src/removeoverlap.cpp

   1 /** \file
   2  * Interface between Inkscape code (SPItem) and remove-overlaps function.
   3  */
   4 /*
   5 * Authors:
   6 *   Tim Dwyer <tgdwyer@gmail.com>
   7  *   Abhishek Sharma
   8 *
   9 * Copyright (C) 2005 Authors
  10 *
  11 * Released under GNU LGPL.  Read the file 'COPYING' for more information.
  12 */
  13 #include "util/glib-list-iterators.h"
  14 #include "sp-item.h"
  15 #include "sp-item-transform.h"
  16 #include "libvpsc/generate-constraints.h"
  17 #include "libvpsc/remove_rectangle_overlap.h"
  18 #include <utility>
  19
  20 using vpsc::Rectangle;
  21
  22 namespace {
  23         struct Record {
  24                 SPItem *item;
  25                 Geom::Point midpoint;
  26                 Rectangle *vspc_rect;
  27
  28                 Record() {}
  29                 Record(SPItem *i, Geom::Point m, Rectangle *r)
  30                 : item(i), midpoint(m), vspc_rect(r) {}
  31         };
  32 }
  33
  34 /**
  35 * Takes a list of inkscape items and moves them as little as possible
  36 * such that rectangular bounding boxes are separated by at least xGap
  37 * horizontally and yGap vertically
  38 */
  39 void removeoverlap(GSList const *const items, double const xGap, double const yGap) {
  40         using Inkscape::Util::GSListConstIterator;
  41         std::list<SPItem *> selected;
  42         selected.insert<GSListConstIterator<SPItem *> >(selected.end(), items, NULL);
  43         std::vector<Record> records;
  44         std::vector<Rectangle *> rs;
  45
  46         Geom::Point const gap(xGap, yGap);
  47         for (std::list<SPItem *>::iterator it(selected.begin());
  48                 it != selected.end();
  49                 ++it)
  50         {
  51                 using Geom::X; using Geom::Y;
  52                 Geom::OptRect item_box((*it)->getBboxDesktop());
  53                 if (item_box) {
  54                         Geom::Point min(item_box->min() - .5*gap);
  55                         Geom::Point max(item_box->max() + .5*gap);
  56                         // A negative gap is allowed, but will lead to problems when the gap is larger than
  57                         // the bounding box (in either X or Y direction, or both); min will have become max
  58                         // now, which cannot be handled by Rectangle() which is called below. And how will
  59                         // removeRectangleOverlap handle such a case?
  60                         // That's why we will enforce some boundaries on min and max here:
  61                         if (max[X] < min[X]) {
  62                                 min[X] = max[X] = (min[X] + max[X])/2;
  63                         }
  64                         if (max[Y] < min[Y]) {
  65                                 min[Y] = max[Y] = (min[Y] + max[Y])/2;
  66                         }
  67                         Rectangle *vspc_rect = new Rectangle(min[X], max[X], min[Y], max[Y]);
  68                         records.push_back(Record(*it, item_box->midpoint(), vspc_rect));
  69                         rs.push_back(vspc_rect);
  70                 }
  71         }
  72         if (!rs.empty()) {
  73                 removeRectangleOverlap(rs.size(), &rs[0], 0.0, 0.0);
  74         }
  75         for ( std::vector<Record>::iterator it = records.begin();
  76               it != records.end();
  77               ++it )
  78         {
  79                 Geom::Point const curr = it->midpoint;
  80                 Geom::Point const dest(it->vspc_rect->getCentreX(),
  81                                      it->vspc_rect->getCentreY());
  82                 sp_item_move_rel(it->item, Geom::Translate(dest - curr));
  83                 delete it->vspc_rect;
  84         }
  85 }