/**
* For command history tracking and undo functionality
* @module history
* @license MIT
* @copyright 2010 Jeff Schiller
*/
import {getHref, setHref, getRotationAngle, isNullish} from './utilities.js';
import {removeElementFromListMap} from './svgtransformlist.js';
/**
* Group: Undo/Redo history management
*/
export const HistoryEventTypes = {
BEFORE_APPLY: 'before_apply',
AFTER_APPLY: 'after_apply',
BEFORE_UNAPPLY: 'before_unapply',
AFTER_UNAPPLY: 'after_unapply'
};
// const removedElements = {};
/**
* Base class for commands.
*/
class Command {
/**
* @returns {string}
*/
getText () {
return this.text;
}
}
// Todo: Figure out why the interface members aren't showing
// up (with or without modules applied), despite our apparently following
// http://usejsdoc.org/tags-interface.html#virtual-comments
/**
* An interface that all command objects must implement.
* @interface module:history.HistoryCommand
*/
/**
* Applies
*
* @function module:history.HistoryCommand#apply
* @param {module:history.HistoryEventHandler}
* @fires module:history~Command#event:history
* @returns {void|true}
*/
/**
*
* Unapplies
* @function module:history.HistoryCommand#unapply
* @param {module:history.HistoryEventHandler}
* @fires module:history~Command#event:history
* @returns {void|true}
*/
/**
* Returns the elements
* @function module:history.HistoryCommand#elements
* @returns {Element[]}
*/
/**
* Gets the text
* @function module:history.HistoryCommand#getText
* @returns {string}
*/
/**
* Gives the type
* @function module:history.HistoryCommand.type
* @returns {string}
*/
/**
* Gives the type
* @function module:history.HistoryCommand#type
* @returns {string}
*/
/**
* @event module:history~Command#event:history
* @type {module:history.HistoryCommand}
*/
/**
* An interface for objects that will handle history events.
* @interface module:history.HistoryEventHandler
*/
/**
*
* @function module:history.HistoryEventHandler#handleHistoryEvent
* @param {string} eventType One of the HistoryEvent types
* @param {module:history~Command#event:history} command
* @listens module:history~Command#event:history
* @returns {void}
*
*/
/**
* History command for an element that had its DOM position changed.
* @implements {module:history.HistoryCommand}
* @param {Element} elem - The DOM element that was moved
* @param {Element} oldNextSibling - The element's next sibling before it was moved
* @param {Element} oldParent - The element's parent before it was moved
* @param {string} [text] - An optional string visible to user related to this change
*/
export class MoveElementCommand extends Command {
constructor (elem, oldNextSibling, oldParent, text) {
super();
this.elem = elem;
this.text = text ? ('Move ' + elem.tagName + ' to ' + text) : ('Move ' + elem.tagName);
this.oldNextSibling = oldNextSibling;
this.oldParent = oldParent;
this.newNextSibling = elem.nextSibling;
this.newParent = elem.parentNode;
}
type () { // eslint-disable-line class-methods-use-this
return 'svgedit.history.MoveElementCommand';
}
/**
* Re-positions the element.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
apply (handler) {
// TODO(codedread): Refactor this common event code into a base HistoryCommand class.
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this);
}
this.elem = this.newParent.insertBefore(this.elem, this.newNextSibling);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this);
}
}
/**
* Positions the element back to its original location.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
this.elem = this.oldParent.insertBefore(this.elem, this.oldNextSibling);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this);
}
}
/**
* @returns {Element[]} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
MoveElementCommand.type = MoveElementCommand.prototype.type;
/**
* History command for an element that was added to the DOM.
* @implements {module:history.HistoryCommand}
*
* @param {Element} elem - The newly added DOM element
* @param {string} text - An optional string visible to user related to this change
*/
export class InsertElementCommand extends Command {
constructor (elem, text) {
super();
this.elem = elem;
this.text = text || ('Create ' + elem.tagName);
this.parent = elem.parentNode;
this.nextSibling = this.elem.nextSibling;
}
type () { // eslint-disable-line class-methods-use-this
return 'svgedit.history.InsertElementCommand';
}
/**
* Re-inserts the new element.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
apply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this);
}
this.elem = this.parent.insertBefore(this.elem, this.nextSibling);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this);
}
}
/**
* Removes the element.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
this.parent = this.elem.parentNode;
this.elem = this.elem.parentNode.removeChild(this.elem);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this);
}
}
/**
* @returns {Element[]} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
InsertElementCommand.type = InsertElementCommand.prototype.type;
/**
* History command for an element removed from the DOM.
* @implements {module:history.HistoryCommand}
* @param {Element} elem - The removed DOM element
* @param {Node} oldNextSibling - The DOM element's nextSibling when it was in the DOM
* @param {Element} oldParent - The DOM element's parent
* @param {string} [text] - An optional string visible to user related to this change
*/
export class RemoveElementCommand extends Command {
constructor (elem, oldNextSibling, oldParent, text) {
super();
this.elem = elem;
this.text = text || ('Delete ' + elem.tagName);
this.nextSibling = oldNextSibling;
this.parent = oldParent;
// special hack for webkit: remove this element's entry in the svgTransformLists map
removeElementFromListMap(elem);
}
type () { // eslint-disable-line class-methods-use-this
return 'svgedit.history.RemoveElementCommand';
}
/**
* Re-removes the new element.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
apply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this);
}
removeElementFromListMap(this.elem);
this.parent = this.elem.parentNode;
this.elem = this.parent.removeChild(this.elem);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this);
}
}
/**
* Re-adds the new element.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
removeElementFromListMap(this.elem);
if (isNullish(this.nextSibling)) {
if (window.console) {
console.log('Error: reference element was lost'); // eslint-disable-line no-console
}
}
this.parent.insertBefore(this.elem, this.nextSibling); // Don't use `before` or `prepend` as `this.nextSibling` may be `null`
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this);
}
}
/**
* @returns {Element[]} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
RemoveElementCommand.type = RemoveElementCommand.prototype.type;
/**
* @typedef {"#text"|"#href"|string} module:history.CommandAttributeName
*/
/**
* @typedef {PlainObject<module:history.CommandAttributeName, string>} module:history.CommandAttributes
*/
/**
* History command to make a change to an element.
* Usually an attribute change, but can also be textcontent.
* @implements {module:history.HistoryCommand}
* @param {Element} elem - The DOM element that was changed
* @param {module:history.CommandAttributes} attrs - Attributes to be changed with the values they had *before* the change
* @param {string} text - An optional string visible to user related to this change
*/
export class ChangeElementCommand extends Command {
constructor (elem, attrs, text) {
super();
this.elem = elem;
this.text = text ? ('Change ' + elem.tagName + ' ' + text) : ('Change ' + elem.tagName);
this.newValues = {};
this.oldValues = attrs;
for (const attr in attrs) {
if (attr === '#text') {
this.newValues[attr] = elem.textContent;
} else if (attr === '#href') {
this.newValues[attr] = getHref(elem);
} else {
this.newValues[attr] = elem.getAttribute(attr);
}
}
}
type () { // eslint-disable-line class-methods-use-this
return 'svgedit.history.ChangeElementCommand';
}
/**
* Performs the stored change action.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {true}
*/
apply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this);
}
let bChangedTransform = false;
Object.entries(this.newValues).forEach(([attr, value]) => {
if (value) {
if (attr === '#text') {
this.elem.textContent = value;
} else if (attr === '#href') {
setHref(this.elem, value);
} else {
this.elem.setAttribute(attr, value);
}
} else if (attr === '#text') {
this.elem.textContent = '';
} else {
this.elem.setAttribute(attr, '');
this.elem.removeAttribute(attr);
}
if (attr === 'transform') { bChangedTransform = true; }
});
// relocate rotational transform, if necessary
if (!bChangedTransform) {
const angle = getRotationAngle(this.elem);
if (angle) {
const bbox = this.elem.getBBox();
const cx = bbox.x + bbox.width / 2,
cy = bbox.y + bbox.height / 2;
const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('');
if (rotate !== this.elem.getAttribute('transform')) {
this.elem.setAttribute('transform', rotate);
}
}
}
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this);
}
return true;
}
/**
* Reverses the stored change action.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {true}
*/
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
let bChangedTransform = false;
Object.entries(this.oldValues).forEach(([attr, value]) => {
if (value) {
if (attr === '#text') {
this.elem.textContent = value;
} else if (attr === '#href') {
setHref(this.elem, value);
} else {
this.elem.setAttribute(attr, value);
}
} else if (attr === '#text') {
this.elem.textContent = '';
} else {
this.elem.removeAttribute(attr);
}
if (attr === 'transform') { bChangedTransform = true; }
});
// relocate rotational transform, if necessary
if (!bChangedTransform) {
const angle = getRotationAngle(this.elem);
if (angle) {
const bbox = this.elem.getBBox();
const cx = bbox.x + bbox.width / 2,
cy = bbox.y + bbox.height / 2;
const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('');
if (rotate !== this.elem.getAttribute('transform')) {
this.elem.setAttribute('transform', rotate);
}
}
}
// Remove transformlist to prevent confusion that causes bugs like 575.
removeElementFromListMap(this.elem);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this);
}
return true;
}
/**
* @returns {Element[]} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
ChangeElementCommand.type = ChangeElementCommand.prototype.type;
// TODO: create a 'typing' command object that tracks changes in text
// if a new Typing command is created and the top command on the stack is also a Typing
// and they both affect the same element, then collapse the two commands into one
/**
* History command that can contain/execute multiple other commands.
* @implements {module:history.HistoryCommand}
*/
export class BatchCommand extends Command {
/**
* @param {string} [text] - An optional string visible to user related to this change
*/
constructor (text) {
super();
this.text = text || 'Batch Command';
this.stack = [];
}
type () { // eslint-disable-line class-methods-use-this
return 'svgedit.history.BatchCommand';
}
/**
* Runs "apply" on all subcommands.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
apply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this);
}
const len = this.stack.length;
for (let i = 0; i < len; ++i) {
this.stack[i].apply(handler);
}
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this);
}
}
/**
* Runs "unapply" on all subcommands.
* @param {module:history.HistoryEventHandler} handler
* @fires module:history~Command#event:history
* @returns {void}
*/
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
for (let i = this.stack.length - 1; i >= 0; i--) {
this.stack[i].unapply(handler);
}
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this);
}
}
/**
* Iterate through all our subcommands.
* @returns {Element[]} All the elements we are changing
*/
elements () {
const elems = [];
let cmd = this.stack.length;
while (cmd--) {
const thisElems = this.stack[cmd].elements();
let elem = thisElems.length;
while (elem--) {
if (!elems.includes(thisElems[elem])) { elems.push(thisElems[elem]); }
}
}
return elems;
}
/**
* Adds a given command to the history stack.
* @param {Command} cmd - The undo command object to add
* @returns {void}
*/
addSubCommand (cmd) {
this.stack.push(cmd);
}
/**
* @returns {boolean} Indicates whether or not the batch command is empty
*/
isEmpty () {
return !this.stack.length;
}
}
BatchCommand.type = BatchCommand.prototype.type;
/**
*
*/
export class UndoManager {
/**
* @param {module:history.HistoryEventHandler} historyEventHandler
*/
constructor (historyEventHandler) {
this.handler_ = historyEventHandler || null;
this.undoStackPointer = 0;
this.undoStack = [];
// this is the stack that stores the original values, the elements and
// the attribute name for begin/finish
this.undoChangeStackPointer = -1;
this.undoableChangeStack = [];
}
/**
* Resets the undo stack, effectively clearing the undo/redo history.
* @returns {void}
*/
resetUndoStack () {
this.undoStack = [];
this.undoStackPointer = 0;
}
/**
* @returns {Integer} Current size of the undo history stack
*/
getUndoStackSize () {
return this.undoStackPointer;
}
/**
* @returns {Integer} Current size of the redo history stack
*/
getRedoStackSize () {
return this.undoStack.length - this.undoStackPointer;
}
/**
* @returns {string} String associated with the next undo command
*/
getNextUndoCommandText () {
return this.undoStackPointer > 0 ? this.undoStack[this.undoStackPointer - 1].getText() : '';
}
/**
* @returns {string} String associated with the next redo command
*/
getNextRedoCommandText () {
return this.undoStackPointer < this.undoStack.length ? this.undoStack[this.undoStackPointer].getText() : '';
}
/**
* Performs an undo step.
* @returns {void}
*/
undo () {
if (this.undoStackPointer > 0) {
const cmd = this.undoStack[--this.undoStackPointer];
cmd.unapply(this.handler_);
}
}
/**
* Performs a redo step.
* @returns {void}
*/
redo () {
if (this.undoStackPointer < this.undoStack.length && this.undoStack.length > 0) {
const cmd = this.undoStack[this.undoStackPointer++];
cmd.apply(this.handler_);
}
}
/**
* Adds a command object to the undo history stack.
* @param {Command} cmd - The command object to add
* @returns {void}
*/
addCommandToHistory (cmd) {
// TODO: we MUST compress consecutive text changes to the same element
// (right now each keystroke is saved as a separate command that includes the
// entire text contents of the text element)
// TODO: consider limiting the history that we store here (need to do some slicing)
// if our stack pointer is not at the end, then we have to remove
// 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), elements = new Array(i);
while (i--) {
const elem = elems[i];
if (isNullish(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 (isNullish(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;
}
}