A. Molzer
fa225e820b
I didn't realize we support this in a slightly weird manner where the tag is completely ignored and zune-jpeg performs the upsampling as indicated in the JPEG stream. This is a recurring problem with the compression scheme and tags in TIFF. In the end, decoder can only handle the data as indicated by the JPEG steam and while the specification requires the tags to be consistent with the underlying data, sometimes they are not. The useful fallback is of course to ignore the tag. Ignoring the tag of course buts us in a weird spot for zero-copy decoding since the buffer indication to the caller will be incorrect. For now, maybe the best way of treating subsampling is to upsample all the cases when we add support.
image-tiff
TIFF decoding and encoding library in pure Rust
Supported
Features
- Baseline spec (other than formats and tags listed below as not supported)
- Multipage
- BigTIFF
- Incremental decoding
Formats
This table lists photometric interpretations and sample formats which are supported for encoding and decoding. The entries are ColorType variants for which sample bit depths are supported. Only samples where all bit depths are equal are currently supported. For example, RGB(8) means that the bit depth [8, 8, 8] is supported and will be interpreted as an 8 bit per channel RGB color type.
PhotometricInterpretation |
UINT Format | IEEEFP Format |
|---|---|---|
WhiteIsZero |
Gray(8|16|32|64) | Gray(32|64) |
BlackIsZero |
Gray(8|16|32|64) | Gray(32|64) |
RGB |
RGB(8|16|32|64), RGBA(8|16|32|64) | RGB(32|64), RGBA(32|64) |
RGBPalette |
||
Mask |
||
CMYK |
CMYK(8|16|32|64) | CMYK(32|64) |
CMYKA |
CMYKA(8) | |
YCbCr |
||
CIELab |
Compressions
| Decoding | Encoding | |
|---|---|---|
| None | ✓ | ✓ |
| LZW | ✓ | ✓ |
| Deflate | ✓ | ✓ |
| PackBits | ✓ | ✓ |
| Fax4 | ✓ | not yet |
| JPEG | ✓ | not yet |
| ZSTD | ✓ | not yet |
Not yet supported
Formats and interpretations not listed above or with empty entries are unsupported.
- Baseline tags
ExtraSamples
- Extension tags
Fuzzing
This crate uses cargo-fuzz in order to test the image parser.
After installing it with cargo install cargo-fuzz on a nightly rustc, the
fuzzing harness can be run with recommended settings using
cargo fuzz run decode_image -snone -- -timeout=5.