mirror of
https://github.com/google/blockly.git
synced 2026-05-12 15:10:11 +02:00
Beka Westberg
94 lines
2.6 KiB
TypeScript
94 lines
2.6 KiB
TypeScript
/**
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* @license
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* Copyright 2021 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @fileoverview The abstract class for a component with custom behaviour when a
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* block or bubble is dragged over or dropped on top of it.
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*/
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/**
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* The abstract class for a component with custom behaviour when a
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* block or bubble is dragged over or dropped on top of it.
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* @class
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*/
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import type {IDragTarget} from './interfaces/i_drag_target';
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import type {IDraggable} from './interfaces/i_draggable';
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import type {Rect} from './utils/rect';
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/**
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* Abstract class for a component with custom behaviour when a block or bubble
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* is dragged over or dropped on top of it.
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* @alias Blockly.DragTarget
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*/
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export class DragTarget implements IDragTarget {
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/**
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* The unique id for this component that is used to register with the
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* ComponentManager.
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*/
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// TODO(b/109816955): remove '!', see go/strict-prop-init-fix.
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id!: string;
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/**
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* Constructor for DragTarget. It exists to add the id property and should not
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* be called directly, only by a subclass.
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*/
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constructor() {}
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/**
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* Handles when a cursor with a block or bubble enters this drag target.
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* @param _dragElement The block or bubble currently being dragged.
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*/
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onDragEnter(_dragElement: IDraggable) {}
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// no-op
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/**
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* Handles when a cursor with a block or bubble is dragged over this drag
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* target.
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* @param _dragElement The block or bubble currently being dragged.
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*/
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onDragOver(_dragElement: IDraggable) {}
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// no-op
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/**
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* Handles when a cursor with a block or bubble exits this drag target.
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* @param _dragElement The block or bubble currently being dragged.
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*/
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onDragExit(_dragElement: IDraggable) {}
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// no-op
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/**
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* Handles when a block or bubble is dropped on this component.
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* Should not handle delete here.
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* @param _dragElement The block or bubble currently being dragged.
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*/
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onDrop(_dragElement: IDraggable) {}
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// no-op
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/**
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* Returns the bounding rectangle of the drag target area in pixel units
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* relative to the Blockly injection div.
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* @return The component's bounding box. Null if drag target area should be
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* ignored.
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*/
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getClientRect(): Rect|null {
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return null;
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}
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/**
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* Returns whether the provided block or bubble should not be moved after
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* being dropped on this component. If true, the element will return to where
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* it was when the drag started.
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* @param _dragElement The block or bubble currently being dragged.
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* @return Whether the block or bubble provided should be returned to drag
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* start.
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*/
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shouldPreventMove(_dragElement: IDraggable): boolean {
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return false;
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}
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}
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