MiniLibX Helper Function

This page will showcase some helper functions for the MiniLibX library.

Simple put_pixel function

This is a simple function to put a pixel to the screen by its x and y coordinates.

I based this function on what I found here, and modified it a bit to make sure we only put a pixel that is inside the screen, without this check, the program could segfault if we try to set a value somewhere outside the window.

void ft_put_pixel(t_data *data, int x, int y, int color)
{
    char *pxl;
    
    if (x >= 0 && x < WINDOW_WIDTH && y >= 0 && y < WINDOW_HEIGHT
    {
        pxl = data->addr + (y * data->line_length + x * (data->bits_per_pixel / 8));
        *(unsigned int *)pxl = color;
    }
}

Final code to draw a pixel

#include "mlx.h"
#define	WINDOW_WIDTH 1920
#define WINDOW_HEIGHT 1080

typedef struct	s_data {
	void	*img;
	char	*addr;
	int		bits_per_pixel;
	int		line_length;
	int		endian;
}				t_data;

void ft_put_pixel(t_data *data, int x, int y, int color)
{
    char *pxl;

    if (x >= 0 && x < WINDOW_WIDTH && y >= 0 && y < WINDOW_HEIGHT)
    {
        pxl = data->addr + (y * data->line_length + x * (data->bits_per_pixel / 8));
        *(unsigned int *)pxl = color;
    }
}

int	main(void)
{
	void	*mlx;
	void	*mlx_win;
	t_data	img;

	mlx = mlx_init();
	mlx_win = mlx_new_window(mlx, 1920, 1080, "Hello world!");
	img.img = mlx_new_image(mlx, 1920, 1080);
	img.addr = mlx_get_data_addr(img.img, &img.bits_per_pixel, &img.line_length,
								&img.endian);
	ft_put_pixel(&img, WINDOW_WIDTH/2, WINDOW_HEIGHT/2, 0xFF0000);
	mlx_put_image_to_window(mlx, mlx_win, img.img, 0, 0);
	mlx_loop(mlx);
}

If you look closely, this will draw a red pixel at the very center of the window.

Draw Line function (~Naive line algorithm)

There is no function in MiniLibX to draw a line between two points, but this will be particularly useful when you try to code FdF, you'll have to join all your points by lines, so, here you go.

This function uses some function of the math library so make sure you can use it in your project and include it (#include <math.h>). For FdF, Fractol and so-long, all the math library are authorized.

void ft_draw_line(t_data *data, int x1, int y1, int x2, int y2, int color)
{
    int step;
    int x;
    int y;
    int i;
    int delta_x;
    int delta_y;
    
    delta_x = x2 - x1;
    delta_y = y2 - y1;
    if (abs(delta_x) >= abs(delta_y))
        step = abs(delta_x);
    else
        step = abs(delta_y);
    delta_x = delta_x / step;
    delta_y = delta_y / step;
    x = x1;
    y = x2;
    i = 0;
    while (i < step)
    {
        ft_put_pixel(data, x, y, color);
        x += delta_x;
        y += delta_y;
        i++;
    }
}

You will have to find a way to make it pass the Norm, you can check how I did this here.