BL831 Crystal Centering UI

Touchscreen interface for video-based crystal centering at the BL831 beamline (Advanced Light Source, Lawrence Berkeley National Laboratory). Displays a live camera feed with beam overlay and provides controls for goniometer rotation, centering, zoom, pin selection, and light adjustment.

Video is captured via FFmpeg (Axis IP cameras or V4L2 devices). Button presses are translated to DCSS commands through a touch server.

Install

Download the latest release zip from the releases page and unzip:

unzip crystmntui-*-distribution.zip -d /opt/crystmntui

This gives you:

/opt/crystmntui/
  bin/crystmntui        # launcher script
  lib/crystmntui-*-bundled.jar
  examples/             # theme configs and assets

Add bin/ to your PATH or run directly: /opt/crystmntui/bin/crystmntui

Requires JRE 11+.

Build from Source

Requires JDK 11+ and Maven 3.6+.

mvn package

The bundled jar is written to target/.

Usage

crystmntui \
  -v axis://host/axis-cgi/mjpg/video.cgi?camera=1 \
  -t touch://hostname:14000

Or launch directly with Java:

java -jar crystmntui-*-bundled.jar \
  -v axis://host/axis-cgi/mjpg/video.cgi?camera=1 \
  -t touch://hostname:14000

Options

Flag	Description
-v, --video	Video source URI (axis:// or v4l2://)
-t, --touch	Touch server URI (touch://hostname:port)
-c, --config	Path to config file
-w, --window	Window size (1920x1080) or full. Default: full (undecorated kiosk mode)
-i, --interpolation	Image scaling: nearest, bilinear, or bicubic
-e, --emulate	Emulate old-style touch coordinates
-l, --list-v4l2	List available V4L2 video capture URIs

V4L2 example

crystmntui -v v4l2://video0/MJPG/640x480/30fps -t touch://localhost:14000

Config Files

A .config file is a Java properties file that controls theming and button overrides. Pass it with -c.

CLI defaults

Config files can set defaults for CLI options using cli.<long-flag-name>. Command line flags override these.

cli.video=axis://host/axis-cgi/mjpg/video.cgi?camera=1
cli.touch=touch://hostname:14000
cli.window=1920x1080
cli.emulate=false
cli.interpolation=bilinear

UI properties

ui.background=#000810
ui.border-color=#00e5ff
ui.borderless-buttons=true

Button overrides

Each button can have a custom icon, pressed icon, command, or be hidden:

button.ZoomIn.icon=ZoomIn.png
button.ZoomIn.pressed=ZoomIn-pressed.png
button.ZoomIn.command=some_touch_command
button.ZoomIn.hidden=true

Icon paths are resolved relative to the config file's directory. Available button names: ZoomIn, ZoomOut, Plus10, Plus90, HalfTurn, Minus90, Minus10, Undo, Park, UnPark, Polarizer, Light, Pin24mm..Pin10mm, MoveUp, MoveDown, MoveLeft, MoveRight, MoveIn, MoveOut, Center.

The Light button acts as a vertical slider. The Center button maps to clicks on the video area.

Themes

Two example themes are included under examples/:

• dark-neon — Cyan neon glow on dark background
• arc-reactor — Brushed metal with stamped beveled buttons

Each theme directory contains a config file, button PNGs (normal and -pressed variants), and the HTML design file used to generate the assets.

crystmntui \
  -v axis://host/axis-cgi/mjpg/video.cgi?camera=1 \
  -t touch://hostname:14000 \
  -c examples/arc-reactor/arc-reactor.config

Hardware

Linux only. V4L2 device access requires the camerainfo library (included).

• Axis IP cameras — MJPEG streams via axis://host/path?camera=N
• V4L2 devices — Local capture via v4l2://deviceN/FORMAT/WxH/FPS. Use -l to list available devices. Tested with USB HDMI capture cards.
• Touchscreen — Any display; touch events are translated to DCSS commands via the touch server