imageproc map_pixels_mut from slice

main.rs

use image::{ImageBuffer, Rgba};
use imageproc::{map::map_pixels_mut, window::display_image};

const WIDTH: u32 = 500;
const HEIGHT: u32 = 500;
const NUM_PIXELS: u32 = WIDTH * HEIGHT;
const PIXEL_SIZE: u32 = 4;
const NUM_BYTES: u32 = NUM_PIXELS * PIXEL_SIZE;

fn main() {
    // let mut data = [0u8; NUM_BYTES as usize];
    // let buf = &mut data[..];
    let buf = unsafe {
        let x = 1u8;
        let ptr = x as *mut _;
        std::slice::from_raw_parts_mut(ptr, NUM_BYTES as usize)
    };

    let mut image: ImageBuffer<Rgba<u8>, &mut [u8]> =
        ImageBuffer::from_raw(WIDTH, HEIGHT, buf).expect("No image");

    map_pixels_mut(&mut image, |x, y, p| Rgba([100, p.0[1], p.0[2], 255]));

    display_image("", &image, WIDTH, HEIGHT);
}