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libs/gil/example/mandelbrot.cpp

/*
    Copyright 2005-2007 Adobe Systems Incorporated
   
    Use, modification and distribution are 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).

    See http://opensource.adobe.com/gil for most recent version including documentation.
*/

/*************************************************************************************************/

/// \file
/// \brief Test file for convolve_rows() and convolve_cols() in the numeric extension
/// \author Lubomir Bourdev and Hailin Jin
/// \date February 27, 2007

#include <boost/gil/image.hpp>
#include <boost/gil/typedefs.hpp>
#include <boost/gil/extension/io/jpeg_io.hpp>

using namespace boost::gil;

// Models a Unary Function
template <typename P>   // Models PixelValueConcept
struct mandelbrot_fn {
    typedef point2<ptrdiff_t>    point_t;

    typedef mandelbrot_fn        const_t;
    typedef P                    value_type;
    typedef value_type           reference;
    typedef value_type           const_reference;
    typedef point_t              argument_type;
    typedef reference            result_type;
    BOOST_STATIC_CONSTANT(bool, is_mutable=false);

    value_type                    _in_color,_out_color;
    point_t                       _img_size;
    static const int MAX_ITER=100;        // max number of iterations

    mandelbrot_fn() {}
    mandelbrot_fn(const point_t& sz, const value_type& in_color, const value_type& out_color) : _in_color(in_color), _out_color(out_color), _img_size(sz) {}

    result_type operator()(const point_t& p) const {
        // normalize the coords to (-2..1, -1.5..1.5)
        // (actually make y -1.0..2 so it is asymmetric, so we can verify some view factory methods)
        double t=get_num_iter(point2<double>(p.x/(double)_img_size.x*3-2, p.y/(double)_img_size.y*3-1.0f));//1.5f));
        t=pow(t,0.2);

        value_type ret;
        for (int k=0; k<num_channels<P>::value; ++k)
            ret[k]=(typename channel_type<P>::type)(_in_color[k]*t + _out_color[k]*(1-t));
        return ret;
    }

private:
    double get_num_iter(const point2<double>& p) const {
        point2<double> Z(0,0);
        for (int i=0; i<MAX_ITER; ++i) {
            Z = point2<double>(Z.x*Z.x - Z.y*Z.y + p.x, 2*Z.x*Z.y + p.y);
            if (Z.x*Z.x + Z.y*Z.y > 4)
                return i/(double)MAX_ITER;
        }
        return 0;
    }
};

int main() {
    typedef mandelbrot_fn<rgb8_pixel_t> deref_t;
    typedef deref_t::point_t            point_t;
    typedef virtual_2d_locator<deref_t,false> locator_t;
    typedef image_view<locator_t> my_virt_view_t;

    boost::function_requires<PixelLocatorConcept<locator_t> >();
    gil_function_requires<StepIteratorConcept<locator_t::x_iterator> >();

    point_t dims(200,200);
    my_virt_view_t mandel(dims, locator_t(point_t(0,0), point_t(1,1), deref_t(dims, rgb8_pixel_t(255,0,255), rgb8_pixel_t(0,255,0))));
    jpeg_write_view("out-mandelbrot.jpg",mandel);

    return 0;
}