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https://github.com/google/blockly.git
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105 lines
3.0 KiB
TypeScript
105 lines
3.0 KiB
TypeScript
/**
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* @license
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* Copyright 2017 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* Methods for dragging a workspace visually.
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*
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* @class
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*/
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import * as goog from '../closure/goog/goog.js';
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goog.declareModuleId('Blockly.WorkspaceDragger');
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import * as common from './common.js';
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import {Coordinate} from './utils/coordinate.js';
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import type {WorkspaceSvg} from './workspace_svg.js';
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/**
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* Class for a workspace dragger. It moves the workspace around when it is
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* being dragged by a mouse or touch.
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* Note that the workspace itself manages whether or not it has a drag surface
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* and how to do translations based on that. This simply passes the right
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* commands based on events.
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*/
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export class WorkspaceDragger {
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private readonly horizontalScrollEnabled_: boolean;
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private readonly verticalScrollEnabled_: boolean;
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protected startScrollXY_: Coordinate;
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/** @param workspace The workspace to drag. */
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constructor(private workspace: WorkspaceSvg) {
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/** Whether horizontal scroll is enabled. */
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this.horizontalScrollEnabled_ = this.workspace.isMovableHorizontally();
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/** Whether vertical scroll is enabled. */
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this.verticalScrollEnabled_ = this.workspace.isMovableVertically();
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/**
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* The scroll position of the workspace at the beginning of the drag.
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* Coordinate system: pixel coordinates.
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*/
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this.startScrollXY_ = new Coordinate(workspace.scrollX, workspace.scrollY);
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}
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/**
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* Sever all links from this object.
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*
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* @suppress {checkTypes}
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* @internal
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*/
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dispose() {
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// AnyDuringMigration because: Type 'null' is not assignable to type
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// 'WorkspaceSvg'.
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this.workspace = null as AnyDuringMigration;
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}
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/**
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* Start dragging the workspace.
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*
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* @internal
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*/
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startDrag() {
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if (common.getSelected()) {
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common.getSelected()!.unselect();
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}
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this.workspace.setupDragSurface();
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}
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/**
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* Finish dragging the workspace and put everything back where it belongs.
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*
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* @param currentDragDeltaXY How far the pointer has moved from the position
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* at the start of the drag, in pixel coordinates.
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* @internal
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*/
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endDrag(currentDragDeltaXY: Coordinate) {
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// Make sure everything is up to date.
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this.drag(currentDragDeltaXY);
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this.workspace.resetDragSurface();
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}
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/**
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* Move the workspace based on the most recent mouse movements.
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*
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* @param currentDragDeltaXY How far the pointer has moved from the position
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* at the start of the drag, in pixel coordinates.
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* @internal
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*/
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drag(currentDragDeltaXY: Coordinate) {
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const newXY = Coordinate.sum(this.startScrollXY_, currentDragDeltaXY);
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if (this.horizontalScrollEnabled_ && this.verticalScrollEnabled_) {
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this.workspace.scroll(newXY.x, newXY.y);
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} else if (this.horizontalScrollEnabled_) {
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this.workspace.scroll(newXY.x, this.workspace.scrollY);
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} else if (this.verticalScrollEnabled_) {
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this.workspace.scroll(this.workspace.scrollX, newXY.y);
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} else {
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throw new TypeError('Invalid state.');
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}
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}
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}
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