config_gen/src/line.cpp (4ef7955) - libetherpix · BlinkenArea

line.cpp

/*
 * EtherPix config file generator
 *
 * Copyright 2010-2017 Stefan Schuermans <stefan schuermans info>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3 of the License.
 *
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>

#include "box.h"
#include "constants.h"
#include "line.h"
#include "point.h"

Line::Line()
{
}

Line::Line(const Point &start, const Point &end):
  mStart(start),
  mEnd(end)
{
}

double Line::length() const
{
  return (mEnd - mStart).abs();
}

void Line::getBounds(Box &bounds) const
{
  bounds.mBL = mStart;
  bounds.mTR = mEnd;
  bounds.fix();
}

bool Line::isIntersecting(const Line *pLine) const
{
  return getIntersection(pLine, NULL);
}

bool Line::getIntersection(const Line *pLine, Point *pIntersect) const
{
  Point d1 = mEnd - mStart;
  Point d2 = pLine->mEnd - pLine->mStart;
  Point ds = mStart - pLine->mStart;
  double denom = d2.mY * d1.mX - d2.mX * d1.mY;
  double num1 = d2.mX * ds.mY - d2.mY * ds.mX;
  double num2 = d1.mX * ds.mY - d1.mY * ds.mX;
  if (denom >= -EPSILON && denom <= EPSILON) // parallel
    return false;
  double prm1 = num1 / denom;
  double prm2 = num2 / denom;
  if (prm1 < -EPSILON || prm1 > 1.0 + EPSILON ||
      prm2 < -EPSILON || prm2 > 1.0 + EPSILON)
    return false;
  if (pIntersect)
    *pIntersect = mStart + d1 * prm1;
  return true;
}

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