/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2009  Sandro Santilli <strk@keybit.net>
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation. 
 * See the COPYING file for more information.
 *
 **********************************************************************
 *
 * Last port: operation/buffer/BufferParameters.java r278 (JTS-1.12)
 *
 **********************************************************************/

#include <cstdlib> // for std::abs()
#include <cmath> // for cos

#include <geos/platform.h>
#include <geos/operation/buffer/BufferParameters.h>


#ifndef M_PI
#define M_PI        3.14159265358979323846
#endif

namespace geos {
namespace operation { // geos.operation
namespace buffer { // geos.operation.buffer

// public static const
const double BufferParameters::DEFAULT_MITRE_LIMIT = 5.0;

// public
BufferParameters::BufferParameters()
    :
    quadrantSegments(DEFAULT_QUADRANT_SEGMENTS),
    endCapStyle(CAP_ROUND),
    joinStyle(JOIN_ROUND),
    mitreLimit(DEFAULT_MITRE_LIMIT),
    _isSingleSided(false)
{}

// public
BufferParameters::BufferParameters(int quadrantSegments)
	:
	quadrantSegments(DEFAULT_QUADRANT_SEGMENTS),
	endCapStyle(CAP_ROUND),
	joinStyle(JOIN_ROUND),
	mitreLimit(DEFAULT_MITRE_LIMIT),
	_isSingleSided(false)
{
	setQuadrantSegments(quadrantSegments);
}

// public
BufferParameters::BufferParameters(int quadrantSegments,
                                   EndCapStyle endCapStyle)
	:
	quadrantSegments(DEFAULT_QUADRANT_SEGMENTS),
	endCapStyle(CAP_ROUND),
	joinStyle(JOIN_ROUND),
	mitreLimit(DEFAULT_MITRE_LIMIT),
	_isSingleSided(false)
{
	setQuadrantSegments(quadrantSegments);
	setEndCapStyle(endCapStyle);
}

// public
BufferParameters::BufferParameters(int quadrantSegments,
                                   EndCapStyle endCapStyle,
                                   JoinStyle joinStyle,
                                   double mitreLimit)
	:
	quadrantSegments(DEFAULT_QUADRANT_SEGMENTS),
	endCapStyle(CAP_ROUND),
	joinStyle(JOIN_ROUND),
	mitreLimit(DEFAULT_MITRE_LIMIT),
	_isSingleSided(false)
{
	setQuadrantSegments(quadrantSegments);
	setEndCapStyle(endCapStyle);
	setJoinStyle(joinStyle);
	setMitreLimit(mitreLimit);
}

// public
void
BufferParameters::setQuadrantSegments(int quadSegs)
{
	quadrantSegments = quadSegs;

	/**
	 * Indicates how to construct fillets.
	 * If qs >= 1, fillet is round, and qs indicates number of
	 * segments to use to approximate a quarter-circle.
	 * If qs = 0, fillet is bevelled flat (i.e. no filleting is performed)
	 * If qs < 0, fillet is mitred, and absolute value of qs
	 * indicates maximum length of mitre according to
	 *
	 * mitreLimit = |qs|
	 */
	if (quadrantSegments == 0)
		joinStyle = JOIN_BEVEL;
	if (quadrantSegments < 0) {
		joinStyle = JOIN_MITRE;
		mitreLimit = std::abs(quadrantSegments);
	}

	if (quadSegs <= 0) {
		quadrantSegments = 1;
	}

	/**
	 * If join style was set by the quadSegs value,
	 * use the default for the actual quadrantSegments value.
	 */
	if (joinStyle != JOIN_ROUND) {
		quadrantSegments = DEFAULT_QUADRANT_SEGMENTS;
	}
}

// public static
double
BufferParameters::bufferDistanceError(int quadSegs)
{
	double alpha = M_PI / 2.0 / quadSegs;
	return 1 - cos(alpha / 2.0);
}

} // namespace geos.operation.buffer
} // namespace geos.operation
} // namespace geos

