WebP bindings for Rust

• webp: Rust-idiomatic wrappers for libwebp (not yet implemented)
• libwebp: safe wrappers for libwebp-sys
• libwebp-sys: hand-written raw bindings of the C libwebp library

webp

The webp crate is not yet implemented.

libwebp

The libwebp crate has three features:

• 0.5: use APIs >= libwebp-0.5.0. Especially, it uses the WebPFree instead of free if the feature is specified.
• 0.6: use APIs >= libwebp-0.6.0. Assumes 0.5.
• bundled: compiles the bundled libwebp C library. Requires the cc crate. Automatically assumes 0.6.

The interface is similar to the C++ API, but with these modifications:

• Multiple values are returned as tuples, not through return-pointers. Return-pointer parameters are eliminated.
• Pairs of pointers and lengths are combined into slice parameters.
• Cleanup functions like WebPFree and WebPIDelete aren't wrapped. They're called in Drop implementation instead.
• Some functions return Result to avoid invalid values in case of failure.
• C-specific types like c_int are avoided.

Example:

#[macro_use]
extern crate approx;
extern crate libwebp;
use libwebp::*;

fn main() {
    let data = b"\
        RIFFV\x00\x00\x00WEBPVP8\x20\
        J\x00\x00\x00\xD0\x01\x00\x9D\x01*\x03\x00\x02\x00\x02\x00\
        4%\xA8\x02t\x01\x0E\xFE\x03\x8E\x00\x00\xFE\xAD\xFF\xF1\
        \x5C\xB4\xF8\xED\xFF\xF0\xC0\xBA\xBF\x93\x05\xEA\x0C\x9F\x93?\
        \xE8\xC0\xBF?\xFF\xA9\xBF\xFF${\xCB\xFFF\x05\xF9\xFF\
        \xFDM\xFE0\xE5\x86\xAA\x071#o\x00\x00\x00";
    let (width, height, data) = WebPDecodeRGBA(data).unwrap();
    assert_eq!((width, height), (3, 2));
    assert_abs_diff_eq!(data[0], 86, epsilon = 1);
}

libwebp-sys

The libwebp-sys crate has three features:

• 0.5: use APIs >= libwebp-0.5.0. Especially, it uses the WebPFree instead of free if the feature is specified.
• 0.6: use APIs >= libwebp-0.6.0. Assumes 0.5.
• bundled: compiles the bundled libwebp C library. Requires the cc crate. Automatically assumes 0.6.

It's a direct translation of the following libwebp public interfaces:

• webp/decode.h
• webp/encode.h
• webp/types.h
• webp/demux.h
• webp/mux.h
• webp/mux_types.h

All definitions are placed directly under the crate.