removeoverlap.cpp

/** \file
 * Interface between Inkscape code (SPItem) and remove-overlaps function.
 */
/*
* Authors:
*   Tim Dwyer <tgdwyer@gmail.com>
*
* Copyright (C) 2005 Authors
*
* Released under GNU LGPL.  Read the file 'COPYING' for more information.
*/
#include "util/glib-list-iterators.h"
#include "sp-item.h"
#include "sp-item-transform.h"
#include "libvpsc/generate-constraints.h"
#include "libvpsc/remove_rectangle_overlap.h"

using vpsc::Rectangle;

/**
* Takes a list of inkscape items and moves them as little as possible
* such that rectangular bounding boxes are separated by at least xGap
* horizontally and yGap vertically
*/
00025 void removeoverlap(GSList const *const items, double const xGap, double const yGap) {
      if(!items) {
            return;
      }

      using Inkscape::Util::GSListConstIterator;
      std::list<SPItem *> selected;
      selected.insert<GSListConstIterator<SPItem *> >(selected.end(), items, NULL);
      if (selected.empty()) return;
      int n=selected.size();

      //Check 2 or more selected objects
      if (n < 2) return;

      Rectangle **rs = new Rectangle*[n];
      int i=0;

      NR::Point const gap(xGap, yGap);
      for (std::list<SPItem *>::iterator it(selected.begin());
            it != selected.end();
            ++it)
      {
            using NR::X; using NR::Y;
            NR::Rect const item_box(sp_item_bbox_desktop(*it));
            
            /* The current algorithm requires widths & heights to be strictly positive. */
            NR::Point min(item_box.min());
            NR::Point max(item_box.max());
            for (unsigned d = 0; d < 2; ++d) {
                  double const minsize = 1; // arbitrary positive number
                  if (max[d] - min[d] + gap[d] < minsize) {
                        double const mid = .5 * (min[d] + max[d]);
                        min[d] = mid - .5*minsize;
                        max[d] = mid + .5*minsize;
                  } else {
                        min[d] -= .5*gap[d];
                        max[d] += .5*gap[d];
                  }
            }
            rs[i++] = new Rectangle(min[X], max[X],
                              min[Y], max[Y]);
      }
      removeRectangleOverlap(n, rs, 0.0, 0.0);
      i=0;
      for (std::list<SPItem *>::iterator it(selected.begin());
            it != selected.end();
            ++it)
      {
            NR::Rect const item_box(sp_item_bbox_desktop(*it));
            Rectangle *r = rs[i++];
            NR::Point const curr(item_box.midpoint());
            NR::Point const dest(r->getCentreX(),
                             r->getCentreY());
            sp_item_move_rel(*it, NR::translate(dest - curr));
            delete r;
      }
      delete [] rs;
}