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91 lines
3.0 KiB
C++
91 lines
3.0 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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//
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// Copyright Barend Gehrels 2007-2009, Geodan, Amsterdam, the Netherlands
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// Qt Example
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// Qt is a well-known and often used platform independent widget library
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// To build and run this example:
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// 1) download (from http://qt.nokia.com), configure and make QT
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// 2) if necessary, adapt Qt clause in include path
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#include <sstream>
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#include <QtGui>
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#include <boost/geometry/geometry.hpp>
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#include <boost/geometry/geometries/register/point.hpp>
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#include <boost/geometry/geometries/register/ring.hpp>
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// Adapt a QPointF such that it can be handled by GGL
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BOOST_GEOMETRY_REGISTER_POINT_2D_GET_SET(QPointF, double, cs::cartesian, x, y, setX, setY)
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// Adapt a QPolygonF as well.
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// A QPolygonF has no holes (interiors) so it is similar to a GGL ring
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BOOST_GEOMETRY_REGISTER_RING(QPolygonF)
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int main(int argc, char *argv[])
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{
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// This usage QApplication and QLabel is adapted from
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// http://en.wikipedia.org/wiki/Qt_(toolkit)#Qt_hello_world
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QApplication app(argc, argv);
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// Declare a polygon. This is just Qt. The Qt Polygon can be used
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// in GGL as well, just by its oneline registration above.
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QPolygonF polygon;
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// Qt methods can be used, in this case to add points
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polygon
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<< QPointF(10, 20) << QPointF(20, 30)
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<< QPointF(30, 20) << QPointF(20, 10)
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<< QPointF(10, 20);
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// GGL methods can be used, e.g. to calculate area
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std::ostringstream out;
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out << "GGL area: " << boost::geometry::area(polygon) << std::endl;
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// Some functionality is defined in both Qt and GGL
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QPointF p(20,20);
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out << "Qt contains: "
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<< (polygon.containsPoint(p, Qt::WindingFill) ? "yes" : "no")
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<< std::endl
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<< "GGL within: "
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<< (boost::geometry::within(p, polygon) ? "yes" : "no")
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<< std::endl;
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// Detail: if point is ON boundary, Qt says yes, GGL says no.
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// Qt defines an iterator
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// (which is actually required for GGL, it's part of the ring-concept)
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// such that GGL can use the points of this polygon
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QPolygonF::const_iterator it;
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for (it = polygon.begin(); it != polygon.end(); ++it)
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{
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// Stream Delimiter-Separated, just to show something GGL can do
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out << boost::geometry::dsv(*it) << std::endl;
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}
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// Stream the polygon as well
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out << boost::geometry::dsv(polygon) << std::endl;
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// Just show what we did in a label
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QLabel label(out.str().c_str());
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label.show();
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return app.exec();
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// What else could be useful, functionality that GGL has and Qt not (yet)?
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// - simplify a polygon (to get less points and preserve shape)
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// - clip a polygon with a box
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// - calculate the centroid
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// - calculate the perimeter
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// - calculate the convex hull
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// - transform it using matrix transformations
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}
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