svgedit/editor/history.js

601 lines
17 KiB
JavaScript

/**
* Package: svedit.history
*
* Licensed under the MIT License
*
* Copyright(c) 2010 Jeff Schiller
*/
import {getHref, setHref, getRotationAngle} from './svgutils.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 = {};
/**
* An interface that all command objects must implement.
* @typedef {Object} svgedit.history.HistoryCommand
* void apply(svgedit.history.HistoryEventHandler);
* void unapply(svgedit.history.HistoryEventHandler);
* Element[] elements();
* String getText();
*
* static String type();
* }
*
* Interface: svgedit.history.HistoryEventHandler
* An interface for objects that will handle history events.
*
* interface svgedit.history.HistoryEventHandler {
* void handleHistoryEvent(eventType, command);
* }
*
* eventType is a string conforming to one of the HistoryEvent types.
* command is an object fulfilling the HistoryCommand interface.
*/
/**
* @class svgedit.history.MoveElementCommand
* @implements svgedit.history.HistoryCommand
* History command for an element that had its DOM position changed
* @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 {
constructor (elem, oldNextSibling, oldParent, text) {
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;
}
getText () {
return this.text;
}
type () {
return 'svgedit.history.MoveElementCommand';
}
/**
* Re-positions the element
* @param {{handleHistoryEvent: function}} handler
*/
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 {{handleHistoryEvent: function}} handler
*/
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 {Array} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
MoveElementCommand.type = MoveElementCommand.prototype.type;
/**
* @implements svgedit.history.HistoryCommand
* History command for an element that was added to the DOM
*
* @param elem - The newly added DOM element
* @param text - An optional string visible to user related to this change
*/
export class InsertElementCommand {
constructor (elem, text) {
this.elem = elem;
this.text = text || ('Create ' + elem.tagName);
this.parent = elem.parentNode;
this.nextSibling = this.elem.nextSibling;
}
type () {
return 'svgedit.history.InsertElementCommand';
}
getText () {
return this.text;
}
// Re-Inserts the new element
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
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 {Array} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
InsertElementCommand.type = InsertElementCommand.prototype.type;
/**
* @implements svgedit.history.HistoryCommand
* History command for an element removed from the DOM
* @param elem - The removed DOM element
* @param oldNextSibling - The DOM element's nextSibling when it was in the DOM
* @param oldParent - The DOM element's parent
* @param {String} [text] - An optional string visible to user related to this change
*/
export class RemoveElementCommand {
constructor (elem, oldNextSibling, oldParent, text) {
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 () {
return 'svgedit.history.RemoveElementCommand';
}
getText () {
return this.text;
}
// Re-removes the new element
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
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
removeElementFromListMap(this.elem);
if (this.nextSibling == null) {
if (window.console) {
console.log('Error: reference element was lost');
}
}
this.parent.insertBefore(this.elem, this.nextSibling);
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this);
}
}
/**
* @returns {Array} Array with element associated with this command
*/
elements () {
return [this.elem];
}
}
RemoveElementCommand.type = RemoveElementCommand.prototype.type;
/**
* @implements svgedit.history.HistoryCommand
* History command to make a change to an element.
* Usually an attribute change, but can also be textcontent.
* @param elem - The DOM element that was changed
* @param attrs - An object with the attributes to be changed and the values they had *before* the change
* @param {String} text - An optional string visible to user related to this change
*/
export class ChangeElementCommand {
constructor (elem, attrs, text) {
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 () {
return 'svgedit.history.ChangeElementCommand';
}
getText () {
return this.text;
}
// Performs the stored change action
apply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this);
}
let bChangedTransform = false;
for (const attr in this.newValues) {
if (this.newValues[attr]) {
if (attr === '#text') {
this.elem.textContent = this.newValues[attr];
} else if (attr === '#href') {
setHref(this.elem, this.newValues[attr]);
} else {
this.elem.setAttribute(attr, this.newValues[attr]);
}
} 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
unapply (handler) {
if (handler) {
handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this);
}
let bChangedTransform = false;
for (const attr in this.oldValues) {
if (this.oldValues[attr]) {
if (attr === '#text') {
this.elem.textContent = this.oldValues[attr];
} else if (attr === '#href') {
setHref(this.elem, this.oldValues[attr]);
} else {
this.elem.setAttribute(attr, this.oldValues[attr]);
}
} 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 {Array} 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
/**
* @implements svgedit.history.HistoryCommand
* History command that can contain/execute multiple other commands
* @param {String} [text] - An optional string visible to user related to this change
*/
export class BatchCommand {
constructor (text) {
this.text = text || 'Batch Command';
this.stack = [];
}
type () {
return 'svgedit.history.BatchCommand';
}
getText () {
return this.text;
}
// Runs "apply" on all subcommands
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
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 and returns 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 cmd - The undo command object to add
*/
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;
/**
* @param historyEventHandler - an object that conforms to the HistoryEventHandler interface
* (see above)
*/
export class UndoManager {
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
resetUndoStack () {
this.undoStack = [];
this.undoStackPointer = 0;
}
/**
* @returns {Number} Integer with the current size of the undo history stack
*/
getUndoStackSize () {
return this.undoStackPointer;
}
/**
* @returns {Number} Integer with the 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
undo () {
if (this.undoStackPointer > 0) {
const cmd = this.undoStack[--this.undoStackPointer];
cmd.unapply(this.handler_);
}
}
// Performs a redo step
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 cmd - The command object to add
*/
addCommandToHistory (cmd) {
// FIXME: 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 attrName - The name of the attribute being changed
* @param elems - Array of DOM elements being changed
*/
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 (elem == null) { 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 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 == null) { 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;
}
}