GUIPlugin Documentation

This documentation provides information on GUIPlugins and GUILayouts to help with designing your own plugins for Xi-CAM. API reference documentation is also included at the bottom.

If you are new to developing Xi-CAM plugins, it is recommended that you follow the quick-start documentation first.

For more general development resources, see the resources documentation.

What Is A GUIPlugin?

A GUIPlugin is an interactive user-facing plugin in Xi-CAM. It can be used to visualize and analyze data.

GUIPlugins make use of the qtpy Python package for interactive GUI components. See the resources documentation for more information.

Where is GUIPlugin?


What Does a GUIPlugin Look Like?

First, let’s look at what Xi-CAM looks like when you first load it:

Main window of Xi-CAM on startup, with three installed plugins.

Main window of Xi-CAM when running xicam. Note that there are three installed GUIPlugins here; if you haven’t installed any plugins, you won’t see any listed.

As you can see, the main window of Xi-CAM after it has finished loading shows any installed GUIPlugins, a citation / references widget, a preview widget, and a data browser widget. The data browser widget can be used to load data into a GUIPlugin. The data preview widget can be used to “preview” data before loading it.

It is important to keep in mind a few concepts for GUIPlugins:

  • A GUIPlugin can have one or more stages.

  • Each stage is defined with a GUILayout.

  • A GUILayout is defined with a widget (or multiple widgets).

These concepts are explored in more detail later in this document.

How Do I Create a GUIPlugin?

To create a GUIPlugin, you will need:

  • a derived class of GUIPlugin

  • a file with a xicam.plugins.GUIPlugin entry point

Although you may structure your plugin’s code and support files as you like, we recommend using a cookiecutter template that we have created for Xi-CAM’s GUIPlugin.

What is cookiecutter?

cookiecutter is a templating tool that can be used to interactively create python project. For more information, see the cookiecutter documentation.

Install cookiecutter

In your active environment, you will need to pip install cookiecutter.

Run cookiecutter with the Xi-CAM GUIPlugin Template

Now, in the directory of your choice (the home directory, ~, should work if you are unsure), run the following:


This will download the template for creating a GUIPlugin, then present you with a series of prompts.

A prompt will look like prompt [default value]: . If you want to use the default value specified, hit the enter key. Otherwise, respond to the prompt with the value you would like.

Here are the prompts with their descriptions:

prompt default value description
package_name my_plugin name of the package to create (will be xicam.package_name)
plugin_name MyPlugin name of the GUIPlugin class to create (name of your gui plugin in code)
display_name My Plugin name of the GUIPlugin as it will appear in the Xi-CAM GUI
plugin_version 1.0.0 current plugin version number
author_name author's name
author_email author's email
author_url url for the author/plugin (e.g. plugin GitHub repo url)
description description of the plugin
dependencies packages the plugin depends on
keywords [Xi-cam, plugin] keywords to tag the plugin with (when packaging)

This will create a python package with some files and code to get started developing a GUIPlugin. You can always change the names of your plugin, package, etc. later by hand.

The GUIPlugin you created will be implemented in xicam.package_name/xicam/package_name/

For purposes of this documentation, we will refer to these values by their defaults.

Installing Your GUIPlugin

When you create a new plugin package using cookiecutter, one of the files it generates is This contains meta-information about the package. When you run pip install of your package, it uses this information to create a disribution. also defines entry points, which Xi-CAM uses to find plugins.

For more information about entry points in Xi-CAM, see the following documentation.

Navigate to your created package directory and create an editable pip install:

cd xicam.my_plugin
pip install -e .

This tells pip install your file locally by looking at the file, and the -e allows you to make changes to your code without having to reinstall.

If you change an entry point in, you must reinstall.

Selecting and Activating a GUIPlugin

We can activate any of the installed GUIPlugins by clicking on their name at the top. Let’s click on “My Plugin”:

Xi-CAM MyPlugin

MyPlugin’s interface.

Note that this plugin doesn’t do much yet; it simply displays the text “Stage 1…” You can also click “Stage 2” at the top, and you will see the text “Stage 2…” in the center.

How is MyPlugin Implemented?

The code for MyPlugin is implemented in xicam.package_name/xicam/package_name/

from qtpy.QtWidgets import QLabel

from xicam.plugins import GUIPlugin, GUILayout

class MyPlugin(GUIPlugin):
    # Defines the name of the plugin (how it is displayed in Xi-CAM)
    name = "My Plugin"

    def __init__(self, *args, **kwargs):
        # Insert code here

        # Modify stages here
        self.stages = {'Stage 1': GUILayout(QLabel("Stage 1...")),
                       "Stage 2": GUILayout(QLabel("Stage 2..."))}

        # Initialize the parent class, GUIPlugin
        super(MyPlugin, self).__init__(*args, **kwargs)

Cookiecutter set up this starter code for us. We have a derived version of GUIPlugin, which we call MyPlugin. It has the name “My Plugin”, which is how it will appear in the Xi-CAM GUI.

We then have an __init__ method to describe how to create a MyPlugin. Notice that there is a QLabel, which is simply text, added into two GUILayouts. These layouts are then added to the interface via self.stages.

What Is a Stage?

Visually, a stage is a stand-alone interface for a GUIPlugin. A GUIPlugin must have at least one stage but may have multiple stages. With multiple stages, each stage has its own interface and each stage can be selected in the top bar of Xi-CAM.

Stages for a GUIPlugin are accessible with self.stages. self.stages is a dictionary where each

  • key is the name of the stage

  • value is a GUILayouts

For example, we might define two stages as:

self.stages = {"A": GUILayout(QLabel("1")),
               "B": GUILayout(QLabel("2"))}

This will look like:

MyPlugin with multiple stages

The interface of a plugin named “My Plugin” with multiple stages, “A” and “B”. Note that “A” is currently selected, so we see the label “1” in the middle of the window.

What Is a GUILayout?

A GUILayout is a layout used to describe how widgets should be organized in a stage in a GUIPlugin.

Layout of Xi-CAM, corresponding to a GUILayout.

The layout corresponds to a 3x3 grid in the Xi-CAM main window, with the names center, left, right, lefttop, righttop, leftbottom, rightbottom. These names correspond to the arguments you can pass when creating a GUILayout.

You must provide at least one widget, which will be the center widget.

What Is a QLabel?

QLabel is a Qt widget provided by the Qt backend Xi-CAM makes use of. It acts a widget that holds simple text.

For more information on Qt, see Qt for Python Documentation.

How Do I Load Data into My Plugin?

In order to load data into a GUIPlugin, you must:

  • have access to or configure a databroker catalog

  • re-implement appendCatalog in your GUIPlugin derived class

    • this will need to have access to an internal widget to display the data

  • have a GUIPlugin selected in Xi-CAM

Configuring a Databroker Catalog

For purposes of this documentation, we will be using a sample msgpack catalog and a starter catalog.yml file you can download.

For general help about databroker, catalogs, and configuration, there is excellent documentation here: Additional documentation about catalogs can be found here:







After downloading these files, we will want to do three things:

  1. Decide where to put our data and move it there

  2. Update our catalog.yml paths to have a path directory the data is in

  3. Move our catalog.yml to a place it can be discovered

Moving the msgpack Data

You can choose where you’d like to copy or move your data. For purposes of this guide, we will create a new directory in our home called catalogs and move the downloaded msgpack file there.

Updating catalog.yml

Now that we’ve moved / copied our sample catalog msgpack file, we need to update our catalog.yml to tell it where it can find that data.

We will want to add a line under paths in catalog.yml that is the complete file path to the catalogs directory we added above.

Making catalog.yml Discoverable

To know where we can put our catalog.yml file, we can run the following in a Python interpreter:

from databroker import catalog_search_path

You can move the catalog.yml file in any of the paths listed. Note that typically there will be a more user-oriented path and a more global system-level path for the catalogs to find. You can copy the catalog.yml file to either (or both) path depending on how you want a machine set up.

Implementing appendCatalog

Let’s implement the appendCatalog method in MyPlugin so we can load the catalog. We will also be adding a widget to view the loaded catalog.

Inside of the MyPlugin class (located in xicam/my_plugin/, add the appendCatalog as follows:

from qtpy.QtWidgets import QLabel

from xicam.core.msg import logMessage
from xicam.plugins import GUILayout, GUIPlugin
from xicam.gui.widgets.imageviewmixins import CatalogView

class MyPlugin(GUIPlugin):
    # Define the name of the plugin (how it is displayed in Xi-CAM)
    name = "My Plugin"

    def __init__(self, *args, **kwargs):
        self._catalog_viewer = CatalogView()
        self._stream = "primary"
        self._field = "img"

        catalog_viewer_layout = GUILayout(self._catalog_viewer)
        # Modify stages here
        # self.stages = {"Stage 1": GUILayout(QLabel("Stage 1..."))}
        self.stages = {"View Catalog": catalog_viewer_layout}

        super(MyPlugin, self).__init__(*args, **kwargs)

    def appendCatalog(self, catalog):
        self._catalog_viewer.setCatalog(catalog, self._stream, self._field)
        logMessage(f"Opening catalog with stream {self._stream} and field {self._field}.")

API Reference