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