calibre-plugins/crosspoint_reader/README.md

CrossPoint Reader Calibre Plugin

This plugin adds CrossPoint Reader as a wireless device in Calibre. It uploads EPUB files over WebSocket to the CrossPoint web server.

Protocol:

• Connect to ws://:/
• Send: START:::
• Wait for READY
• Send binary frames with file content
• Wait for DONE (or ERROR:)

Default settings:

• Auto-discover device via UDP
• Host fallback: 192.168.4.1
• Port: 81
• Upload path: /

Optimizer

The plugin can optimize EPUBs before transfer, mirroring the optimizer built into the CrossPoint web server. When enabled (Preferences > Plugins > device config > "Optimize EPUBs before transfer"), each EPUB is processed before upload:

• Every image is scaled to fit the device screen, converted to grayscale, and re-encoded as JPEG (quality configurable, default 85). Optional auto-crop trims uniform page margins.
• The container is rewritten: raster images are renamed to .jpg, stale <img> width/height are stripped, SVG covers/wrapped images are unwrapped, OPF media-types and cover meta are fixed, the NCX identifier is synced, a small defensive stylesheet is injected, and the archive is re-zipped mimetype-first.

The target screen size comes from the device profile — X4 = 480×800, X3 = 528×792 — which is auto-detected from the device's /api/status endpoint on connect (matching the web UI), or can be set manually (Auto / X4 / X3) in the plugin settings.

When a transfer starts, a live dialog opens and streams the optimization steps as they happen (per book: each image's before→after size, fixes, and upload), then finishes with the totals. When several books are sent at once they are processed in turn in the same dialog, which ends with combined totals. If optimization fails for a book, the original is sent unchanged so a transfer is never blocked.

Using the optimizer

1. Open Preferences → Plugins, expand Device Interface plugins, select CrossPoint Reader, and click Customize plugin.
2. Check Optimize EPUBs before transfer.
3. Set the options below it (they enable once the box is checked):
   • Device target — leave on Auto-detect to read X3/X4 from the device on connect, or force X4 / X3. Auto-detect falls back to X4 if the device can't be queried.
   • JPEG quality — 1–100 (default 85). Lower = smaller files.
   • Convert images to grayscale — on by default (recommended for e-ink).
   • Auto-crop uniform margins — off by default; trims solid page borders.
4. Click OK, then restart Calibre if it was already running so the new settings take effect.
5. Send a book to the device as usual (right-click → Send to device, or the Send to device toolbar button). The EPUB is optimized just before upload.
6. As the transfer runs, a live dialog opens and streams each step — per book, the images processed/cropped and fixes applied — and ends with the combined totals (and a Close button). Selecting multiple books processes them one after another in the same dialog. The same steps are also written to the plugin Log (visible in the config dialog when Enable debug logging is on).

To turn the feature off, uncheck Optimize EPUBs before transfer — books are then sent exactly as Calibre exports them.

Install:

1. Download the latest release from the releases page (or zip the contents of this directory).
2. In Calibre: Preferences > Plugins > Load plugin from file.
3. The device should appear in Calibre once it is discoverable on the network.

No configuration needed. The plugin auto-discovers the device via UDP and falls back to 192.168.4.1:81.