *> const &it) const
 245 {
 246     /* FIXME: this needs implementing properly; I think we have to do the
 247     ** intersection of c with the objects.
 248     */
 249     return _doFreeSnap(p, it);
 250 }
 251
 252 /**
 253  *  \return true if this Snapper will snap at least one kind of point.
 254  */
 255 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
 256 {
 257     return (_enabled && _snap_to != 0 && (_snap_to_paths || _snap_to_nodes));
 258 }
 259
 260
 261 /*
 262   Local Variables:
 263   mode:c++
 264   c-file-style:"stroustrup"
 265   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 266   indent-tabs-mode:nil
 267   fill-column:99
 268   End:
 269 */
 270 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :