620 lines
18 KiB
JavaScript
620 lines
18 KiB
JavaScript
/* eslint-disable no-console */
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/**
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* For command history tracking and undo functionality.
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* @module history
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* @license MIT
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* @copyright 2010 Jeff Schiller
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*/
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import { getHref, setHref, getRotationAngle, getBBox } from './utilities.js'
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/**
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* Group: Undo/Redo history management.
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*/
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export const HistoryEventTypes = {
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BEFORE_APPLY: 'before_apply',
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AFTER_APPLY: 'after_apply',
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BEFORE_UNAPPLY: 'before_unapply',
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AFTER_UNAPPLY: 'after_unapply'
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}
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/**
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* Base class for commands.
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*/
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export class Command {
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/**
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* @returns {string}
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*/
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getText () {
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return this.text
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}
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/**
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* @param {module:history.HistoryEventHandler} handler
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* @param {callback} applyFunction
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* @returns {void}
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*/
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apply (handler, applyFunction) {
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handler && handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this)
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applyFunction(handler)
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handler && handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this)
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}
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/**
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* @param {module:history.HistoryEventHandler} handler
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* @param {callback} unapplyFunction
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* @returns {void}
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*/
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unapply (handler, unapplyFunction) {
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handler && handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this)
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unapplyFunction()
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handler && handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this)
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}
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/**
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* @returns {Element[]} Array with element associated with this command
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* This function needs to be surcharged if multiple elements are returned.
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*/
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elements () {
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return [this.elem]
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}
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/**
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* @returns {string} String with element associated with this command
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*/
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type () {
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return this.constructor.name
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}
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}
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// Todo: Figure out why the interface members aren't showing
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// up (with or without modules applied), despite our apparently following
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// http://usejsdoc.org/tags-interface.html#virtual-comments
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/**
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* An interface that all command objects must implement.
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* @interface module:history.HistoryCommand
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*/
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/**
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* Applies.
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*
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* @function module:history.HistoryCommand#apply
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void|true}
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*/
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/**
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*
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* Unapplies.
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* @function module:history.HistoryCommand#unapply
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void|true}
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*/
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/**
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* Returns the elements.
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* @function module:history.HistoryCommand#elements
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* @returns {Element[]}
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*/
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/**
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* Gets the text.
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* @function module:history.HistoryCommand#getText
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* @returns {string}
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*/
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/**
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* Gives the type.
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* @function module:history.HistoryCommand.type
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* @returns {string}
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*/
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/**
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* @event module:history~Command#event:history
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* @type {module:history.HistoryCommand}
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*/
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/**
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* An interface for objects that will handle history events.
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* @interface module:history.HistoryEventHandler
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*/
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/**
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*
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* @function module:history.HistoryEventHandler#handleHistoryEvent
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* @param {string} eventType One of the HistoryEvent types
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* @param {module:history~Command#event:history} command
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* @listens module:history~Command#event:history
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* @returns {void}
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*
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*/
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/**
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* History command for an element that had its DOM position changed.
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* @implements {module:history.HistoryCommand}
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*/
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export class MoveElementCommand extends Command {
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/**
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* @param {Element} elem - The DOM element that was moved
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* @param {Element} oldNextSibling - The element's next sibling before it was moved
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* @param {Element} oldParent - The element's parent before it was moved
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* @param {string} [text] - An optional string visible to user related to this change
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*/
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constructor (elem, oldNextSibling, oldParent, text) {
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super()
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this.elem = elem
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this.text = text ? ('Move ' + elem.tagName + ' to ' + text) : ('Move ' + elem.tagName)
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this.oldNextSibling = oldNextSibling
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this.oldParent = oldParent
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this.newNextSibling = elem.nextSibling
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this.newParent = elem.parentNode
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}
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/**
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* Re-positions the element.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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apply (handler) {
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super.apply(handler, () => {
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this.elem = this.newParent.insertBefore(this.elem, this.newNextSibling)
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})
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}
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/**
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* Positions the element back to its original location.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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unapply (handler) {
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super.unapply(handler, () => {
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this.elem = this.oldParent.insertBefore(this.elem, this.oldNextSibling)
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})
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}
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}
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/**
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* History command for an element that was added to the DOM.
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* @implements {module:history.HistoryCommand}
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*/
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export class InsertElementCommand extends Command {
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/**
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* @param {Element} elem - The newly added DOM element
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* @param {string} text - An optional string visible to user related to this change
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*/
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constructor (elem, text) {
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super()
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this.elem = elem
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this.text = text || ('Create ' + elem.tagName)
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this.parent = elem.parentNode
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this.nextSibling = this.elem.nextSibling
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}
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/**
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* Re-inserts the new element.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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apply (handler) {
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super.apply(handler, () => {
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this.elem = this.parent.insertBefore(this.elem, this.nextSibling)
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})
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}
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/**
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* Removes the element.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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unapply (handler) {
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super.unapply(handler, () => {
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this.parent = this.elem.parentNode
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this.elem.remove()
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})
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}
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}
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/**
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* History command for an element removed from the DOM.
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* @implements {module:history.HistoryCommand}
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*/
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export class RemoveElementCommand extends Command {
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/**
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* @param {Element} elem - The removed DOM element
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* @param {Node} oldNextSibling - The DOM element's nextSibling when it was in the DOM
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* @param {Element} oldParent - The DOM element's parent
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* @param {string} [text] - An optional string visible to user related to this change
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*/
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constructor (elem, oldNextSibling, oldParent, text) {
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super()
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this.elem = elem
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this.text = text || ('Delete ' + elem.tagName)
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this.nextSibling = oldNextSibling
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this.parent = oldParent
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}
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/**
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* Re-removes the new element.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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apply (handler) {
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super.apply(handler, () => {
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this.parent = this.elem.parentNode
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this.elem.remove()
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})
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}
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/**
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* Re-adds the new element.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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unapply (handler) {
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super.unapply(handler, () => {
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if (!this.nextSibling) {
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console.error('Reference element was lost')
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}
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this.parent.insertBefore(this.elem, this.nextSibling) // Don't use `before` or `prepend` as `this.nextSibling` may be `null`
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})
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}
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}
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/**
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* @typedef {"#text"|"#href"|string} module:history.CommandAttributeName
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*/
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/**
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* @typedef {PlainObject<module:history.CommandAttributeName, string>} module:history.CommandAttributes
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*/
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/**
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* History command to make a change to an element.
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* Usually an attribute change, but can also be textcontent.
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* @implements {module:history.HistoryCommand}
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*/
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export class ChangeElementCommand extends Command {
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/**
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* @param {Element} elem - The DOM element that was changed
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* @param {module:history.CommandAttributes} attrs - Attributes to be changed with the values they had *before* the change
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* @param {string} text - An optional string visible to user related to this change
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*/
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constructor (elem, attrs, text) {
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super()
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this.elem = elem
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this.text = text ? ('Change ' + elem.tagName + ' ' + text) : ('Change ' + elem.tagName)
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this.newValues = {}
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this.oldValues = attrs
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for (const attr in attrs) {
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if (attr === '#text') {
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this.newValues[attr] = (elem) ? elem.textContent : ''
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} else if (attr === '#href') {
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this.newValues[attr] = getHref(elem)
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} else {
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this.newValues[attr] = elem.getAttribute(attr)
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}
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}
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}
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/**
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* Performs the stored change action.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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apply (handler) {
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super.apply(handler, () => {
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let bChangedTransform = false
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Object.entries(this.newValues).forEach(([attr, value]) => {
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if (value) {
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if (attr === '#text') {
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this.elem.textContent = value
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} else if (attr === '#href') {
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setHref(this.elem, value)
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} else {
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this.elem.setAttribute(attr, value)
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}
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} else if (attr === '#text') {
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this.elem.textContent = ''
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} else {
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this.elem.setAttribute(attr, '')
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this.elem.removeAttribute(attr)
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}
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if (attr === 'transform') { bChangedTransform = true }
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})
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// relocate rotational transform, if necessary
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if (!bChangedTransform) {
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const angle = getRotationAngle(this.elem)
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if (angle) {
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const bbox = getBBox(this.elem)
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const cx = bbox.x + bbox.width / 2
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const cy = bbox.y + bbox.height / 2
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const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('')
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if (rotate !== this.elem.getAttribute('transform')) {
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this.elem.setAttribute('transform', rotate)
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}
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}
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}
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})
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}
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/**
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* Reverses the stored change action.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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unapply (handler) {
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super.unapply(handler, () => {
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let bChangedTransform = false
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Object.entries(this.oldValues).forEach(([attr, value]) => {
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if (value) {
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if (attr === '#text') {
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this.elem.textContent = value
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} else if (attr === '#href') {
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setHref(this.elem, value)
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} else {
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this.elem.setAttribute(attr, value)
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}
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} else if (attr === '#text') {
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this.elem.textContent = ''
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} else {
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this.elem.removeAttribute(attr)
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}
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if (attr === 'transform') { bChangedTransform = true }
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})
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// relocate rotational transform, if necessary
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if (!bChangedTransform) {
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const angle = getRotationAngle(this.elem)
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if (angle) {
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const bbox = getBBox(this.elem)
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const cx = bbox.x + bbox.width / 2
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const cy = bbox.y + bbox.height / 2
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const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('')
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if (rotate !== this.elem.getAttribute('transform')) {
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this.elem.setAttribute('transform', rotate)
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}
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}
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}
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})
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}
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}
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// TODO: create a 'typing' command object that tracks changes in text
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// if a new Typing command is created and the top command on the stack is also a Typing
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// and they both affect the same element, then collapse the two commands into one
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/**
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* History command that can contain/execute multiple other commands.
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* @implements {module:history.HistoryCommand}
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*/
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export class BatchCommand extends Command {
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/**
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* @param {string} [text] - An optional string visible to user related to this change
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*/
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constructor (text) {
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super()
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this.text = text || 'Batch Command'
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this.stack = []
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}
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/**
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* Runs "apply" on all subcommands.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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apply (handler) {
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super.apply(handler, () => {
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this.stack.forEach((stackItem) => {
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console.assert(stackItem, 'stack item should not be null')
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stackItem && stackItem.apply(handler)
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})
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})
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}
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/**
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* Runs "unapply" on all subcommands.
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* @param {module:history.HistoryEventHandler} handler
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* @fires module:history~Command#event:history
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* @returns {void}
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*/
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unapply (handler) {
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super.unapply(handler, () => {
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this.stack.reverse().forEach((stackItem) => {
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console.assert(stackItem, 'stack item should not be null')
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stackItem && stackItem.unapply(handler)
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})
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})
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}
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/**
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* Iterate through all our subcommands.
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* @returns {Element[]} All the elements we are changing
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*/
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elements () {
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const elems = []
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let cmd = this.stack.length
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while (cmd--) {
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if (!this.stack[cmd]) continue
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const thisElems = this.stack[cmd].elements()
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let elem = thisElems.length
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while (elem--) {
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if (!elems.includes(thisElems[elem])) { elems.push(thisElems[elem]) }
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}
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}
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return elems
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}
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/**
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* Adds a given command to the history stack.
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* @param {Command} cmd - The undo command object to add
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* @returns {void}
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*/
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addSubCommand (cmd) {
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console.assert(cmd !== null, 'cmd should not be null')
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this.stack.push(cmd)
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}
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/**
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* @returns {boolean} Indicates whether or not the batch command is empty
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*/
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isEmpty () {
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return !this.stack.length
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}
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}
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/**
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*
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*/
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export class UndoManager {
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/**
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* @param {module:history.HistoryEventHandler} historyEventHandler
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*/
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constructor (historyEventHandler) {
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this.handler_ = historyEventHandler || null
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this.undoStackPointer = 0
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this.undoStack = []
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// this is the stack that stores the original values, the elements and
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// the attribute name for begin/finish
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this.undoChangeStackPointer = -1
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this.undoableChangeStack = []
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}
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/**
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* Resets the undo stack, effectively clearing the undo/redo history.
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* @returns {void}
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*/
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resetUndoStack () {
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this.undoStack = []
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this.undoStackPointer = 0
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}
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/**
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* @returns {Integer} Current size of the undo history stack
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*/
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getUndoStackSize () {
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return this.undoStackPointer
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}
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/**
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* @returns {Integer} Current size of the redo history stack
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*/
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getRedoStackSize () {
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return this.undoStack.length - this.undoStackPointer
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}
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/**
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* @returns {string} String associated with the next undo command
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*/
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getNextUndoCommandText () {
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return this.undoStackPointer > 0 ? this.undoStack[this.undoStackPointer - 1].getText() : ''
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}
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/**
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* @returns {string} String associated with the next redo command
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*/
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getNextRedoCommandText () {
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return this.undoStackPointer < this.undoStack.length ? this.undoStack[this.undoStackPointer].getText() : ''
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}
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/**
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* Performs an undo step.
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* @returns {void}
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*/
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undo () {
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if (this.undoStackPointer > 0) {
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const cmd = this.undoStack[--this.undoStackPointer]
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cmd.unapply(this.handler_)
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}
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}
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/**
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* Performs a redo step.
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* @returns {void}
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*/
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redo () {
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if (this.undoStackPointer < this.undoStack.length && this.undoStack.length > 0) {
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const cmd = this.undoStack[this.undoStackPointer++]
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cmd.apply(this.handler_)
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}
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}
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/**
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* Adds a command object to the undo history stack.
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* @param {Command} cmd - The command object to add
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* @returns {void}
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*/
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addCommandToHistory (cmd) {
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// TODO: we MUST compress consecutive text changes to the same element
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// (right now each keystroke is saved as a separate command that includes the
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// entire text contents of the text element)
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// TODO: consider limiting the history that we store here (need to do some slicing)
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// if our stack pointer is not at the end, then we have to remove
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// all commands after the pointer and insert the new command
|
|
if (this.undoStackPointer < this.undoStack.length && this.undoStack.length > 0) {
|
|
this.undoStack = this.undoStack.splice(0, this.undoStackPointer)
|
|
}
|
|
this.undoStack.push(cmd)
|
|
this.undoStackPointer = this.undoStack.length
|
|
}
|
|
|
|
/**
|
|
* This function tells the canvas to remember the old values of the
|
|
* `attrName` attribute for each element sent in. The elements and values
|
|
* are stored on a stack, so the next call to `finishUndoableChange()` will
|
|
* pop the elements and old values off the stack, gets the current values
|
|
* from the DOM and uses all of these to construct the undo-able command.
|
|
* @param {string} attrName - The name of the attribute being changed
|
|
* @param {Element[]} elems - Array of DOM elements being changed
|
|
* @returns {void}
|
|
*/
|
|
beginUndoableChange (attrName, elems) {
|
|
const p = ++this.undoChangeStackPointer
|
|
let i = elems.length
|
|
const oldValues = new Array(i); const elements = new Array(i)
|
|
while (i--) {
|
|
const elem = elems[i]
|
|
if (!elem) { continue }
|
|
elements[i] = elem
|
|
oldValues[i] = elem.getAttribute(attrName)
|
|
}
|
|
this.undoableChangeStack[p] = {
|
|
attrName,
|
|
oldValues,
|
|
elements
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This function returns a `BatchCommand` object which summarizes the
|
|
* change since `beginUndoableChange` was called. The command can then
|
|
* be added to the command history.
|
|
* @returns {BatchCommand} Batch command object with resulting changes
|
|
*/
|
|
finishUndoableChange () {
|
|
const p = this.undoChangeStackPointer--
|
|
const changeset = this.undoableChangeStack[p]
|
|
const { attrName } = changeset
|
|
const batchCmd = new BatchCommand('Change ' + attrName)
|
|
let i = changeset.elements.length
|
|
while (i--) {
|
|
const elem = changeset.elements[i]
|
|
if (!elem) { continue }
|
|
const changes = {}
|
|
changes[attrName] = changeset.oldValues[i]
|
|
if (changes[attrName] !== elem.getAttribute(attrName)) {
|
|
batchCmd.addSubCommand(new ChangeElementCommand(elem, changes, attrName))
|
|
}
|
|
}
|
|
this.undoableChangeStack[p] = null
|
|
return batchCmd
|
|
}
|
|
}
|