exr 0.9.0

Read and write OpenEXR files without any unsafe code
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50


extern crate image as png;

// exr imports
extern crate exr;
use exr::prelude::rgba_image as rgb_exr;

fn main() {

    // read the image from a file and keep only the png buffer
    let (_info, png_buffer) = rgb_exr::ImageInfo::read_pixels_from_file(
        "tests/images/valid/openexr/MultiResolution/Kapaa.exr",
        rgb_exr::read_options::high(),

        // how to create an empty png buffer from exr image meta data (used for loading the exr image)
        |info: &rgb_exr::ImageInfo| -> png::RgbaImage {
            png::ImageBuffer::new(
                info.resolution.width() as u32,
                info.resolution.height() as u32
            )
        },

        // set each pixel in the png buffer from the exr file
        |png_pixels: &mut png::RgbaImage, position: rgb_exr::Vec2<usize>, pixel: rgb_exr::Pixel| {
            png_pixels.put_pixel(
                position.x() as u32, position.y() as u32,

                png::Rgba([
                    tone_map(pixel.red.to_f32()),
                    tone_map(pixel.green.to_f32()),
                    tone_map(pixel.blue.to_f32()),
                    (pixel.alpha_or_default().to_f32() * 255.0) as u8,
                ])
            );
        },
    ).unwrap();


    /// compress any possible f32 into the range of [0,1].
    /// and then convert it to an unsigned byte.
    fn tone_map(linear: f32) -> u8 {
        // TODO does the `image` crate expect gamma corrected data?
        let clamped = (linear - 0.5).tanh() * 0.5 + 0.5;
        (clamped * 255.0) as u8
    };

    // save the png buffer to a png file
    png_buffer.save("tests/images/out/rgb.png").unwrap();
    println!("created image rgb.png")
}