Code shared from the Rust Playground

playground.rs

use std::ops::Index;

#[derive(Debug)]
struct Image<P> {
    width: usize,
    pixels: Vec<P>,
}

impl<P: Default + Copy> Image<P> {
    /// Create a new image of the given size.
    fn new(width: usize, height: usize) -> Image<P> {
        Image {
            width,
            pixels: vec![P::default(); width * height]
        }
    }
}

impl<P> Index<usize> for Image<P> {
    type Output = [P];
    
    fn index(&self, row: usize) -> &Self::Output {
        let start = row * self.width;
        &self.pixels[start .. start + self.width]
    }
}

fn main() {
    let image: Image<u32> = Image::new(10, 10);
    println!("{:?}", &image[0]);
    println!("{:?}", image.index(0));
}