Files
blockly/core/drag_target.ts
Christopher Allen 11c219c537 feat(dragging): Create (new) IDragger and IDraggable interfaces (#7953)
* chore(dragging): Rename core/interfaces/i_draggable.ts

  Rename core/interfaces/i_draggable.ts to
  core/interfaces/i_draggable.old.ts to make room for new
  IDraggable.  Do not rename actual interface as it's not yet
  clear that it will be necessary for both to coexist as
  imports in the same file.


* feat(dragging): Introduce new IDraggable interface

* feat(dragging): Introduce new IDragger interface

---------

Co-authored-by: Beka Westberg <bwestberg@google.com>
2024-03-22 16:21:14 +00:00

94 lines
2.6 KiB
TypeScript

/**
* @license
* Copyright 2021 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
/**
* The abstract class for a component with custom behaviour when a
* block or bubble is dragged over or dropped on top of it.
*
* @class
*/
// Former goog.module ID: Blockly.DragTarget
import type {IDragTarget} from './interfaces/i_drag_target.js';
import type {IDraggable} from './interfaces/i_draggable.old.js';
import type {Rect} from './utils/rect.js';
/**
* Abstract class for a component with custom behaviour when a block or bubble
* is dragged over or dropped on top of it.
*/
export class DragTarget implements IDragTarget {
/**
* The unique id for this component that is used to register with the
* ComponentManager.
*/
// TODO(b/109816955): remove '!', see go/strict-prop-init-fix.
id!: string;
/**
* Constructor for DragTarget. It exists to add the id property and should not
* be called directly, only by a subclass.
*/
constructor() {}
/**
* Handles when a cursor with a block or bubble enters this drag target.
*
* @param _dragElement The block or bubble currently being dragged.
*/
onDragEnter(_dragElement: IDraggable) {}
// no-op
/**
* Handles when a cursor with a block or bubble is dragged over this drag
* target.
*
* @param _dragElement The block or bubble currently being dragged.
*/
onDragOver(_dragElement: IDraggable) {}
// no-op
/**
* Handles when a cursor with a block or bubble exits this drag target.
*
* @param _dragElement The block or bubble currently being dragged.
*/
onDragExit(_dragElement: IDraggable) {}
// no-op
/**
* Handles when a block or bubble is dropped on this component.
* Should not handle delete here.
*
* @param _dragElement The block or bubble currently being dragged.
*/
onDrop(_dragElement: IDraggable) {}
// no-op
/**
* Returns the bounding rectangle of the drag target area in pixel units
* relative to the Blockly injection div.
*
* @returns The component's bounding box. Null if drag target area should be
* ignored.
*/
getClientRect(): Rect | null {
return null;
}
/**
* Returns whether the provided block or bubble should not be moved after
* being dropped on this component. If true, the element will return to where
* it was when the drag started.
*
* @param _dragElement The block or bubble currently being dragged.
* @returns Whether the block or bubble provided should be returned to drag
* start.
*/
shouldPreventMove(_dragElement: IDraggable): boolean {
return false;
}
}