image_formats

MIT NIHS image format implementations, version 0.1.0

Desmond Germans, 2019

If you use this, mention my name somewhere, and also, do one good deed for your friends.

WARNING: NIHS stands for Not Invented Here Syndrome. If this bothers you, please use the official image format crates (there are a few, for instance image-0.23.0) and associated dependencies.

format coverage

format	decode	encode	tested	optimization
BMP	yes	in progress	yes
PNG	yes	soon	yes	improved huffman for LZ77
JPEG	in progress	soon	in progress
GIF	later	later
TGA	later	later
PBM	later	later
TIFF	later	later
XBM	later	later
WEBP	later	later

how to use

Each format has a test, decode and encode function, in their own namespace (bmp, png, jpeg, etc.).

Image

A small struct that stores resolution (image.width, image.height) and pixel data (image.data). The pixels are stored as u32, in ARGB order.

fn test(bytes: &[u8]) -> Option<(usize,usize)>

This tests if bytes are a valid image of that format. Returns Some((width,height)) if valid. Returns None otherwise.

fn decode(bytes: &[u8]) -> Result<Image,String>

Decodes bytes in that format. If succesful, returns Ok(image), otherwise it returns Err(message).

fn encode(image: &Image) -> Result<Vec<u8>,String>

Encodes image in that format. If succesful, returns the encoded bytes as Ok(Vec<u8>), otherwise it returns Err(message).

examples

Load a BMP file:

use image_formats::bmp;

fn load_as_bmp(name: &str) {
    let mut file = File::open(&name).unwrap();
    let mut buffer = Vec::new();
    file.read_to_end(&mut buffer).unwrap();
    match bmp::decode(&buffer) {
        Ok(image) => {
            println!("Loaded. The image is {}x{} pixels.",image.width,image.height);
        },
        Err(msg) => {
            println!("Error: {}",msg);
        }
    }
}

Save image as PNG:

use image_formats::png;

fn save_as_png(name: &str,image: &Image) {
    match png::encode(&image) {
        Ok(bytes) => {
            let mut file = File::create(&name).unwrap();
            file.write_all(&bytes).unwrap();
        },
        Err(msg) => {
            println!("Error: {}",msg);
        }
    }
}

Load any format:

use image_formats::*;

fn load(name: &str) -> Result<Image,String> {
    let mut file = File::open(&name).unwrap();
    let mut buffer = Vec::new();
    if let Some((width,height)) = png::test(&buffer) {
        return png::decode(&buffer);
    }
    if let Some((width,height)) = bmp::test(&buffer) {
        return bmp::decode(&buffer);
    }
    if let Some((width,height)) = jpeg::test(&buffer) {
        return jpeg::decode(&buffer);
    }

    // ...

    return Err("unknown format".to_string());
}

But, but, my image doesn't work?!

email it to me at [email protected]