84 lines
2.6 KiB
Rust
84 lines
2.6 KiB
Rust
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extern crate jpeg_decoder as jpeg;
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extern crate png;
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use std::env;
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use std::fs::File;
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use std::io::{self, BufReader, Write};
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use std::process;
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fn usage() -> ! {
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write!(io::stderr(), "usage: decode image.jpg image.png").unwrap();
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process::exit(1)
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}
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fn main() {
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let mut args = env::args().skip(1);
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let input_path = args.next().unwrap_or_else(|| usage());
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let output_path = args.next().unwrap_or_else(|| usage());
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let input_file = File::open(input_path).expect("The specified input file could not be opened");
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let mut decoder = jpeg::Decoder::new(BufReader::new(input_file));
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let mut data = decoder.decode().expect("Decoding failed. If other software can successfully decode the specified JPEG image, then it's likely that there is a bug in jpeg-decoder");
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let info = decoder.info().unwrap();
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eprintln!("{:?}", info);
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eprintln!("Exif: {}", decoder.exif_data().is_some());
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eprintln!("ICC: {}", decoder.icc_profile().is_some());
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let output_file = File::create(output_path).unwrap();
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let mut encoder = png::Encoder::new(output_file, info.width as u32, info.height as u32);
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match info.pixel_format {
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jpeg::PixelFormat::L16 => {
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encoder.set_depth(png::BitDepth::Sixteen);
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encoder.set_color(png::ColorType::Grayscale);
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},
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jpeg::PixelFormat::RGB24 => {
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encoder.set_depth(png::BitDepth::Eight);
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encoder.set_color(png::ColorType::RGB);
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},
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jpeg::PixelFormat::CMYK32 => {
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data = cmyk_to_rgb(&mut data);
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encoder.set_depth(png::BitDepth::Eight);
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encoder.set_color(png::ColorType::RGB)
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},
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jpeg::PixelFormat::L8 => {
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encoder.set_depth(png::BitDepth::Eight);
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encoder.set_color(png::ColorType::Grayscale);
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},
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}
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encoder.write_header()
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.expect("writing png header failed")
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.write_image_data(&data)
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.expect("png encoding failed");
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}
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fn cmyk_to_rgb(input: &[u8]) -> Vec<u8> {
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let size = input.len() - input.len() / 4;
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let mut output = Vec::with_capacity(size);
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for pixel in input.chunks(4) {
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let c = pixel[0] as f32 / 255.0;
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let m = pixel[1] as f32 / 255.0;
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let y = pixel[2] as f32 / 255.0;
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let k = pixel[3] as f32 / 255.0;
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// CMYK -> CMY
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let c = c * (1.0 - k) + k;
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let m = m * (1.0 - k) + k;
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let y = y * (1.0 - k) + k;
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// CMY -> RGB
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let r = (1.0 - c) * 255.0;
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let g = (1.0 - m) * 255.0;
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let b = (1.0 - y) * 255.0;
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output.push(r as u8);
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output.push(g as u8);
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output.push(b as u8);
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}
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output
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}
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