CTagger

CTagger is a desktop application for annotating neuroimaging experiment events using the Hierarchical Event Descriptor (HED) standard. It provides a graphical interface with automatic tag suggestions, validation, and HED schema browsing capabilities.

About HED

The Hierarchical Event Descriptor (HED) is a standard for describing experiment events in neuroimaging data. HED enables detailed, human-readable, and machine-actionable annotation of events, making shared data analysis-ready. Learn more at hedtags.org.

Documentation

For detailed usage instructions and tutorials, see the CTagger User Guide.

Download

Download the latest pre-built release from the Releases page.

Usage

CTagger can be used in two ways:

Standalone Application

Run the downloaded JAR file:

java -jar CTagger.jar

Requirements: Java Runtime Environment (JRE) 8 or higher

EEGLAB Plugin

CTagger is integrated into EEGLAB through the HEDTools plugin.

Building from Source

Prerequisites

• Java JDK 8 or higher (tested with JDK 21)
• Gradle 8.5+ (wrapper included)

Build Instructions

1. Clone the repository:

   git clone https://github.com/hed-standard/ctagger.git
   cd ctagger

2. Build the JAR:

   ./gradlew jar

   On Windows:

   gradlew.bat jar

3. The compiled JAR will be located at:

   build/libs/CTagger.jar
   

Running Locally

After building, run the application:

java -jar build/libs/CTagger.jar

Development

Project Structure

• src/main/kotlin/ - Kotlin source files
• src/main/java/ - Java source files
• build.gradle - Gradle build configuration
• gradle/ - Gradle wrapper files

Technology Stack

• Language: Kotlin 1.9.25 + Java
• Build System: Gradle 8.5
• GUI Framework: Java Swing
• Dependencies:
  • Gson 2.10.1 (JSON parsing)
  • Jsoup 1.17.2 (HTML parsing)
  • Fuel 2.3.0 (HTTP client)
  • kotlinx-coroutines 1.5.1 (async operations)
  • univocity-parsers 2.9.0 (CSV/TSV parsing)

Building for Development

Clean and build with full output:

./gradlew clean build

Run tests:

./gradlew test

HED Validation

CTagger validates annotations against HED schemas using the HED validation service. The default schema version is 8.4.0, but other versions can be selected from the application menu.

Contributing

Bug reports and feature requests can be submitted through GitHub Issues.

License

MIT Licence

Support

• User guide: https://www.hedtags.org/hed-resources/CTaggerGuide.html
• HED homepage: https://www.hedtags.org
• Issues: GitHub Issues