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| <title>Custom Polygon Set</title> |
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| <p><font face="Courier New">/*<br> |
| Copyright 2008 Intel Corporation<br> |
| <br> |
| Use, modification and distribution are subject to the Boost Software License,<br> |
| Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at<br> |
| http://www.boost.org/LICENSE_1_0.txt).<br> |
| */<br> |
| #include <boost/polygon/polygon.hpp><br> |
| #include <list><br> |
| #include <time.h><br> |
| #include <cassert><br> |
| #include <deque><br> |
| #include <iostream><br> |
| namespace gtl = boost::polygon;<br> |
| using namespace boost::polygon::operators;<br><br> |
| //once again we make our usage of the library generic<br> |
| //and parameterize it on the polygon set type<br> |
| template <typename PolygonSet><br> |
| void test_polygon_set() {<br> |
| using namespace gtl; <br> |
| PolygonSet ps;<br> |
| ps += rectangle_data<int>(0, 0, 10, 10);<br> |
| PolygonSet ps2;<br> |
| ps2 += rectangle_data<int>(5, 5, 15, 15);<br> |
| PolygonSet ps3;<br> |
| assign(ps3, ps * ps2); <br> |
| PolygonSet ps4;<br> |
| ps4 += ps + ps2;<br> |
| assert(area(ps4) == area(ps) + area(ps2) - area(ps3));<br> |
| assert(equivalence((ps + ps2) - (ps * ps2), ps ^ ps2));<br> |
| rectangle_data<int> rect;<br> |
| assert(extents(rect, ps ^ ps2));<br> |
| assert(area(rect) == 225);<br> |
| assert(area(rect ^ (ps ^ ps2)) == area(rect) - area(ps ^ ps2)); <br> |
| }<br> |
| <br> |
| //first thing is first, lets include all the code from previous examples<br> |
| <br> |
| //the CPoint example<br> |
| struct CPoint {<br> |
| int x;<br> |
| int y;<br> |
| };<br> |
| <br> |
| namespace boost { namespace polygon {<br> |
| template <><br> |
| struct geometry_concept<CPoint> { typedef point_concept type; };<br> |
| template <><br> |
| struct point_traits<CPoint> {<br> |
| typedef int coordinate_type;<br> |
| <br> |
| static inline coordinate_type get(const CPoint& point, <br> |
| |
| orientation_2d orient) {<br> |
| if(orient == HORIZONTAL)<br> |
| return point.x;<br> |
| return point.y;<br> |
| }<br> |
| };<br> |
| <br> |
| template <><br> |
| struct point_mutable_traits<CPoint> {<br> |
| static inline void set(CPoint& point, orientation_2d orient, |
| int value) {<br> |
| if(orient == HORIZONTAL)<br> |
| point.x = value;<br> |
| else<br> |
| point.y = value;<br> |
| }<br> |
| static inline CPoint construct(int x_value, int y_value) {<br> |
| CPoint retval;<br> |
| retval.x = x_value;<br> |
| retval.y = y_value; <br> |
| return retval;<br> |
| }<br> |
| };<br> |
| } }<br> |
| <br> |
| //the CPolygon example<br> |
| typedef std::list<CPoint> CPolygon;<br> |
| <br> |
| //we need to specialize our polygon concept mapping in boost polygon<br> |
| namespace boost { namespace polygon {<br> |
| //first register CPolygon as a polygon_concept type<br> |
| template <><br> |
| struct geometry_concept<CPolygon>{ typedef polygon_concept type; };<br> |
| <br> |
| template <><br> |
| struct polygon_traits<CPolygon> {<br> |
| typedef int coordinate_type;<br> |
| typedef CPolygon::const_iterator iterator_type;<br> |
| typedef CPoint point_type;<br> |
| <br> |
| // Get the begin iterator<br> |
| static inline iterator_type begin_points(const CPolygon& t) {<br> |
| return t.begin();<br> |
| }<br> |
| <br> |
| // Get the end iterator<br> |
| static inline iterator_type end_points(const CPolygon& t) {<br> |
| return t.end();<br> |
| }<br> |
| <br> |
| // Get the number of sides of the polygon<br> |
| static inline std::size_t size(const CPolygon& t) {<br> |
| return t.size();<br> |
| }<br> |
| <br> |
| // Get the winding direction of the polygon<br> |
| static inline winding_direction winding(const CPolygon& t) {<br> |
| return unknown_winding;<br> |
| }<br> |
| };<br> |
| <br> |
| template <><br> |
| struct polygon_mutable_traits<CPolygon> {<br> |
| //expects stl style iterators<br> |
| template <typename iT><br> |
| static inline CPolygon& set_points(CPolygon& t, <br> |
| |
| iT input_begin, iT input_end) {<br> |
| t.clear();<br> |
| while(input_begin != input_end) {<br> |
| t.push_back(CPoint());<br> |
| gtl::assign(t.back(), *input_begin);<br> |
| ++input_begin;<br> |
| }<br> |
| return t;<br> |
| }<br> |
| <br> |
| };<br> |
| } }<br> |
| <br> |
| //OK, finally we get to declare our own polygon set type<br> |
| typedef std::deque<CPolygon> CPolygonSet;<br> |
| <br> |
| //deque isn't automatically a polygon set in the library<br> |
| //because it is a standard container there is a shortcut<br> |
| //for mapping it to polygon set concept, but I'll do it<br> |
| //the long way that you would use in the general case.<br> |
| namespace boost { namespace polygon {<br> |
| //first we register CPolygonSet as a polygon set<br> |
| template <><br> |
| struct geometry_concept<CPolygonSet> { typedef polygon_set_concept type; |
| };<br> |
| <br> |
| //next we map to the concept through traits<br> |
| template <><br> |
| struct polygon_set_traits<CPolygonSet> {<br> |
| typedef int coordinate_type;<br> |
| typedef CPolygonSet::const_iterator iterator_type;<br> |
| typedef CPolygonSet operator_arg_type;<br> |
| <br> |
| static inline iterator_type begin(const CPolygonSet& |
| polygon_set) {<br> |
| return polygon_set.begin();<br> |
| }<br> |
| <br> |
| static inline iterator_type end(const CPolygonSet& |
| polygon_set) {<br> |
| return polygon_set.end();<br> |
| }<br> |
| <br> |
| //don't worry about these, just return false from them<br> |
| static inline bool clean(const CPolygonSet& polygon_set) { |
| return false; }<br> |
| static inline bool sorted(const CPolygonSet& polygon_set) { |
| return false; }<br> |
| };<br> |
| <br> |
| template <><br> |
| struct polygon_set_mutable_traits<CPolygonSet> {<br> |
| template <typename input_iterator_type><br> |
| static inline void set(CPolygonSet& polygon_set, |
| input_iterator_type input_begin, input_iterator_type input_end) {<br> |
| polygon_set.clear();<br> |
| //this is kind of cheesy. I am copying the |
| unknown input geometry<br> |
| //into my own polygon set and then calling get to |
| populate the<br> |
| //deque<br> |
| polygon_set_data<int> ps;<br> |
| ps.insert(input_begin, input_end);<br> |
| ps.get(polygon_set);<br> |
| //if you had your own odd-ball polygon set you |
| would probably have<br> |
| //to iterate through each polygon at this point |
| and do something<br> |
| //extra<br> |
| }<br> |
| };<br> |
| } }<br> |
| <br> |
| int main() {<br> |
| long long c1 = clock();<br> |
| for(int i = 0; i < 1000; ++i) <br> |
| test_polygon_set<CPolygonSet>();<br> |
| long long c2 = clock();<br> |
| for(int i = 0; i < 1000; ++i) <br> |
| test_polygon_set<gtl::polygon_set_data<int> >();<br> |
| long long c3 = clock();<br> |
| long long diff1 = c2 - c1;<br> |
| long long diff2 = c3 - c2;<br> |
| if(diff1 > 0 && diff2)<br> |
| std::cout << "library polygon_set_data is " << |
| float(diff1)/float(diff2) << "X faster than custom polygon set deque of CPolygon" |
| << std::endl;<br> |
| else<br> |
| std::cout << "operation was too fast" << std::endl;<br> |
| return 0;<br> |
| }</font></p> |
| <p><font face="Courier New">//Now you know how to map your own data type to |
| polygon set concept<br> |
| //Now you also know how to make your application code that operates on geometry<br> |
| //data type agnostic from point through polygon set |
| </font></p> |
| |
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| <table class="docinfo" rules="none" frame="void" id="table1"> |
| <colgroup> |
| <col class="docinfo-name"><col class="docinfo-content"> |
| </colgroup> |
| <tbody vAlign="top"> |
| <tr> |
| <th class="docinfo-name">Copyright:</th> |
| <td>Copyright © Intel Corporation 2008-2010.</td> |
| </tr> |
| <tr class="field"> |
| <th class="docinfo-name">License:</th> |
| <td class="field-body">Distributed under the Boost Software License, |
| Version 1.0. (See accompanying file <tt class="literal"> |
| <span class="pre">LICENSE_1_0.txt</span></tt> or copy at |
| <a class="reference" target="_top" href="http://www.boost.org/LICENSE_1_0.txt"> |
| http://www.boost.org/LICENSE_1_0.txt</a>)</td> |
| </tr> |
| </table> |
| |
| </body> |
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