/*************************************************************
*
* Copyright (c) 2019-2022 The MathJax Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @fileoverview Mixin that adds hidden MathML to the output
*
* @author dpvc@mathjax.org (Davide Cervone)
*/
import {Handler} from '../core/Handler.js';
import {MathDocument, AbstractMathDocument, MathDocumentConstructor} from '../core/MathDocument.js';
import {MathItem, AbstractMathItem, STATE, newState} from '../core/MathItem.js';
import {MmlNode} from '../core/MmlTree/MmlNode.js';
import {SerializedMmlVisitor} from '../core/MmlTree/SerializedMmlVisitor.js';
import {OptionList, expandable} from '../util/Options.js';
import {StyleList} from '../util/StyleList.js';
/*==========================================================================*/
export class LimitedMmlVisitor extends SerializedMmlVisitor {
/**
* @override
*/
protected getAttributes(node: MmlNode): string {
/**
* Remove id from attribute output
*/
return super.getAttributes(node).replace(/ ?id=".*?"/, '');
}
}
/**
* Generic constructor for Mixins
*/
export type Constructor<T> = new(...args: any[]) => T;
/*==========================================================================*/
/**
* Add STATE value for having assistive MathML (after TYPESETTING)
*/
newState('ASSISTIVEMML', 153);
/**
* The functions added to MathItem for assistive MathML
*
* @template N The HTMLElement node class
* @template T The Text node class
* @template D The Document class
*/
export interface AssistiveMmlMathItem<N, T, D> extends MathItem<N, T, D> {
/**
* @param {MathDocument} document The document where assistive MathML is being added
* @param {boolean} force True to force assistive MathML even if enableAssistiveMml is false
*/
assistiveMml(document: MathDocument<N, T, D>, force?: boolean): void;
}
/**
* The mixin for adding assistive MathML to MathItems
*
* @param {B} BaseMathItem The MathItem class to be extended
* @return {AssistiveMathItem} The augmented MathItem class
*
* @template N The HTMLElement node class
* @template T The Text node class
* @template D The Document class
* @template B The MathItem class to extend
*/
export function AssistiveMmlMathItemMixin<N, T, D, B extends Constructor<AbstractMathItem<N, T, D>>>(
BaseMathItem: B
): Constructor<AssistiveMmlMathItem<N, T, D>> & B {
return class extends BaseMathItem {
/**
* @param {MathDocument} document The MathDocument for the MathItem
* @param {boolean} force True to force assistive MathML evenif enableAssistiveMml is false
*/
public assistiveMml(document: AssistiveMmlMathDocument<N, T, D>, force: boolean = false) {
if (this.state() >= STATE.ASSISTIVEMML) return;
if (!this.isEscaped && (document.options.enableAssistiveMml || force)) {
const adaptor = document.adaptor;
//
// Get the serialized MathML
//
const mml = document.toMML(this.root).replace(/\n */g, '').replace(/<!--.*?-->/g, '');
//
// Parse is as HTML and retrieve the <math> element
//
const mmlNodes = adaptor.firstChild(adaptor.body(adaptor.parse(mml, 'text/html')));
//
// Create a container for the hidden MathML
//
const node = adaptor.node('mjx-assistive-mml', {
unselectable: 'on', display: (this.display ? 'block' : 'inline')
}, [mmlNodes]);
//
// Hide the typeset math from assistive technology and append the MathML that is visually
// hidden from other users
//
adaptor.setAttribute(adaptor.firstChild(this.typesetRoot) as N, 'aria-hidden', 'true');
adaptor.setStyle(this.typesetRoot, 'position', 'relative');
adaptor.append(this.typesetRoot, node);
}
this.state(STATE.ASSISTIVEMML);
}
};
}
/*==========================================================================*/
/**
* The functions added to MathDocument for assistive MathML
*
* @template N The HTMLElement node class
* @template T The Text node class
* @template D The Document class
*/
export interface AssistiveMmlMathDocument<N, T, D> extends AbstractMathDocument<N, T, D> {
/**
* @param {MmlNode} node The node to be serializes
* @return {string} The serialization of the node
*/
toMML: (node: MmlNode) => string;
/**
* Add assistive MathML to the MathItems in the MathDocument
*
* @return {AssistiveMmlMathDocument} The MathDocument (so calls can be chained)
*/
assistiveMml(): AssistiveMmlMathDocument<N, T, D>;
}
/**
* The mixin for adding assistive MathML to MathDocuments
*
* @param {B} BaseDocument The MathDocument class to be extended
* @return {AssistiveMmlMathDocument} The Assistive MathML MathDocument class
*
* @template N The HTMLElement node class
* @template T The Text node class
* @template D The Document class
* @template B The MathDocument class to extend
*/
export function AssistiveMmlMathDocumentMixin<N, T, D,
B extends MathDocumentConstructor<AbstractMathDocument<N, T, D>>>(
BaseDocument: B
): MathDocumentConstructor<AssistiveMmlMathDocument<N, T, D>> & B {
return class BaseClass extends BaseDocument {
/**
* @override
*/
public static OPTIONS: OptionList = {
...BaseDocument.OPTIONS,
enableAssistiveMml: true,
renderActions: expandable({
...BaseDocument.OPTIONS.renderActions,
assistiveMml: [STATE.ASSISTIVEMML]
})
};
/**
* styles needed for the hidden MathML
*/
public static assistiveStyles: StyleList = {
'mjx-assistive-mml': {
position: 'absolute !important',
top: '0px', left: '0px',
clip: 'rect(1px, 1px, 1px, 1px)',
padding: '1px 0px 0px 0px !important',
border: '0px !important',
display: 'block !important',
width: 'auto !important',
overflow: 'hidden !important',
/*
* Don't allow the assistive MathML to become part of the selection
*/
'-webkit-touch-callout': 'none',
'-webkit-user-select': 'none',
'-khtml-user-select': 'none',
'-moz-user-select': 'none',
'-ms-user-select': 'none',
'user-select': 'none'
},
'mjx-assistive-mml[display="block"]': {
width: '100% !important'
}
};
/**
* Visitor used for serializing internal MathML nodes
*/
protected visitor: LimitedMmlVisitor;
/**
* Augment the MathItem class used for this MathDocument, and create the serialization visitor.
*
* @override
* @constructor
*/
constructor(...args: any[]) {
super(...args);
const CLASS = (this.constructor as typeof BaseClass);
const ProcessBits = CLASS.ProcessBits;
if (!ProcessBits.has('assistive-mml')) {
ProcessBits.allocate('assistive-mml');
}
this.visitor = new LimitedMmlVisitor(this.mmlFactory);
this.options.MathItem =
AssistiveMmlMathItemMixin<N, T, D, Constructor<AbstractMathItem<N, T, D>>>(
this.options.MathItem
);
if ('addStyles' in this) {
(this as any).addStyles(CLASS.assistiveStyles);
}
}
/**
* @param {MmlNode} node The node to be serializes
* @return {string} The serialization of the node
*/
public toMML(node: MmlNode): string {
return this.visitor.visitTree(node);
}
/**
* Add assistive MathML to the MathItems in this MathDocument
*/
public assistiveMml() {
if (!this.processed.isSet('assistive-mml')) {
for (const math of this.math) {
(math as AssistiveMmlMathItem<N, T, D>).assistiveMml(this);
}
this.processed.set('assistive-mml');
}
return this;
}
/**
* @override
*/
public state(state: number, restore: boolean = false) {
super.state(state, restore);
if (state < STATE.ASSISTIVEMML) {
this.processed.clear('assistive-mml');
}
return this;
}
};
}
/*==========================================================================*/
/**
* Add assitive MathML support a Handler instance
*
* @param {Handler} handler The Handler instance to enhance
* @return {Handler} The handler that was modified (for purposes of chainging extensions)
*
* @template N The HTMLElement node class
* @template T The Text node class
* @template D The Document class
*/
export function AssistiveMmlHandler<N, T, D>(handler: Handler<N, T, D>): Handler<N, T, D> {
handler.documentClass =
AssistiveMmlMathDocumentMixin<N, T, D, MathDocumentConstructor<AbstractMathDocument<N, T, D>>>(
handler.documentClass
);
return handler;
}