1 files changed, 83 insertions, 0 deletions
diff --git a/vendor/jpeg-decoder/examples/decode.rs b/vendor/jpeg-decoder/examples/decode.rs
new file mode 100644
index 0000000..13934fe
--- /dev/null
+++ b/vendor/jpeg-decoder/examples/decode.rs
@@ -0,0 +1,83 @@
+extern crate jpeg_decoder as jpeg;
+extern crate png;
+
+use std::env;
+use std::fs::File;
+use std::io::{self, BufReader, Write};
+use std::process;
+
+fn usage() -> ! {
+    write!(io::stderr(), "usage: decode image.jpg image.png").unwrap();
+    process::exit(1)
+}
+
+fn main() {
+    let mut args = env::args().skip(1);
+    let input_path = args.next().unwrap_or_else(|| usage());
+    let output_path = args.next().unwrap_or_else(|| usage());
+
+    let input_file = File::open(input_path).expect("The specified input file could not be opened");
+    let mut decoder = jpeg::Decoder::new(BufReader::new(input_file));
+    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");
+    let info = decoder.info().unwrap();
+
+    eprintln!("{:?}", info);
+    eprintln!("Exif: {}", decoder.exif_data().is_some());
+    eprintln!("ICC: {}", decoder.icc_profile().is_some());
+
+    let output_file = File::create(output_path).unwrap();
+    let mut encoder = png::Encoder::new(output_file, info.width as u32, info.height as u32);
+
+    match info.pixel_format {
+        jpeg::PixelFormat::L16 => {
+            encoder.set_depth(png::BitDepth::Sixteen);
+            encoder.set_color(png::ColorType::Grayscale);
+        },
+        jpeg::PixelFormat::RGB24  => {
+            encoder.set_depth(png::BitDepth::Eight);
+            encoder.set_color(png::ColorType::RGB);
+        },
+        jpeg::PixelFormat::CMYK32 => {
+            data = cmyk_to_rgb(&mut data);
+            encoder.set_depth(png::BitDepth::Eight);
+            encoder.set_color(png::ColorType::RGB)
+        },
+        jpeg::PixelFormat::L8 => {
+            encoder.set_depth(png::BitDepth::Eight);
+            encoder.set_color(png::ColorType::Grayscale);
+        },
+    }
+    
+    encoder.write_header()
+           .expect("writing png header failed")
+           .write_image_data(&data)
+           .expect("png encoding failed");
+}
+
+fn cmyk_to_rgb(input: &[u8]) -> Vec<u8> {
+    let size = input.len() - input.len() / 4;
+    let mut output = Vec::with_capacity(size);
+
+    for pixel in input.chunks(4) {
+        let c = pixel[0] as f32 / 255.0;
+        let m = pixel[1] as f32 / 255.0;
+        let y = pixel[2] as f32 / 255.0;
+        let k = pixel[3] as f32 / 255.0;
+
+        // CMYK -> CMY
+        let c = c * (1.0 - k) + k;
+        let m = m * (1.0 - k) + k;
+        let y = y * (1.0 - k) + k;
+
+        // CMY -> RGB
+        let r = (1.0 - c) * 255.0;
+        let g = (1.0 - m) * 255.0;
+        let b = (1.0 - y) * 255.0;
+
+        output.push(r as u8);
+        output.push(g as u8);
+        output.push(b as u8);
+    }
+
+    output
+}