@theia/core
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Theia is a cloud & desktop IDE framework implemented in TypeScript.
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text/typescript
// *****************************************************************************
// Copyright (C) 2022 Ericsson and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0.
//
// This Source Code may also be made available under the following Secondary
// Licenses when the conditions for such availability set forth in the Eclipse
// Public License v. 2.0 are satisfied: GNU General Public License, version 2
// with the GNU Classpath Exception which is available at
// https://www.gnu.org/software/classpath/license.html.
//
// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
// *****************************************************************************
import { inject, injectable } from 'inversify';
import { Disposable, DisposableCollection, disposableTimeout, isOSX } from '../common';
import { MarkdownString } from '../common/markdown-rendering/markdown-string';
import { animationFrame } from './browser';
import { MarkdownRenderer, MarkdownRendererFactory } from './markdown-rendering/markdown-renderer';
import { PreferenceService } from './preferences';
import '../../src/browser/style/hover-service.css';
export type HoverPosition = 'left' | 'right' | 'top' | 'bottom';
export namespace HoverPosition {
export function invertIfNecessary(position: HoverPosition, target: DOMRect, host: DOMRect, totalWidth: number, totalHeight: number): HoverPosition {
if (position === 'left') {
if (target.left - host.width - 5 < 0) {
return 'right';
}
} else if (position === 'right') {
if (target.right + host.width + 5 > totalWidth) {
return 'left';
}
} else if (position === 'top') {
if (target.top - host.height - 5 < 0) {
return 'bottom';
}
} else if (position === 'bottom') {
if (target.bottom + host.height + 5 > totalHeight) {
return 'top';
}
}
return position;
}
}
export interface HoverRequest {
content: string | MarkdownString | HTMLElement
target: HTMLElement
/**
* The position where the hover should appear.
* Note that the hover service will try to invert the position (i.e. right -> left)
* if the specified content does not fit in the window next to the target element
*/
position: HoverPosition
/**
* Additional css classes that should be added to the hover box.
* Used to style certain boxes different e.g. for the extended tab preview.
*/
cssClasses?: string[]
/**
* A function to render a visual preview on the hover.
* Function that takes the desired width and returns a HTMLElement to be rendered.
*/
visualPreview?: (width: number) => HTMLElement | undefined;
}
()
export class HoverService {
protected static hostClassName = 'theia-hover';
protected static styleSheetId = 'theia-hover-style';
(PreferenceService) protected readonly preferences: PreferenceService;
(MarkdownRendererFactory) protected readonly markdownRendererFactory: MarkdownRendererFactory;
protected _markdownRenderer: MarkdownRenderer | undefined;
protected get markdownRenderer(): MarkdownRenderer {
this._markdownRenderer ||= this.markdownRendererFactory();
return this._markdownRenderer;
}
protected _hoverHost: HTMLElement | undefined;
protected get hoverHost(): HTMLElement {
if (!this._hoverHost) {
this._hoverHost = document.createElement('div');
this._hoverHost.classList.add(HoverService.hostClassName);
this._hoverHost.style.position = 'absolute';
}
return this._hoverHost;
}
protected pendingTimeout: Disposable | undefined;
protected hoverTarget: HTMLElement | undefined;
protected lastHidHover = Date.now();
protected readonly disposeOnHide = new DisposableCollection();
requestHover(request: HoverRequest): void {
if (request.target !== this.hoverTarget) {
this.cancelHover();
this.pendingTimeout = disposableTimeout(() => this.renderHover(request), this.getHoverDelay());
}
}
protected getHoverDelay(): number {
return Date.now() - this.lastHidHover < 200
? 0
: this.preferences.get('workbench.hover.delay', isOSX ? 1500 : 500);
}
protected async renderHover(request: HoverRequest): Promise<void> {
const host = this.hoverHost;
let firstChild: HTMLElement | undefined;
const { target, content, position, cssClasses } = request;
if (cssClasses) {
host.classList.add(...cssClasses);
}
this.hoverTarget = target;
if (content instanceof HTMLElement) {
host.appendChild(content);
firstChild = content;
} else if (typeof content === 'string') {
host.textContent = content;
} else {
const renderedContent = this.markdownRenderer.render(content);
this.disposeOnHide.push(renderedContent);
host.appendChild(renderedContent.element);
firstChild = renderedContent.element;
}
// browsers might insert linebreaks when the hover appears at the edge of the window
// resetting the position prevents that
host.style.left = '0px';
host.style.top = '0px';
document.body.append(host);
if (request.visualPreview) {
// If just a string is being rendered use the size of the outer box
const width = firstChild ? firstChild.offsetWidth : this.hoverHost.offsetWidth;
const visualPreview = request.visualPreview(width);
if (visualPreview) {
host.appendChild(visualPreview);
}
}
await animationFrame(); // Allow the browser to size the host
const updatedPosition = this.setHostPosition(target, host, position);
this.disposeOnHide.push({
dispose: () => {
this.lastHidHover = Date.now();
host.classList.remove(updatedPosition);
if (cssClasses) {
host.classList.remove(...cssClasses);
}
}
});
this.listenForMouseOut();
}
protected setHostPosition(target: HTMLElement, host: HTMLElement, position: HoverPosition): HoverPosition {
const targetDimensions = target.getBoundingClientRect();
const hostDimensions = host.getBoundingClientRect();
const documentWidth = document.body.getBoundingClientRect().width;
// document.body.getBoundingClientRect().height doesn't work as expected
// scrollHeight will always be accurate here: https://stackoverflow.com/a/44077777
const documentHeight = document.documentElement.scrollHeight;
position = HoverPosition.invertIfNecessary(position, targetDimensions, hostDimensions, documentWidth, documentHeight);
if (position === 'top' || position === 'bottom') {
const targetMiddleWidth = targetDimensions.left + (targetDimensions.width / 2);
const middleAlignment = targetMiddleWidth - (hostDimensions.width / 2);
const furthestRight = Math.min(documentWidth - hostDimensions.width, middleAlignment);
const left = Math.max(0, furthestRight);
const top = position === 'top'
? targetDimensions.top - hostDimensions.height - 5
: targetDimensions.bottom + 5;
host.style.setProperty('--theia-hover-before-position', `${targetMiddleWidth - left - 5}px`);
host.style.top = `${top}px`;
host.style.left = `${left}px`;
} else {
const targetMiddleHeight = targetDimensions.top + (targetDimensions.height / 2);
const middleAlignment = targetMiddleHeight - (hostDimensions.height / 2);
const furthestTop = Math.min(documentHeight - hostDimensions.height, middleAlignment);
const top = Math.max(0, furthestTop);
const left = position === 'left'
? targetDimensions.left - hostDimensions.width - 5
: targetDimensions.right + 5;
host.style.setProperty('--theia-hover-before-position', `${targetMiddleHeight - top - 5}px`);
host.style.left = `${left}px`;
host.style.top = `${top}px`;
}
host.classList.add(position);
return position;
}
protected listenForMouseOut(): void {
const handleMouseMove = (e: MouseEvent) => {
if (e.target instanceof Node && !this.hoverHost.contains(e.target) && !this.hoverTarget?.contains(e.target)) {
this.cancelHover();
}
};
document.addEventListener('mousemove', handleMouseMove);
this.disposeOnHide.push({ dispose: () => document.removeEventListener('mousemove', handleMouseMove) });
}
cancelHover(): void {
this.pendingTimeout?.dispose();
this.unRenderHover();
this.disposeOnHide.dispose();
this.hoverTarget = undefined;
}
protected unRenderHover(): void {
this.hoverHost.remove();
this.hoverHost.replaceChildren();
}
}