This guide is based on the Basic guide. It is recommended to review it for a comprehensive understanding of this guide.

BasicLasso/marquee selectionConnectionsCommentsRerouteArea Plugin

Selectable nodes

As explained in the Basic guide, you can enable node selection by using the selectableNodes extension

const selector = AreaExtensions.selector()
const accumulating = AreaExtensions.accumulateOnCtrl()
AreaExtensions.selectableNodes(area, selector, { accumulating });

The code indicates that users can select multiple nodes by holding down the Ctrl key, then these nodes can be moved together

Selectable custom elements

All elements added to the area can be added to the selector. They can act like nodes: can be selected and moved alongside other elements that are currently selected

Let's take a look at an example of adding an element to the selector

const id = 'element-id'
const label = 'element-type'
  translate(dx, dy) {
    // change position of current element by dx,dy
  unselect() {
    // triggered when removed from selector
    // here you can trigger styles updating

Once this step is completed, the translate function will be called every time a selected node or other element is moved.

Before making other selected elements move with the element being dragged, you need to mark the element that the user is directly interacting with.

selector.pick({ id, label })

When an event such as pointermove is triggered on your element, it's important to verify that it is a grabbed element, and then apply the offset to all the others.

if (selector.isPicked({ id, label })) selector.translate(dx, dy)

where dx, dy is an offset of your element within the area's coordinates. Keep in mind that if transform.k isn't equal to 1, the values will deviate from the screen coordinates.

This pick + isPicked approach prevents looping when calling selector.translate not only on the pointermove event, but also on any position changes of the element through other means.

Removing an element from the selector can be easily achieved by:

selector.remove({ id, label })

Extend selector

Apart from the AreaExtensions.selector() function, you have the option to directly use the AreaExtensions.Selector class.

const selector = new AreaExtensions.Selector()

The benefit of using a class-based selector is that it can be expanded and customized to include the functionalities you need, like tracking the selected or unselected elements

import type { SelectorEntity } from 'rete-area-plugin/_types/extensions/selectable'
class MySelector<E extends SelectorEntity> extends AreaExtensions.Selector<E> {
  add(entity: E, accumulate: boolean): void {
    super.add(entity, accumulate)
    console.log('added', entity)
  remove(entity: E): void {
    console.log('removed', entity)

Other use cases