-//! holds scaling operations, at current only the Nearest Neighbor

-use crate::Image;

-

-/// [Nearest Neighbor](https://en.wikipedia.org/wiki/Nearest-neighbor_interpolation) image scaling algorithm implementation.

-/// Use [`Nearest::scale`].

-pub struct Nearest;

-impl Nearest {

- /// Resize a image.

- /// # Safety

- ///

- /// `image` must be as big or bigger than `width`, `height.

- #[must_use = "function does not modify the original image"]

- pub unsafe fn scale<const N: usize>(

- image: Image<&[u8], N>,

- width: u32,

- height: u32,

- ) -> Image<Vec<u8>, N> {

- let x_scale = image.width() as f32 / width as f32;

- let y_scale = image.height() as f32 / height as f32;

- let mut out = Image::alloc(width, height);

- for y in 0..height {

- for x in 0..width {

- let x1 = ((x as f32 + 0.5) * x_scale).floor() as u32;

- let y1 = ((y as f32 + 0.5) * y_scale).floor() as u32;

- // SAFETY: i asked the caller to make sure its ok

- let px = unsafe { image.pixel(x1, y1) };

- // SAFETY: were looping over the width and height of out. its ok.

- unsafe { out.set_pixel(x, y, px) };

- }

- }

- out

- }

-}

-

-#[test]

-fn test_nearest() {

- let i = Image::<_, 3>::open("tdata/cat.png");

- assert_eq!(

- unsafe { Nearest::scale(i.as_ref(), 268, 178) }.buffer,

- Image::<_, 3>::open("tdata/small_cat.png").buffer

- );

-}