Support reading images other thant RGB

[edgarriba]

Expand kornia_io::functional::read_image_any to read / decode images in more formats such as u16

reference: https://github.com/kornia/kornia-rs/blob/main/crates/kornia-io/src/functional.rs#L104

NOTE: Take especial care when constructing the Image to avoid copies: https://github.com/kornia/kornia-rs/blob/main/crates/kornia-io/src/functional.rs#L130

[edgarriba]

@emilmgeorge this is another use case for allowing Tensor / Image to be created with zero copy overhead

[emilmgeorge]

NOTE: Take especial care when constructing the Image to avoid copies: https://github.com/kornia/kornia-rs/blob/main/crates/kornia-io/src/functional.rs#L130

kornia-rs/crates/kornia-io/src/functional.rs

Line 130 in a4b5fd4

img.to_rgb8().to_vec(),

Here img.into_rgb8().into_vec() could be used instead:

• into_rgb8() creates a copy only if img is not already in RGB8 format.
• into_vec() consumes the image and gives us the inner vector without copy. to_vec, on the other hand, seems to point to slice::to_vec (according to rust-analyzer) which copies.

[edgarriba]

@emilmgeorge awesome, I'll give it a shot. Also we can start supporting to return a generic C. What's your opinion to encode the PixelFormat too in the Image struct ? I like the current definition because is very flexible to have more generic imgproc operators, but at the same time i kind of miss the color space semantics.

[edgarriba]

a small pov here #154 feel free to comment

[emilmgeorge]

Your implementation in #154 looks good. 👍🏼 I do not have any better ideas.