StaxPrint

A native macOS app that prints your photos to a Fujifilm Instax® SHARE SP-2 over Wi-Fi. It's written in Swift with SwiftUI, Core Image and Metal, so the preview stays smooth while you move, zoom, tilt and colour-correct a photo.

• Printer Wi-Fi. Joins the printer's INSTAX-xxxxxxxx network and switches back to your usual Wi-Fi afterwards. A light shows whether the printer is reachable.
• Printer status. Shows the model, firmware, battery, prints left in the pack ("6 / 10") and lifetime prints.
• Photo. Opens or takes a dropped JPEG, PNG, HEIC, TIFF and more.
  • Colours are converted to sRGB, and iPhone HDR photos (Display P3 / PQ) are tone-mapped so they don't come out washed out.
  • Fill (crop) or Fit (white border), plus 90° rotate.
  • Trackpad: two-finger scroll moves, pinch zooms, two-finger rotate tilts. Mouse: drag moves, ⌘-scroll zooms. Double-click resets.
  • Brightness, contrast, saturation and tilt sliders, all live on the GPU.
• Print. Renders exactly what the preview shows at 600×800, asks before using a print, then shows progress.

Build and run

Needs macOS 14+ and Xcode 15+ (or the Swift 5.10+ toolchain).

swift run StaxPrint                                  # run from source
./scripts/make-app.sh && open build/StaxPrint.app    # build a release .app (ad-hoc signed)

If macOS blocks Wi-Fi switching or local-network access, start it from Terminal.app.

Using it

1. Turn the SP-2 on, type its network name (printed on the printer, e.g. INSTAX-12345678) and press Join printer Wi-Fi. While you're joined, your Mac has no internet over Wi-Fi, because the printer's network is a direct link.
2. Enter the PIN (factory default 1111) and press Connect.
3. Open a photo, frame it, and press Print photo.
4. Press Back to my Wi-Fi when you're done. The printer also turns itself off after a few idle minutes.

The log is also written to ~/Library/Logs/StaxPrint.log.

Command-line tool

swift run instax-tool status                         # printer status (uses no film)
swift run instax-tool render photo.heic out.png mode=fit tilt=5   # save the exact 600x800 print as PNG
swift run instax-tool fake-server 18080              # a fake SP-2 on 127.0.0.1 that saves what it receives
INSTAX_HOST=127.0.0.1 INSTAX_PORT=18080 swift run StaxPrint     # point the app at the fake printer
swift run -c release instax-tool bench photo.heic    # preview frame timing

Tests

swift test                     # packets, image layout, rendering, full print sequence against the fake printer
python3 Tests/crosscheck.py    # byte-for-byte check against the Python reference (needs Pillow)

How it works

The SP-2 is a TCP server at 192.168.0.251:8080 on its own Wi-Fi network. Each command is a big-endian packet: 24 type len16 session32 pin16 00 00 payload ~sum16 0D 0A. A picture is sent as 600×800 RGB, turned to landscape and written column by column, with each column as 600 red, then 600 green, then 600 blue bytes. That's 1,440,000 bytes in 24 segments of 60,000.

Path	What's there
Sources/InstaxKit	Protocol.swift (packets and replies), ImageLayout.swift, TCPSocket.swift, SP2Client.swift (status and print sequence), PhotoRenderer.swift (load, colour-manage, compose, render)
Sources/StaxPrint	The SwiftUI app; PreviewView.swift is the Metal preview and handles the gestures
Sources/InstaxFake	Fake SP-2 server for tests
Sources/instax-tool	Command-line tool
assets/	Logo and app icon; regenerate them with swift scripts/make-logo.swift

Credits

The protocol comes from jpwsutton/instax_api (MIT License, © 2016 James Sutton). StaxPrint is released under the MIT License.

"Instax" and "SHARE SP-2" are trademarks of FUJIFILM. They're used here only to describe compatibility. StaxPrint isn't affiliated with or endorsed by FUJIFILM.