Rust version of LodePNG

This is a pure Rust PNG image decoder and encoder. Allows easy reading and writing of PNG files without any system dependencies.

The easiest way to use LodePNG is to include the lodepng crate. To do so, add this to your Cargo.toml:

toml [dependencies] lodepng = "2.0.0"

See API reference for details. Requires Rust 1.21 or later.

Loading image example

rust let image = lodepng::decode32_file("in.png")?;

returns image of type lodepng::Bitmap<lodepng::RGBA<u8>> with fields .width, .height, and .buffer (the buffer is a Vec).

The RGB/RGBA pixel types are from the RGB crate, which you can import separately to use the same pixel struct throughout the program, without casting. But if you want to read the image buffer as bunch of raw bytes, ignoring the RGB(A) pixel structure, use:

rust [dependencies] rgb = "0.8"

rust extern crate rgb; use rgb::*; … let bytes: &[u8] = image.buffer.as_bytes();

Saving image example

rust lodepng::encode32_file("out.png", &buffer, width, height)

The buffer can be a slice of any type as long as it has 4 bytes per element (e.g. struct RGBA or (u8,u8,u8,u8)).

Advanced

```rust let mut state = lodepng::State::new(); state.rememberunknownchunks(true);

match state.decode("in.png") { Ok(lodepng::Image::RGB(image)) => {…} Ok(lodepng::Image::RGBA(image)) => {…} Ok(lodepng::Image::RGBA16(image)) => {…} Ok(lodepng::Image::Gray(image)) => {…} Ok(_) => {…} Err(err) => {…} }

for chunk in state.infopng().unknownchunks() { println!("{:?} = {:?}", chunk.name(), chunk.data()); }

// Color profile (to be used with e.g. LCMS2) let iccdata = state.infopng().get_icc(); ```

Upgrading from 1.x