kylin-code/extensions/markdown-language-features/preview-src/activeLineMarker.ts

35 lines
1.1 KiB
TypeScript

/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
import { getElementsForSourceLine } from './scroll-sync';
export class ActiveLineMarker {
private _current: any;
onDidChangeTextEditorSelection(line: number, documentVersion: number) {
const { previous } = getElementsForSourceLine(line, documentVersion);
this._update(previous && previous.element);
}
_update(before: HTMLElement | undefined) {
this._unmarkActiveElement(this._current);
this._markActiveElement(before);
this._current = before;
}
_unmarkActiveElement(element: HTMLElement | undefined) {
if (!element) {
return;
}
element.className = element.className.replace(/\bcode-active-line\b/g, '');
}
_markActiveElement(element: HTMLElement | undefined) {
if (!element) {
return;
}
element.className += ' code-active-line';
}
}