53 lines
1.8 KiB
Rust
53 lines
1.8 KiB
Rust
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extern crate image as png;
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// exr imports
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extern crate exr;
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/// Converts one rgba exr with one layer to one png, or fail.
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fn main() {
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use exr::prelude::*;
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use exr::prelude as exrs;
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// read from the exr file directly into a new `png::RgbaImage` image without intermediate buffers
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let reader = exrs::read()
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.no_deep_data()
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.largest_resolution_level()
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.rgba_channels(
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|resolution, _channels: &RgbaChannels| -> png::RgbaImage {
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png::ImageBuffer::new(
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resolution.width() as u32,
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resolution.height() as u32
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)
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},
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// set each pixel in the png buffer from the exr file
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|png_pixels, position, (r,g,b,a): (f32,f32,f32,f32)| { // TODO implicit argument types!
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png_pixels.put_pixel(
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position.x() as u32, position.y() as u32,
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png::Rgba([tone_map(r), tone_map(g), tone_map(b), (a * 255.0) as u8])
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);
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}
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)
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.first_valid_layer()
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.all_attributes();
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// an image that contains a single layer containing an png rgba buffer
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let image: Image<Layer<SpecificChannels<png::RgbaImage, RgbaChannels>>> = reader
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.from_file("generated_rgba.exr")
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.expect("run the `1_write_rgba` example to generate the required file");
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/// compress any possible f32 into the range of [0,1].
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/// and then convert it to an unsigned byte.
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fn tone_map(linear: f32) -> u8 {
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// TODO does the `image` crate expect gamma corrected data?
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let clamped = (linear - 0.5).tanh() * 0.5 + 0.5;
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(clamped * 255.0) as u8
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}
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// save the png buffer to a png file
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let png_buffer = &image.layer_data.channel_data.pixels;
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png_buffer.save("rgb.png").unwrap();
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println!("created image rgb.png")
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}
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