“二进制表达式的无效操作数”当使用 Boost.Geometry 时？

Question

当我尝试增强几何差异函数时，我收到一个很长的编译器错误，而具有相同接口和可能相关实现工作的并集和交集：

bg::unique_(OldPolygon, Node->Polygon, NodePolygon); // compiles
bg::intersection(OldPolygon, Node->Polygon, NodePolygon); // compiles
bg::difference(OldPolygon, Node->Polygon, NodePolygon); // dies

第一个错误是：

boost/range/size.hpp:32:13: error: invalid operands to
    binary expression ('
         boost::reverse_iterator<
             __gnu_cxx::__normal_iterator<
                 const GraphPoint *,
                 std::vector<
                     GraphPoint,
                     std::allocator<GraphPoint>
                 >
             >
         >' and 'int')
            BOOST_ASSERT( (boost::end(rng) - boost::begin(rng)) >= 0 &&
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

似乎由于某种原因，迭代器差异返回反向迭代器而不是距离。 ..

类型声明为：

namespace bg = boost::geometry;

struct GraphPoint
{
    int x, y;
    GraphPoint(int x, int y) : x(x), y(y) { }
    GraphPoint() : x(0), y(0) { }
    GraphPoint(const GraphPoint &other) : x(other.x), y(other.y) { }

    bool operator ==(const GraphPoint &other) const
    {
        return x == other.x && y == other.y;
    }
};

BOOST_GEOMETRY_REGISTER_POINT_2D(GraphPoint, int, bg::cs::cartesian, x, y)

typedef bg::model::polygon<GraphPoint> Polygon;
typedef Polygon::ring_type Ring;
typedef bg::model::multi_polygon<Polygon> MultiPolygon;

MultiPolygon OldPolygon;
struct Node
{
    Polygon Polygon;
}
MultiPolygon NodePolygon;

完整的错误位于此处，以防有人喜欢挖掘。
我怎样才能编译这个？

Answer 1

我根据您的示例成功编译了一个示例：

• VS2005 SP1 (Vista x64)
• boost 1.48.0（刚刚下载）

我必须修改 Node 结构，这是生成的代码：

#include <boost/geometry/geometry.hpp> 
#include <boost/geometry/geometries/register/point.hpp>
#include <boost/geometry/geometries/register/ring.hpp>
#include <boost/geometry/geometries/geometries.hpp>
#include <boost/geometry/multi/geometries/multi_polygon.hpp> // boost 1_48_0
//#include <boost/geometry/multi/geometries/multi_geometries.hpp> // if boost comes from SVN

namespace bg = boost::geometry;

struct GraphPoint
{
    int x, y;
    GraphPoint(int x, int y) : x(x), y(y) { }
    GraphPoint() : x(0), y(0) { }
    GraphPoint(const GraphPoint &other) : x(other.x), y(other.y) { }

    bool operator ==(const GraphPoint &other) const
    {
        return x == other.x && y == other.y;
    }
};

BOOST_GEOMETRY_REGISTER_POINT_2D(GraphPoint, int, bg::cs::cartesian, x, y)

typedef bg::model::polygon<GraphPoint> Polygon;
typedef Polygon::ring_type Ring;
typedef bg::model::multi_polygon<Polygon> MultiPolygon;

MultiPolygon OldPolygon;
MultiPolygon NodePolygon;

struct Node
{
    Polygon p;
} node;

int main(int argc, char* argv[])
{
    bg::unique(OldPolygon); // only one parameter
    bg::intersection(OldPolygon, node.p, NodePolygon);
    bg::difference(OldPolygon, node.p, NodePolygon);

    return 0;
}

我收到两个警告（警告 C4244：'='：从 'double' 到 'int' 的转换，可能会丢失数据）但它可以编译。