Developing ImageJ2 Plugins

<!DOCTYPE html> <html> <head> <title>Developing ImageJ2 Plugins</title> <meta charset="utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=3" /> <meta content="ImageJ Wiki" property="og:site_name"> <meta content="Developing ImageJ2 Plugins" property="og:title"> <meta content="article" property="og:type"> <meta content="The ImageJ wiki is a community-edited knowledge base on topics relating to ImageJ, a public domain program for processing and analyzing scientific images, and its ecosystem of derivatives and variants, including ImageJ2, Fiji, and others." property="og:description"> <meta content="https://imagej.github.io/develop/plugins" property="og:url"> <meta content="https://imagej.github.io/media/icons/imagej2.png" property="og:image"> <link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png"> <link rel="manifest" href="/site.webmanifest"> <link rel="mask-icon" href="/safari-pinned-tab.svg" color="#5bbad5"> <meta name="msapplication-TileColor" content="#da532c"> <meta name="theme-color" content="#ffffff"> <link rel="stylesheet" href="/assets/css/lightbox.min.css" /> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/instantsearch.css@7/themes/algolia-min.css"/> <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/dygraphs@2.1.0/dist/dygraph.min.js"></script> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/dygraphs@2.1.0/dist/dygraph.min.css" /> <link rel="stylesheet" href="/assets/css/main.css" /> <link rel="stylesheet" href="/assets/css/layout.css"/> <link rel="stylesheet" href="/assets/css/includes.css" /> <link rel="stylesheet" href="/assets/css/dock.css"/> <noscript><link rel="stylesheet" href="/assets/css/noscript.css" /></noscript> <link rel="stylesheet" href="/assets/css/page.css" /> </head> <body class="is-preload">  <section id="top-bar"> <a href="/"><img id="site-logo" src="/media/icons/imagej2.png"></a> <div id="search-panel"> <div id="search-box"></div> </div> </section>  <div class="page-info"> <a href="https://github.com/imagej/imagej.github.io/commits/main/_pages/develop/plugins.md">Page history</a> <a href="https://github.com/imagej/imagej.github.io/edit/main/_pages/develop/plugins.md">Edit this page</a> <a href="/editing">How do I edit this website?</a></div> <section id="left-column" class="sidebar dock">  <div class="menu dockable"> <div class="drag-handle"></div><h3>ImageJ Docs</h3> <ul> <li><a href="/downloads">Download</a></li> <li><details><summary>Learn</summary><ul> <li><details><summary><a href="/learn">ImageJ Basics</a></summary><ul> <li><a href="/tutorials">Tutorials</a></li> <li><a href="/learn/user-guides">User Guides</a></li> <li><a href="/learn/keyboard-shortcuts">Keyboard Shortcuts</a></li> <li><a href="/learn/tips-and-tricks">Tips and Tricks</a></li> <li><a href="/learn/troubleshooting">Troubleshooting</a></li> <li><a href="/learn/faq">Frequently Asked Questions</a></li> <li><details><summary><a href="/platforms">Supported Platforms</a></summary><ul> <li><a href="/platforms/windows">Windows</a></li> <li><a href="/platforms/macos">MacOS</a></li> <li><a href="/platforms/linux">Linux</a></li> <li><a href="/platforms/pi">Raspberry Pi</a></li> <li><a href="/platforms/android">Android</a></li> </ul></details></li>  <li><details><summary><a href="/formats">File Formats</a></summary><ul> <li><a href="/formats/bio-formats">Bio-Formats</a></li> <li><a href="/formats/video">Video formats</a></li> <li><a href="/formats/quicktime">QuickTime</a></li> <li><a href="/formats/tiff">TIFF</a></li> <li><a href="/formats/pdf">PDF</a></li> <li><a href="/formats/dicom">DICOM</a></li> <li><a href="/formats/lsm">Zeiss LSM</a></li> <li><a href="/formats/olympus">Olympus VSI</a></li> <li><a href="/formats/lurawave">Opera Flex</a></li> <li><a href="/formats/fib-sem">FIB-SEM</a></li> </ul></details></li>  </ul></details></li>  <li><details><summary><a href="/imaging">Scientific Imaging</a></summary><ul> <li><a href="/imaging/principles">Principles of Scientific Imaging</a></li> <li><a href="/imaging/annotating-images">Annotating Images</a></li> <li><a href="/imaging/colocalization-analysis">Colocalization</a></li> <li><a href="/imaging/color-image-processing">Color Image Processing</a></li> <li><a href="/imaging/deconvolution">Deconvolution</a></li> <li><a href="/imaging/image-intensity-processing">Image Intensity Processing</a></li> <li><a href="/imaging/particle-analysis">Particle Analysis</a></li> <li><a href="/imaging/registration">Registration</a></li> <li><a href="/imaging/segmentation">Segmentation</a></li> <li><a href="/imaging/stack-slice-manipulations">Stack-slice Manipulations</a></li> <li><a href="/imaging/t-functions">T-functions</a></li> <li><a href="/imaging/tracking">Tracking</a></li> <li><a href="/imaging/visualization">Visualization</a></li> <li><a href="/imaging/z-functions">Z-functions</a></li> </ul></details></li>  </ul></details></li>  <li><details open><summary><a href="/plugins">Extend</a></summary><ul> <li><a href="/list-of-extensions">List of Extensions</a></li> <li><details><summary><a href="/update-sites">Update Sites</a></summary><ul> <li><a href="/list-of-update-sites">List of Update Sites</a></li> <li><a href="/update-sites/following">Following an Update Site</a></li> <li><a href="/update-sites/setup">Creating an Update Site</a></li> <li><a href="/update-sites/tos">Terms of Service</a></li> <li><a href="/update-sites/automatic-uploads">Automatic Upload</a></li> <li><a href="/update-sites/core-uploads">Uploading to Core Sites</a></li> <li><a href="/update-sites/faq">Update Sites FAQ</a></li> <li><a href="/update-sites/stats">Statistics</a></li> </ul></details></li>  <li><details><summary><a href="/scripting">Scripting</a></summary><ul> <li><a href="/scripting/basics">Scripting Basics</a></li> <li><a href="/scripting/script-editor">Script Editor</a></li> <li><a href="/scripting/parameters">Parameters</a></li> <li><a href="/scripting/user-input">User Input</a></li> <li><a href="/scripting/auto-imports">Auto Import</a></li> <li><a href="/scripting/templates">Templates</a></li> <li><a href="/scripting/batch">Batch Processing</a></li> <li><a href="/scripting/headless">Running Headlessly</a></li> <li><a href="/scripting/comparisons">Scripting Comparisons</a></li> <li><a href="/scripting/toolbox">Toolbox</a></li> <li><details><summary>Languages</summary><ul> <li><a href="/scripting/beanshell">BeanShell Scripting</a></li> <li><a href="/scripting/groovy">Groovy Scripting</a></li> <li><a href="/scripting/macro">ImageJ Macro</a></li> <li><a href="/scripting/javascript">JavaScript</a></li> <li><a href="/scripting/clojure">Lisp (Clojure)</a></li> <li><a href="/scripting/matlab">MATLAB</a></li> <li><a href="/scripting/jython">Python (Jython)</a></li> <li><a href="/scripting/python">Python (native)</a></li> <li><a href="/scripting/renjin">R (Renjin)</a></li> <li><a href="/scripting/jruby">Ruby (JRuby)</a></li> <li><a href="/scripting/scala">Scala Scripting</a></li> </ul></details></li>  </ul></details></li>  <li><details open><summary><a href="/develop">Development</a></summary><ul> <li><a href="/develop/philosophy">Philosophy</a></li> <li><a href="/develop/architecture">Architecture</a></li> <li><a href="/develop/source">Source code</a></li> <li><a href="/develop/project-management">Project management</a></li> <li><a href="/develop/coding-style">Coding style</a></li> <li><a href="/develop/javadoc">Using Javadoc</a></li> <li><a href="/develop/debugging">Debugging</a></li> <li><a href="/develop/wish-list">Wish list</a></li> <li><details><summary>Tools</summary><ul> <li><a href="/develop/github">GitHub</a></li> <li><a href="/develop/maven">Maven</a></li> <li><a href="/develop/ci">CI/CD</a></li> <li><a href="/develop/dotfiles">Dotfiles</a></li> <li><details><summary><a href="/develop/ides">IDEs</a></summary><ul> <li><a href="/develop/eclipse">Eclipse</a></li> <li><a href="/develop/netbeans">NetBeans</a></li> <li><a href="/develop/intellij">IntelliJ IDEA</a></li> <li><a href="/develop/command-line">Command Line</a></li> </ul></details></li> </ul></details></li>  <li><details open><summary>Guides</summary><ul> <li><a class="current-page">Writing plugins</a></li> <li><a href="/develop/improving-the-code">Contributing to a plugin</a></li> <li><a href="/develop/releasing">Development lifecycle</a></li> <li><a href="/develop/building-a-pom">Building a POM</a></li> <li><a href="/develop/debugging-exercises">Hands-on debugging</a></li> <li><a href="/develop/writing-ops">Adding new ops</a></li> <li><a href="/develop/formats">Adding new formats</a></li> <li><a href="/develop/native-libraries">Using native libraries</a></li> <li><a href="/develop/tips">Tips for developers</a></li> <li><a href="/develop/cpp-tips">Tips for C++ developers</a></li> <li><a href="/develop/ij1-plugins">ImageJ 1.x plugins</a></li> <li><a href="/develop/versioning">Versioning</a></li> <li><a href="/develop/logging">Logging</a></li> <li><a href="/develop/uber-jars">Uber-JARs</a></li> </ul></details></li>  <li><details><summary><a href="/develop/git">Git</a></summary><ul> <li><a href="/develop/git/eclipse">Git in Eclipse (EGit)</a></li> <li><a href="/develop/git/mini-howto">Git mini howto</a></li> <li><a href="/develop/git/workshop">Git workshop</a></li> <li><a href="/develop/git/conflicts">Git conflicts</a></li> <li><a href="/develop/git/topic-branches">Git topic branches</a></li> <li><a href="/develop/git/notes">Git notes</a></li> <li><a href="/develop/git/reflogs">Git reflogs</a></li> <li><a href="/develop/git/submodules">Git submodules</a></li> <li><a href="/develop/git/pinpoint-regressions">How to pinpoint regressions</a></li> <li><a href="/develop/git/publish-a-repository">How to publish a git repository</a></li> <li><a href="/develop/git/extract-a-subproject">How to extract a subproject</a></li> </ul></details></li>  </ul></details></li>  </ul></details></li>  <li><details><summary><a href="/contribute">Contribute</a></summary><ul> <li><a href="/contribute/citing">Citing</a></li> <li><a href="/people">Contributors</a></li> <li><a href="/orgs">Organizations</a></li> <li><a href="/contribute/governance">Governance</a></li> <li><a href="/contribute/funding">Funding</a></li> <li><a href="/contribute/fiji">Contributing to Fiji</a></li> <li><details><summary><a href="/licensing">Licensing</a></summary><ul> <li><details><summary><a href="/licensing/open-source">Open Source</a></summary><ul> <li><a href="/licensing/apache">Apache</a></li> <li><a href="/licensing/bsd">BSD</a></li> <li><a href="/licensing/epl">EPL</a></li> <li><a href="/licensing/gpl">GPL</a></li> <li><a href="/licensing/lgpl">LGPL</a></li> <li><a href="/licensing/mit">MIT</a></li> <li><a href="/licensing/public-domain">Public domain</a></li> <li><a href="/licensing/big">BIG</a></li> </ul></details></li>  <li><a href="/licensing/closed-source">Proprietary</a></li> </ul></details></li>  <li><details><summary><a href="/editing">Editing the Wiki</a></summary><ul> <li><a href="/editing/advanced">Advanced Editing</a></li> <li><a href="/editing/buttons">Buttons</a></li> <li><a href="/editing/citations">Citations</a></li> <li><a href="/editing/code">Source Code</a></li> <li><a href="/editing/debugging">Debugging</a></li> <li><a href="/editing/headers">Headers</a></li> <li><a href="/editing/icons">Icons</a></li> <li><a href="/editing/images">Images</a></li> <li><a href="/editing/keys">Keyboard Shortcuts</a></li> <li><a href="/editing/linking">Linking</a></li> <li><a href="/editing/math">Math Expressions</a></li> <li><a href="/editing/menu-paths">Menu Paths</a></li> <li><a href="/editing/navigation">Navigation</a></li> <li><a href="/editing/notices">Notices</a></li> <li><a href="/editing/people">People</a></li> <li><a href="/editing/pitfalls">Pitfalls</a></li> <li><a href="/editing/quizzes">Quizzes</a></li> <li><a href="/editing/statbox">Statbox</a></li> <li><a href="/editing/symbols">Symbols</a></li> <li><a href="/editing/tables">Tables</a></li> <li><a href="/editing/tooltips">Tooltips</a></li> <li><a href="/editing/videos">Videos</a></li> <li><a href="/editing/whitespace">Whitespace</a></li> </ul></details></li>  </ul></details></li>  <li><details><summary><a href="/discuss">Discuss</a></summary><ul> <li><a href="/discuss/bugs">Reporting Issues</a></li> <li><a href="/discuss/mailing-lists">Mailing Lists</a></li> <li><a href="/discuss/chat">Chat</a></li> </ul></details></li>  <li><details><summary>Explore</summary><ul> <li><a href="/news">News</a></li> <li><details><summary><a href="/events">Events</a></summary><ul> <li><a href="/events/presentations">Presentations</a></li> <li><a href="/events/conferences">Conferences</a></li> <li><a href="/events/hackathons">Hackathons</a></li> <li><a href="/events">More...</a></li> </ul></details></li>  <li><details><summary><a href="/libs">Libraries</a></summary><ul> <li><a href="/libs/imagej-ops">ImageJ Ops</a></li> <li><a href="/libs/imagej-common">ImageJ Common</a></li> <li><a href="/libs/imagej-legacy">ImageJ Legacy</a></li> <li><a href="/libs/scijava">SciJava</a></li> <li><a href="/libs/scifio">SCIFIO</a></li> <li><details><summary><a href="/libs/imglib2">ImgLib2</a></summary><ul> <li><a href="/libs/imglib2/getting-started">Getting Started</a></li> <li><a href="/libs/imglib2/accessors">Accessors</a></li> <li><a href="/libs/imglib2/accessibles">Accessibles</a></li> <li><a href="/libs/imglib2/examples">Examples</a></li> <li><a href="/libs/imglib2/workshop-introductory">Introductory Workshop</a></li> <li><a href="/libs/imglib2/workshop-advanced">Advanced Workshop</a></li> <li><a href="/libs/imglib2/matlab">ImgLib2 images in MATLAB</a></li> <li><a href="/libs/imglib2/benchmarks">Benchmarks</a></li> <li><a href="/libs/imglib2/faq">FAQ</a></li> <li><a href="/libs/imglib2/developing">Developing ImgLib2</a></li> <li><a href="/libs/imglib2/discussion">ImgLib2 Discussion</a></li> </ul></details></li>  <li><a href="/libs">More...</a></li> </ul></details></li>  <li><details><summary><a href="/software">Software</a></summary><ul> <li><a href="/software/nih-image">NIH Image</a></li> <li><a href="/software/imagej">ImageJ</a></li> <li><a href="/software/imagej2">ImageJ2</a></li> <li><a href="/software/fiji">Fiji</a></li> <li><a href="/software">More...</a></li> </ul></details></li>  </ul></details></li>  </ul> </div> </section> <section id="right-column" class="sidebar dock">   <div id="toc" class="toc menu dockable"> <div class="drag-handle"></div> <h3>Page contents</h3> <ul data-toc="#content" data-toc-headings="h1,h2,h3,h4,h5,h6"></ul> </div> </section>  <div class="container"> <header class="major special"> <a class="project-icon shadowed-box" href="/software/imagej2"><span class="tooltip"><img src="/media/icons/imagej2.png"><span class="tooltiptext" style="top: 80%; left: 25%; width: 20em">This page describes content relating to the ImageJ2 platform. Click the logo for details.</span></span></a> <h1>Developing ImageJ2 Plugins</h1> <span class="project-counterweight"> </span> </header> </div>   <section id="page" class="main style1"> <div class="container"> <div class="box alt"></div> <div id="content" class="page-content"> <div class="notice" style="font-size: 2; background: #ebf2f8; border-left: 10px solid #67a1fe"><div class="notice-icon"><img src="/media/icons/info.svg" width="32" /></div><div class="notice-content"><p>This guide provides a technical overview of <a href="/plugins">plugins</a>, including how to <strong>create new plugins</strong>.</p> <p>If you are interested in developing an <strong>existing</strong> plugin instead, see <a href="/develop/improving-the-code">Contributing to a plugin</a>.</p> <p>If you have completed a plugin that you would like to <strong>share with the community</strong>, see <a href="/contribute/distributing">Distributing your plugins</a>.</p> <p>If you are new to Java development, see the <a href="/develop/beginners-guide">beginner’s guide to starting a Fiji project</a>.</p> <p>For instructions on plugin development for the original <a href="/software/imagej">ImageJ</a>, see <a href="/develop/ij1-plugins">Developing Plugins for ImageJ</a>.</p> </div> </div> <h2 id="requirements">Requirements</h2> <p>As ImageJ2 is built using the <a href="/develop/project-management">SciJava principles of project management</a>, this guide assumes a basic familiarity with these topics and tools, especially:</p> <table> <thead> <tr> <th> </th> <th> </th> </tr> </thead> <tbody> <tr> <td><a href="/develop/git"><img src="/media/icons/git.png" width="64px" /></a></td> <td><a href="/develop/maven"><img src="/media/icons/maven.png" width="64px" /></a></td> </tr> <tr> <td><a href="/develop/git">Git</a></td> <td><a href="/develop/maven">Maven</a></td> </tr> </tbody> </table> <p>Additionally, at a minimum, you should clone the <a href="https://github.com/imagej/tutorials/">imagej/tutorials repository</a>. This will give you a local copy of the tutorials discussed in this guide, as well as templates for use in your own development.</p> <p>For the complete “developer experience”, you can go through the <a href="https://help.github.com/categories/bootcamp/">GitHub Bootcamp</a>. At the least, once you’ve <a href="https://help.github.com/articles/create-a-repo/">created your own repository</a> and cloned a local copy, you will have a home ready for when your <a href="#starting-your-own-plugin">very own plugin</a> arrives!</p> <h2 id="what-is-a-plugin">What is a “plugin”?</h2> <p>Conceptually, a <strong>plugin</strong> is a new piece of functionality added to ImageJ. Nearly all aspects of ImageJ are <em>pluggable</em>, meaning plugins can be provided <em>ad hoc</em> to perform specified functions. The ImageJ core needs only know what general operations are available; then when the program is running, the options for how to complete a requested operation will be determined by which plugins are available at that time.</p> <p>Technically, ImageJ is built on the <a href="/libs/scijava#scijava-common">SciJava Common</a> plugin framework. Within this framework, a plugin is a Java class <a href="https://docs.oracle.com/javase/tutorial/java/annotations/index.html">annotated</a> with the <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/plugin/Plugin.java">@Plugin</a> annotation. Classes annotated in this way are then automatically discovered and indexed at <a href="https://en.wikipedia.org/wiki/Run_time_(program_lifecycle_phase)">“runtime”</a>, when the application is launched by a user (as opposed to <a href="https://en.wikipedia.org/wiki/Compile_time">“compile-time”</a>).</p> <h3 id="plugin-types">Plugin types</h3> <p>There is no limit to how many plugins can be discovered at runtime. To allow efficient retrieval of plugins, each class is annotated with a specific <strong>type</strong> - typically a <a href="https://docs.oracle.com/javase/tutorial/java/concepts/interface.html">Java interface</a> - by which the plugin will be indexed. This indexing follows Java type hierarchies.</p> <p>For example, given the following plugins:</p> <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Plugin</span><span class="o">(</span><span class="n">type</span><span class="o">=</span><span class="nc">Service</span><span class="o">.</span><span class="na">class</span><span class="o">)</span> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">MyService</span> <span class="kd">implements</span> <span class="nc">Service</span> <span class="o">{</span> <span class="o">}</span> <span class="nd">@Plugin</span><span class="o">(</span><span class="n">type</span><span class="o">=</span><span class="nc">SpecialService</span><span class="o">.</span><span class="na">class</span><span class="o">)</span> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">SpecialService</span> <span class="kd">implements</span> <span class="nc">Service</span> <span class="o">{</span> <span class="o">}</span> </code></pre></div></div> <details class="shadowed-box"> <summary><span><strong>Quiz!</strong> Which of these plugins would we expect back if asking the <a href="/develop/plugins#the-context">Context</a> for plugins of type <code class="language-plaintext highlighter-rouge">Service</code> plugin?</span></summary> <span><strong>Answer:</strong> It would give back both the <code class="language-plaintext highlighter-rouge">MyService</code> and <code class="language-plaintext highlighter-rouge">SpecialService</code> plugins, since <code class="language-plaintext highlighter-rouge">SpecialService</code> is a subclass of <code class="language-plaintext highlighter-rouge">Service</code>.</span> </details> <details class="shadowed-box"> <summary><span><strong>Quiz!</strong> What if we asked for plugins of type <code class="language-plaintext highlighter-rouge">SpecialService</code>?</span></summary> <span><strong>Answer:</strong> It would just return the <code class="language-plaintext highlighter-rouge">SpecialService</code> plugin, since <code class="language-plaintext highlighter-rouge">MyService</code> is <strong>not</strong> a <code class="language-plaintext highlighter-rouge">SpecialService</code>.</span> </details> <h3 id="plugin-priority">Plugin priority</h3> <p>When plugins are retrieved from a <a href="/develop/plugins#the-context">Context</a> it’s possible to get more than one match. In these cases, the plugin classes are returned in order of the <strong>priority</strong> of the class’s <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/plugin/Plugin.java#L108-L129">@Plugin annotation</a>. Priorities are simply double values; as a starting point, priority constants can be used from the <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/Priority.java">Priority</a> class.</p> <p>For example, given the following plugins:</p> <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Plugin</span><span class="o">(</span><span class="n">priority</span><span class="o">=</span><span class="nc">Priority</span><span class="o">.</span><span class="na">HIGH</span><span class="o">)</span> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">MyService</span> <span class="kd">implements</span> <span class="nc">Service</span> <span class="o">{</span> <span class="o">}</span> <span class="nd">@Plugin</span><span class="o">(</span><span class="n">priority</span><span class="o">=</span><span class="mi">224</span><span class="o">)</span> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">SpecialService</span> <span class="kd">implements</span> <span class="nc">Service</span> <span class="o">{</span> <span class="o">}</span> </code></pre></div></div> <details class="shadowed-box"> <summary><span><strong>Quiz!</strong> Which plugin would be returned first if we asked the Context for a <code class="language-plaintext highlighter-rouge">Service</code> plugin?</span></summary> <span><strong>Answer:</strong> The <code class="language-plaintext highlighter-rouge">SpecialService</code> plugin would come back first. If we look at the <code class="language-plaintext highlighter-rouge">Priority</code> class we see that <code class="language-plaintext highlighter-rouge">HIGH</code> simply <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/Priority.java#L54-L55">resolves to 100</a>.</span> </details> <p>We can also use <em>relative priorities</em> when referring to particular priority constants. This is a nice way to give the best chance that sorting will remain the same even if these constants change in the future:</p> <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Plugin</span><span class="o">(</span><span class="n">priority</span><span class="o">=</span><span class="nc">Priority</span><span class="o">.</span><span class="na">HIGH</span><span class="o">+</span><span class="mi">124</span><span class="o">)</span> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">SpecialService</span> <span class="kd">implements</span> <span class="nc">Service</span> <span class="o">{</span> <span class="o">}</span> </code></pre></div></div> <h2 id="what-makes-up-the-scijava-plugin-framework">What makes up the SciJava plugin framework?</h2> <h3 id="the-context">The Context</h3> <p>References to all the <code class="language-plaintext highlighter-rouge">@Plugin</code>-annotated classes that are discovered are contained in a single, master <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/Context.java">Context</a>. Each application is responsible for creating its own <code class="language-plaintext highlighter-rouge">Context</code> to manage plugins and contextual state.</p> <p>In ImageJ, a <code class="language-plaintext highlighter-rouge">Context</code> is automatically created when <a href="https://github.com/imagej/imagej/blob/imagej-2.0.0-rc-39/src/main/java/net/imagej/ImageJ.java">the application starts up</a>, so plugin developers do not need to create their own. In fact, creating your own <code class="language-plaintext highlighter-rouge">Context</code> typically causes problems, as it will be a different container than ImageJ is using. Instead, plugin instances within a common <code class="language-plaintext highlighter-rouge">Context</code> are provided automatically by the framework—you just have to ask.</p> <p>Typically, ImageJ plugin developers will be writing <a href="#Services">Service</a> and/or <a href="#Commands">Command</a> plugins. If you need to use another plugin - for example the <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/log/LogService.java">LogService</a> - you <strong>should not</strong> manually create it as this effectively disconnects you from your <code class="language-plaintext highlighter-rouge">Context</code> (Your <a href="#Services">Service</a> and/or <a href="#Commands">Command</a> plugins are created by the application container and managed by the plugin framework automatically). Instead, you should ask your <code class="language-plaintext highlighter-rouge">Context</code> for an instance by adding a field of the desired type and annotating it with the <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/plugin/Parameter.java">@Parameter annotation</a>. For example:</p> <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Plugin</span> <span class="kd">public</span> <span class="kd">class</span> <span class="nc">MyPlugin</span> <span class="o">{</span> <span class="c1">// This @Parameter notation is 'asking' the Context</span> <span class="c1">// for an instance of LogService.</span> <span class="nd">@Parameter</span> <span class="kd">private</span> <span class="nc">LogService</span> <span class="n">logService</span><span class="o">;</span> <span class="kd">public</span> <span class="kt">void</span> <span class="nf">log</span><span class="o">(</span><span class="nc">String</span> <span class="n">message</span><span class="o">)</span> <span class="o">{</span> <span class="c1">// Just use the LogService!</span> <span class="c1">// There is no need to construct it, since the Context</span> <span class="c1">// has already provided an appropriate instance.</span> <span class="n">logService</span><span class="o">.</span><span class="na">info</span><span class="o">(</span><span class="n">message</span><span class="o">);</span> <span class="o">}</span> <span class="o">}</span> </code></pre></div></div> <p>This will allow the <code class="language-plaintext highlighter-rouge">Context</code> to provide you with the appropriate instance of your requested service.</p> <p>In some cases, manual plugin construction is unavoidable. Understand that if the <code class="language-plaintext highlighter-rouge">MyPlugin</code> class above is manually constructed—i.e. via <code class="language-plaintext highlighter-rouge">new MyPlugin()</code>—the <code class="language-plaintext highlighter-rouge">LogService</code> parameter will be <code class="language-plaintext highlighter-rouge">null</code>. Automatic population only occurs if the plugin instance itself is retrieved via the framework. When you must manually construct a plugin instance, you can still re-connect it to an existing <code class="language-plaintext highlighter-rouge">Context</code> via its <em>injection</em> mechanism:</p> <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="kd">class</span> <span class="nc">MyService</span> <span class="o">{</span> <span class="c1">// This service will manually create plugin instances</span> <span class="c1">// So, we need a reference to our containing Context</span> <span class="c1">// Then we can use it to inject our plugins.</span> <span class="nd">@Parameter</span> <span class="kd">private</span> <span class="nc">Context</span> <span class="n">context</span><span class="o">;</span> <span class="kd">public</span> <span class="kt">void</span> <span class="nf">doStuff</span><span class="o">()</span> <span class="o">{</span> <span class="c1">// Manually create a plugin instance</span> <span class="c1">// It is not connected to a Context yet</span> <span class="nc">MyPlugin</span> <span class="n">plugin</span> <span class="o">=</span> <span class="k">new</span> <span class="nc">MyPlugin</span><span class="o">();</span> <span class="c1">// Inject the plugin instance with our Context,</span> <span class="c1">// so the logService field of the plugin will be</span> <span class="c1">// populated.</span> <span class="n">context</span><span class="o">.</span><span class="na">inject</span><span class="o">(</span><span class="n">plugin</span><span class="o">);</span> <span class="c1">// Now that our plugin is injected, we can use</span> <span class="c1">// it with the knowledge that its parameters</span> <span class="c1">// have been populated</span> <span class="n">plugin</span><span class="o">.</span><span class="na">log</span><span class="o">(</span><span class="s">"Success!"</span><span class="o">);</span> <span class="o">}</span> <span class="o">}</span> </code></pre></div></div> <h3 id="services">Services</h3> <p>Services provide two important functions to the SciJava framework: utility methods and persistent state. If you want to add reusable Java methods that can be used throughout the SciJava framework, then you should create a <code class="language-plaintext highlighter-rouge">Service</code> to provide this functionality. If you need to track Context-wide variables or configuration, a <code class="language-plaintext highlighter-rouge">Service</code> should be used to encapsulate that state.</p> <p>Conceptually, a <code class="language-plaintext highlighter-rouge">Service</code> satisfies the role of <a href="https://en.wikipedia.org/wiki/Utility_class">static utility classes</a> on a per-Context basis. In this way, only one <a href="http://math.hws.edu/javanotes/c5/s1.html">instance</a> of each <code class="language-plaintext highlighter-rouge">Service</code> class can be associated with a given <code class="language-plaintext highlighter-rouge">Context</code> instance; an association that occurs automatically during <code class="language-plaintext highlighter-rouge">Context</code> creation. Furthermore, when a <code class="language-plaintext highlighter-rouge">Context</code> is asked for an implementation of a given <code class="language-plaintext highlighter-rouge">Service</code>, only the highest priority instance will be returned.</p> <p>Services often build on or reuse functionality defined in each other. For example, the <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/plugin/PluginService.java">PluginService</a> sees ubiquitous use in retrieving and working with plugin instances. For such reuse, <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/plugin/Parameter.java">@Parameter annotation</a> can be used to declare inter-service requirements. During <code class="language-plaintext highlighter-rouge">Context</code> startup, these relationships will be resolved automatically.</p> <h3 id="commands">Commands</h3> <p>Whereas <a href="#Services">Services</a> provide internal functionality, <code class="language-plaintext highlighter-rouge">Commands</code> are plugins designed to be executed as one-offs, typically interacting with users to achieve some desired outcome. When opening the ImageJ GUI, Commands are what populate your menu structure: exposing functionality and algorithms in a way that can be consumed by non-developers.</p> <p>When writing <code class="language-plaintext highlighter-rouge">Commands</code> you will often declare <a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/plugin/Parameter.java">@Parameters</a> on fields that <strong>can not</strong> be resolved automatically by the <code class="language-plaintext highlighter-rouge">Context</code>—for example, numeric values or file paths. Instead of being instantiated at <code class="language-plaintext highlighter-rouge">Context</code> startup as a <code class="language-plaintext highlighter-rouge">Service</code> would be, <code class="language-plaintext highlighter-rouge">Commands</code> are created and executed on demand.</p> <p>When a <code class="language-plaintext highlighter-rouge">Command</code> is executed, it goes through a series of pre-processing steps to populate its <code class="language-plaintext highlighter-rouge">@Parameters</code> using its associated <a href="#the-context">Context</a>. If any parameters are left unresolved and a UI is available, the framework will automatically build and display an appropriate dialog to get user input. In this way, input harvesting is decoupled from functional operation—allowing developers to focus on what’s really important without repetition of code. This also means that Commands can typically run <a href="/learn/headless">headlessly</a> without any extra development effort.</p> <p>A common pattern in <code class="language-plaintext highlighter-rouge">Command</code> development is to wrap <code class="language-plaintext highlighter-rouge">Service</code> functionality. For example, opening an image from a path is a fundamental operation in ImageJ. To this end, developers can directly use the <a href="https://github.com/scifio/scifio/blob/scifio-0.25.0/src/main/java/io/scif/services/DatasetIOService.java">DatasetIOService</a>. Users then get this same functionality from the menus via the <a href="https://github.com/imagej/imagej-plugins-commands/blob/imagej-plugins-commands-0.6.0/src/main/java/net/imagej/plugins/commands/io/OpenDataset.java">OpenDataset command</a>—which itself simply calls into the <code class="language-plaintext highlighter-rouge">DatasetIOService</code>.</p> <h3 id="other-plugins">Other plugins</h3> <p>Because virtually everything is a plugin in ImageJ, there are too many to explicitly enumerate, let alone cover in a tutorial. To get ideas for functionality that can be added, a good starting point is to look for services in the <a href="/develop/source#javadocs">javadoc</a>, or the <a href="http://search.imagej.net/">ImageJ search portal</a>. Many service types have supplemental plugins for easy functional extension. In particular, the <a href="https://github.com/imagej/imagej-common/">imagej-common</a> and <a href="https://github.com/scijava/scijava-common/">scijava-common</a> repositories will contain plugin definitions for many essential operations.</p> <p>A brief list of some of the more useful plugin types to extend:</p> <ul> <li><a href="/libs/imagej-ops">Ops</a> provide a reusable set of image processing algorithms.</li> <li><a href="/develop/formats">Image formats</a> allow new types of images to be opened in ImageJ.</li> <li><a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/convert/Converter.java">Converters</a> allow the framework to interchange types, outside of normal Java class hierarchy restrictions.</li> <li><a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/module/process/PreprocessorPlugin.java">Input Preprocessors</a> give you control over the population of <code class="language-plaintext highlighter-rouge">@Parameters</code>.</li> <li><a href="https://github.com/scijava/scijava-common/blob/scijava-common-2.47.0/src/main/java/org/scijava/display/Display.java">Displays</a> control how UI elements are presented to users.</li> </ul> <p>If you know the function you want to modify but can’t determine its location in the code, please <a href="/discuss">ask other developers.</a> You’re part of the community now!</p> <h2 id="example-projects">Example projects</h2> <p>Remember the <a href="https://github.com/imagej/tutorials/">imagej/tutorials repository</a> we <a href="#Requirements">said you should clone</a>? Now’s the time to put it to use!</p> <p>Because the ImageJ API is designed to be maximally flexible and extensible, if you’re just getting started with development it can be overwhelming to figure out exactly which part of the code base you should be working on. The <code class="language-plaintext highlighter-rouge">imagej/tutorials</code> repository contains a selection of minimal projects illustrating how your own project(s) could be structured to perform common tasks. Most of these projects also have extensive documentation via comments in the code, to highlight particular functions and use cases.</p> <p>You do not need to understand every project in this repository, nor must you go through them in a particular order! Instead, you should read through the following topics and focus on the projects that look particularly interesting and relevant to your goals. Your target for learning should be to understand the code in these selected projects, and how changes to that code will be reflected in the experiences of users and other developers.</p> <p>Because these tutorials use <a href="/develop/git">Git</a> for source control, you have complete freedom to modify and play with the code. Worst-case scenario, you always have a big reset button via the command:</p> <div class="language-shell highlighter-rouge"><div class="highlight"><pre class="highlight"><code>git reset <span class="nt">--hard</span> origin/master </code></pre></div></div> <p>There are always other options for saving or restoring your work—<a href="https://git-scm.com/book/en/v1/Git-Tools-Stashing">stashing</a> or <a href="https://git-scm.com/book/en/v2/Git-Branching-Branches-in-a-Nutshell">branching</a>, for example—but their use will depend on your personal comfort and knowledge of Git.</p> <h3 id="tips">Tips</h3> <ul> <li>Most of these examples have a <a href="https://docs.oracle.com/javase/tutorial/getStarted/application/index.html">Main method</a> to see the code in action.</li> <li>All of these projects are <a href="/develop/maven">Mavenized</a>.</li> <li>You can look at the <a href="https://maven.apache.org/guides/introduction/introduction-to-the-pom.html">pom.xml</a> to figure out <a href="/develop/source">which libraries</a> that particular project is using.</li> <li>You can <a href="http://maven.apache.org/archives/maven-1.x/start/quick-start.html">compile and build</a> from the command line by running <code class="language-plaintext highlighter-rouge">mvn</code> from any project’s top-level directory (any directory containing a <code class="language-plaintext highlighter-rouge">pom.xml</code>).</li> <li>Building a project results in a <code class="language-plaintext highlighter-rouge">jar</code> output in the <code class="language-plaintext highlighter-rouge">$PROJECT/target/</code> directory.</li> <li>For a more “real-world” experience, you can drop the <code class="language-plaintext highlighter-rouge">jar</code> you built into the <code class="language-plaintext highlighter-rouge">ImageJ2.app/jars/</code> directory of an <a href="/downloads">ImageJ installation</a> to try out any of the example plugins.</li> <li>If you’re not sure how to find your plugin within ImageJ, use the <a href="/learn#the-search-bar">search bar</a>!</li> <li>You can also import each project into <a href="/develop/eclipse">Eclipse</a>/<a href="/develop/netbeans">NetBeans</a>/<a href="/develop/intellij">IntelliJ IDEA</a> as a <a href="https://books.sonatype.com/m2eclipse-book/reference/creating-sect-importing-projects.html">maven project</a>.</li> </ul> <h3 id="first-steps">First steps</h3> <p>The <a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/adv/IntroToImageJAPI.java">IntroToImageJ API</a> class documents many common functions and structures in ImageJ, and is a great starting point.</p> <h3 id="basic-plugins">Basic plugins</h3> <p>These projects provide minimal examples with thorough online documentation.</p> <ul> <li><a href="https://github.com/imagej/example-imagej-command">example-imagej-command</a> - A minimal template for an ImageJ command plugin</li> <li>Look at some <a href="https://github.com/imagej/tutorials/tree/-/java/simple-commands/src/main/java">simple commands</a> and see how they interact with users</li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/working-with-modules/src/main/java/WorkingWithModules.java">Getting started with modules</a>—the foundation of many user-facing plugin types, including <a href="#Commands">commands</a></li> </ul> <h3 id="targeted-tasks">Targeted tasks</h3> <p>These projects are examples of specific <em>use cases</em> within the ImageJ API.</p> <ul> <li><a href="https://github.com/imagej/tutorials/master/java/execute-commands/src/main/java/ExecuteCommands.java">Execute commands programmatically</a></li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/datasets/LoadAndDisplayDataset.java">Open a dataset</a></li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/images/AddROIs.java">Combine ROIs</a></li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/listen-to-events/src/main/java/ListenToEvents.java">React to framework events</a>—such as creating a dataset</li> </ul> <h3 id="working-with-ops">Working with Ops</h3> <ul> <li><a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/ops/UsingOps.java">Using Ops</a></li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/add-two-datasets/src/main/java/AddTwoDatasets.java">Add datasets</a></li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/ops/CreateANewOp.java">Create a new Op type</a></li> <li></li> </ul> <h3 id="working-with-user-input">Working with user input</h3> <ul> <li><a href="https://github.com/imagej/tutorials/tree/-/java/howtos/src/main/java/howto/ui">Look at all the widgets!</a></li> <li><a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/ui/preview/CommandWithPreview.java">Previewable commands</a></li> </ul> <h3 id="plugin-development">Plugin development</h3> <ul> <li><a href="https://github.com/imagej/tutorials/blob/-/java/howtos/src/main/java/howto/plugins/create/CreateANewPluginType.java">Create a new plugin type</a> </li> </ul> <h2 id="starting-your-own-plugin">Starting your own plugin</h2> <h3 id="general-guidelines">General guidelines</h3> <p>ImageJ adheres to <a href="/develop/coding-style#interface-driven-design">interface-driven design</a>. From a practical point of view, this means:</p> <p>If you are <strong>creating</strong> a new plugin type…</p> <ul> <li>Use interfaces for base plugin type</li> <li>Create an abstract class implementing this interface that handles all the boilerplate.</li> <li>Your abstract class can likely extend a general abstract class provided in <a href="https://github.com/imagej/imagej-common/">imagej-common</a> or <a href="https://github.com/scijava/scijava-common/">scijava-common</a></li> </ul> <p>If you are <strong>implementing</strong> an existing plugin type…</p> <ul> <li>Just extend the appropriate abstract class! Let your compiler tell you which methods are missing.</li> </ul> <h3 id="adopt-an-existing-project">Adopt an existing project</h3> <p>You already <a href="#Requirements">created your own GitHub repository</a>, right??</p> <p>When you’re just getting started with tools like <a href="/develop/git">Git</a> and <a href="/develop/maven">Maven</a>, it’s not easy to comprehend the nuances of how new projects should be set up and configured. It’s much easier to copy a working project to use as a starting point and go from there.</p> <p>The <a href="#example-projects">example projects</a> are designed precisely to serve as such starting points for new projects. Once you have a solid idea of what kind of plugin you want to write, pick the project that discusses your area of choice and simply copy it to your own GitHub repo. From there, you can make changes as needed.</p> <p>At this point, if you haven’t already, we <strong>STRONGLY RECOMMEND</strong> importing your project into an <a href="/develop/ides">IDE</a> like <a href="/develop/eclipse">Eclipse</a>. This will make <a href="/develop/eclipse">development</a> and <a href="http://help.eclipse.org/mars/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Freference%2Fref-menu-refactor.htm">refactoring</a> much easier. Modern IDEs also have excellent <a href="/develop/git">Git</a> and <a href="/develop/maven">Maven</a> integration, which will allow you to take advantage of the fact that the example projects are already set up as Mavenized Git repositories.</p> <p>In addition to modifying and developing the source code itself, there are several things you should do to properly identify and configure your project:</p> <h4 id="update-your-pom">Update your POM</h4> <ul> <li>For your <a href="https://maven.apache.org/pom.html#inheritance">parent pom</a>, we recommend that you extend <a href="https://github.com/scijava/pom-scijava"><code class="language-plaintext highlighter-rouge">pom-scijava</code></a>. This will provide <a href="https://maven.apache.org/pom.html#dependency-management">dependency management</a> of a lot of common useful dependencies, including the entire <a href="/develop/architecture#definitions">ImageJ2 software stack</a> and all <a href="/software/fiji">Fiji</a> components. Try to use the newest available version of <code class="language-plaintext highlighter-rouge">pom-scijava</code>.</li> <li>Update your <a href="https://maven.apache.org/pom.html#maven-coordinates">groupId</a>. ImageJ projects use a <code class="language-plaintext highlighter-rouge">net.imagej</code> groupId, while Fiji projects use <code class="language-plaintext highlighter-rouge">sc.fiji</code>—or you may use your own if you do not plan to distribute your plugin with the core ImageJ or Fiji projects.</li> <li>Update your <a href="https://maven.apache.org/pom.html#maven-coordinates">artifactId</a> to something appropriate based on the intended use of your project.</li> <li>Update your <name> and <description> to something appropriate for your new artifactId.</description></name></li> <li>Add a <developer> block to your pom, to identify yourself (see [this example](https://github.com/scijava/pom-scijava/blob/pom-scijava-16.1.0/pom.xml#L32-L47) for formatting).</developer></li> </ul> <h4 id="code-changes">Code changes</h4> <ul> <li>If you updated your pom’s groupId, you should similarly update the <a href="https://docs.oracle.com/javase/tutorial/java/package/namingpkgs.html">package</a> structure (found in <a href="https://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html"><code class="language-plaintext highlighter-rouge">src/main/java</code></a>) to match.</li> </ul> <h4 id="optional-changes">Optional changes</h4> <ul> <li>If you want to use additional <a href="/develop/source">ImageJ or Fiji projects</a> as libraries, you will need to add them as dependencies in the <a href="https://maven.apache.org/pom.html#Dependencies">dependency block</a> of your <code class="language-plaintext highlighter-rouge">pom.xml</code>. Note that you will not need to specify a <version>, as these are managed by the `pom-scijava` parent pom.</version></li> <li>If your copied <code class="language-plaintext highlighter-rouge">pom.xml</code> has a <a href="https://github.com/imagej/tutorials/blob/249c699dbdb9308f8a5539f0f39cf84d2612b273/simple-commands/pom.xml#L22-L24">main method specification</a> you will likely need to remove or update it as appropriate.</li> <li>If you want to add non-Java files to your plugin, such as sample images or <a href="/scripting">demo scripts</a>, refer to the <a href="https://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html">standard maven layout</a>.</li> </ul> <h2 id="next-steps">Next Steps</h2> <p>There are further guides available dedicated to developing particular types of plugins:</p> <ul> <li><a href="/develop/writing-ops">Adding new ops</a></li> <li><a href="/develop/formats">Adding new file formats</a></li> </ul> <p>Once you have completed plugins and want to get them out to users, you can familiarize yourself with the articles on:</p> <ul> <li><a href="/contribute/distributing">Plugin distribution</a></li> <li><a href="/develop/releasing">The development lifecycle</a></li> <li><a href="/contribute/fiji">Core contribution requirements</a></li> </ul> <p>As always, if you ever need assistance, <a href="/discuss">just ask</a>!</p> </div> </div> </section>  <section id="footer"> <ul class="icons"> <li><a href="https://forum.image.sc/tag/imagej" class="icon alt"><img src="/media/icons/image-sc.png" width="24" style="vertical-align: middle; margin-top: -10px"><span class="label">Forum</span></a></li> <li><a href="https://twitter.com/hashtag/ImageJ" class="icon brands alt fa-twitter"><span class="label">Twitter</span></a></li> <li><a href="https://github.com/imagej" class="icon brands alt fa-github"><span class="label">GitHub</span></a></li> </ul> <ul class="copyright"> <li>Design: <a href="http://html5up.net">HTML5 UP</a></li> </ul> </section>  <nav role="navigation"> <div id="ham-toggle"> <input type="checkbox" /> <span></span>  <span></span>  <span></span>  <ul id="ham-menu"> <div class="menu"><h3>ImageJ Docs</h3> <ul> <li><a href="/downloads">Download</a></li> <li><details><summary>Learn</summary><ul> <li><details><summary><a href="/learn">ImageJ Basics</a></summary><ul> <li><a href="/tutorials">Tutorials</a></li> <li><a href="/learn/user-guides">User Guides</a></li> <li><a href="/learn/keyboard-shortcuts">Keyboard Shortcuts</a></li> <li><a href="/learn/tips-and-tricks">Tips and Tricks</a></li> <li><a href="/learn/troubleshooting">Troubleshooting</a></li> <li><a href="/learn/faq">Frequently Asked Questions</a></li> <li><details><summary><a href="/platforms">Supported Platforms</a></summary><ul> <li><a href="/platforms/windows">Windows</a></li> <li><a href="/platforms/macos">MacOS</a></li> <li><a href="/platforms/linux">Linux</a></li> <li><a href="/platforms/pi">Raspberry Pi</a></li> <li><a href="/platforms/android">Android</a></li> </ul></details></li>  <li><details><summary><a href="/formats">File Formats</a></summary><ul> <li><a href="/formats/bio-formats">Bio-Formats</a></li> <li><a href="/formats/video">Video formats</a></li> <li><a href="/formats/quicktime">QuickTime</a></li> <li><a href="/formats/tiff">TIFF</a></li> <li><a href="/formats/pdf">PDF</a></li> <li><a href="/formats/dicom">DICOM</a></li> <li><a href="/formats/lsm">Zeiss LSM</a></li> <li><a href="/formats/olympus">Olympus VSI</a></li> <li><a href="/formats/lurawave">Opera Flex</a></li> <li><a href="/formats/fib-sem">FIB-SEM</a></li> </ul></details></li>  </ul></details></li>  <li><details><summary><a href="/imaging">Scientific Imaging</a></summary><ul> <li><a href="/imaging/principles">Principles of Scientific Imaging</a></li> <li><a href="/imaging/annotating-images">Annotating Images</a></li> <li><a href="/imaging/colocalization-analysis">Colocalization</a></li> <li><a href="/imaging/color-image-processing">Color Image Processing</a></li> <li><a href="/imaging/deconvolution">Deconvolution</a></li> <li><a href="/imaging/image-intensity-processing">Image Intensity Processing</a></li> <li><a href="/imaging/particle-analysis">Particle Analysis</a></li> <li><a href="/imaging/registration">Registration</a></li> <li><a href="/imaging/segmentation">Segmentation</a></li> <li><a href="/imaging/stack-slice-manipulations">Stack-slice Manipulations</a></li> <li><a href="/imaging/t-functions">T-functions</a></li> <li><a href="/imaging/tracking">Tracking</a></li> <li><a href="/imaging/visualization">Visualization</a></li> <li><a href="/imaging/z-functions">Z-functions</a></li> </ul></details></li>  </ul></details></li>  <li><details open><summary><a href="/plugins">Extend</a></summary><ul> <li><a href="/list-of-extensions">List of Extensions</a></li> <li><details><summary><a href="/update-sites">Update Sites</a></summary><ul> <li><a href="/list-of-update-sites">List of Update Sites</a></li> <li><a href="/update-sites/following">Following an Update Site</a></li> <li><a href="/update-sites/setup">Creating an Update Site</a></li> <li><a href="/update-sites/tos">Terms of Service</a></li> <li><a href="/update-sites/automatic-uploads">Automatic Upload</a></li> <li><a href="/update-sites/core-uploads">Uploading to Core Sites</a></li> <li><a href="/update-sites/faq">Update Sites FAQ</a></li> <li><a href="/update-sites/stats">Statistics</a></li> </ul></details></li>  <li><details><summary><a href="/scripting">Scripting</a></summary><ul> <li><a href="/scripting/basics">Scripting Basics</a></li> <li><a href="/scripting/script-editor">Script Editor</a></li> <li><a href="/scripting/parameters">Parameters</a></li> <li><a href="/scripting/user-input">User Input</a></li> <li><a href="/scripting/auto-imports">Auto Import</a></li> <li><a href="/scripting/templates">Templates</a></li> <li><a href="/scripting/batch">Batch Processing</a></li> <li><a href="/scripting/headless">Running Headlessly</a></li> <li><a href="/scripting/comparisons">Scripting Comparisons</a></li> <li><a href="/scripting/toolbox">Toolbox</a></li> <li><details><summary>Languages</summary><ul> <li><a href="/scripting/beanshell">BeanShell Scripting</a></li> <li><a href="/scripting/groovy">Groovy Scripting</a></li> <li><a href="/scripting/macro">ImageJ Macro</a></li> <li><a href="/scripting/javascript">JavaScript</a></li> <li><a href="/scripting/clojure">Lisp (Clojure)</a></li> <li><a href="/scripting/matlab">MATLAB</a></li> <li><a href="/scripting/jython">Python (Jython)</a></li> <li><a href="/scripting/python">Python (native)</a></li> <li><a href="/scripting/renjin">R (Renjin)</a></li> <li><a href="/scripting/jruby">Ruby (JRuby)</a></li> <li><a href="/scripting/scala">Scala Scripting</a></li> </ul></details></li>  </ul></details></li>  <li><details open><summary><a href="/develop">Development</a></summary><ul> <li><a href="/develop/philosophy">Philosophy</a></li> <li><a href="/develop/architecture">Architecture</a></li> <li><a href="/develop/source">Source code</a></li> <li><a href="/develop/project-management">Project management</a></li> <li><a href="/develop/coding-style">Coding style</a></li> <li><a href="/develop/javadoc">Using Javadoc</a></li> <li><a href="/develop/debugging">Debugging</a></li> <li><a href="/develop/wish-list">Wish list</a></li> <li><details><summary>Tools</summary><ul> <li><a href="/develop/github">GitHub</a></li> <li><a href="/develop/maven">Maven</a></li> <li><a href="/develop/ci">CI/CD</a></li> <li><a href="/develop/dotfiles">Dotfiles</a></li> <li><details><summary><a href="/develop/ides">IDEs</a></summary><ul> <li><a href="/develop/eclipse">Eclipse</a></li> <li><a href="/develop/netbeans">NetBeans</a></li> <li><a href="/develop/intellij">IntelliJ IDEA</a></li> <li><a href="/develop/command-line">Command Line</a></li> </ul></details></li> </ul></details></li>  <li><details open><summary>Guides</summary><ul> <li><a class="current-page">Writing plugins</a></li> <li><a href="/develop/improving-the-code">Contributing to a plugin</a></li> <li><a href="/develop/releasing">Development lifecycle</a></li> <li><a href="/develop/building-a-pom">Building a POM</a></li> <li><a href="/develop/debugging-exercises">Hands-on debugging</a></li> <li><a href="/develop/writing-ops">Adding new ops</a></li> <li><a href="/develop/formats">Adding new formats</a></li> <li><a href="/develop/native-libraries">Using native libraries</a></li> <li><a href="/develop/tips">Tips for developers</a></li> <li><a href="/develop/cpp-tips">Tips for C++ developers</a></li> <li><a href="/develop/ij1-plugins">ImageJ 1.x plugins</a></li> <li><a href="/develop/versioning">Versioning</a></li> <li><a href="/develop/logging">Logging</a></li> <li><a href="/develop/uber-jars">Uber-JARs</a></li> </ul></details></li>  <li><details><summary><a href="/develop/git">Git</a></summary><ul> <li><a href="/develop/git/eclipse">Git in Eclipse (EGit)</a></li> <li><a href="/develop/git/mini-howto">Git mini howto</a></li> <li><a href="/develop/git/workshop">Git workshop</a></li> <li><a href="/develop/git/conflicts">Git conflicts</a></li> <li><a href="/develop/git/topic-branches">Git topic branches</a></li> <li><a href="/develop/git/notes">Git notes</a></li> <li><a href="/develop/git/reflogs">Git reflogs</a></li> <li><a href="/develop/git/submodules">Git submodules</a></li> <li><a href="/develop/git/pinpoint-regressions">How to pinpoint regressions</a></li> <li><a href="/develop/git/publish-a-repository">How to publish a git repository</a></li> <li><a href="/develop/git/extract-a-subproject">How to extract a subproject</a></li> </ul></details></li>  </ul></details></li>  </ul></details></li>  <li><details><summary><a href="/contribute">Contribute</a></summary><ul> <li><a href="/contribute/citing">Citing</a></li> <li><a href="/people">Contributors</a></li> <li><a href="/orgs">Organizations</a></li> <li><a href="/contribute/governance">Governance</a></li> <li><a href="/contribute/funding">Funding</a></li> <li><a href="/contribute/fiji">Contributing to Fiji</a></li> <li><details><summary><a href="/licensing">Licensing</a></summary><ul> <li><details><summary><a href="/licensing/open-source">Open Source</a></summary><ul> <li><a href="/licensing/apache">Apache</a></li> <li><a href="/licensing/bsd">BSD</a></li> <li><a href="/licensing/epl">EPL</a></li> <li><a href="/licensing/gpl">GPL</a></li> <li><a href="/licensing/lgpl">LGPL</a></li> <li><a href="/licensing/mit">MIT</a></li> <li><a href="/licensing/public-domain">Public domain</a></li> <li><a href="/licensing/big">BIG</a></li> </ul></details></li>  <li><a href="/licensing/closed-source">Proprietary</a></li> </ul></details></li>  <li><details><summary><a href="/editing">Editing the Wiki</a></summary><ul> <li><a href="/editing/advanced">Advanced Editing</a></li> <li><a href="/editing/buttons">Buttons</a></li> <li><a href="/editing/citations">Citations</a></li> <li><a href="/editing/code">Source Code</a></li> <li><a href="/editing/debugging">Debugging</a></li> <li><a href="/editing/headers">Headers</a></li> <li><a href="/editing/icons">Icons</a></li> <li><a href="/editing/images">Images</a></li> <li><a href="/editing/keys">Keyboard Shortcuts</a></li> <li><a href="/editing/linking">Linking</a></li> <li><a href="/editing/math">Math Expressions</a></li> <li><a href="/editing/menu-paths">Menu Paths</a></li> <li><a href="/editing/navigation">Navigation</a></li> <li><a href="/editing/notices">Notices</a></li> <li><a href="/editing/people">People</a></li> <li><a href="/editing/pitfalls">Pitfalls</a></li> <li><a href="/editing/quizzes">Quizzes</a></li> <li><a href="/editing/statbox">Statbox</a></li> <li><a href="/editing/symbols">Symbols</a></li> <li><a href="/editing/tables">Tables</a></li> <li><a href="/editing/tooltips">Tooltips</a></li> <li><a href="/editing/videos">Videos</a></li> <li><a href="/editing/whitespace">Whitespace</a></li> </ul></details></li>  </ul></details></li>  <li><details><summary><a href="/discuss">Discuss</a></summary><ul> <li><a href="/discuss/bugs">Reporting Issues</a></li> <li><a href="/discuss/mailing-lists">Mailing Lists</a></li> <li><a href="/discuss/chat">Chat</a></li> </ul></details></li>  <li><details><summary>Explore</summary><ul> <li><a href="/news">News</a></li> <li><details><summary><a href="/events">Events</a></summary><ul> <li><a href="/events/presentations">Presentations</a></li> <li><a href="/events/conferences">Conferences</a></li> <li><a href="/events/hackathons">Hackathons</a></li> <li><a href="/events">More...</a></li> </ul></details></li>  <li><details><summary><a href="/libs">Libraries</a></summary><ul> <li><a href="/libs/imagej-ops">ImageJ Ops</a></li> <li><a href="/libs/imagej-common">ImageJ Common</a></li> <li><a href="/libs/imagej-legacy">ImageJ Legacy</a></li> <li><a href="/libs/scijava">SciJava</a></li> <li><a href="/libs/scifio">SCIFIO</a></li> <li><details><summary><a href="/libs/imglib2">ImgLib2</a></summary><ul> <li><a href="/libs/imglib2/getting-started">Getting Started</a></li> <li><a href="/libs/imglib2/accessors">Accessors</a></li> <li><a href="/libs/imglib2/accessibles">Accessibles</a></li> <li><a href="/libs/imglib2/examples">Examples</a></li> <li><a href="/libs/imglib2/workshop-introductory">Introductory Workshop</a></li> <li><a href="/libs/imglib2/workshop-advanced">Advanced Workshop</a></li> <li><a href="/libs/imglib2/matlab">ImgLib2 images in MATLAB</a></li> <li><a href="/libs/imglib2/benchmarks">Benchmarks</a></li> <li><a href="/libs/imglib2/faq">FAQ</a></li> <li><a href="/libs/imglib2/developing">Developing ImgLib2</a></li> <li><a href="/libs/imglib2/discussion">ImgLib2 Discussion</a></li> </ul></details></li>  <li><a href="/libs">More...</a></li> </ul></details></li>  <li><details><summary><a href="/software">Software</a></summary><ul> <li><a href="/software/nih-image">NIH Image</a></li> <li><a href="/software/imagej">ImageJ</a></li> <li><a href="/software/imagej2">ImageJ2</a></li> <li><a href="/software/fiji">Fiji</a></li> <li><a href="/software">More...</a></li> </ul></details></li>  </ul></details></li>  </ul> </div> </ul> </div> </nav> <div id="dock-overlay-left" class="dock-overlay" data-dock-target="left-column"></div> <div id="dock-overlay-right" class="dock-overlay" data-dock-target="right-column"></div>  <div id="search-results"> <div id="search-hits"></div> <div id="pagination"></div> </div>   <script src="/assets/js/jquery.min.js"></script> <script src="/assets/js/jquery.scrolly.min.js"></script> <script src="/assets/js/browser.min.js"></script> <script src="/assets/js/breakpoints.min.js"></script> <script src="/assets/js/util.js"></script> <script src="/assets/js/jquery.toc.js"></script> <script src="/assets/js/lightbox.min.js"></script>   <script src="/assets/js/main.js"></script> <script src="/assets/js/dock.js"></script> <script src="/assets/js/code.js"></script>  <script src="https://cdn.jsdelivr.net/npm/anchor-js/anchor.min.js"></script> <script>anchors.add('#page h1, #page h2, #page h3, #page h4, #page h5, #page h6');</script>  <script src="https://cdn.jsdelivr.net/npm/citation-js@0.4.0-9"></script> <script src="/assets/js/cite.js"></script>  <script src="https://cdn.jsdelivr.net/npm/algoliasearch@4.13.0/dist/algoliasearch-lite.umd.js"></script> <script src="https://cdn.jsdelivr.net/npm/instantsearch.js@4.40.3/dist/instantsearch.production.min.js"></script> <script src="/assets/js/search.js"></script> <script src="/assets/js/search-tweaks.js"></script> </body> </html>

CINXE.COM

Developing ImageJ2 Plugins