// Boost.Geometry (aka GGL, Generic Geometry Library)
//
// Copyright Barend Gehrels 2007-2009, Geodan, Amsterdam, the Netherlands
// Copyright Bruno Lalande 2008, 2009
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// GD example

// GD is a well-known and often used graphic library to write GIF (and other formats)

// To build and run this example:
// 1) This example uses also shapelib, see 08_shapelib_example for necessary proceudre
// 2) download GD from http://www.libgd.org
// 3) add 11 files mentioned below to the project or makefile
// 4) for windows, add define NONDLL to indicate GD is not used as a DLL
// GD FILES necessary: gd.c, gd_gd.c, gd_gif_out.c, gd_io*.c, gd_security.c, gd_topal.c, gdhelpers.c, gdtables.c
// Alternativelly, install GD using OSGeo4W installer from http://trac.osgeo.org/osgeo4w/
// that provides Windows binary packages

#include <cmath>
#include <cstdio>
#include <vector>

#include <boost/geometry/geometry.hpp>
#include <boost/geometry/algorithms/area.hpp>
#include <boost/geometry/geometries/cartesian2d.hpp>
#include <boost/geometry/extensions/gis/latlong/latlong.hpp>

#include <gd.h>
#include "shapelib_common.hpp"

int main()
{
    std::string filename = "c:/data/spatial/shape/world_free/world.shp";

    // The world is measured in latlong (degrees), so latlong (point_ll_deg, ring_ll_deg) is appropriate.
    // (It is possible to change this in point_xy)
    // We ignore holes in this sample.
    // So declare a ring_ll_deg (= closed ring, polygon without holes)
    std::vector<boost::geometry::ring_ll_deg> rings;

    // Open a shapefile, for example world countries
    try
    {
        read_shapefile(filename, rings);
    }
    catch(const std::string& s)
    {
        std::cout << s << std::endl;
        return 1;
    }

    // Create a GD image.
    // A world map, as world.shp, is usually mapped in latitude-longitude (-180..180 and -90..90)
    // For this sample we use a very simple "transformation"
    // mapping to 0..720 and 0..360
    const double factor = 2.0;
    gdImagePtr im = gdImageCreateTrueColor(int(360 * factor), int(180 * factor));

    // Allocate three colors
    int blue = gdImageColorResolve(im, 0, 52, 255);
    int green = gdImageColorResolve(im, 0, 255, 0);
    int black = gdImageColorResolve(im, 0, 0, 0);

    // Paint background
    gdImageFilledRectangle(im, 0, 0, im->sx, im->sy, blue);

    // Paint all rings
    for (std::vector<boost::geometry::ring_ll_deg>::const_iterator it = rings.begin(); it != rings.end(); ++it)
    {
        const boost::geometry::ring_ll_deg& ring = *it;

        // If wished, suppress too small polygons.
        // (Note that even in latlong, area is calculated in square meters)
        const double a = boost::geometry::area(ring);
        if (std::fabs(a) > 5000.0e6)
        {
            const int n = ring.size();
            gdPoint* points = new gdPoint[n];

            for (int i = 0; i < n; i++)
            {
                // Translate lon/lat or x/y to GD x/y points
                points[i].x = int(factor * (boost::geometry::get<0>(ring[i]) + 180.0));
                points[i].y = im->sy - int(factor * (boost::geometry::get<1>(ring[i]) + 90.0));
            }

            // Draw the polygon...
            gdImageFilledPolygon(im, points, n, green);
            // .. and the outline...
            gdImagePolygon(im, points, n, black);

            delete[] points;
        }
    }

    // Use GD to create a GIF file
    std::FILE* out = std::fopen("world.gif", "wb");
    if (out != NULL)
    {
        gdImageGif(im, out);
        std::fclose(out);
    }

    gdImageDestroy(im);

    return 0;
}