tiff 0.11.3

TIFF decoding and encoding library in pure Rust
Documentation 
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use tiff::decoder::{Decoder, DecodingResult, Limits, TiffCodingUnit};

use std::fs::File;
use std::path::PathBuf;

const TEST_IMAGE_DIR: &str = "./tests/images/";

#[test]
fn read_all_planes() {
    let path = PathBuf::from(TEST_IMAGE_DIR).join("planar-rgb-u8.tif");
    let file = File::open(path).unwrap();
    let io = std::io::BufReader::new(file);

    let mut tif = Decoder::new(io).unwrap();
    let layout = tif.image_buffer_layout().unwrap();
    assert_eq!(layout.planes, 3);
    let plane_stride = layout.plane_stride.map_or(0, |x| x.get());

    eprintln!("{:?}", layout);
    let mut buffer = vec![0u8; layout.complete_len];
    tif.read_image_bytes(&mut buffer).unwrap();

    // Mainly you can see: these are different and non-zero. Otherwise these magic constants just
    // depend on the file itself that is being used.
    const PLANE_EXCPECTED_SUMS: [u32; 3] = [15417630, 13007788, 11103530];

    for (plane, expected) in (0..layout.planes).zip(PLANE_EXCPECTED_SUMS) {
        let plane_data = &buffer[plane_stride * plane..][..layout.len];
        let sum: u32 = plane_data.iter().copied().map(u32::from).sum();
        assert_eq!(sum, expected);
    }
}

#[test]
fn read_first_coding_unit() {
    let path = PathBuf::from(TEST_IMAGE_DIR).join("planar-rgb-u8.tif");
    let file = File::open(path).unwrap();
    let io = std::io::BufReader::new(file);

    let mut tif = Decoder::new(io).unwrap();
    let layout = tif.image_coding_unit_layout(TiffCodingUnit(0)).unwrap();

    assert_eq!(layout.planes, 3);
    let plane_stride = layout.plane_stride.map_or(0, |x| x.get());
    eprintln!("{:?}", layout);
    let mut buffer = vec![0u8; layout.complete_len];

    struct Expected {
        plane_sums: [u32; 3],
        unit: TiffCodingUnit,
    }

    // Mainly you can see: these are different and non-zero. Otherwise these magic constants just
    // depend on the file itself that is being used. Also this varies by what unit we are reading.
    const PLANE_EXCPECTED_SUMS: [Expected; 2] = [
        Expected {
            plane_sums: [856853, 767686, 688532],
            unit: TiffCodingUnit(0),
        },
        Expected {
            plane_sums: [883679, 797329, 711086],
            unit: TiffCodingUnit(1),
        },
    ];

    for expected in PLANE_EXCPECTED_SUMS {
        tif.read_coding_unit_bytes(expected.unit, &mut buffer)
            .unwrap();

        for (plane, expected) in (0..layout.planes).zip(expected.plane_sums) {
            let plane_data = &buffer[plane_stride * plane..][..layout.len];
            let sum: u32 = plane_data.iter().copied().map(u32::from).sum();
            assert_eq!(sum, expected);
        }
    }
}

#[test]
fn read_planes_by_limits() {
    let path = PathBuf::from(TEST_IMAGE_DIR).join("planar-rgb-u8.tif");
    let file = File::open(path).unwrap();
    let io = std::io::BufReader::new(file);

    let mut limits = Limits::default();
    let mut buffer = DecodingResult::U8(vec![]);

    // Make room for 1 plane.
    let mut tif = Decoder::new(io).unwrap();
    tif = tif.with_limits({
        limits.decoding_buffer_size = 374 * 499;
        limits.clone()
    });

    tif.read_image_to_buffer(&mut buffer).unwrap();
    assert_eq!(buffer.as_buffer(0).byte_len(), 374 * 499);

    // Make room for 2 planes.
    tif = tif.with_limits({
        limits.decoding_buffer_size = 374 * 499 * 2;
        limits.clone()
    });

    tif.read_image_to_buffer(&mut buffer).unwrap();
    assert_eq!(buffer.as_buffer(0).byte_len(), 374 * 499);

    // Make room for 3 planes.
    tif = tif.with_limits({
        limits.decoding_buffer_size = 374 * 499 * 3;
        limits.clone()
    });

    tif.read_image_to_buffer(&mut buffer).unwrap();
    assert_eq!(buffer.as_buffer(0).byte_len(), 374 * 499 * 3);

    // Make room for 4 planes?
    tif = tif.with_limits({
        limits.decoding_buffer_size = 374 * 499 * 4;
        limits.clone()
    });

    tif.read_image_to_buffer(&mut buffer).unwrap();
    assert_eq!(buffer.as_buffer(0).byte_len(), 374 * 499 * 3);
}