Crate j2k_jpeg 

JPEG decoder optimized for whole-slide images.

See the top-level README for project positioning. The primary entry point is Decoder — start with Decoder::inspect for header-only parsing.

Structs

CacheStats

Cache hit/miss counters reported by codec contexts.

DecodeOptions

Public decode options for JPEG reads.

DecodeOutcome

Non-fatal outcome of a successful decode. See spec Section 2.

DecodeRequest

Owned-output JPEG decode request.

DecodedTile

Result for one successful prepared JPEG tile decode.

Decoder

A borrowed view of a JPEG stream ready to decode. Constructed via Decoder::new or Decoder::from_view. Decoder<'a>: Send + Sync.

DecoderContext

Shared decode context for WSI tile batches.

DeviceBatchSummary

Lightweight summary used for batching without materializing scan bytes.

EncodedJpeg

Encoded baseline JPEG bytes and the backend that produced them.

Info

Header-derived image metadata. Populated by Decoder::inspect and by Decoder::new. scan_count is the number of SOS markers observed in the input — for sequential this is always 1; for progressive it is the count of refinement passes.

JpegBackendEligibility

Backend eligibility result with a stable rejection reason.

JpegBatchSession

Reusable JPEG tile-batch runtime for WSI viewport loops.

JpegCapabilityReport

Parsed JPEG metadata and backend eligibility for one request.

JpegCapabilityRequest

Capability request for a JPEG decode route.

JpegCodec

JPEG codec marker type for j2k-core trait integrations.

JpegDecodeRequest

Complete JPEG decode request used by backend path resolution.

JpegEncodeOptions

Options controlling baseline JPEG encoding.

JpegOutputBuffer

Caller-owned reusable host pixel buffer.

JpegResolvedDecode

Parsed JPEG metadata plus the selected backend path.

JpegScanRanges

Byte ranges around the first Start-of-Scan marker.

JpegSegment

One marker segment in a JPEG byte stream.

JpegSegmentIter

Iterator over marker segments in a JPEG byte stream.

JpegSofInfo

Parsed Start-of-Frame facts.

JpegTilePrepareOptions

Options for preparing TIFF/WSI JPEG tile payloads.

JpegView

A parsed borrowed view of a JPEG stream.

McuGeometry

Minimum coded unit geometry derived from SOF sampling factors.

PassthroughCandidate

A borrowed compressed frame/tile that may be copied unchanged.

PassthroughRequirements

Destination requirements for copying compressed bytes unchanged.

PreparedJpegTileJob

One decode request for a JPEG tile already normalized by prepare_tiff_jpeg_tile.

Rect

Inclusive axis-aligned rectangle in image coordinates.

RestartIndex

Restart-marker index for a single-scan JPEG stream.

RestartSegment

One restart-addressable entropy segment in the original JPEG byte stream.

SamplingFactors

Per-component (H, V) sampling factors, stored in declaration order.

ScratchPool

Pool of decoder-internal scratch buffers, reusable across many Decoder::decode_into_with_scratch / decode_rows_with_scratch calls.

TileBatchOptions

Worker configuration for CPU tile batches.

TileDecodeOutput

Caller-owned output target for one context-reused tile decode helper.

Enums

BatchDecodeError

Error returned by a fallible batch boundary.

BatchInfrastructureError

Failure in batch scheduling, allocation, or worker-result collection.

BuilderConflictReason

Invalid decoder-builder input configuration.

ColorSpace

Declared input color space after APP14 detection.

ColorTransform

Override for APP14 color-transform detection.

CompressedPayloadKind

Encapsulation shape of the compressed bytes.

CompressedTransferSyntax

Compressed syntax carried by a source frame or accepted by a destination.

DecodeRowsError

Error wrapper used by row-streaming decode when either the codec or the caller-provided row sink can fail.

Downscale

Power-of-two downscale requested during decode.

DuplicateTablePolicy

Duplicate JPEG table handling policy.

HuffmanFailure

Huffman entropy decoder failure category.

JpegBackend

JPEG encoder backend selector.

JpegDecodeOp

JPEG decode operation shape for capability routing.

JpegEncodeError

Errors produced by baseline JPEG encoding.

JpegError

Fatal JPEG decode or API error.

JpegResolvedDecodePath

Normalized JPEG decode path selected for a request.

JpegSamples

Borrowed input samples for baseline JPEG encoding.

JpegSubsampling

JPEG baseline chroma subsampling mode.

MarkerKind

A category of JPEG marker. Carried in JpegError::UnexpectedMarker and related variants so callers can branch on marker class without parsing the raw byte.

PassthroughDecision

Result of a passthrough eligibility check.

PassthroughRejectReason

First reason a compressed payload was rejected for byte-preserving copy.

PixelFormat

Concrete interleaved pixel format.

PixelLayout

Channel layout independent of sample width.

PreparedJpeg

Prepared JPEG bytes, borrowed when unchanged and owned when normalized.

ProgressiveScanStateError

Cross-scan progressive coefficient-state violation.

ProgressiveScanTerminationError

Entropy condition that made a progressive scan terminator invalid.

SampleType

Integer sample width used by a pixel format or row sink.

SamplingFactorsError

Error returned when constructing SamplingFactors from caller input.

SofKind

Start-of-frame variant. Determines the decode pipeline.

TableKind

JPEG table class used in diagnostics.

UnsupportedReason

Reason an otherwise recognized SOF marker cannot be decoded.

Warning

Non-fatal notices emitted during decode. See spec Section 6.

Traits

CodecContext

Reusable codec state cached across decode calls.

ComponentRowWriter

Receives decoded component rows before they are packed into the final interleaved pixel format.

ImageCodec

Common associated types shared by image codecs.

ImageDecode

Borrowed-image decode API for codecs that parse compressed bytes directly.

ImageDecodeRows

Row-streaming decode API for large images or stripe-oriented callers.

RowSink

Destination for row-streaming decode output.

Sample

Supported integer sample type for row-oriented APIs.

TileBatchDecode

Stateless tile-batch decode helpers that reuse caller-owned context.

TileDecompress

Tile payload decompression API for container codecs such as Deflate, Zstd, LZW, and uncompressed data.

Functions

decode_prepared_jpeg_tiles_rgb8

Decode prepared TIFF/WSI JPEG tiles into caller-owned RGB8 output buffers.

decode_tile_into

One-shot parse-plus-decode of an independent JPEG tile into the caller’s buffer, reusing a pre-allocated ScratchPool. This is the primitive WSI tile-batch readers want: one function call per tile, with all heap state external.

decode_tiles_into

Decode independent JPEG tiles into caller-owned output buffers using a scoped CPU worker pool.

decode_tiles_region_scaled_into

Decode independent JPEG tile regions at reduced resolution into caller-owned output buffers using a scoped CPU worker pool.

decode_tiles_scaled_into

Decode independent JPEG tiles at reduced resolution into caller-owned output buffers using a scoped CPU worker pool.

encode_jpeg_baseline

Encode grayscale or RGB samples as a baseline JPEG codestream.

find_scan_ranges

Find the first SOS header and scan data ranges.

is_sof_marker

Return true for JPEG SOF marker classes.

iter_segments

Iterate over JPEG marker segments.

parse_dri

Parse a Define Restart Interval payload.

parse_sof_info

Parse a Start-of-Frame payload.

prepare_tiff_jpeg_tile

Prepare a TIFF/WSI JPEG tile for decode.

rewrite_sof_dimensions

Return a copy of input with the first SOF dimensions rewritten.

Type Aliases

PreparedTileBatchError

Allocation, scheduling, or collection failure for a prepared JPEG batch.

TileBatchError

Error returned by decode_tiles_into, annotated with the failing tile index from the caller’s input order when a codec error occurs, or carrying a typed infrastructure error when no tile index applies.

TileDecodeJob

One tile decode request for decode_tiles_into.

TileRegionScaledDecodeJob

One ROI+scaled tile decode request for decode_tiles_region_scaled_into.

TileScaledDecodeJob

One scaled tile decode request for decode_tiles_scaled_into.