QGIS API Documentation  2.2.0-Valmiera
qgsgeometrysimplifier.cpp
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1 /***************************************************************************
2  qgsgeometrysimplifier.cpp
3  ---------------------
4  begin : December 2013
5  copyright : (C) 2013 by Alvaro Huarte
6  email : http://wiki.osgeo.org/wiki/Alvaro_Huarte
7
8  ***************************************************************************
9  * *
10  * This program is free software; you can redistribute it and/or modify *
11  * it under the terms of the GNU General Public License as published by *
12  * the Free Software Foundation; either version 2 of the License, or *
13  * (at your option) any later version. *
14  * *
15  ***************************************************************************/
16
17 #include <limits>
18 #include "qgsgeometrysimplifier.h"
19
21 {
22 }
23
26 {
27  return ( envelope.xMaximum() - envelope.xMinimum() ) < mapToPixelTol && ( envelope.yMaximum() - envelope.yMinimum() ) < mapToPixelTol;
28 }
29
31 bool QgsAbstractGeometrySimplifier::canbeGeneralizedByDeviceBoundingBox( const QVector<QPointF>& points, float mapToPixelTol )
32 {
33  double xmin = std::numeric_limits<double>::max(), x, y;
34  double ymin = std::numeric_limits<double>::max();
35  double xmax = -std::numeric_limits<double>::max();
36  double ymax = -std::numeric_limits<double>::max();
37
38  for ( int i = 0, numPoints = points.size(); i < numPoints; ++i )
39  {
40  x = points[i].x();
41  y = points[i].y();
42
43  if ( xmin > x ) xmin = x;
44  if ( ymin > y ) ymin = y;
45  if ( xmax < x ) xmax = x;
46  if ( ymax < y ) ymax = y;
47  }
48  return canbeGeneralizedByDeviceBoundingBox( QgsRectangle( xmin, ymin, xmax, ymax ), mapToPixelTol );
49 }
50
51 /***************************************************************************/
55 QgsTopologyPreservingSimplifier::QgsTopologyPreservingSimplifier( double tolerance ) : mTolerance( tolerance )
56 {
57 }
59 {
60 }
61
64 {
65  return geometry->simplify( mTolerance );
66 }
67
70 {
71  QgsGeometry* g = geometry->simplify( mTolerance );
72
73  if ( g )
74  {
75  size_t wkbSize = g->wkbSize();
76  unsigned char* wkb = ( unsigned char* )malloc( wkbSize );
77  memcpy( wkb, g->asWkb(), wkbSize );
78  geometry->fromWkb( wkb, wkbSize );
79  delete g;
80
81  return true;
82  }
83  return false;
84 }