embedblocks/jpeg-roi-decoder

changelog

# Changelog

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## [0.3.0] - 2026-05-02

### Added
- **True streaming input** — decoder now runs a single forward pass through the JPEG byte stream. The source never rewinds. Non-seekable sources (HTTP, UART, TCP, FreeRTOS queue, DMA ring buffer) are now fully supported.
- `jpeg_read_cb_t` — new read callback typedef: `size_t (*)(uint8_t *dst, size_t max, void *ctx)`. This is the sole source abstraction. When `dst` is `NULL`, the decoder is requesting a skip; seekable sources can implement this as `fseek` (zero RAM, zero copy).
- `jpeg_reader_t` — lightweight `{ cb, ctx }` struct that pairs the callback with a caller-owned context. Embeds no internal state.
- `jpeg_view_intent_t` — replaces `jpeg_view_t`. Now includes `reader` and `chunk_buffer` fields directly. `work_buffer` is intentionally kept separate (passed to `jpeg_decoder_decode_view()`) to keep execution resources out of the intent struct.
- `input_func` retry loop — handles partial reads from the callback without any internal staging buffer. TJpgDec's own buffer is passed directly to `reader.cb` (zero copy).

### Changed
- `jpeg_decoder_decode_view()` signature changed: first argument is now `const jpeg_view_intent_t *intent` (source embedded inside intent). Old signature took a separate `jpeg_source_t` as the first argument.
- `jpeg_decode_request_t.source` renamed to `.reader` (`jpeg_reader_t`).
- `decode_context_t` internal field `source` replaced by `reader`.
- RTOS worker task now owns the **full decode lifecycle** — `tjpgd_sys_prepare` and `tjpgd_sys_decomp` both run in the worker. Previously, `prepare` (header parse + probe) ran in the calling task before the job was queued.
- `jpeg_decoder_probe()` signature changed: takes `jpeg_reader_t` by value instead of `jpeg_source_t`. Caller is responsible for resetting their own source context after a probe call; the component provides no reset mechanism.
- `jpeg_view_default()` now returns `jpeg_view_intent_t` with `reader = {NULL, NULL}` and `chunk_buffer = NULL`.
- `decode_job_t` internal type updated: carries `jpeg_reader_t reader` instead of stream fields; `use_intent` flag selects high-level vs low-level core path.
- `done_callback` is now always fired — even on early parameter validation errors — so callers can always rely on it for cleanup (e.g. closing files, freeing resources).

### Removed
- `jpeg_source_t` — replaced by `jpeg_reader_t`.
- `jpeg_view_t` — replaced by `jpeg_view_intent_t`.
- `jpeg_decoder_source_from_file()` — callers implement a 5-line `file_read_cb`. Example provided in README and header comments.
- `jpeg_decoder_source_from_buffer()` — callers implement a 7-line `buf_read_cb` with a `buf_ctx_t`. Example provided in README and header comments.
- `jpeg_roi_decoder_helpers.c` — file deleted entirely. The component ships no source backends.
- `seek()` field on source abstraction — no seek operation exists anywhere in the new API. Callers who need to seek do so inside their own callback.
- `jpeg_decoder_prepare_view_request()` internal helper — logic absorbed into `jpeg_decoder_core_run_view()`.
- Double header parse — `probe()` followed by `seek(0)` followed by a second `prepare()` inside `core_run` is gone. One prepare, one decomp, no rewind.

### Migration from 0.2.x

| 0.2.x | 0.3.x |
|---|---|
| `jpeg_source_t` | `jpeg_reader_t` |
| `jpeg_view_t` | `jpeg_view_intent_t` |
| `jpeg_decoder_source_from_file(fp)` | Write a `file_read_cb`; set `reader = { file_read_cb, fp }` |
| `jpeg_decoder_source_from_buffer(data, len)` | Write a `buf_read_cb` with a `buf_ctx_t` |
| `jpeg_decoder_decode_view(src, &view, ...)` | `jpeg_decoder_decode_view(&view, ...)` |
| `jpeg_decode_request_t.source` | `jpeg_decode_request_t.reader` |

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## [0.2.0] - 2026-04-04

### Fix
- UART example fixed, now correctly received

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## [0.1.0] - 2026-04-04

### Release
- First release