Files
image-tiff/tests/decode_libtiffpic.rs
T
Lilith River 83409cbdf3 feat: add YCbCr chroma subsampling support for non-JPEG compression
Add YCbCrUpsamplingReader that converts chroma-subsampled YCbCr block
data to full-resolution 3-bytes-per-pixel output. Each block of h×v
pixels stores h*v Y samples plus one shared Cb and Cr sample; the
reader expands these into per-pixel (Y, Cb, Cr) triples.

This enables decoding YCbCr TIFFs with any supported compression
method (uncompressed, LZW, Deflate, etc.), not just JPEG. Two more
libtiffpic test images now decode with verified hashes:
- dscf0013.tif (uncompressed YCbCr 2,1 subsampling)
- ycbcr-cat.tif (LZW-compressed YCbCr 2,2 subsampling)

The remaining two YCbCr test images (smallliz.tif, zackthecat.tif)
use Old JPEG compression (type 6) which is a separate unsupported
feature.
2026-03-10 22:46:59 -06:00

365 lines
12 KiB
Rust

use std::collections::HashMap;
use std::{fs::File, path};
use tiff::decoder::{Decoder, DecodingResult};
use tiff::tags::{ByteOrder, Type};
use tiff::ColorType;
use libtest_mimic::{Arguments, Failed, Trial};
use walkdir::WalkDir;
const REFERENCE_DIR: &str = "tests/libtiffpic";
// `find test/libtiffpic -type f | sort`
//
// Each entry maps a file path to its expected behavior:
// None = not a TIFF file, skip entirely
// Some(0) = TIFF with unsupported features, decode-only smoke test
// Some(nonzero) = TIFF with full CRC32 hash verification of decoded output
const FILES: &[(&str, Option<u32>)] = &[
("tests/libtiffpic/caspian.tif", Some(0x4ea8d4e4)),
("tests/libtiffpic/cramps.tif", Some(0xdfa2fba4)),
("tests/libtiffpic/cramps-tile.tif", Some(0xdfa2fba4)),
("tests/libtiffpic/CVS/Entries", None),
("tests/libtiffpic/CVS/Repository", None),
("tests/libtiffpic/CVS/Root", None),
("tests/libtiffpic/depth/CVS/Entries", None),
("tests/libtiffpic/depth/CVS/Repository", None),
("tests/libtiffpic/depth/CVS/Root", None),
(
"tests/libtiffpic/depth/flower-minisblack-02.tif",
Some(0x1c90f515),
),
(
"tests/libtiffpic/depth/flower-minisblack-04.tif",
Some(0x0f4813cb),
),
(
"tests/libtiffpic/depth/flower-minisblack-06.tif",
Some(0xf0c0a901),
),
(
"tests/libtiffpic/depth/flower-minisblack-08.tif",
Some(0xe797b15b),
),
(
"tests/libtiffpic/depth/flower-minisblack-10.tif",
Some(0xdee442ec),
),
(
"tests/libtiffpic/depth/flower-minisblack-12.tif",
Some(0x4810c4e9),
),
(
"tests/libtiffpic/depth/flower-minisblack-14.tif",
Some(0x7e03cf03),
),
(
"tests/libtiffpic/depth/flower-minisblack-16.tif",
Some(0x8e0add32),
),
(
"tests/libtiffpic/depth/flower-minisblack-24.tif",
Some(0x5cf29313),
),
(
"tests/libtiffpic/depth/flower-minisblack-32.tif",
Some(0x80025eee),
),
(
"tests/libtiffpic/depth/flower-palette-02.tif",
Some(0xaeb21cff),
),
(
"tests/libtiffpic/depth/flower-palette-04.tif",
Some(0x339d428b),
),
(
"tests/libtiffpic/depth/flower-palette-08.tif",
Some(0xb6b203e9),
),
(
"tests/libtiffpic/depth/flower-palette-16.tif",
Some(0x4e02308f),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-02.tif",
Some(0x8f16cf35),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-04.tif",
Some(0x95e97f94),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-08.tif",
Some(0x98134e7c),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-10.tif",
Some(0xa2ad8f4d),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-12.tif",
Some(0xfad187fc),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-14.tif",
Some(0x93fdc170),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-16.tif",
Some(0x25e1066b),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-24.tif",
Some(0x25cdf743),
),
(
"tests/libtiffpic/depth/flower-rgb-contig-32.tif",
Some(0x195dde9c),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-02.tif",
Some(0xcc0281ca),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-04.tif",
Some(0x867134b2),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-08.tif",
Some(0x2341af83),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-10.tif",
Some(0x79211047),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-12.tif",
Some(0x14a0ff72),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-14.tif",
Some(0xc077389d),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-16.tif",
Some(0xd0849282),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-24.tif",
Some(0x433d333b),
),
(
"tests/libtiffpic/depth/flower-rgb-planar-32.tif",
Some(0xd0780b23),
),
(
"tests/libtiffpic/depth/flower-separated-contig-08.tif",
Some(0x97fb03a6),
),
(
"tests/libtiffpic/depth/flower-separated-contig-16.tif",
Some(0xb6ee0135),
),
(
"tests/libtiffpic/depth/flower-separated-planar-08.tif",
Some(0x502e93fa),
),
(
"tests/libtiffpic/depth/flower-separated-planar-16.tif",
Some(0x50e580d9),
),
("tests/libtiffpic/depth/genimages", None),
("tests/libtiffpic/depth/README.txt", None),
("tests/libtiffpic/depth/summary.txt", None),
("tests/libtiffpic/dscf0013.tif", Some(0x6896e83a)),
("tests/libtiffpic/fax2d.tif", Some(0xc2f30c6f)),
// No support for direct CCITT Group 3 1D format
("tests/libtiffpic/g3test.g3", None),
("tests/libtiffpic/g3test.tif", Some(0x304b606b)),
("tests/libtiffpic/jello.tif", Some(0xb03dbda9)),
("tests/libtiffpic/jim___ah.tif", Some(0x81a27b7f)),
("tests/libtiffpic/jim___cg.tif", Some(0xfd31747c)),
("tests/libtiffpic/jim___dg.tif", Some(0x8c6a5e8f)),
("tests/libtiffpic/jim___gg.tif", Some(0x8c6a5e8f)),
("tests/libtiffpic/ladoga.tif", Some(0x9b118511)),
("tests/libtiffpic/off_l16.tif", Some(0xd434a2d9)),
("tests/libtiffpic/off_luv24.tif", Some(0x2bee71a2)),
("tests/libtiffpic/off_luv32.tif", Some(0xffaa1e2e)),
("tests/libtiffpic/oxford.tif", Some(0x355d2e3e)),
("tests/libtiffpic/pc260001.tif", Some(0xdb56b753)),
("tests/libtiffpic/quad-jpeg.tif", Some(0xcba22475)),
("tests/libtiffpic/quad-lzw.tif", Some(0)), // invalid LZW stream
("tests/libtiffpic/quad-tile.tif", Some(0x6055f9ee)),
("tests/libtiffpic/README", None),
("tests/libtiffpic/smallliz.tif", Some(0)), // unsupported Old JPEG compression (type 6)
("tests/libtiffpic/strike.tif", Some(0x016b0f6a)),
("tests/libtiffpic/text.tif", Some(0)), // unsupported compression
("tests/libtiffpic/ycbcr-cat.tif", Some(0x388a9d8f)),
("tests/libtiffpic/zackthecat.tif", Some(0)), // unsupported Old JPEG compression (type 6)
];
fn main() {
let args: Vec<String> = std::env::args().collect();
if args.iter().any(|a| a == "--print-hashes") {
print_reference_hashes();
return;
}
let mut candidates: HashMap<_, _> = FILES.iter().copied().collect();
let mut trials = Vec::new();
for entry in WalkDir::new(REFERENCE_DIR) {
let entry = entry.unwrap();
if !entry.file_type().is_file() {
continue;
}
let Some(path) = entry.path().to_str() else {
continue;
};
let path = path.replace(std::path::MAIN_SEPARATOR, "/"); // always use UNIX path separators
// Mark this path as consumed in either case by removing it.
let Some(expected_hash) = candidates.remove(path.as_str()) else {
panic!("File {} not in reference list", path);
};
// None = non-image file, skip
let Some(expected_hash) = expected_hash else {
continue;
};
let path = path.to_string();
trials.push(Trial::test(
path.to_string(),
move || -> Result<(), Failed> { decode_and_verify(&path, expected_hash) },
));
}
if !candidates.is_empty() {
for (path, _) in candidates {
eprintln!("Reference file {} not found in directory walk", path);
}
panic!("Some reference files were not found");
}
let args = Arguments::from_args();
libtest_mimic::run(&args, trials).exit();
}
/// Map DecodingResult variant to a TIFF Type for byte-order normalization.
fn sample_type_of(result: &DecodingResult) -> Type {
match result {
DecodingResult::U8(_) => Type::BYTE,
DecodingResult::I8(_) => Type::SBYTE,
DecodingResult::U16(_) => Type::SHORT,
DecodingResult::I16(_) => Type::SSHORT,
DecodingResult::U32(_) => Type::LONG,
DecodingResult::I32(_) => Type::SLONG,
DecodingResult::F32(_) => Type::FLOAT,
DecodingResult::U64(_) => Type::LONG8,
DecodingResult::I64(_) => Type::SLONG8,
DecodingResult::F64(_) => Type::DOUBLE,
DecodingResult::F16(_) => Type::SHORT, // f16 is 2 bytes like SHORT
}
}
/// Hash color type into the hasher (discriminant + fields).
fn hash_color_type(hasher: &mut crc32fast::Hasher, color_type: ColorType) {
match color_type {
ColorType::Gray(n) => hasher.update(&[0, n]),
ColorType::RGB(n) => hasher.update(&[1, n]),
ColorType::Palette(n) => hasher.update(&[2, n]),
ColorType::GrayA(n) => hasher.update(&[3, n]),
ColorType::RGBA(n) => hasher.update(&[4, n]),
ColorType::CMYK(n) => hasher.update(&[5, n]),
ColorType::CMYKA(n) => hasher.update(&[6, n]),
ColorType::YCbCr(n) => hasher.update(&[7, n]),
ColorType::Lab(n) => hasher.update(&[8, n]),
ColorType::Multiband {
bit_depth,
num_samples,
} => {
hasher.update(&[9, bit_depth]);
hasher.update(&num_samples.to_le_bytes());
}
other => panic!("compute_tiff_hash: unhandled ColorType {other:?}"),
}
}
/// Compute a CRC32 hash of the full decoded TIFF output using read_image_to_buffer.
///
/// Hashes per page: page index, dimensions, color type, TIFF sample type tag,
/// and decoded sample data normalized to little-endian byte order.
fn compute_hash(path: &std::path::Path) -> Result<u32, tiff::TiffError> {
let img_file = File::open(path)?;
let mut decoder = Decoder::open(img_file)?;
let mut hasher = crc32fast::Hasher::new();
let mut buffer = DecodingResult::U8(vec![]);
let mut page = 0u32;
while decoder.more_images() {
decoder.next_image()?;
let (width, height) = decoder.dimensions()?;
let color_type = decoder.colortype()?;
let _layout = decoder.read_image_to_buffer(&mut buffer)?;
hasher.update(&page.to_le_bytes());
hasher.update(&width.to_le_bytes());
hasher.update(&height.to_le_bytes());
hash_color_type(&mut hasher, color_type);
let sample_type = sample_type_of(&buffer);
hasher.update(&sample_type.to_u16().to_le_bytes());
let mut buf = buffer.as_buffer(0);
let bytes = buf.as_bytes_mut();
ByteOrder::native().convert(sample_type, bytes, ByteOrder::LittleEndian);
hasher.update(bytes);
page += 1;
}
hasher.update(&page.to_le_bytes());
Ok(hasher.finalize())
}
fn decode_and_verify(path: &str, expected_hash: u32) -> Result<(), Failed> {
let full_path = path::PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(path);
if expected_hash == 0 {
// Smoke test: try to decode, tolerate errors (unsupported formats)
let _ = compute_hash(&full_path);
return Ok(());
}
let actual_hash = compute_hash(&full_path)
.map_err(|e| Failed::from(format!("Decoding failed for {path}: {e}")))?;
if actual_hash != expected_hash {
return Err(Failed::from(format!(
"{path}: expected hash 0x{expected_hash:08x} but got 0x{actual_hash:08x}"
)));
}
Ok(())
}
/// Print reference hashes for all decodable files (use --print-hashes).
fn print_reference_hashes() {
for &(path, expected) in FILES {
if expected.is_none() {
continue;
}
let full_path = path::PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(path);
match compute_hash(&full_path) {
Ok(hash) => eprintln!("(\"{path}\", Some(0x{hash:08x})),"),
Err(e) => eprintln!("// {path}: FAILED: {e}"),
}
}
}