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#include <stdio.h>
#include <math.h>
#include <complex.h>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
const char *HELP = "julia usage:\n"
"julia <complex num>[a+bj] <resolution>[integer] <depth>[integer] <bounds>[x-,x+,y-,y+]\n"
"\n"
"\tcomplex_num: a complex number in the form a + bj where j is the "
"imaginary unit.\n"
"\tresolution: resolution (in pixels) of the image\n"
"\tdepth: iteration count for the julia function, warning: slow at high values >100\n"
"\tbounds: the bounds of the graphs as a comma separated list without spaces "
"in the form: minX,maxX,minY,maxY.\n"
"\tBounds above 2 are generally not interesting.\n"
"\n"
"All arguments are required. This command prints bitmap directly to stdout which is "
"(probably) not what you want. You should always pipe the output somewhere like:\n"
"julia 1+1j 300 -1,1,-1,1 > file.bmp";
const int RGB_MODE = 3; // don't care about transparency, so we go for 8 bit channel
int julia(double complex z, double complex c, int d) {
// z: coordinate
// c: complex seed
// d: depth, iteration count
int ic = 0; // iteration count
while(ic < d){
if(cabs(z) > 2)
break;
z = z * z + c;
ic++;
}
return ic;
}
int write_image(double complex seed, int r, int depth, float bounds[4]) {
float x, y;
int pixels = r * r;
int cur_pixel = 3 * pixels - 1;
char const *filename = "/dev/stdout";
// In a bitmap: 3 bytes makes a pixel (RGB)
uint8_t *img_data = (uint8_t *) STBI_MALLOC(pixels * 3 * sizeof(uint8_t));
// In this image library, data is stored in a
// 1-D array separated by row, so you need to fill
// the pixels horizontally first
float dx = bounds[1] - bounds[0];
float dy = bounds[3] - bounds[2];
if (dx <= 0 || dy <= 0)
return 0; // failure (to match stbi_write)
for(y = bounds[2]; y < bounds[3]; y += dy/((float) r - 1)) {
for(x = bounds[0]; x < bounds[1]; x += dx/((float) r - 1)) {
double complex z = x + y * I;
int out = julia(z, seed, depth);
img_data[cur_pixel - 2] = out % 32 * 8;
img_data[cur_pixel - 1] = out % 16 * 16;
img_data[cur_pixel] = out % 8 * 32;
cur_pixel -= 3;
}
}
// returns 0 on failure
return stbi_write_bmp(filename, r, r, RGB_MODE, img_data);
}
int main(int argc, char *argv[]) {
double complex seed;
int res, depth;
float b[4];
if(argc != 5) {
printf("%s\n", HELP);
return 1;
}
else {
float re, img;
sscanf(argv[1], "%f+%fj", &re, &img);
sscanf(argv[2], "%d", &res);
sscanf(argv[3], "%d", &depth);
sscanf(argv[4], "%f,%f,%f,%f", &b[0], &b[1], &b[2], &b[3]);
seed = re + img * I;
if (!write_image(seed, res, depth, b)) {
printf("Error in arguments, could not make image\n");
return 1;
}
}
return 0;
}
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