include/geos/simplify/TaggedLineStringSimplifier.h

   1 /**********************************************************************
   2  *
   3  * GEOS - Geometry Engine Open Source
   4  * http://geos.osgeo.org
   5  *
   6  * Copyright (C) 2006 Refractions Research Inc.
   7  *
   8  * This is free software; you can redistribute and/or modify it under
   9  * the terms of the GNU Lesser General Licence as published
  10  * by the Free Software Foundation.
  11  * See the COPYING file for more information.
  12  *
  13  **********************************************************************
  14  *
  15  * Last port: simplify/TaggedLineStringSimplifier.java r536 (JTS-1.12+)
  16  *
  17  **********************************************************************
  18  *
  19  * NOTES: This class can be optimized to work with vector<Coordinate*>
  20  *        rather then with CoordinateSequence
  21  *
  22  **********************************************************************/
  23
  24 #ifndef GEOS_SIMPLIFY_TAGGEDLINESTRINGSIMPLIFIER_H
  25 #define GEOS_SIMPLIFY_TAGGEDLINESTRINGSIMPLIFIER_H
  26
  27 #include <geos/export.h>
  28 #include <cstddef>
  29 #include <vector>
  30 #include <memory>
  31
  32 #ifdef _MSC_VER
  33 #pragma warning(push)
  34 #pragma warning(disable: 4251) // warning C4251: needs to have dll-interface to be used by clients of class
  35 #endif
  36
  37 // Forward declarations
  38 namespace geos {
  39         namespace algorithm {
  40                 class LineIntersector;
  41         }
  42         namespace geom {
  43                 class CoordinateSequence;
  44                 class LineSegment;
  45         }
  46         namespace simplify {
  47                 class TaggedLineSegment;
  48                 class TaggedLineString;
  49                 class LineSegmentIndex;
  50         }
  51 }
  52
  53 namespace geos {
  54 namespace simplify { // geos::simplify
  55
  56
  57 /** \brief
  58  * Simplifies a TaggedLineString, preserving topology
  59  * (in the sense that no new intersections are introduced).
  60  * Uses the recursive Douglas-Peucker algorithm.
  61  *
  62  */
  63 class GEOS_DLL TaggedLineStringSimplifier {
  64
  65 public:
  66
  67         TaggedLineStringSimplifier(LineSegmentIndex* inputIndex,
  68                 LineSegmentIndex* outputIndex);
  69
  70         /** \brief
  71          * Sets the distance tolerance for the simplification.
  72          *
  73          * All vertices in the simplified geometry will be within this
  74          * distance of the original geometry.
  75          *
  76          * @param d the approximation tolerance to use
  77          */
  78         void setDistanceTolerance(double d);
  79
  80         /**
  81          * Simplifies the given {@link TaggedLineString}
  82          * using the distance tolerance specified.
  83          *
  84          * @param line the linestring to simplify
  85          */
  86         void simplify(TaggedLineString* line);
  87
  88
  89 private:
  90
  91         // externally owned
  92         LineSegmentIndex* inputIndex;
  93
  94         // externally owned
  95         LineSegmentIndex* outputIndex;
  96
  97         std::auto_ptr<algorithm::LineIntersector> li;
  98
  99         /// non-const as segments are possibly added to it
 100         TaggedLineString* line;
 101
 102         const geom::CoordinateSequence* linePts;
 103
 104         double distanceTolerance;
 105
 106         void simplifySection(std::size_t i, std::size_t j,
 107                         std::size_t depth);
 108
 109         static std::size_t findFurthestPoint(
 110                         const geom::CoordinateSequence* pts,
 111                         std::size_t i, std::size_t j,
 112                         double& maxDistance);
 113
 114         bool hasBadIntersection(const TaggedLineString* parentLine,
 115                        const std::vector<std::size_t>& sectionIndex,
 116                        const geom::LineSegment& candidateSeg);
 117
 118         bool hasBadInputIntersection(const TaggedLineString* parentLine,
 119                        const std::vector<std::size_t>& sectionIndex,
 120                        const geom::LineSegment& candidateSeg);
 121
 122         bool hasBadOutputIntersection(const geom::LineSegment& candidateSeg);
 123
 124         bool hasInteriorIntersection(const geom::LineSegment& seg0,
 125                         const geom::LineSegment& seg1) const;
 126
 127         std::auto_ptr<TaggedLineSegment> flatten(
 128                         std::size_t start, std::size_t end);
 129
 130         /** \brief
 131          * Tests whether a segment is in a section of a TaggedLineString
 132          *
 133          * @param line
 134          * @param sectionIndex
 135          * @param seg
 136          * @return
 137          */
 138         static bool isInLineSection(
 139                 const TaggedLineString* parentLine,
 140                 const std::vector<std::size_t>& sectionIndex,
 141                 const TaggedLineSegment* seg);
 142
 143         /** \brief
 144          * Remove the segs in the section of the line
 145          *
 146          * @param line
 147          * @param pts
 148          * @param sectionStartIndex
 149          * @param sectionEndIndex
 150          */
 151         void remove(const TaggedLineString* line,
 152                         std::size_t start,
 153                         std::size_t end);
 154
 155 };
 156
 157 inline void
 158 TaggedLineStringSimplifier::setDistanceTolerance(double d)
 159 {
 160         distanceTolerance = d;
 161 }
 162
 163 } // namespace geos::simplify
 164 } // namespace geos
 165
 166 #ifdef _MSC_VER
 167 #pragma warning(pop)
 168 #endif
 169
 170 #endif // GEOS_SIMPLIFY_TAGGEDLINESTRINGSIMPLIFIER_H
 171