Crate j2k_jpeg_metal 

Apple Metal GPU-backed JPEG decode and encode adapters for j2k-jpeg.

The crate exposes the same CPU-visible JPEG decode surface as j2k-jpeg, with optional Metal-resident surfaces and batch submission helpers on macOS. Non-macOS builds keep the public API available but return Error::MetalUnavailable for explicit Metal-only work.

Modules

viewport

Viewport planning and composition helpers for JPEG decode surfaces.

Structs

Codec

JPEG codec marker used by J2K’s generic decode traits.

Decoder

JPEG decoder that can return host or Metal-resident surfaces.

DecoderContext

Shared decode context for WSI tile batches.

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.

JpegBaselineMetalEncodeTile

Placeholder encode tile type for non-macOS builds.

JpegRectPublic

Inclusive axis-aligned rectangle in image coordinates.

JpegTileBatch

Convenience wrapper for submitting a group of JPEG tiles to one decoder session.

MetalBackendSession

Placeholder Metal session for non-macOS builds.

MetalSession

Shared batching session used by JpegTileBatch and submit APIs.

ScratchPool

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

Surface

Decoded image surface returned by the JPEG Metal backend.

Enums

Error

Errors returned by the Metal JPEG backend.

JpegDownscale

Power-of-two downscale requested during decode.

JpegPixelFormat

Concrete interleaved pixel format.

SurfaceResidency

Where a decoded surface is currently resident.

Functions

encode_jpeg_baseline_batch_from_metal_buffers

Return Error::MetalUnavailable for batch Metal encode requests on non-macOS hosts.

encode_jpeg_baseline_from_metal_buffer

Return Error::MetalUnavailable for Metal encode requests on non-macOS hosts.