Customization Service

There are a lot of places where users may want to configure certain elements differently between different modes or for different deployments. A mode example might be the use of a custom overlay showing mode related DICOM header information such as radiation dose or patient age.

The use of this service enables these to be defined in a typed fashion by providing an easy way to set default values for this, but to allow a non-default value to be specified by the configuration or mode.

This service is a UI service in that part of the registration allows for registering UI components and types to deal with, but it does not directly provide an UI displayable elements unless customized to do so.

Note: Customization Service itself doesn't implement the actual customization, but rather just provide mechanism to register reusable prototypes, to configure those prototypes with actual configurations, and to use the configured objects (components, data, whatever). Actual implementation of the customization is totally up to the component that supports customization. (for example, `CustomizableViewportOverlay` component uses `CustomizationService` to implement viewport overlay that is easily customizable from configuration.)

Global, Default and Mode customizations

There are various customization sets that define the lifetime/setup of the customization. The global customizations are those used for overriding customizations defined elsewhere, and allow replacing a customization.

Mode customizations are only registered for the lifetime of the mode, allowing the mode definition to update/modify the underlying behaviour. This is related to default customizations, which provide a fallback if the mode or global customization isn't defined. Default customizations may only be defined once, otherwise throwing an exception.

Append and Merge Customizations

In addition to the replace a customization, there is the ability to merge or append a customization. The merge customization simply applies the lodash merge functionality to the existing customization, with the new one, while the append customization modifies the customization by appending to the value.

Append Behaviour

When a list is found in the destination object, the append source object is examined to see how to handle the change. If the source is simply a list, then the list object is appended, and no additional changes are performed. However, if the source is an object other than a list, then the iterable attributes of the object are examined to match child objects to the destination list, according to the following table:

• Natural or zero number value - match the given index location and merge at the point
• Fractional number value - insert at a new point in the list, starting from the end or beginning
• keyword - match a value having the same id as the keyword, inserting at the end, or at _priority as defined in the keywords above.

Example Append

const destination = [
  1,
  {id: 'two', value: 2},
  {id: 'three', value: 3}
]

const source = {
  two: { value: 'updated2' },
  1: { extraValue: 2 },
  1.0001: { id: 'inserted', value: 1.0001 },
  -1: { value: -3 },
}

Results in two updates to destination[1], the first using an id match on 'two', while the second one does a positional match on 1, resulting in the value {id: 'two', value: 'updated2', extraValue: 2 }

Then, it inserts the id 'inserted' after position 1.

Finally, position -1 (the end position) is updated from value 3 to value -3.

The ordering is not specified on any of these insertions, so can happen out of order. Use multiple updates to perform order specific inserts.

Registering customizable modules (or defining customization prototypes)

Extensions and Modes can register customization templates they support. It is done by adding getCustomizationModule() in the extension or mode definition.

Below is the protocol of the getCustomizationModule(), if defined in Typescript.

  getCustomizationModule() : { name: string, value: any }[]

If the name is 'default', it is the a default customization, while if it is 'global', then it is a priority/over-riding customization.

In the value of each customizations, you will define customization prototype(s). These customization prototype(s) can be considered like "Prototype" in Javascript. These can be used to extend the customization definitions from configurations. Default customizations will be often used to define all the customization prototypes, Default customizations will be often used to define all the customization prototypes, as they will be loaded automatically along with the defining extension or mode.

For example, the @ohif/extension-default extension defines,

  getCustomizationModule: () => [
    //...

    {
      name: 'default',
      value: [
        {
          id: 'ohif.overlayItem',
          content: function (props) {
            if (this.condition && !this.condition(props)) return null;

            const { instance } = props;
            const value =
              instance && this.attribute
                ? instance[this.attribute]
                : this.contentF && typeof this.contentF === 'function'
                ? this.contentF(props)
                : null;
            if (!value) return null;

            return (
              <span
                className="overlay-item flex flex-row"
                style={{ color: this.color || undefined }}
                title={this.title || ''}
              >
                {this.label && (
                  <span className="mr-1 shrink-0">{this.label}</span>
                )}
                <span className="font-light">{value}</span>
              </span>
            );
          },
        },
      ],
    },

    //...
  ],

And this ohif.overlayItem object will be used as a prototype (and template) to define items to be displayed on CustomizableViewportOverlay. See how we use the ohif.overlayItem in the example below.

Configuring customizations

There are several ways to register customizations. The APP_CONFIG.customizationService field is used as a per-configuration entry. This object can list single configurations by id, or it can list sets of customizations by referring to the customizationModule in an extension.

NOTE that these definitions from APP_CONFIG will be loaded by default, just like extension/modes default customization.

Below is the example configuration for CustomizableViewportOverlay component customization, using the customization prototype ohif.overlayItem defined in ohif/extension-defaul extension.:

window.config = {
  //...

  // in the APP_CONFIG file set the top right area to show the patient name
  // using PN: as a prefix when the study has a non-empty patient name.
  customizationService: {
    cornerstoneOverlayTopRight: {
      id: 'cornerstoneOverlayTopRight',
      items: [
        {
          id: 'PatientNameOverlay',
          // Note below that here we are using the customization prototype of
          // `ohif.overlayItem` which was registered to the customization module in
          // `ohif/extension-default` extension.
          customizationType: 'ohif.overlayItem',
          // the following props are passed to the `ohif.overlayItem` prototype
          // which is used to render the overlay item based on the label, color,
          // conditions, etc.
          attribute: 'PatientName',
          label: 'PN:',
          title: 'Patient Name',
          color: 'yellow',
          condition: ({ instance }) =>
            instance &&
            instance.PatientName &&
            instance.PatientName.Alphabetic,
          contentF: ({ instance, formatters: { formatPN } }) =>
            formatPN(instance.PatientName.Alphabetic) +
            ' ' +
            (instance.PatientSex ? '(' + instance.PatientSex + ')' : ''),
        },
      ],
    },
  },

  //...
}

In the customization configuration, you can use customizationType fields to define the prototype that customization object should inherit from. The customizationType field is simply the id of another customization object.

Implementing customization using CustomizationService

Mode Customizations

Mode-specific customizations are no different from the global ones, except that the mode customizations are specific to one mode and are not globally applied. Mode-specific customizations are also cleared before the mode onModeEnter is called, and they can have new values registered in the onModeEnter

Following on our example above to customize the overlay, we can now add a mode customization with a bottom-right overlay.

// Import the type from the extension itself
import OverlayUICustomization from "@ohif/cornerstone-extension";

// In the mode itself, customizations can be registered:
onModeEnter: {
  // Note how the object can be strongly typed
  const bottomRight: OverlayUICustomization =     {
      id: 'cornerstoneOverlayBottomRight',
      // Note the type is the previously registered ohif.cornerstoneOverlay
      customizationType: 'ohif.cornerstoneOverlay',
      // The cornerstoneOverlay definition requires an items list here.
      items: [
        // Custom definitions for the context menu here.
      ],
    };
  customizationService.addModeCustomizations(bottomRight);
}

The mode customizations are retrieved via the getModeCustomization function, providing an id, and optionally a default value. The retrieval will return, in order:

1. Global customization with the given id.
2. Mode customization with the id.
3. The default value specified.

The return value then inherits the customizationType instance, so that the value can be typed and have default values and functionality provided. The object can then be used in a way defined by the extension provided that customization point.

const cornerstoneOverlay = customizationService.getModeCustomization(
  "cornerstoneOverlay",
  { customizationType: "ohif.cornerstoneOverlay" },
);

const { component: overlayComponent, props } =
  customizationService.getComponent(cornerstoneOverlay);

return (
  <defaultComponent {...props} overlay={cornerstoneOverlay}></defaultComponent>
);

This example shows fetching the default component to render this object. The returned object would be a sub-type of ohif.cornerstoneOverlay if defined. This object can be a React component or other object such as a commands list, for example (this example comes from the context menu customizations as that one uses commands lists):

cornerstoneContextMenu = customizationService.get(
  "cornerstoneContextMenu",
  defaultMenu,
);
commandsManager.run(cornerstoneContextMenu, extraProps);

Global Customizations

Global customizations are retrieved in the same was as mode customizations, except that the getGlobalCustomization is called instead of the mode call.

Types

Some types for the customization service are provided by the @ohif/ui types export. Additionally, extensions can provide a Types export with custom typing, allowing for better typing for the extension specific capabilities. This allows for having strong typing when declaring customizations, for example:

import { Types } from '@ohif/ui';

const customContextMenu: Types.ContextMenu.Menu =
    {
      id: 'cornerstoneContextMenu',
      customizationType: 'ohif.contextMenu',
      // items will be type checked to be in accordance with UIContextMenu.items
      items: [ ... ]
    },

Inheritance

JavaScript property inheritance can be supplied by defining customizations with id corresponding to the customizationType value. For example:

getCustomizationModule = () => ([
  {
    name: 'default',
    value: [
      {
        id: 'ohif.overlayItem',
        content: function (props) {
          return (<p><b>{this.label}</b> {props.instance[this.attribute]}</p>)
        },
      },
    ],
  }
])

defines an overlay item which has a React content object as the render value. This can then be used by specifying a customizationType of ohif.overlayItem, for example:

const overlayItem: Types.UIOverlayItem = {
  id: 'anOverlayItem',
  customizationType: 'ohif.overlayItem',
  attribute: 'PatientName',
  label: 'PN:',
};

Customizations

This section can be used to specify various customization capabilities.

Text color for StudyBrowser tabs

This is the recommended pattern for deep customization of class attributes, making it fine grained, and have it apply a set of attributes, mostly from tailwind. In this case it is a double indirection, as the buttons class uses it's own internal class names.

• Name: 'class:StudyBrowser'
• Attributes: true for the is active true text color false for the is active false text color. ** Values are button colors, from the Button class, eg default, white, black

customRoutes

• Name: customRoutes global
• Attributes: routes of type List of route objects (see route/index.tsx) is a set of route objects to add. Should any element of routes match an existing baked in element, the baked in one will be replaced. ** notFoundRoute is the route to display when nothing is found (this has to be at the end of the overall list, so can't be added to routes)

Example

{
  id: 'customRoutes',
  routes: [
    {
      path: '/myroute',
      children: MyRouteReactFunction,
    }
  ],
}

There is a usage of this example commented out in config/default.js that looks like the code below. This example is provided by the default extension, again with commented out code. Uncomment the getCustomizationModule customRoutes code in the default module to activate this, and then go to: http://localhost:3000/custom to see the custom route.

Note the name of this is the customization module name, which usually won't match the id, and in fact there can be multiple customization objects defined for a single customization module, to allow for customizing sets of related values.

customizationService: [
    // Shows a custom route -access via http://localhost:3000/custom
    '@ohif/extension-default.customizationModule.helloPage',
],

Customizable Viewport Overlay

Below is the full example configuration of the customizable viewport overlay and the screenshot of the result overlay.

There are working examples that can be run with:

set APP_CONFIG=config/customization.js
yarn dev

// this is part of customization.js, an example customization dataset
window.config = {

   // This shows how to append to the customization data
   customizationService: [
    {
      id: '@ohif/cornerstoneOverlay',
      // Append recursively, rather than replacing
      merge: 'Append',
      topRightItems: {
        id: 'cornerstoneOverlayTopRight',
        items: [
          {
            id: 'PatientNameOverlay',
            // Note below that here we are using the customization prototype of
            // `ohif.overlayItem` which was registered to the customization module in
            // `ohif/extension-default` extension.
            customizationType: 'ohif.overlayItem',
            // the following props are passed to the `ohif.overlayItem` prototype
            // which is used to render the overlay item based on the label, color,
            // conditions, etc.
            attribute: 'PatientName',
            label: 'PN:',
            title: 'Patient Name',
            color: 'yellow',
            condition: ({ instance }) => instance?.PatientName,
            contentF: ({ instance, formatters: { formatPN } }) =>
              formatPN(instance.PatientName) +
              (instance.PatientSex ? ' (' + instance.PatientSex + ')' : ''),
          },
        ],
      },

      topLeftItems: {
        items: {
          // Note the -10000 means -10000 + length of existing list, which is
          // much before the start of hte list, so put the new value at the start.
          '-10000':
          {
            id: 'Species',
            customizationType: 'ohif.overlayItem',
            label: 'Species:',
            color: 'red',
            background: 'green',
            condition: ({ instance }) =>
              instance?.PatientSpeciesDescription,
            contentF: ({ instance }) =>
              instance.PatientSpeciesDescription +
              '/' +
              instance.PatientBreedDescription,
          },
        },
      },
    },
...

Context Menus

Context menus can be created by defining the menu structure and click interaction, as defined in the ContextMenu/types. There are examples below specific to the cornerstone context, because the actual click handler and attributes used to decide when and how to display the menu are specific to the context used for where the menu is displayed.

Cornerstone Context Menu

The default cornerstone context menu can be customized by setting the cornerstoneContextMenu. For a full example, see findingsContextMenu.

Customizable Cornerstone Viewport Click Behaviour

The behaviour on clicking on the cornerstone viewport can be customized by setting the cornerstoneViewportClickCommands. This is intended to support both the cornerstone 3D internal commands as well as things like context menus. Currently it supports buttons 1-3, as well as modifier keys by associating a commands list with the button to click. See initContextMenu for more details.

Please add additional customizations above this section

3rd Party implementers may be added to this table via pull requests.