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
51
52
53
|
extern crate image as png;
// exr imports
extern crate exr;
/// Converts one rgba exr with one layer to one png, or fail.
fn main() {
use exr::prelude::*;
use exr::prelude as exrs;
// read from the exr file directly into a new `png::RgbaImage` image without intermediate buffers
let reader = exrs::read()
.no_deep_data()
.largest_resolution_level()
.rgba_channels(
|resolution, _channels: &RgbaChannels| -> png::RgbaImage {
png::ImageBuffer::new(
resolution.width() as u32,
resolution.height() as u32
)
},
// set each pixel in the png buffer from the exr file
|png_pixels, position, (r,g,b,a): (f32,f32,f32,f32)| { // TODO implicit argument types!
png_pixels.put_pixel(
position.x() as u32, position.y() as u32,
png::Rgba([tone_map(r), tone_map(g), tone_map(b), (a * 255.0) as u8])
);
}
)
.first_valid_layer()
.all_attributes();
// an image that contains a single layer containing an png rgba buffer
let image: Image<Layer<SpecificChannels<png::RgbaImage, RgbaChannels>>> = reader
.from_file("generated_rgba.exr")
.expect("run the `1_write_rgba` example to generate the required file");
/// 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
let png_buffer = &image.layer_data.channel_data.pixels;
png_buffer.save("rgb.png").unwrap();
println!("created image rgb.png")
}
|
