/* * Copyright (C) 2024 Yomitan 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/>. */ import {computeZoomScale, isPointInAnyRect} from './document-util.js'; import {DOMTextScanner} from './dom-text-scanner.js'; import {TextSourceElement} from './text-source-element.js'; import {TextSourceRange} from './text-source-range.js'; export class TextSourceGenerator { constructor() { /** @type {RegExp} @readonly */ this._transparentColorPattern = /rgba\s*\([^)]*,\s*0(?:\.0+)?\s*\)/; /** @type {import('text-source-generator').GetRangeFromPointHandler[]} @readonly */ this._getRangeFromPointHandlers = []; } /** * @param {number} x * @param {number} y * @param {import('document-util').GetRangeFromPointOptions} options * @returns {?import('text-source').TextSource} */ getRangeFromPoint(x, y, options) { for (const handler of this._getRangeFromPointHandlers) { const result = handler(x, y, options); if (result !== null) { return result; } } return this._getRangeFromPointInternal(x, y, options); } /** * Registers a custom handler for scanning for text or elements at the input position. * @param {import('text-source-generator').GetRangeFromPointHandler} handler The handler callback which will be invoked when calling `getRangeFromPoint`. */ registerGetRangeFromPointHandler(handler) { this._getRangeFromPointHandlers.push(handler); } /** * Extract a sentence from a document. * @param {import('text-source').TextSource} source The text source object, either `TextSourceRange` or `TextSourceElement`. * @param {boolean} layoutAwareScan Whether or not layout-aware scan mode should be used. * @param {number} extent The length of the sentence to extract. * @param {boolean} terminateAtNewlines Whether or not a sentence should be terminated at newline characters. * @param {import('text-scanner').SentenceTerminatorMap} terminatorMap A mapping of characters that terminate a sentence. * @param {import('text-scanner').SentenceForwardQuoteMap} forwardQuoteMap A mapping of quote characters that delimit a sentence. * @param {import('text-scanner').SentenceBackwardQuoteMap} backwardQuoteMap A mapping of quote characters that delimit a sentence, which is the inverse of forwardQuoteMap. * @returns {{text: string, offset: number}} The sentence and the offset to the original source. */ extractSentence(source, layoutAwareScan, extent, terminateAtNewlines, terminatorMap, forwardQuoteMap, backwardQuoteMap) { // Scan text source = source.clone(); const startLength = source.setStartOffset(extent, layoutAwareScan); const endLength = source.setEndOffset(extent * 2 - startLength, true, layoutAwareScan); const text = source.text(); const textLength = text.length; const textEndAnchor = textLength - endLength; /** Relative start position of the sentence (inclusive). */ let cursorStart = startLength; /** Relative end position of the sentence (exclusive). */ let cursorEnd = textEndAnchor; // Move backward let quoteStack = []; for (; cursorStart > 0; --cursorStart) { // Check if the previous character should be included. let c = text[cursorStart - 1]; if (c === '\n' && terminateAtNewlines) { break; } if (quoteStack.length === 0) { let terminatorInfo = terminatorMap.get(c); if (typeof terminatorInfo !== 'undefined') { // Include the previous character while it is a terminator character and is included at start. while (terminatorInfo[0] && cursorStart > 0) { --cursorStart; if (cursorStart === 0) { break; } c = text[cursorStart - 1]; terminatorInfo = terminatorMap.get(c); if (typeof terminatorInfo === 'undefined') { break; } } break; } } let quoteInfo = forwardQuoteMap.get(c); if (typeof quoteInfo !== 'undefined') { if (quoteStack.length === 0) { // Include the previous character while it is a quote character and is included at start. while (quoteInfo[1] && cursorStart > 0) { --cursorStart; if (cursorStart === 0) { break; } c = text[cursorStart - 1]; quoteInfo = forwardQuoteMap.get(c); if (typeof quoteInfo === 'undefined') { break; } } break; } else if (quoteStack[0] === c) { quoteStack.pop(); continue; } } quoteInfo = backwardQuoteMap.get(c); if (typeof quoteInfo !== 'undefined') { quoteStack.unshift(quoteInfo[0]); } } // Move forward quoteStack = []; for (; cursorEnd < textLength; ++cursorEnd) { // Check if the following character should be included. let c = text[cursorEnd]; if (c === '\n' && terminateAtNewlines) { break; } if (quoteStack.length === 0) { let terminatorInfo = terminatorMap.get(c); if (typeof terminatorInfo !== 'undefined') { // Include the following character while it is a terminator character and is included at end. while (terminatorInfo[1] && cursorEnd < textLength) { ++cursorEnd; if (cursorEnd === textLength) { break; } c = text[cursorEnd]; terminatorInfo = terminatorMap.get(c); if (typeof terminatorInfo === 'undefined') { break; } } break; } } let quoteInfo = backwardQuoteMap.get(c); if (typeof quoteInfo !== 'undefined') { if (quoteStack.length === 0) { // Include the following character while it is a quote character and is included at end. while (quoteInfo[1] && cursorEnd < textLength) { ++cursorEnd; if (cursorEnd === textLength) { break; } c = text[cursorEnd]; quoteInfo = forwardQuoteMap.get(c); if (typeof quoteInfo === 'undefined') { break; } } break; } else if (quoteStack[0] === c) { quoteStack.pop(); continue; } } quoteInfo = forwardQuoteMap.get(c); if (typeof quoteInfo !== 'undefined') { quoteStack.unshift(quoteInfo[0]); } } // Trim whitespace for (; cursorStart < startLength && this._isWhitespace(text[cursorStart]); ++cursorStart) { /* NOP */ } for (; cursorEnd > textEndAnchor && this._isWhitespace(text[cursorEnd - 1]); --cursorEnd) { /* NOP */ } // Result return { text: text.substring(cursorStart, cursorEnd), offset: startLength - cursorStart }; } /** * Scans the document for text or elements with text information at the given coordinate. * Coordinates are provided in [client space](https://developer.mozilla.org/en-US/docs/Web/CSS/CSSOM_View/Coordinate_systems). * @param {number} x The x coordinate to search at. * @param {number} y The y coordinate to search at. * @param {import('document-util').GetRangeFromPointOptions} options Options to configure how element detection is performed. * @returns {?import('text-source').TextSource} A range for the hovered text or element, or `null` if no applicable content was found. */ _getRangeFromPointInternal(x, y, options) { const {deepContentScan, normalizeCssZoom} = options; const elements = this._getElementsFromPoint(x, y, deepContentScan); /** @type {?HTMLDivElement} */ let imposter = null; /** @type {?HTMLDivElement} */ let imposterContainer = null; /** @type {?Element} */ let imposterSourceElement = null; if (elements.length > 0) { const element = elements[0]; switch (element.nodeName.toUpperCase()) { case 'IMG': case 'BUTTON': case 'SELECT': return TextSourceElement.create(element); case 'INPUT': if (/** @type {HTMLInputElement} */ (element).type === 'text') { imposterSourceElement = element; [imposter, imposterContainer] = this._createImposter(/** @type {HTMLInputElement} */ (element), false); } break; case 'TEXTAREA': imposterSourceElement = element; [imposter, imposterContainer] = this._createImposter(/** @type {HTMLTextAreaElement} */ (element), true); break; } } const range = this._caretRangeFromPointExt(x, y, deepContentScan ? elements : [], normalizeCssZoom); if (range !== null) { if (imposter !== null) { this._setImposterStyle(/** @type {HTMLDivElement} */ (imposterContainer).style, 'z-index', '-2147483646'); this._setImposterStyle(imposter.style, 'pointer-events', 'none'); return TextSourceRange.createFromImposter(range, /** @type {HTMLDivElement} */ (imposterContainer), /** @type {HTMLElement} */ (imposterSourceElement)); } return TextSourceRange.create(range); } else { if (imposterContainer !== null) { const {parentNode} = imposterContainer; if (parentNode !== null) { parentNode.removeChild(imposterContainer); } } return null; } } /** * @param {CSSStyleDeclaration} style * @param {string} propertyName * @param {string} value */ _setImposterStyle(style, propertyName, value) { style.setProperty(propertyName, value, 'important'); } /** * @param {HTMLInputElement|HTMLTextAreaElement} element * @param {boolean} isTextarea * @returns {[imposter: ?HTMLDivElement, container: ?HTMLDivElement]} */ _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 = Number.parseFloat(elementStyle.width) + (elementRect.width - imposterRect.width); const height = Number.parseFloat(elementStyle.height) + (elementRect.height - imposterRect.height); this._setImposterStyle(imposterStyle, 'width', `${width}px`); this._setImposterStyle(imposterStyle, 'height', `${height}px`); } if (imposterRect.left !== elementRect.left || imposterRect.top !== elementRect.top) { 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]; } /** * @param {number} x * @param {number} y * @param {boolean} all * @returns {Element[]} */ _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] : []; } /** * @param {number} x * @param {number} y * @param {Range} range * @param {boolean} normalizeCssZoom * @returns {boolean} */ _isPointInRange(x, y, range, normalizeCssZoom) { // Require a text node to start const {startContainer} = range; if (startContainer.nodeType !== Node.TEXT_NODE) { return false; } // Convert CSS zoom coordinates if (normalizeCssZoom) { const scale = computeZoomScale(startContainer); x /= scale; y /= scale; } // Scan forward const nodePre = range.endContainer; const offsetPre = range.endOffset; try { const {node, offset, content} = new DOMTextScanner(nodePre, offsetPre, true, false).seek(1); range.setEnd(node, offset); if (!this._isWhitespace(content) && isPointInAnyRect(x, y, range.getClientRects())) { return true; } } finally { range.setEnd(nodePre, offsetPre); } // Scan backward const {node, offset, content} = new DOMTextScanner(startContainer, range.startOffset, true, false).seek(-1); range.setStart(node, offset); if (!this._isWhitespace(content) && 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; } /** * @param {number} x * @param {number} y * @returns {?Range} */ _caretRangeFromPoint(x, y) { if (typeof document.caretRangeFromPoint === 'function') { // Chrome, Edge return document.caretRangeFromPoint(x, y); } // @ts-expect-error - caretPositionFromPoint is non-standard if (typeof document.caretPositionFromPoint === 'function') { // Firefox return this._caretPositionFromPoint(x, y); } // No support return null; } /** * @param {number} x * @param {number} y * @returns {?Range} */ _caretPositionFromPoint(x, y) { // @ts-expect-error - caretPositionFromPoint is non-standard const position = /** @type {(x: number, y: number) => ?{offsetNode: Node, offset: number}} */ (document.caretPositionFromPoint)(x, y); if (position === null) { return null; } const node = position.offsetNode; if (node === null) { return null; } let offset = 0; const {nodeType} = node; switch (nodeType) { case Node.TEXT_NODE: offset = position.offset; break; case Node.ELEMENT_NODE: // Elements with user-select: all will return the element // instead of a text point inside the element. if (this._isElementUserSelectAll(/** @type {Element} */ (node))) { return this._caretPositionFromPointNormalizeStyles(x, y, /** @type {Element} */ (node)); } break; } try { const range = document.createRange(); range.setStart(node, offset); range.setEnd(node, offset); return range; } catch (e) { // Firefox throws new DOMException("The operation is insecure.") // when trying to select a node from within a ShadowRoot. return null; } } /** * @param {number} x * @param {number} y * @param {Element} nextElement * @returns {?Range} */ _caretPositionFromPointNormalizeStyles(x, y, nextElement) { /** @type {Map<Element, ?string>} */ const previousStyles = new Map(); try { while (true) { if (nextElement instanceof HTMLElement) { this._recordPreviousStyle(previousStyles, nextElement); nextElement.style.setProperty('user-select', 'text', 'important'); } // @ts-expect-error - caretPositionFromPoint is non-standard const position = /** @type {(x: number, y: number) => ?{offsetNode: Node, offset: number}} */ (document.caretPositionFromPoint)(x, y); if (position === null) { return null; } const node = position.offsetNode; if (node === null) { return null; } let offset = 0; const {nodeType} = node; switch (nodeType) { case Node.TEXT_NODE: offset = position.offset; break; case Node.ELEMENT_NODE: // Elements with user-select: all will return the element // instead of a text point inside the element. if (this._isElementUserSelectAll(/** @type {Element} */ (node))) { if (previousStyles.has(/** @type {Element} */ (node))) { // Recursive return null; } nextElement = /** @type {Element} */ (node); continue; } break; } try { const range = document.createRange(); range.setStart(node, offset); range.setEnd(node, offset); return range; } catch (e) { // Firefox throws new DOMException("The operation is insecure.") // when trying to select a node from within a ShadowRoot. return null; } } } finally { this._revertStyles(previousStyles); } } /** * @param {number} x * @param {number} y * @param {Element[]} elements * @param {boolean} normalizeCssZoom * @returns {?Range} */ _caretRangeFromPointExt(x, y, elements, normalizeCssZoom) { /** @type {?Map<Element, ?string>} */ let previousStyles = null; 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, normalizeCssZoom)) { return range; } startContinerPre = startContainer; } if (previousStyles === null) { previousStyles = new Map(); } i = this._disableTransparentElement(elements, i, previousStyles); if (i < 0) { return null; } } } finally { if (previousStyles !== null && previousStyles.size > 0) { this._revertStyles(previousStyles); } } } /** * @param {Element[]} elements * @param {number} i * @param {Map<Element, ?string>} previousStyles * @returns {number} */ _disableTransparentElement(elements, i, previousStyles) { while (true) { if (i >= elements.length) { return -1; } const element = elements[i++]; if (this._isElementTransparent(element)) { if (element instanceof HTMLElement) { this._recordPreviousStyle(previousStyles, element); element.style.setProperty('pointer-events', 'none', 'important'); } return i; } } } /** * @param {Map<Element, ?string>} previousStyles * @param {Element} element */ _recordPreviousStyle(previousStyles, element) { if (previousStyles.has(element)) { return; } const style = element.hasAttribute('style') ? element.getAttribute('style') : null; previousStyles.set(element, style); } /** * @param {Map<Element, ?string>} previousStyles */ _revertStyles(previousStyles) { for (const [element, style] of previousStyles.entries()) { if (style === null) { element.removeAttribute('style'); } else { element.setAttribute('style', style); } } } /** * @param {Element} element * @returns {boolean} */ _isElementTransparent(element) { if ( element === document.body || element === document.documentElement ) { return false; } const style = window.getComputedStyle(element); return ( Number.parseFloat(style.opacity) <= 0 || style.visibility === 'hidden' || (style.backgroundImage === 'none' && this._isColorTransparent(style.backgroundColor)) ); } /** * @param {string} cssColor * @returns {boolean} */ _isColorTransparent(cssColor) { return this._transparentColorPattern.test(cssColor); } /** * @param {Element} element * @returns {boolean} */ _isElementUserSelectAll(element) { return getComputedStyle(element).userSelect === 'all'; } /** * @param {string} string * @returns {boolean} */ _isWhitespace(string) { return string.trim().length === 0; } }