src/layer.cpp (d7d942d) - dxfngc · BlinkenArea

layer.cpp

/* drawing (DXF) to G-code (NGC) converter
 * Copyright 2013 Stefan Schuermans <stefan@schuermans.info>
 * Copyleft: CC-BY-SA http://creativecommons.org/licenses/by-sa/3.0/
 */

#include <list>

#include "gcode.h"
#include "layer.h"
#include "path.h"
#include "settings.h"

/**
 * @brief add a new empty path to the layer
 * @return reference to new empty path
 */
Path & Layer::addPath()
{
  mPaths.push_back(Path());
  return mPaths.back();
}

/**
 * @brief improve paths
 * @param[in] eqDist maximum distance of two points to be considered equal
 */
void Layer::improvePaths(double eqDist)
{
  Paths::iterator path, other, best;
  bool change;
  double smallest, dist;

// join paths with equal begin/end points
  do {
    change = false;
    // process all paths
    for (path = mPaths.begin(); path != mPaths.end(); ++path) {
      // check all paths following aftet the current one
      other = path;
      ++other;
      while (other != mPaths.end()) {
        // paths can be joined
        if (other->mPoints.front().equals(path->mPoints.back(),
                                          eqDist)) {
          path->appendPath(*other);
          other = mPaths.erase(other);
          change = true;
        }
        else if (other->mPoints.back().equals(path->mPoints.back(),
                                              eqDist)) {
          path->appendReversedPath(*other);
          other = mPaths.erase(other);
          change = true;
        }
        else if (other->mPoints.back().equals(path->mPoints.front(),
                                              eqDist)) {
          path->prependPath(*other);
          other = mPaths.erase(other);
          change = true;
        }
        else if (other->mPoints.front().equals(path->mPoints.front(),
                                               eqDist)) {
          path->prependReversedPath(*other);
          other = mPaths.erase(other);
          change = true;
        }
        // paths cannot be joined -> move to next one
        else
          ++other;
      } // while other
    } // for path
  } while (change);

// remove nearby points in paths
  for (path = mPaths.begin(); path != mPaths.end(); ++path)
    path->removeEqPoints(eqDist);

// remove empty paths
  path = mPaths.begin();
  while (path != mPaths.end())
    if (path->mPoints.empty())
      path = mPaths.erase(path);
    else
      ++path;

// sort paths to minimize unproductive move distance
  for (path = mPaths.begin(); path != mPaths.end(); ++path) {
    // find path starting at closest distance from current paths end
    other = path;
    ++other;
    best = mPaths.end();
    while (other != mPaths.end()) {
      // calculate (squared) distance from path.end to other.begin
      //   path and other are never empty here
      //   empty paths have been removed before
      dist = (path->mPoints.back() - other->mPoints.front()).abs_sq();
      // keep path with smallest (squared) distance
      if (best == mPaths.end() || dist < smallest) {
        best = other;
        smallest = dist;
      }
      ++other;
    } // while other
    // use best path as next one, i.e. swap best path with next one
    other = path;
    other++;
    if (other != mPaths.end() && best != mPaths.end())
      mPaths.splice(other, mPaths, best);
  } // for path
}

/**
 * @brief convert layer to G-code
 * @param[in] settings G-code creation settings
 * @param[in,out] gcode new G-code is appended to existing G-code
 */
void Layer::toGCode(const Settings &settings, GCode &gcode) const
{
  Paths::const_iterator path;
  for (path = mPaths.begin(); path != mPaths.end(); ++path)
    path->toGCode(settings, gcode);
}

dxfngc

sort paths in order to shorten unproductive move distance