/********************************************************************** * * GEOS - Geometry Engine Open Source * http://geos.osgeo.org * * Copyright (C) 2009 Sandro Santilli * * 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 r378 (JTS-1.12) * **********************************************************************/ #pragma once #include //#include //#include // for composition //#include // for composition //#include // for composition #ifdef _MSC_VER #pragma warning(push) #pragma warning(disable: 4251) // warning C4251: needs to have dll-interface to be used by clients of class #endif // Forward declarations namespace geos { namespace geom { class CoordinateSequence; class PrecisionModel; } namespace operation { namespace buffer { class OffsetCurveVertexList; } } } namespace geos { namespace operation { // geos.operation namespace buffer { // geos.operation.buffer /** \brief * Contains the parameters which * describe how a buffer should be constructed. * */ class GEOS_DLL BufferParameters { public: /// End cap styles enum EndCapStyle { /// Specifies a round line buffer end cap style. CAP_ROUND = 1, /// Specifies a flat line buffer end cap style. CAP_FLAT = 2, /// Specifies a square line buffer end cap style. CAP_SQUARE = 3 }; /// Join styles enum JoinStyle { /// Specifies a round join style. JOIN_ROUND = 1, /// Specifies a mitre join style. JOIN_MITRE = 2, /// Specifies a bevel join style. JOIN_BEVEL = 3 }; /// \brief /// The default number of facets into which to divide a fillet /// of 90 degrees. /// /// A value of 8 gives less than 2% max error in the buffer distance. /// For a max error of < 1%, use QS = 12. /// For a max error of < 0.1%, use QS = 18. /// static const int DEFAULT_QUADRANT_SEGMENTS = 8; /// The default mitre limit /// /// Allows fairly pointy mitres. /// static const double DEFAULT_MITRE_LIMIT; // 5.0 (in .cpp file) /// Creates a default set of parameters BufferParameters(); /// Creates a set of parameters with the given quadrantSegments value. /// /// @param quadrantSegments the number of quadrant segments to use /// BufferParameters(int quadrantSegments); /// \brief /// Creates a set of parameters with the /// given quadrantSegments and endCapStyle values. /// /// @param quadrantSegments the number of quadrant segments to use /// @param endCapStyle the end cap style to use /// BufferParameters(int quadrantSegments, EndCapStyle endCapStyle); /// \brief /// Creates a set of parameters with the /// given parameter values. /// /// @param quadrantSegments the number of quadrant segments to use /// @param endCapStyle the end cap style to use /// @param joinStyle the join style to use /// @param mitreLimit the mitre limit to use /// BufferParameters(int quadrantSegments, EndCapStyle endCapStyle, JoinStyle joinStyle, double mitreLimit); /// Gets the number of quadrant segments which will be used /// /// @return the number of quadrant segments /// int getQuadrantSegments() const { return quadrantSegments; } /// \brief /// Sets the number of line segments used to approximate /// an angle fillet. /// /// - If quadSegs >= 1, joins are round, /// and quadSegs indicates the number of /// segments to use to approximate a quarter-circle. /// - If quadSegs = 0, joins are bevelled (flat) /// - If quadSegs < 0, joins are mitred, and the value of qs /// indicates the mitre ration limit as ///
    ///    mitreLimit = |quadSegs|
    ///    
/// /// For round joins, quadSegs determines the maximum /// error in the approximation to the true buffer curve. /// /// The default value of 8 gives less than 2% max error in the /// buffer distance. /// /// For a max error of < 1%, use QS = 12. /// For a max error of < 0.1%, use QS = 18. /// The error is always less than the buffer distance /// (in other words, the computed buffer curve is always inside /// the true curve). /// /// @param quadSegs the number of segments in a fillet for a quadrant void setQuadrantSegments(int quadSegs); /// \brief /// Computes the maximum distance error due to a given level /// of approximation to a true arc. /// /// @param quadSegs the number of segments used to approximate /// a quarter-circle /// @return the error of approximation /// static double bufferDistanceError(int quadSegs); /// Gets the end cap style. /// /// @return the end cap style /// EndCapStyle getEndCapStyle() const { return endCapStyle; } /// Specifies the end cap style of the generated buffer. /// /// The styles supported are CAP_ROUND, CAP_BUTT, /// and CAP_SQUARE. /// /// The default is CAP_ROUND. /// /// @param style the end cap style to specify /// void setEndCapStyle(EndCapStyle style) { endCapStyle = style; } /// Gets the join style. /// /// @return the join style /// JoinStyle getJoinStyle() const { return joinStyle; } /// \brief /// Sets the join style for outside (reflex) corners between /// line segments. /// /// Allowable values are JOIN_ROUND (which is the default), /// JOIN_MITRE and JOIN_BEVEL. /// /// @param style the code for the join style /// void setJoinStyle(JoinStyle style) { joinStyle = style; } /// Gets the mitre ratio limit. /// /// @return the limit value /// double getMitreLimit() const { return mitreLimit; } /// Sets the limit on the mitre ratio used for very sharp corners. /// /// The mitre ratio is the ratio of the distance from the corner /// to the end of the mitred offset corner. /// When two line segments meet at a sharp angle, /// a miter join will extend far beyond the original geometry. /// (and in the extreme case will be infinitely far.) /// To prevent unreasonable geometry, the mitre limit /// allows controlling the maximum length of the join corner. /// Corners with a ratio which exceed the limit will be beveled. /// /// @param limit the mitre ratio limit /// void setMitreLimit(double limit) { mitreLimit = limit; } /** * Sets whether the computed buffer should be single-sided. * A single-sided buffer is constructed on only one side of each input line. * * The side used is determined by the sign of the buffer distance: * - a positive distance indicates the left-hand side * - a negative distance indicates the right-hand side * * The single-sided buffer of point geometries is * the same as the regular buffer. * * The End Cap Style for single-sided buffers is * always ignored, * and forced to the equivalent of CAP_FLAT. * * @param p_isSingleSided true if a single-sided buffer should be constructed */ void setSingleSided(bool p_isSingleSided) { _isSingleSided = p_isSingleSided; } /** * Tests whether the buffer is to be generated on a single side only. * * @return true if the generated buffer is to be single-sided */ bool isSingleSided() const { return _isSingleSided; } private: /// Defaults to DEFAULT_QUADRANT_SEGMENTS; int quadrantSegments; /// Defaults to CAP_ROUND; EndCapStyle endCapStyle; /// Defaults to JOIN_ROUND; JoinStyle joinStyle; /// Defaults to DEFAULT_MITRE_LIMIT; double mitreLimit; bool _isSingleSided; }; } // namespace geos::operation::buffer } // namespace geos::operation } // namespace geos #ifdef _MSC_VER #pragma warning(pop) #endif