images.h/main.c

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "images/images.h"
#include "complex.c"

void draw_mandelbrot(int width, int height, int iterations);
void draw_mandelbrot_auto(int width, int iterations);
int test_mandelbrot(Complex c,  int iterations);

int main(int argc, char* argv[]) {
    int width = 3000;
    int iterations = 60;
    if (argc > 1) {
        width = atoi(argv[1]);
    }
    if (argc > 2) {
        iterations = atoi(argv[2]);
    }

    draw_mandelbrot_auto(width, iterations);
}

void draw_mandelbrot_auto(int width, int iterations) {
    draw_mandelbrot(width, 2 * width / 3, iterations);
}

void draw_mandelbrot(int width, int height, int iterations) {
    int center_x = 2 * width / 3;
    int center_y = height / 2;
    float step = 3.0f / width;

    Image img;
    image_new(width, height, &img);

    for (int x = 0; x < width; x++) {
        for (int y = 0; y < height; y++) {
            Complex c = complex_new(
                (x - center_x) * step,
                (y - center_y) * step
            );
            int ret = test_mandelbrot(c, iterations);
            int r = (ret * 160 / iterations);
            int g = (ret * 9 / iterations);
            int b = (ret * 165 / iterations);
            image_set_px(img, x, y, r,g,b);
        }
    }

    image_save_bmp(img, "mandelbrot.bmp");
    image_destroy(img);
}

int test_mandelbrot(Complex c,  int iterations) {
    Complex z = complex_new(0,0);

    for (int i = 0; i < iterations; i++) {
        z = complex_add(complex_mult(z,z), c); // z^2 + c
        if (complex_abs(z) > 2) return i;
    }
    return 0;
}