> For the complete documentation index, see [llms.txt](https://42-cursus.gitbook.io/guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://42-cursus.gitbook.io/guide/minilibx/minilibx-hook-examples.md).

# MiniLibX Hook Examples

{% hint style="info" %}
`keycode` and `mousecode` here are the MacOS ones, on Linux they are different (the escape key on Mac is 53, it's 65307 on Linux) and probably even different on Windows.
{% endhint %}

If you need to find what are hooks for MiniLibX, you can fin more information in the [Events](https://harm-smits.github.io/42docs/libs/minilibx/events.html) and [Hooks](https://harm-smits.github.io/42docs/libs/minilibx/hooks.html) chapter.

Here under I'll show you some examples hooks showing the most important values and some values that are not described in the documentation.

{% code overflow="wrap" lineNumbers="true" %}

```c
#include "mlx.h"
#define WINDOW_HEIGHT 720
#define WINDOW_WIDTH 1280
int main(void)
{
/* 
 * this is the MLX initialisation, I only put it in the example so you can
 * better see what I am doing below
 */
    t_env *env;

    env.mlx = mlx_init();
    env.win = mlx_new_window(env.mlx, WINDOW_WIDTH, WINDOW_HEIGHT, WINDOW_NAME);
    env.img = mlx_new_image(env.mlx, WINDOW_WIDTH, WINDOW_HEIGHT);
    env.addr = mlx_get_data_addr(env.img, &env.bits_per_pixel, &env.line_length, &env.endian);
     /* end of MLX initialisation */
     /* Here I will be declaring the hooks, see below for their implementation.
     */
     mlx_hook(env.win, 4, 0, mouse_handler, &env);
     // mouse_handler will be called everytime a mouse down event is emitted
     mlx_hook(env.win, 2, 1L << 0, key_handler, &env);
     // key_handler will be called everytime a key is pressed
     mlx_hook(env.win, 17, 1L << 0, close_window, &env);
     // close_window is called when we click on the red cross to close the window
     mlx_loop_hook(env.mlx, render, &env);
     // Since MXL loops over and over again, we can use the mlx_loop_hook
     // to execute a function everytime MLX loops over.
     
     mlx_loop(env.mlx);
}
```

{% endcode %}

### Simple key\_pressed\_handler

Since you can filter if you you want to listen to the `keypress` or `keyrelease` event, you can have two different key handlers, you might want to start doing something when we press the `space` key and stop it only when you release it.

{% code overflow="wrap" lineNumbers="true" %}

```c
int key_handler(int keycode, t_env *env)
{
    if (keycode == 53)
        ft_printf("ESCAPE");
    else if (keycode == 0 || keycode == 123)
        ft_printf("LEFT (A / ARROW_LEFT)");
    else if (keycode == 2 || keycode == 124)
        ft_printf("RIGHT (D / ARROW_RIGHT)");
    else if (keycode == 1 || keycode == 125)
        ft_printf("DOWN (S / ARROW_DOWN)");
    else if (keycode == 13 || keycode == 126)
        ft_printf("LEFT (A / ARROW_LEFT)");
    else
        ft_printf("%d\n", keycode);
    return (0);
}
```

{% endcode %}

<figure><img src="/files/R3YQFFdpcb6q5SCS81Wd" alt=""><figcaption><p>key code</p></figcaption></figure>

{% hint style="info" %}
I think here you can see how you could find what `keycode` corresponds to any key on your keyboard by looking at this function.
{% endhint %}

### Simple mouse\_handler

{% code overflow="wrap" lineNumbers="true" %}

```c
int mouse_handler(int mousecode, int x, int y, t_env *env)
{
    /* x and y parameters are the pixel coordinates of the mouse
     * in the window when the event was emitted
     * you can use them to check that the user clicked in a specific region
     * of the window
     */
     if (mousecode == 1)
         ft_printf("Left Click");
     else if (mousecode == 2)
         ft_printf("Right Click");
     else if (mousecode == 3)
         ft_printf("Middle Click");
     else if (mousecode == 4)
         ft_printf("Scroll UP");
     else if (mousecode == 5)
         ft_printf("Scroll DOWN");
     else if (mousecode == 6)
         ft_printf("Scroll right");
     else if (mousecode == 7)
         ft_printf("Scroll left");
     else
         ft_printf("%d\n", mousecode);
}
```

{% endcode %}

### mlx\_loop\_hook

This hook will call a function every time through the MLX loop, we can use this to update what we show on screen. That's why I called it `render` or `draw` most of the time.

For example, in `so-long` I use this hook to draw the map based on what changed. I draw the background completely again, to overwrite what was there, and then I redraw the walls and the player, but the player position can change based on `keypressed` events so the player moves along.\
The same way for collectibles, I don't want to draw them again if I already collected them (you can see the example I described [here](https://github.com/Laendrun/42/blob/main/so_long/src/main.c#L43)).

```c
int render(t_env *env)
{
    draw_background(env);
    draw_map(env);
    draw_player(env);
    draw_moves(env);
}
```

{% hint style="info" %}
These are just examples and simple handlers so that you can better understand how this works and adapt it based on your needs.
{% endhint %}