Crate rusty_jpeg 

Pure-Rust JPEG / MJPEG decoder and encoder — no C, no FFI.

This crate vendors two upstream pure-Rust implementations and carries them forward as one codec (see NOTICE.md for full attribution):

• decode — from jpeg-decoder 0.3.2 (image-rs), MIT OR Apache-2.0.
• encode — from jpeg-encoder 0.7.0, (MIT OR Apache-2.0) AND IJG.

They were merged so the two halves can share primitives — quantization tables, zig-zag order, the profiler — and so the encoder can be held to the decoder as a round-trip oracle, which is the standing correctness gate for every change made here.

Decode

let bytes = std::fs::read("in.jpg").unwrap();
let mut decoder = rusty_jpeg::decode::Decoder::new(&bytes[..]);
let pixels = decoder.decode()?;
let info = decoder.info().unwrap();

The decoder reads any decode::Source: with std that is every std::io::Read; without it, a &[u8].

Encode

use rusty_jpeg::encode::{ColorType, Encoder};
let mut out = Vec::new();
let encoder = Encoder::new(&mut out, 90);
encoder.encode(&[255, 0, 0, 0, 255, 0, 0, 0, 255, 255, 255, 255], 2, 2, ColorType::Rgb)?;

Without std

--no-default-features makes the crate no_std + alloc. The encoder writes into a Vec<u8>, a &mut [u8] or an encode::SliceWriter (a caller-owned buffer that reports how much it holds); the decoder reads a &[u8], and decode::Decoder::scale decodes a sensor-sized picture at 1/2, 1/4 or 1/8 for a fraction of the work. No libm is needed: every float on the coding path was replaced by exact integer arithmetic, so a host and a chip produce the same bytes. Environment knobs (RUSTY_JPEG_*) read as their defaults; a chip’s configuration is a field, not a variable.

Re-exports

pub use decode::ColorTransform;

pub use decode::Decoder;

pub use decode::ImageInfo;

pub use decode::PixelFormat;

pub use encode::ColorType;

pub use encode::Encoder;

pub use encode::EncodingError;

pub use encode::JpegColorType;

pub use encode::QuantizationTableType;

pub use encode::SamplingFactor;

Modules

decode

JPEG decoding.

encode

JPEG encoding.

prof

Feature-gated stage profiler — where the time goes, at zero cost when off.