Rust - image crate: issue saving image buffer

Question

I have a question related to the fractal example (section '6.2 Generating Fractals', https://github.com/PistonDevelopers/image) in examples supplied for image crate

1) At line

image::ImageLuma8(imgbuf).save(fout, image::PNG).unwrap();

I get the following compile error message (rustc 1.25.0):

error[E0061]: this function takes 1 parameter but 2 parameters were supplied
  --> src/main.rs:52:31
   |
52 |     image::ImageLuma8(imgbuf).save(fout, image::PNG).unwrap();
   |                               ^^^^ expected 1 parameter

Thank you for helping!

2) Note in addition that I had to change

use num_complex::Complex;

to

use num::complex::{Complex};

at the beginning of the example. Maybe crate num_complex does not exist any longer ?

open on issue on the github would be more logical, SO is not a support service... the doc is updated, https://docs.rs/image/0.19.0/image/struct.ImageBuffer.html#method.save. — Stargateur, May 11 '18 at 11:59
Please provide a more adequate [MCVE]. Content behind links are very likely to change in the future. What's important here: all relevant dependencies' versions in use, plus a minimal version of that example _in the question itself_. If the compiler error can be reproduced in the [Rust Playground](//play.rust-lang.org), that is a plus. — E_net4, May 11 '18 at 12:06
Sorry Stargateur ! I am a newbie here and did not know I am not supposed to ask this kind of question. Thank you for the link. — TC29, May 11 '18 at 13:09
Thank you E_net4! Rust playground gave me the same error as in my comments. It seems that the code in example on https://github.com/PistonDevelopers/image was not up to date. — TC29, May 11 '18 at 13:23
I actually ran the example on the `master` branch and it compiled and ran just fine. There is probably something different going on in your build. Consider editing your question with all the necessary details, for there's still a chance that it could be salvaged. — E_net4, May 11 '18 at 20:04

madeinQuant · Answer 1 · 2018-05-20T14:28:55.930

In the section "6.2 Generating Fractals" of PistonDevelopers, the original example cannot be compiled successfully. It seems there are some outdated parameters setting, here is an updated version. hope this help.

//! An example of generating julia fractals.
extern crate image;
extern crate num;

use self::num::Complex;
use std::path::Path;

fn main() {
    let max_iterations = 256u16;

    let imgx = 800;
    let imgy = 800;

    let scalex = 4.0 / imgx as f32;
    let scaley = 4.0 / imgy as f32;

    // let mut y = 0;
    // Create a new ImgBuf with width: imgx and height: imgy
    let mut imgbuf: image::GrayImage = image::ImageBuffer::new(imgx, imgy);

    // Iterate over the coordinates and pixels of the image
    for (x, y, pixel) in imgbuf.enumerate_pixels_mut() {
        let cy = y as f32 * scaley - 2.0;
        let cx = x as f32 * scalex - 2.0;

        let mut z = Complex::new(cx, cy);
        let c = Complex::new(-0.4, 0.6);

        let mut i = 0;

        for t in 0..max_iterations {
            if z.norm() > 2.0 {
                break;
            }
            z = z * z + c;
            i = t;
        }

        // Create an 8bit pixel of type Luma and value i
        // and assign in to the pixel at position (x, y)
        *pixel = image::Luma([i as u8]);
    }

    // Save the image as “fractal.png”
    let path = Path::new("fractal.png");

    // We must indicate the image's color type and what format to save as
    image::ImageLuma8(imgbuf).save(path).unwrap();
}

Rust - image crate: issue saving image buffer

1 Answers1