yomichan/ext/fg/js/document-util.js
toasted-nutbread 6da02c6eee
document.js refactor (#719)
* Refactor document.js into a class

* Move public functions first

* Rename private functions

* Rename

* Rename argument

* Use instance of DocumentUtil

* Update tests

* Refactor

* Rename (test-)document.js to (test-)document-util.js
2020-08-09 13:27:21 -04:00

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/*
* Copyright (C) 2016-2020 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/* global
* DOM
* DOMTextScanner
* TextSourceElement
* TextSourceRange
*/
class DocumentUtil {
constructor() {
this._transparentColorPattern = /rgba\s*\([^)]*,\s*0(?:\.0+)?\s*\)/;
}
getRangeFromPoint(x, y, deepContentScan) {
const elements = this._getElementsFromPoint(x, y, deepContentScan);
let imposter = null;
let imposterContainer = null;
let imposterSourceElement = null;
if (elements.length > 0) {
const element = elements[0];
switch (element.nodeName.toUpperCase()) {
case 'IMG':
case 'BUTTON':
return new TextSourceElement(element);
case 'INPUT':
imposterSourceElement = element;
[imposter, imposterContainer] = this._createImposter(element, false);
break;
case 'TEXTAREA':
imposterSourceElement = element;
[imposter, imposterContainer] = this._createImposter(element, true);
break;
}
}
const range = this._caretRangeFromPointExt(x, y, deepContentScan ? elements : []);
if (range !== null) {
if (imposter !== null) {
this._setImposterStyle(imposterContainer.style, 'z-index', '-2147483646');
this._setImposterStyle(imposter.style, 'pointer-events', 'none');
}
return new TextSourceRange(range, '', imposterContainer, imposterSourceElement);
} else {
if (imposterContainer !== null) {
imposterContainer.parentNode.removeChild(imposterContainer);
}
return null;
}
}
extractSentence(source, extent, layoutAwareScan) {
const quotesFwd = {'「': '」', '『': '』', "'": "'", '"': '"'};
const quotesBwd = {'」': '「', '』': '『', "'": "'", '"': '"'};
const terminators = '…。..?!';
const sourceLocal = source.clone();
const position = sourceLocal.setStartOffset(extent, layoutAwareScan);
sourceLocal.setEndOffset(extent * 2 - position, layoutAwareScan, true);
const content = sourceLocal.text();
let quoteStack = [];
let startPos = 0;
for (let i = position; i >= startPos; --i) {
const c = content[i];
if (c === '\n') {
startPos = i + 1;
break;
}
if (quoteStack.length === 0 && (terminators.includes(c) || c in quotesFwd)) {
startPos = i + 1;
break;
}
if (quoteStack.length > 0 && c === quoteStack[0]) {
quoteStack.pop();
} else if (c in quotesBwd) {
quoteStack.unshift(quotesBwd[c]);
}
}
quoteStack = [];
let endPos = content.length;
for (let i = position; i <= endPos; ++i) {
const c = content[i];
if (c === '\n') {
endPos = i + 1;
break;
}
if (quoteStack.length === 0) {
if (terminators.includes(c)) {
endPos = i + 1;
break;
} else if (c in quotesBwd) {
endPos = i;
break;
}
}
if (quoteStack.length > 0 && c === quoteStack[0]) {
quoteStack.pop();
} else if (c in quotesFwd) {
quoteStack.unshift(quotesFwd[c]);
}
}
const text = content.substring(startPos, endPos);
const padding = text.length - text.replace(/^\s+/, '').length;
return {
text: text.trim(),
offset: position - startPos - padding
};
}
// Private
_setImposterStyle(style, propertyName, value) {
style.setProperty(propertyName, value, 'important');
}
_createImposter(element, isTextarea) {
const body = document.body;
if (body === null) { return [null, null]; }
const elementStyle = window.getComputedStyle(element);
const elementRect = element.getBoundingClientRect();
const documentRect = document.documentElement.getBoundingClientRect();
let left = elementRect.left - documentRect.left;
let top = elementRect.top - documentRect.top;
// Container
const container = document.createElement('div');
const containerStyle = container.style;
this._setImposterStyle(containerStyle, 'all', 'initial');
this._setImposterStyle(containerStyle, 'position', 'absolute');
this._setImposterStyle(containerStyle, 'left', '0');
this._setImposterStyle(containerStyle, 'top', '0');
this._setImposterStyle(containerStyle, 'width', `${documentRect.width}px`);
this._setImposterStyle(containerStyle, 'height', `${documentRect.height}px`);
this._setImposterStyle(containerStyle, 'overflow', 'hidden');
this._setImposterStyle(containerStyle, 'opacity', '0');
this._setImposterStyle(containerStyle, 'pointer-events', 'none');
this._setImposterStyle(containerStyle, 'z-index', '2147483646');
// Imposter
const imposter = document.createElement('div');
const imposterStyle = imposter.style;
let value = element.value;
if (value.endsWith('\n')) { value += '\n'; }
imposter.textContent = value;
for (let i = 0, ii = elementStyle.length; i < ii; ++i) {
const property = elementStyle[i];
this._setImposterStyle(imposterStyle, property, elementStyle.getPropertyValue(property));
}
this._setImposterStyle(imposterStyle, 'position', 'absolute');
this._setImposterStyle(imposterStyle, 'top', `${top}px`);
this._setImposterStyle(imposterStyle, 'left', `${left}px`);
this._setImposterStyle(imposterStyle, 'margin', '0');
this._setImposterStyle(imposterStyle, 'pointer-events', 'auto');
if (isTextarea) {
if (elementStyle.overflow === 'visible') {
this._setImposterStyle(imposterStyle, 'overflow', 'auto');
}
} else {
this._setImposterStyle(imposterStyle, 'overflow', 'hidden');
this._setImposterStyle(imposterStyle, 'white-space', 'nowrap');
this._setImposterStyle(imposterStyle, 'line-height', elementStyle.height);
}
container.appendChild(imposter);
body.appendChild(container);
// Adjust size
const imposterRect = imposter.getBoundingClientRect();
if (imposterRect.width !== elementRect.width || imposterRect.height !== elementRect.height) {
const width = parseFloat(elementStyle.width) + (elementRect.width - imposterRect.width);
const height = parseFloat(elementStyle.height) + (elementRect.height - imposterRect.height);
this._setImposterStyle(imposterStyle, 'width', `${width}px`);
this._setImposterStyle(imposterStyle, 'height', `${height}px`);
}
if (imposterRect.x !== elementRect.x || imposterRect.y !== elementRect.y) {
left += (elementRect.left - imposterRect.left);
top += (elementRect.top - imposterRect.top);
this._setImposterStyle(imposterStyle, 'left', `${left}px`);
this._setImposterStyle(imposterStyle, 'top', `${top}px`);
}
imposter.scrollTop = element.scrollTop;
imposter.scrollLeft = element.scrollLeft;
return [imposter, container];
}
_getElementsFromPoint(x, y, all) {
if (all) {
// document.elementsFromPoint can return duplicates which must be removed.
const elements = document.elementsFromPoint(x, y);
return elements.filter((e, i) => elements.indexOf(e) === i);
}
const e = document.elementFromPoint(x, y);
return e !== null ? [e] : [];
}
_isPointInRange(x, y, range) {
// Require a text node to start
if (range.startContainer.nodeType !== Node.TEXT_NODE) {
return false;
}
// Scan forward
const nodePre = range.endContainer;
const offsetPre = range.endOffset;
try {
const {node, offset, content} = new DOMTextScanner(range.endContainer, range.endOffset, true, false).seek(1);
range.setEnd(node, offset);
if (!this._isWhitespace(content) && DOM.isPointInAnyRect(x, y, range.getClientRects())) {
return true;
}
} finally {
range.setEnd(nodePre, offsetPre);
}
// Scan backward
const {node, offset, content} = new DOMTextScanner(range.startContainer, range.startOffset, true, false).seek(-1);
range.setStart(node, offset);
if (!this._isWhitespace(content) && DOM.isPointInAnyRect(x, y, range.getClientRects())) {
// This purposefully leaves the starting offset as modified and sets the range length to 0.
range.setEnd(node, offset);
return true;
}
// No match
return false;
}
_isWhitespace(string) {
return string.trim().length === 0;
}
_caretRangeFromPoint(x, y) {
if (typeof document.caretRangeFromPoint === 'function') {
// Chrome, Edge
return document.caretRangeFromPoint(x, y);
}
if (typeof document.caretPositionFromPoint === 'function') {
// Firefox
return this._caretPositionFromPoint(x, y);
}
// No support
return null;
}
_caretPositionFromPoint(x, y) {
const position = document.caretPositionFromPoint(x, y);
if (position === null) {
return null;
}
const node = position.offsetNode;
if (node === null) {
return null;
}
const range = document.createRange();
const offset = (node.nodeType === Node.TEXT_NODE ? position.offset : 0);
try {
range.setStart(node, offset);
range.setEnd(node, offset);
} catch (e) {
// Firefox throws new DOMException("The operation is insecure.")
// when trying to select a node from within a ShadowRoot.
return null;
}
return range;
}
_caretRangeFromPointExt(x, y, elements) {
const modifications = [];
try {
let i = 0;
let startContinerPre = null;
while (true) {
const range = this._caretRangeFromPoint(x, y);
if (range === null) {
return null;
}
const startContainer = range.startContainer;
if (startContinerPre !== startContainer) {
if (this._isPointInRange(x, y, range)) {
return range;
}
startContinerPre = startContainer;
}
i = this._disableTransparentElement(elements, i, modifications);
if (i < 0) {
return null;
}
}
} finally {
if (modifications.length > 0) {
this._restoreElementStyleModifications(modifications);
}
}
}
_disableTransparentElement(elements, i, modifications) {
while (true) {
if (i >= elements.length) {
return -1;
}
const element = elements[i++];
if (this._isElementTransparent(element)) {
const style = element.hasAttribute('style') ? element.getAttribute('style') : null;
modifications.push({element, style});
element.style.setProperty('pointer-events', 'none', 'important');
return i;
}
}
}
_restoreElementStyleModifications(modifications) {
for (const {element, style} of modifications) {
if (style === null) {
element.removeAttribute('style');
} else {
element.setAttribute('style', style);
}
}
}
_isElementTransparent(element) {
if (
element === document.body ||
element === document.documentElement
) {
return false;
}
const style = window.getComputedStyle(element);
return (
parseFloat(style.opacity) <= 0 ||
style.visibility === 'hidden' ||
(style.backgroundImage === 'none' && this._isColorTransparent(style.backgroundColor))
);
}
_isColorTransparent(cssColor) {
return this._transparentColorPattern.test(cssColor);
}
}