overleaf/services/web/frontend/js/features/source-editor/extensions/math-preview.ts

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import {
repositionTooltips,
showTooltip,
Tooltip,
ViewPlugin,
} from '@codemirror/view'
import {
Compartment,
EditorState,
Extension,
StateField,
TransactionSpec,
} from '@codemirror/state'
import { loadMathJax } from '../../mathjax/load-mathjax'
import { descendantsOfNodeWithType } from '../utils/tree-query'
import {
MathContainer,
mathAncestorNode,
parseMathContainer,
} from '../utils/tree-operations/math'
import { documentCommands } from '../languages/latex/document-commands'
import { debugConsole } from '@/utils/debugging'
import { isSplitTestEnabled } from '@/utils/splitTestUtils'
const REPOSITION_EVENT = 'editor:repositionMathTooltips'
export const mathPreview = (enabled: boolean): Extension => {
if (!isSplitTestEnabled('math-preview')) {
return []
}
return mathPreviewConf.of(enabled ? mathPreviewStateField : [])
}
const mathPreviewConf = new Compartment()
export const setMathPreview = (enabled: boolean): TransactionSpec => ({
effects: mathPreviewConf.reconfigure(enabled ? mathPreviewStateField : []),
})
const mathPreviewStateField = StateField.define<readonly Tooltip[]>({
create: buildTooltips,
update(tooltips, tr) {
if (tr.docChanged || tr.selection) {
tooltips = buildTooltips(tr.state)
}
return tooltips
},
provide: field => [
showTooltip.computeN([field], state => state.field(field)),
ViewPlugin.define(view => {
const listener = () => repositionTooltips(view)
window.addEventListener(REPOSITION_EVENT, listener)
return {
destroy() {
window.removeEventListener(REPOSITION_EVENT, listener)
},
}
}),
],
})
const renderMath = async (
content: string,
displayMode: boolean,
element: HTMLElement,
definitions: string
) => {
const MathJax = await loadMathJax()
MathJax.texReset([0]) // equation numbering is disabled, but this is still needed
try {
await MathJax.tex2svgPromise(definitions)
} catch {
// ignore errors thrown during parsing command definitions
}
const math = await MathJax.tex2svgPromise(content, {
...MathJax.getMetricsFor(element),
display: displayMode,
})
element.textContent = ''
element.append(math)
}
function buildTooltips(state: EditorState): readonly Tooltip[] {
const tooltips: Tooltip[] = []
for (const range of state.selection.ranges) {
if (range.empty) {
const mathContainer = getMathContainer(state, range.from)
const content = buildTooltipContent(state, mathContainer)
if (content && mathContainer) {
const tooltip: Tooltip = {
pos: mathContainer.pos,
above: true,
strictSide: true,
arrow: false,
create() {
const dom = document.createElement('div')
dom.append(content)
dom.className = 'ol-cm-math-tooltip'
return { dom, overlap: true, offset: { x: 0, y: 8 } }
},
}
tooltips.push(tooltip)
}
}
}
return tooltips
}
const getMathContainer = (state: EditorState, pos: number) => {
// if anywhere inside Math, find the whole Math node
const ancestorNode = mathAncestorNode(state, pos)
if (!ancestorNode) return null
const [node] = descendantsOfNodeWithType(ancestorNode, 'Math', 'Math')
if (!node) return null
return parseMathContainer(state, node, ancestorNode)
}
const buildTooltipContent = (
state: EditorState,
math: MathContainer | null
): HTMLDivElement | null => {
if (!math || !math.content.length) return null
const element = document.createElement('div')
element.style.opacity = '0'
element.style.transition = 'opacity .01s ease-in'
element.textContent = math.content
let definitions = ''
const commandState = state.field(documentCommands, false)
if (commandState?.items) {
for (const command of commandState.items) {
if (command.type === 'definition' && command.raw) {
definitions += `${command.raw}\n`
}
}
}
renderMath(math.content, math.displayMode, element, definitions)
.then(() => {
element.style.opacity = '1'
window.dispatchEvent(new Event(REPOSITION_EVENT))
})
.catch(error => {
debugConsole.error(error)
})
return element
}