Images management

Images are a very important tool in MacroLibX in order to embrace its full potential. These functions will allow you to read files directly into a image object. This is very useful for textures or sprites of course.

We’ve already seen here how to load images from disk and display them. Now we’ll see how to create empty images and modify/read pixels from any mlx images.

😶 Making an empty image

The MacroLibX gives a function to create a new image with a custom size. It is called mlx_new_image and is pretty fast forward :

#include "MacroLibX/includes/mlx.h"

int main(void)
{
    void* mlx = mlx_init();
    void* img = mlx_new_image(mlx, 100, 100); // creates a new 100x100 empty image
    // Note that you don't need to create a window to create an image

    mlx_destroy_image(mlx, img);
    mlx_destroy_display(mlx);
}

But creating an empty image is useless if we cannot modify it, that’s what we are going to see right now.

✍️ Modify an image

To modify any image there is mlx_set_image_pixel which is fairly simple to use :

#include "MacroLibX/includes/mlx.h"

int main(void)
{
    void* mlx = mlx_init();
    void* img = mlx_new_image(mlx, 100, 100);

    // here we modify the pixel at 42;10 to the color 0xFFEB5C24
    mlx_set_image_pixel(mlx, img, 42, 10, 0xFFEB5C24);

    mlx_destroy_image(mlx, img);
    mlx_destroy_display(mlx);
}

If you try to modify a pixel that is not in the image (coordinates bellow 0 or outside the image) it will do nothing.

🔎 Reading an image

To read any image there is mlx_get_image_pixel which is as simple to use as mlx_set_image_pixel :

#include "MacroLibX/includes/mlx.h"

int main(void)
{
    void* mlx = mlx_init();
    void* img = mlx_new_image(mlx, 100, 100);

    // here we read the pixel color at 42;10
    int color = mlx_get_image_pixel(mlx, img, 42, 10);

    mlx_destroy_image(mlx, img);
    mlx_destroy_display(mlx);
}

If you try to modify a pixel that is not in the image (coordinates bellow 0 or outside the image) it will return 0.

⚠️ Troubleshooting ⚠️

If you run into glitches when writing or reading pixels from images you can turn off images optimisations by using make IMAGES_OPTIMIZED=false when compiling the MacroLibX.