yomichan/ext/fg/js/range.js

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/*
* Copyright (C) 2016 Alex Yatskov <alex@foosoft.net>
* Author: Alex Yatskov <alex@foosoft.net>
*
* 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 <http://www.gnu.org/licenses/>.
*/
// Polyfill caretRangeFromPoint() using the newer caretPositionFromPoint()
if (!document.caretRangeFromPoint){
document.caretRangeFromPoint = function polyfillcaretRangeFromPoint(x,y){
let range = document.createRange();
let position = document.caretPositionFromPoint(x,y);
if (!position) {
return null;
}
range.setStart(position.offsetNode, position.offset);
range.setEnd(position.offsetNode, position.offset);
return range;
};
}
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class Range {
constructor(range) {
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this.rng = range;
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}
text() {
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return this.rng.toString();
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}
setLength(length) {
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const end = Range.seekEnd(this.rng.startContainer, this.rng.startOffset + length);
this.rng.setEnd(end.node, end.offset);
}
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containsPoint(point) {
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const rect = this.getPaddedRect();
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return point.x >= rect.left && point.x <= rect.right;
}
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getRect() {
return this.rng.getBoundingClientRect();
}
getPaddedRect() {
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const range = this.rng.cloneRange();
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const startOffset = range.startOffset;
const endOffset = range.endOffset;
const node = range.startContainer;
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range.setStart(node, Math.max(0, startOffset - 1));
range.setEnd(node, Math.min(node.length, endOffset + 1));
return range.getBoundingClientRect();
}
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select() {
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const selection = window.getSelection();
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selection.removeAllRanges();
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selection.addRange(this.rng);
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}
deselect() {
const selection = window.getSelection();
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selection.removeAllRanges();
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}
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compareOrigin(range) {
return range.rng.compareBoundaryPoints(Range.END_TO_END, this.rng);
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}
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static seekEnd(node, length) {
const state = {node, offset: 0, length};
if (!Range.seekEndRecurse(node, state)) {
return {node: state.node, offset: state.offset};
}
for (let sibling = node.nextSibling; sibling !== null; sibling = sibling.nextSibling) {
if (!Range.seekEndRecurse(sibling, state)) {
return {node: state.node, offset: state.offset};
}
}
for (let sibling = node.parentElement.nextSibling; sibling !== null; sibling = sibling.nextSibling) {
if (!Range.seekEndRecurse(sibling, state)) {
return {node: state.node, offset: state.offset};
}
}
return {node: state.node, offset: state.offset};
}
static seekEndRecurse(node, state) {
if (node.nodeType === 3) {
const consumed = Math.min(node.length, state.length);
state.node = node;
state.offset = consumed;
state.length -= consumed;
} else {
for (let i = 0; i < node.childNodes.length; ++i) {
if (!Range.seekEndRecurse(node.childNodes[i], state)) {
break;
}
}
}
return state.length > 0;
}
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static fromPoint(point) {
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const range = document.caretRangeFromPoint(point.x, point.y);
return range === null ? null : new Range(range);
}
}