Convert a .webp to .png

help
1

Hi,

does anyone have an idea how to convert a .webp to a .png?
I found this crate https://crates.io/crates/image but I am not sure if I can convert pictures with it.

2

image has a partial webp implementation in pure Rust but it only supports loading of grayscale part of lossy webp.
I've made a binding GitHub - qnighy/libwebp-rs: Rust binding to libwebp
to the C library for my purpose but it doesn't have a good documentation and has unnecessary dependencies. I'm going to remake it at GitHub - qnighy/webp-rs: Rust libwebp bindings but the project is currently stale. Nevertheless it will suffice your need to decode webp images into typical RGBA representations.

3

sounds good. do you maybe have an example for me? Sorry I am not very fit at Rust at the moment...

4

you described how to unwrap the picture if you have the correct representation

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";

How do I get that if I already have a picture on my laptop?

5

I don't know if its correct what I have done so far?

extern crate libwebp;
extern crate image;

use ::std::{*, io::Write, fs::OpenOptions,};
use std::io::Read;
use libwebp::*;
use std::fs::File;
use std::path::Path;
use std::fmt::Debug;

fn main() -> io::Result<()>
{
    let src = "/home/andy/Downloads/8Z.ktnc9tqX.mri";
    let dst = "/home/andy/Downloads/8Z.ktnc9tqX";

    let mut data = fs::read(src)?;
    let n = data.len() + 7;
    let header = [
        82, 73, 70, 70, n as u8, (n >> 8) as u8, (n >> 16) as u8, (n >> 24) as u8, 87, 69, 66, 80, 86, 80, 56,
    ];

    data.iter_mut().for_each(|at_x| *at_x ^= 101); // more efficient

    let newdst = format!("{}.webp", dst);
    let mut f =
        OpenOptions::new()
            .create(true)
            .write(true)
            .truncate(true)
            .open(&newdst)?
        ;
    f.write_all(&header)?;
    f.write_all(&data)?;

    let mut data = File::open(newdst).unwrap();

    let size = data.metadata().unwrap().len() as usize;

    let mut buf = vec![0u8; size];
    data.read(&mut buf).unwrap();

    let (width, height, d) = WebPDecodeRGBA(&buf).unwrap();

    println!("{} {}", width, height);

    //image::save_buffer("image.png", &d, width, height, image::RGB(8)).unwrap();

    let format = image::guess_format(&d);

    println!("{:?}", format);


    Ok(())
}

Pretty sure I did something wrong because if I run the image::save_buffer line I get the following error:

thread 'main' panicked at 'called Result::unwrap() on an Err value: Custom { kind: Other, error: StringError("wrong data size, expected 3544800 got 4726400") }', src/libcore/result.rs:999:5

6

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