yomichan/ext/js/dom/text-source-range.js

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/*
* Copyright (C) 2016-2022 Yomichan Authors
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*
* 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
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
/* global
* DOMTextScanner
* DocumentUtil
*/
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/**
* This class represents a text source that comes from text nodes in the document.
* Sometimes a temporary "imposter" element is created and used to store the text.
* This element is typically hidden from the page and removed after scanning has completed.
*/
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class TextSourceRange {
/**
* Creates a new instance of the class.
* @param {Range} range The selection range.
* @param {number} rangeStartOffset The `startOffset` of the range. This is somewhat redundant
* with the `range` parameter, but it is used when for when imposter elements are removed.
* @param {string} content The `toString()` value of the range. This is somewhat redundant
* with the `range` parameter, but it is used when for when imposter elements are removed.
* @param {?Element} imposterElement The temporary imposter element.
* @param {?Element} imposterSourceElement The source element which the imposter is imitating.
* Must not be `null` if imposterElement is specified.
* @param {?Rect[]} cachedRects A set of cached `DOMRect`s representing the rects of the text source,
* which can be used after the imposter element is removed from the page.
* Must not be `null` if imposterElement is specified.
* @param {?Rect} cachedSourceRect A cached `DOMRect` representing the rect of the `imposterSourceElement`,
* which can be used after the imposter element is removed from the page.
* Must not be `null` if imposterElement is specified.
*/
constructor(range, rangeStartOffset, content, imposterElement, imposterSourceElement, cachedRects, cachedSourceRect) {
this._range = range;
this._rangeStartOffset = rangeStartOffset;
this._content = content;
this._imposterElement = imposterElement;
this._imposterSourceElement = imposterSourceElement;
this._cachedRects = cachedRects;
this._cachedSourceRect = cachedSourceRect;
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}
/**
* Gets the type name of this instance.
* @type {string}
*/
get type() {
return 'range';
}
/**
* The internal range object.
* @type {Range}
*/
get range() {
return this._range;
}
/**
* The starting offset for the range.
* @type {Range}
*/
get rangeStartOffset() {
return this._rangeStartOffset;
}
/**
* The source element that the imposter element is imitating, if present.
* @type {?Element}
*/
get imposterSourceElement() {
return this._imposterSourceElement;
}
/**
* Creates a clone of the instance.
* @returns {TextSourceRange} The new clone.
*/
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clone() {
return new TextSourceRange(
this._range.cloneRange(),
this._rangeStartOffset,
this._content,
this._imposterElement,
this._imposterSourceElement,
this._cachedRects,
this._cachedSourceRect
);
}
/**
* Performs any cleanup that is necessary after the element has been used.
*/
cleanup() {
if (this._imposterElement !== null && this._imposterElement.parentNode !== null) {
this._imposterElement.parentNode.removeChild(this._imposterElement);
}
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}
/**
* Gets the selected text of element, which is the `toString()` version of the range.
* @returns {string} The text content.
*/
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text() {
return this._content;
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}
/**
* Moves the end offset of the text by a set amount of unicode codepoints.
* @param {number} length The maximum number of codepoints to move by.
* @param {boolean} fromEnd Whether to move the offset from the current end position (if `true`) or the start position (if `false`).
* @param {boolean} layoutAwareScan Whether or not HTML layout information should be used to generate
* the string content when scanning.
* @returns {number} The actual number of codepoints that were read.
*/
setEndOffset(length, fromEnd, layoutAwareScan) {
let node;
let offset;
if (fromEnd) {
node = this._range.endContainer;
offset = this._range.endOffset;
} else {
node = this._range.startContainer;
offset = this._range.startOffset;
}
const state = new DOMTextScanner(node, offset, !layoutAwareScan, layoutAwareScan).seek(length);
this._range.setEnd(state.node, state.offset);
this._content = (fromEnd ? this._content + state.content : state.content);
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return length - state.remainder;
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}
/**
* Moves the start offset of the text by a set amount of unicode codepoints.
* @param {number} length The maximum number of codepoints to move by.
* @param {boolean} layoutAwareScan Whether or not HTML layout information should be used to generate
* the string content when scanning.
* @returns {number} The actual number of codepoints that were read.
*/
setStartOffset(length, layoutAwareScan) {
const state = new DOMTextScanner(this._range.startContainer, this._range.startOffset, !layoutAwareScan, layoutAwareScan).seek(-length);
this._range.setStart(state.node, state.offset);
this._rangeStartOffset = this._range.startOffset;
this._content = state.content + this._content;
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return length - state.remainder;
}
/**
* Gets the rects that represent the position and bounds of the text source.
* @returns {DOMRect[]} The rects.
*/
getRects() {
if (this._isImposterDisconnected()) { return this._getCachedRects(); }
return DocumentUtil.convertMultipleRectZoomCoordinates(this._range.getClientRects(), this._range.startContainer);
}
/**
* Gets writing mode that is used for this element.
* See: https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode.
* @returns {string} The rects.
*/
getWritingMode() {
let node = this._isImposterDisconnected() ? this._imposterSourceElement : this._range.startContainer;
if (node !== null && node.nodeType !== Node.ELEMENT_NODE) { node = node.parentElement; }
return DocumentUtil.getElementWritingMode(node);
}
/**
* Selects the text source in the document.
*/
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select() {
if (this._imposterElement !== null) { return; }
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const selection = window.getSelection();
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selection.removeAllRanges();
selection.addRange(this._range);
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}
/**
* Deselects the text source in the document.
*/
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deselect() {
if (this._imposterElement !== null) { return; }
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const selection = window.getSelection();
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selection.removeAllRanges();
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}
/**
* Checks whether another text source has the same starting point.
* @param {TextSourceElement|TextSourceRange} other The other source to test.
* @returns {boolean} `true` if the starting points are equivalent, `false` otherwise.
* @throws {Error} An exception can be thrown if `Range.compareBoundaryPoints` fails,
* which shouldn't happen, but the handler is kept in case of unexpected errors.
*/
hasSameStart(other) {
if (!(
typeof other === 'object' &&
other !== null &&
other instanceof TextSourceRange
)) {
return false;
}
if (this._imposterSourceElement !== null) {
return (
this._imposterSourceElement === other.imposterSourceElement &&
this._rangeStartOffset === other.rangeStartOffset
);
} else {
try {
return this._range.compareBoundaryPoints(Range.START_TO_START, other.range) === 0;
} catch (e) {
if (e.name === 'WrongDocumentError') {
// This can happen with shadow DOMs if the ranges are in different documents.
return false;
}
throw e;
}
}
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}
/**
* Gets a list of the nodes in this text source's range.
* @returns {Node[]} The nodes in the range.
*/
getNodesInRange() {
return DocumentUtil.getNodesInRange(this._range);
}
/**
* Creates a new instance for a given range.
* @param {Range} range The source range.
* @returns {TextSourceRange} A new instance of the class corresponding to the range.
*/
static create(range) {
return new TextSourceRange(range, range.startOffset, range.toString(), null, null, null, null);
}
/**
* Creates a new instance for a given range using an imposter element.
* @param {Range} range The source range.
* @param {Element} imposterElement The temporary imposter element.
* @param {Element} imposterSourceElement The source element which the imposter is imitating.
* @returns {TextSourceRange} A new instance of the class corresponding to the range.
*/
static createFromImposter(range, imposterElement, imposterSourceElement) {
const cachedRects = DocumentUtil.convertMultipleRectZoomCoordinates(range.getClientRects(), range.startContainer);
const cachedSourceRect = DocumentUtil.convertRectZoomCoordinates(imposterSourceElement.getBoundingClientRect(), imposterSourceElement);
return new TextSourceRange(range, range.startOffset, range.toString(), imposterElement, imposterSourceElement, cachedRects, cachedSourceRect);
}
/**
* Checks whether the imposter element has been removed, if the instance is using one.
* @returns {boolean} `true` if the instance has an imposter and it's no longer connected to the document, `false` otherwise.
*/
_isImposterDisconnected() {
return this._imposterElement !== null && !this._imposterElement.isConnected;
}
/**
* Gets the cached rects for a disconnected imposter element.
* @returns {Rect[]} The rects for the element.
*/
_getCachedRects() {
const sourceRect = DocumentUtil.convertRectZoomCoordinates(this._imposterSourceElement.getBoundingClientRect(), this._imposterSourceElement);
return DocumentUtil.offsetDOMRects(
this._cachedRects,
sourceRect.left - this._cachedSourceRect.left,
sourceRect.top - this._cachedSourceRect.top
);
}
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}