# HANDOFF.md

Current state of the comic compression toolchain as of 2026-06-28.

## Repositories

| Repo | Branch | Latest commit |
|------|--------|---------------|
| `comic-compress-new` (CLI) | main | `94f3fab` |
| `iMGcompress-core` (library) | master | `a03d0e5` |
| `iMGcompress` (GUI) | master | `7b7021a` |

## What was done in this session (v3.1.0 / v2.0.0)

### NuGet package updates (all three projects)
- SharpCompress `0.42` → `0.49.1` (CVE GHSA-6c8g-7p36-r338 fixed)
- Magick.NET-Q8-x64 → `14.14.0` (multiple CVEs fixed)
- Imazen.WebP → `11.0.0`
- Imageflow.AllPlatforms + Imageflow.Net → `0.15.1`
- iTextSharp → `5.5.13.5`, itext → `9.6.0`
- McMaster.Extensions.CommandLineUtils → `5.1.0`
- System.Drawing.Common → `10.0.9`

### SharpCompress 0.49 breaking API migration (`iMGcompress-core`)
- `ReaderFactory.Open` → `OpenReader(stream, new ReaderOptions())`
- `RarArchive/ZipArchive.Open` → `OpenArchive(filename, new ReaderOptions())`
- `ZipArchive.Create()` → `CreateArchive()`
- `SaveTo(path, CompressionType)` → `SaveTo(path, new ZipWriterOptions(CompressionType))`
- Return type `ZipArchive` → `IWritableArchive<ZipWriterOptions>`
- Removed `using ZstdSharp` (internalized in 0.49)

### Parallel within-archive compression (`iMGcompress-core`, `-P` flag)
- New `ProcessArchivePAR2` + `CompressEntrySync` in `Compressor.cs`
- Batched 3-phase design: sequential read → `Parallel.For` (`ProcessorCount/2` threads) → sequential write
- Ordering guaranteed by indexed pre-allocated result slots
- Measured speedup: **~3.4–5×** vs serial on i7-12700KF (10 batch size)
- Memory bounded per batch; logs strictly in original entry order from write phase

### MemoryStream pre-sizing (`iMGcompress-core`)
- All `new MemoryStream()` → `new MemoryStream(entry.Size > 0 ? (int)entry.Size : 4096)`
- Eliminates buffer-doubling reallocations on all 9 allocation sites in `Compressor.cs`

### CLI fixes and new flags (`ComicCompress`)
- Fixed missing `OnExecuteAsync` — app was throwing `InvalidOperationException` on launch
- Added `-w|--new-webp`: use Imageflow encoder (experimental; benchmarked 8–15% slower than Imazen.WebP)
- Added `-P|--par-archive`: enable parallel within-archive compression

### GUI (`iMGcompress`)
- Added `checkBox_parArchive` (flat-button, location `382,231`, TabIndex 14)
- Default ON for COMIX and COMIX+PDF modes; OFF for IMAGE and ZEBRA
- Wired into `FileProcessor.ProcessorFlags` constructor
- Version bumped to `2.0.0 (28/06/2026)`

### Other
- Added `CLAUDE.md` to `comic-compress-new` with build commands and architecture notes

## Current versions

- CLI (`ComicCompress`): `3.1.0 (28/06/2026)` — see `Program.cs`
- GUI (`iMGcompress`): `2.0.0 (28/06/2026)` — see `MGCompress.cs`

## Known state / open items

- **Imageflow encoder** (`-w` flag) is wired and working but consistently slower than Imazen.WebP across all tested archive sizes. Kept as an experimental path only.
- **`libwebp.dll`** must be present alongside the executable — it is checked into the repo root of both `comic-compress-new` and `iMGcompress-core`.
- The GUI runs single-threaded on the UI thread (`button_start_Click` is synchronous). Long jobs block the window. Not addressed in this session.