Mandelbrot set: Difference between revisions

This code assumes there exists a function DrawPixel taking as arguments the x and y position, followed by the red, green and blue components of the color. Note that this function is not part of standard C.

}

</lang>

=={{header|C++}}==

This generic function assumes that the image can be accessed like a two-dimensional array of colors. It may be passed a true array (in which case the Mandelbrot set will simply be drawn into that array, which then might be saved as image file), or a class which maps the subscript operator to the pixel drawing routine of some graphics library. In the latter case, there must be functions get_first_dimension and get_second_dimension defined for that type, to be found by argument dependent lookup. The code provides those functions for built-in arrays.

<lang cpp>

#include <cstdlib>

#include <complex>

// get dimensions for arrays

teplate<typename ElementType, std::size_t dim1, std::size_t dim2>

std::size_t get_first_dimension(ElementType (&a)[dim1][dim2])

{

return dim1;

}

teplate<typename ElementType, std::size_t dim1, std::size_t dim2>

std::size_t get_second_dimension(ElementType (&a)[dim1][dim2])

{

return dim2;

}

template<typename ColorType, typename ImageType>

void draw_Mandelbrot(ImageType& image, // where to draw the image

ColorType set_color, ColorType non_set_color, // which colors to use for set/non-set points

double cxmin, double cxmax, double cymin, double cymax, // the rectangle to draw in the complex plane

unsigned int max_iterations) // the maximum number of iterations

{

std::size_t const ixsize = get_first_dimension(ImageType);

std::size_t const iysize = get_first_dimension(ImageType);

for (std::size_t ix = 0; ix < ixsize; ++ix)

for (std::size_t iy = 0; iy < iysize; ++iy)

{

std::complex c(cxmin + ix/(ixsize-1.0)*(cxmax-cxmin), cymin + iy/(iysize-1.0)*(cymax-cymin));

std::complex z = 0;

unsigned int iterations = 0;

while (iterations < max_iterations && std::norm(z) < 4.0) // note: std::norm(z) gives the *squared* absolute value of z

{

z = z*z + c;

++iterations;

}

if (iterations == max_iterations)

image[ix][iy] = set_color;

else

image[ix][iy] = non_set_color;

}