119 lines
4.2 KiB
C++
119 lines
4.2 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2011 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#ifndef MAPNIK_METAWRITER_INMEM_HPP
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#define MAPNIK_METAWRITER_INMEM_HPP
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// mapnik
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#include <mapnik/config.hpp>
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#include <mapnik/metawriter.hpp>
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// boost
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#include <boost/shared_ptr.hpp>
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// stl
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#include <list>
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namespace mapnik {
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/**
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* Keeps metadata information in-memory, where it can be retrieved by whatever's
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* calling Mapnik and custom output provided.
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*
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* Stored data is all in image coordinates in the current implementation.
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*
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* This is most useful when Mapnik is being called from Python, and the result
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* of the metawriter can be queried and injected into the (meta)tile or whatever
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* in a very flexible way. E.g: for a GUI app the metawriter can be used to
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* create hit areas, for a web app it could be used to create an HTML image map.
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*
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* Because this is kept in-memory, applying this metawriter to features which are
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* very common in the rendered image will increase memory usage, especially if
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* many attributes are also kept.
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*/
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class MAPNIK_DECL metawriter_inmem
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: public metawriter, private boost::noncopyable {
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public:
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/**
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* Construct an in-memory writer which keeps properties specified by the
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* dflt_properties argument. For example: if dflt_properties contains "name",
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* then the name attribute of rendered features referencing this metawriter
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* will be kept in memory.
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*/
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metawriter_inmem(metawriter_properties dflt_properties);
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~metawriter_inmem();
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virtual void add_box(box2d<double> const& box, Feature const& feature,
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CoordTransform const& t,
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metawriter_properties const& properties);
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virtual void add_text(placement const& p,
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face_set_ptr face,
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Feature const& feature,
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CoordTransform const& t,
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metawriter_properties const& properties);
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virtual void add_polygon(path_type & path,
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Feature const& feature,
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CoordTransform const& t,
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metawriter_properties const& properties);
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virtual void add_line(path_type & path,
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Feature const& feature,
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CoordTransform const& t,
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metawriter_properties const& properties);
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virtual void start(metawriter_property_map const& properties);
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/**
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* An instance of a rendered feature. The box represents the image
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* coordinates of a bounding box around the feature. The properties
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* are the intersection of the features' properties and the "kept"
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* properties of the metawriter.
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*/
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struct MAPNIK_DECL meta_instance {
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box2d<double> box;
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std::map<std::string, value> properties;
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};
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typedef std::list<meta_instance> meta_instance_list;
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// const-only access to the instances.
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const meta_instance_list &instances() const;
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// utility iterators for use in the python bindings.
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meta_instance_list::const_iterator inst_begin() const;
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meta_instance_list::const_iterator inst_end() const;
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private:
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std::list<meta_instance> instances_;
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void add_vertices(path_type & path,
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Feature const& feature,
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CoordTransform const& t,
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metawriter_properties const& properties);
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};
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/** Shared pointer to metawriter_inmem object. */
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typedef boost::shared_ptr<metawriter_inmem> metawriter_inmem_ptr;
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}
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#endif // MAPNIK_METAWRITER_INMEM_HPP
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