HackMD/public/js/lib/syncscroll.js

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/* eslint-env browser, jquery */
/* global _ */
// Inject line numbers for sync scroll.
import markdownitContainer from 'markdown-it-container'
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import { md } from '../extra'
import modeType from './modeType'
import appState from './appState'
function addPart (tokens, idx) {
if (tokens[idx].map && tokens[idx].level === 0) {
const startline = tokens[idx].map[0] + 1
const endline = tokens[idx].map[1]
tokens[idx].attrJoin('class', 'part')
tokens[idx].attrJoin('data-startline', startline)
tokens[idx].attrJoin('data-endline', endline)
}
}
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md.renderer.rules.blockquote_open = function (tokens, idx, options, env, self) {
tokens[idx].attrJoin('class', 'raw')
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.renderer.rules.table_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.renderer.rules.bullet_list_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.renderer.rules.list_item_open = function (tokens, idx, options, env, self) {
tokens[idx].attrJoin('class', 'raw')
if (tokens[idx].map) {
const startline = tokens[idx].map[0] + 1
const endline = tokens[idx].map[1]
tokens[idx].attrJoin('data-startline', startline)
tokens[idx].attrJoin('data-endline', endline)
}
return self.renderToken(...arguments)
}
md.renderer.rules.ordered_list_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.renderer.rules.link_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.renderer.rules.paragraph_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.renderer.rules.heading_open = function (tokens, idx, options, env, self) {
tokens[idx].attrJoin('class', 'raw')
addPart(tokens, idx)
return self.renderToken(...arguments)
}
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md.renderer.rules.fence = (tokens, idx, options, env, self) => {
const token = tokens[idx]
const info = token.info ? md.utils.unescapeAll(token.info).trim() : ''
let langName = ''
let highlighted
if (info) {
langName = info.split(/\s+/g)[0]
if (/!$/.test(info)) token.attrJoin('class', 'wrap')
token.attrJoin('class', options.langPrefix + langName.replace(/=$|=\d+$|=\+$|!$|=!/, ''))
token.attrJoin('class', 'hljs')
token.attrJoin('class', 'raw')
}
if (options.highlight) {
highlighted = options.highlight(token.content, langName) || md.utils.escapeHtml(token.content)
} else {
highlighted = md.utils.escapeHtml(token.content)
}
if (highlighted.indexOf('<pre') === 0) {
return `${highlighted}\n`
}
if (tokens[idx].map && tokens[idx].level === 0) {
const startline = tokens[idx].map[0] + 1
const endline = tokens[idx].map[1]
return `<pre class="part" data-startline="${startline}" data-endline="${endline}"><code${self.renderAttrs(token)}>${highlighted}</code></pre>\n`
}
return `<pre><code${self.renderAttrs(token)}>${highlighted}</code></pre>\n`
}
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md.renderer.rules.code_block = (tokens, idx, options, env, self) => {
if (tokens[idx].map && tokens[idx].level === 0) {
const startline = tokens[idx].map[0] + 1
const endline = tokens[idx].map[1]
return `<pre class="part" data-startline="${startline}" data-endline="${endline}"><code>${md.utils.escapeHtml(tokens[idx].content)}</code></pre>\n`
}
return `<pre><code>${md.utils.escapeHtml(tokens[idx].content)}</code></pre>\n`
}
function renderContainer (tokens, idx, options, env, self) {
tokens[idx].attrJoin('role', 'alert')
tokens[idx].attrJoin('class', 'alert')
tokens[idx].attrJoin('class', `alert-${tokens[idx].info.trim()}`)
addPart(tokens, idx)
return self.renderToken(...arguments)
}
md.use(markdownitContainer, 'success', { render: renderContainer })
md.use(markdownitContainer, 'info', { render: renderContainer })
md.use(markdownitContainer, 'warning', { render: renderContainer })
md.use(markdownitContainer, 'danger', { render: renderContainer })
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window.preventSyncScrollToEdit = false
window.preventSyncScrollToView = false
const editScrollThrottle = 5
const viewScrollThrottle = 5
const buildMapThrottle = 100
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let viewScrolling = false
let editScrolling = false
let editArea = null
let viewArea = null
let markdownArea = null
let editor
export function setupSyncAreas (edit, view, markdown, _editor) {
editArea = edit
viewArea = view
markdownArea = markdown
editor = _editor
editArea.on('scroll', _.throttle(syncScrollToView, editScrollThrottle))
viewArea.on('scroll', _.throttle(syncScrollToEdit, viewScrollThrottle))
}
let scrollMap, lineHeightMap, viewTop, viewBottom
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export function clearMap () {
scrollMap = null
lineHeightMap = null
viewTop = null
viewBottom = null
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}
window.viewAjaxCallback = clearMap
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const buildMap = _.throttle(buildMapInner, buildMapThrottle)
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// Build offsets for each line (lines can be wrapped)
// That's a bit dirty to process each line everytime, but ok for demo.
// Optimizations are required only for big texts.
function buildMapInner (callback) {
if (!viewArea || !markdownArea) return
let i, offset, nonEmptyList, pos, a, b, _lineHeightMap, linesCount, acc, _scrollMap
offset = viewArea.scrollTop() - viewArea.offset().top
_scrollMap = []
nonEmptyList = []
_lineHeightMap = []
viewTop = 0
viewBottom = viewArea[0].scrollHeight - viewArea.height()
acc = 0
const lines = editor.getValue().split('\n')
const lineHeight = editor.defaultTextHeight()
for (i = 0; i < lines.length; i++) {
const str = lines[i]
_lineHeightMap.push(acc)
if (str.length === 0) {
acc++
continue
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}
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const h = editor.heightAtLine(i + 1) - editor.heightAtLine(i)
acc += Math.round(h / lineHeight)
}
_lineHeightMap.push(acc)
linesCount = acc
for (i = 0; i < linesCount; i++) {
_scrollMap.push(-1)
}
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nonEmptyList.push(0)
// make the first line go top
_scrollMap[0] = viewTop
const parts = markdownArea.find('.part').toArray()
for (i = 0; i < parts.length; i++) {
const $el = $(parts[i])
let t = $el.attr('data-startline') - 1
if (t === '') {
return
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}
t = _lineHeightMap[t]
if (t !== 0 && t !== nonEmptyList[nonEmptyList.length - 1]) {
nonEmptyList.push(t)
}
_scrollMap[t] = Math.round($el.offset().top + offset - 10)
}
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nonEmptyList.push(linesCount)
_scrollMap[linesCount] = viewArea[0].scrollHeight
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pos = 0
for (i = 1; i < linesCount; i++) {
if (_scrollMap[i] !== -1) {
pos++
continue
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}
a = nonEmptyList[pos]
b = nonEmptyList[pos + 1]
_scrollMap[i] = Math.round((_scrollMap[b] * (i - a) + _scrollMap[a] * (b - i)) / (b - a))
}
_scrollMap[0] = 0
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scrollMap = _scrollMap
lineHeightMap = _lineHeightMap
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if (window.loaded && callback) callback()
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}
// sync view scroll progress to edit
let viewScrollingTimer = null
export function syncScrollToEdit (event, preventAnimate) {
if (appState.currentMode !== modeType.both || !appState.syncscroll || !editArea) return
if (window.preventSyncScrollToEdit) {
if (typeof window.preventSyncScrollToEdit === 'number') {
window.preventSyncScrollToEdit--
} else {
window.preventSyncScrollToEdit = false
}
return
}
if (!scrollMap || !lineHeightMap) {
buildMap(() => {
syncScrollToEdit(event, preventAnimate)
})
return
}
if (editScrolling) return
const scrollTop = viewArea[0].scrollTop
let lineIndex = 0
for (let i = 0, l = scrollMap.length; i < l; i++) {
if (scrollMap[i] > scrollTop) {
break
} else {
lineIndex = i
}
}
let lineNo = 0
let lineDiff = 0
for (let i = 0, l = lineHeightMap.length; i < l; i++) {
if (lineHeightMap[i] > lineIndex) {
break
} else {
lineNo = lineHeightMap[i]
lineDiff = lineHeightMap[i + 1] - lineNo
}
}
let posTo = 0
let topDiffPercent = 0
let posToNextDiff = 0
const scrollInfo = editor.getScrollInfo()
const textHeight = editor.defaultTextHeight()
const preLastLineHeight = scrollInfo.height - scrollInfo.clientHeight - textHeight
const preLastLineNo = Math.round(preLastLineHeight / textHeight)
const preLastLinePos = scrollMap[preLastLineNo]
if (scrollInfo.height > scrollInfo.clientHeight && scrollTop >= preLastLinePos) {
posTo = preLastLineHeight
topDiffPercent = (scrollTop - preLastLinePos) / (viewBottom - preLastLinePos)
posToNextDiff = textHeight * topDiffPercent
posTo += Math.ceil(posToNextDiff)
} else {
posTo = lineNo * textHeight
topDiffPercent = (scrollTop - scrollMap[lineNo]) / (scrollMap[lineNo + lineDiff] - scrollMap[lineNo])
posToNextDiff = textHeight * lineDiff * topDiffPercent
posTo += Math.ceil(posToNextDiff)
}
if (preventAnimate) {
editArea.scrollTop(posTo)
} else {
const posDiff = Math.abs(scrollInfo.top - posTo)
var duration = posDiff / 50
duration = duration >= 100 ? duration : 100
editArea.stop(true, true).animate({
scrollTop: posTo
}, duration, 'linear')
}
viewScrolling = true
clearTimeout(viewScrollingTimer)
viewScrollingTimer = setTimeout(viewScrollingTimeoutInner, duration * 1.5)
}
function viewScrollingTimeoutInner () {
viewScrolling = false
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}
// sync edit scroll progress to view
let editScrollingTimer = null
export function syncScrollToView (event, preventAnimate) {
if (appState.currentMode !== modeType.both || !appState.syncscroll || !viewArea) return
if (window.preventSyncScrollToView) {
if (typeof preventSyncScrollToView === 'number') {
window.preventSyncScrollToView--
} else {
window.preventSyncScrollToView = false
}
return
}
if (!scrollMap || !lineHeightMap) {
buildMap(() => {
syncScrollToView(event, preventAnimate)
})
return
}
if (viewScrolling) return
let lineNo, posTo
let topDiffPercent, posToNextDiff
const scrollInfo = editor.getScrollInfo()
const textHeight = editor.defaultTextHeight()
lineNo = Math.floor(scrollInfo.top / textHeight)
// if reach the last line, will start lerp to the bottom
const diffToBottom = (scrollInfo.top + scrollInfo.clientHeight) - (scrollInfo.height - textHeight)
if (scrollInfo.height > scrollInfo.clientHeight && diffToBottom > 0) {
topDiffPercent = diffToBottom / textHeight
posTo = scrollMap[lineNo + 1]
posToNextDiff = (viewBottom - posTo) * topDiffPercent
posTo += Math.floor(posToNextDiff)
} else {
topDiffPercent = (scrollInfo.top % textHeight) / textHeight
posTo = scrollMap[lineNo]
posToNextDiff = (scrollMap[lineNo + 1] - posTo) * topDiffPercent
posTo += Math.floor(posToNextDiff)
}
if (preventAnimate) {
viewArea.scrollTop(posTo)
} else {
const posDiff = Math.abs(viewArea.scrollTop() - posTo)
var duration = posDiff / 50
duration = duration >= 100 ? duration : 100
viewArea.stop(true, true).animate({
scrollTop: posTo
}, duration, 'linear')
}
editScrolling = true
clearTimeout(editScrollingTimer)
editScrollingTimer = setTimeout(editScrollingTimeoutInner, duration * 1.5)
}
function editScrollingTimeoutInner () {
editScrolling = false
}