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Preview new forum/comment posts and edits on MangaDex. Shows a formatted preview of your post/comment beside the edit box.
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// ==UserScript==
// @name Mangadex Preview Post
// @description Preview new forum/comment posts and edits on MangaDex. Shows a formatted preview of your post/comment beside the edit box.
// @namespace https://github.com/Brandon-Beck
// @author Brandon Beck
// @license MIT
// @icon https://mangadex.org/favicon-96x96.png
// @version 0.3.6
// @grant GM_xmlhttpRequest
// @require https://gitcdn.xyz/cdn/pegjs/pegjs/30f32600084d8da6a50b801edad49619e53e2a05/website/vendor/pegjs/peg.js
// @match https://mangadex.org/*
// ==/UserScript==
'use strict'
const isUserscript = window.GM_xmlhttpRequest !== undefined
// This is used when run in Browser Console / Bookmarklet mode
// Loads the same scripts used in UserScript.
// Does not run at all in userscript mode.
function loadScript(url) {
// Adding the script tag to the head as suggested before
const { head } = document
const script = document.createElement('script')
script.type = 'text/javascript'
script.src = url
// Then bind the event to the callback function.
// There are several events for cross browser compatibility.
return new Promise((resolve ,reject) => {
// script.onreadystatechange = resolve
script.onload = resolve
script.onerror = reject
// Fire the loading
head.appendChild(script)
})
}
// Ensure Console/Bookmarklet is not run on other sites.
if (!isUserscript && !window.location.href.startsWith('https://mangadex.org')) {
alert('Mangadex Post Preview script only works on https://mangadex.org')
throw Error('Mangadex Post Preview script only works on https://mangadex.org')
}
const ERROR_IMG = 'https://i.pinimg.com/originals/e3/04/73/e3047319a8ae7192cb462141c30953a8.gif'
const LOADING_IMG = 'https://i.redd.it/ounq1mw5kdxy.gif'
const imageBlobs = {}
function getImageBlob(url) {
if (!imageBlobs[url]) {
imageBlobs[url] = new Promise((ret ,err) => {
GM_xmlhttpRequest({
method: 'GET'
,url
,responseType: 'blob'
,onerror: err
,ontimeout: err
,onload: (response) => {
if (((response.status >= 200 && response.status <= 299) || response.status === 304)
&& response.response) {
imageBlobs[url] = Promise.resolve(response.response)
return ret(imageBlobs[url])
}
return err(response)
}
})
})
}
return imageBlobs[url]
}
function getImageObjectURL(url) {
return getImageBlob(url).then(b => URL.createObjectURL(b))
}
const imgCache = {}
// Clones are made because the same image may be used more than once in a post.
function cloneImageCacheEntry(source) {
const element = source.element.cloneNode()
// Take for granted that we are loaded if our source was loaded.
// Not necessarily true, but things should already be set as if it were
// since we cloned the values.
const { loadPromise } = source
return {
element ,loadPromise
}
}
// Firefox Speed Test: Fastest to Slowest
// getImgForURLViaFetch: Caches blobs
// -- No noticable lag or problems with several small images on page.
// -- Very usable with Hell's test, though there is a small bit of lag
// -- (Rebuilds hell in under 1 second.
// -- Does better than getImgForURL does with a normal post with small images)
// getImgForURLViaImg: Caches imgs, clones on reuse
// -- Holding down a key causes noticable shakyness. No real script lag,
// -- but the images width/height seem to start off at 0 and then
// -- suddenly grow. Verry offsetting to look at
// -- Survives Hell's test almost just as well. Very minor additional lag.
// -- As such, I believe this is quite scalable.
// getImgForURLNoCache: Creates new img and sets src like normal
// -- Noticable lag. Preview will not update while a key is being spammed.
// -- Slightly jumpy like above, but not as noticable since the lag
// -- spreads it out.
// -- Survives Hell's test just as well as getImgForURLViaImg.
// -- Whatever benifit we get from cloning may not apply here.
// -- Perhaps due to the fact we are looking up only 1 image several hundrad times.
// BROKEN getImgForURLViaFetchClone: Caches Img of blobs.
// -- Does not work when image is used multiple times, for some reason.
// -- Should be comparable to getImgForURLViaFetch, if it worked.
// -- Failed to render any images for hell's test.
function getImgForURL(url) {
if (isUserscript) {
return getImgForURLViaFetch(url)
}
return getImgForURLViaImg(url)
}
function getImgForURLViaImg(url) {
if (imgCache[url] !== undefined) {
return cloneImageCacheEntry(imgCache[url])
}
// TODO add images loaded in thread to cache.
const element = document.createElement('img')
// element.element.src=LOADING_IMG
const loadPromise = new Promise((ret ,err) => {
element.onload = () => ret(element)
element.onerror = e => err(new Error(e.toString()))
element.src = url
})
imgCache[url] = {
element ,loadPromise
}
// First use. Clone not needed since gaurenteed to be unused
return imgCache[url]
}
function getImgForURLNoCache(url) {
// TODO add images loaded in thread to cache.
const element = document.createElement('img')
// element.element.src=LOADING_IMG
const loadPromise = new Promise((ret ,err) => {
element.onload = () => ret(element)
element.onerror = e => err(new Error(e.toString()))
element.src = url
})
// First use. Clone not needed since gaurenteed to be unused
return {
element ,loadPromise
}
}
function getImgForURLViaFetch(url) {
// TODO add images loaded in thread to cache.
const promise = getImageObjectURL(url)
const element = document.createElement('img')
// element.element.src=LOADING_IMG
const loadPromise = promise.then(e => new Promise((resolve ,reject) => {
element.onload = () => {
URL.revokeObjectURL(e)
resolve(element)
}
element.onerror = (err) => {
URL.revokeObjectURL(e)
reject(new Error(err.toString()))
}
element.src = e
}))
// Clone not needed since a new img is generated every time.
return {
element ,loadPromise
}
}
function getImgForURLViaFetchClone(url) {
if (imgCache[url] !== undefined) {
return cloneImageCacheEntry(imgCache[url])
}
// TODO add images loaded in thread to cache.
const promise = getImageObjectURL(url)
const element = document.createElement('img')
// element.element.src=LOADING_IMG
// NOTE: Must not revoke object url if cloning is to be done
const loadPromise = promise.then(e => new Promise((resolve ,reject) => {
element.onload = () => {
// URL.revokeObjectURL(e)
resolve(element)
}
element.onerror = (err) => {
// URL.revokeObjectURL(e)
reject(new Error(err.toString()))
}
element.src = e
}))
imgCache[url] = {
element ,loadPromise
}
return imgCache[url]
}
/* PEG grammer */
// New version will enable:
// Partial rebuilds! only update what changed
// Autoscrolling Edit Preview! Ensure the line you are editing is visible as you change it.
// FIXME Img is text only. not recursive
let generatedBBCodePegParser
function bbcodePegParser() {
if (generatedBBCodePegParser) return generatedBBCodePegParser
generatedBBCodePegParser = peg.generate(String.raw`
start = res:Expressions? {return res}
Expressions = reses:Expression+ {
let astroot = [{type:"root",content:[],location:[0,0]}]
let stack = [astroot[0]]
let astcur = astroot[0]
reses.forEach((res) => {
let thisast = {}
if (res.type == "open") {
thisast.type = res.type
thisast.tag = res.content
thisast.content = []
// Must update end location when tag closes
thisast.location = res.location
astcur.content.push(thisast)
astcur.location[1] = res.location[1]
astcur=thisast
stack.push(thisast)
}
else if (res.type == "prefix") {
// cannot directly nest bullet in bullet (must have a non-prexix container class)
if (astcur.type == "*") {
// FIXME are we supposed to subtract 1 here?
astcur.location = res.location[0] // - 1
stack.pop()
astcur=stack[stack.length -1]
}
thisast.type = res.type
thisast.tag = res.content
thisast.content = []
thisast.location = res.location
astcur.content.push(thisast)
astcur.location[1] = res.location[1]
astcur=thisast
stack.push(thisast)
}
else if (res.type == "opendata") {
thisast.type = res.type
thisast.tag = res.content
thisast.data = res.attr
thisast.content = []
thisast.location = res.location
astcur.content.push(thisast)
astcur.location[1] = res.location[1]
astcur=thisast
stack.push(thisast)
}
else if (res.type == "close") {
let idx = Object.values(stack).reverse().findIndex((e)=>e.tag == res.content)
if (idx != -1 ) {
idx=idx+1
// NOTE should we set ast location end? Yes!
for (let i = stack.length -idx; i < stack.length; i++) {
stack[i].location[1] = res.location[1]
}
stack.splice(-idx,idx)
astcur.location[1] = res.location[1]
astcur=stack[stack.length -1]
}
else {
thisast.type="error"
thisast.content="[/" + res.content + "]"
thisast.location = res.location
astcur.location[1] = res.location[1]
astcur.content.push(thisast)
}
}
else if (res.type == "linebreak" ) {
// TODO should check if prefix instead if prefix is to be expanded appon
if (astcur.tag == "*") {
// FIXME are we supposed to subtract 1 here?
astcur.location[1] = res.location[0] // - 1
// Are Linebreaks added when we are exiting a prefix? Seems like it!
// Not sure why though...
astcur.content.push(res)
stack.pop()
astcur=stack[stack.length -1]
}
else {
astcur.location[1] = res.location[1]
astcur.content.push(res)
}
}
else {
astcur.location[1] = res.location[1]
astcur.content.push(res)
}
})
// Close all tags (location). Remember we start at 1 bc root is just a container
for (let i = 1; i < stack.length; i++) {
stack[i].location[1] = astcur.location[1]
}
//stack.splice(start, end) not needed
return astroot[0].content
}
Expression = res:(OpenTag / OpenDataTag / CloseTag / PrefixTag / LineBreak / Text )
/*head:Term tail:(_ ("+" / "-") _ Term)* {
return tail.reduce(function(result, element) {
if (element[1] === "+") { return result + element[3]; }
if (element[1] === "-") { return result - element[3]; }
}, head);
}
*/
Tag = tag:(OpenCloseTag / PrefixTag) {return tag}
OpenCloseTag = open:(OpenTag / OpenDataTag) content:Expression? close:CloseTag?
&{
let hasClose = close != null
if (false && hasClose && open.tag != close.tag) {
throw new Error(
"Expected [/" + open.tag + "] but [/" + close.tag + "] found."
);
}
return true
} {
return {type:open.tag, data:open.attr, content}
}
PrefixTag = "[" tag:PrefixTagList "]" { return {type:"prefix", content:tag, location:[location().start.offset,location().end.offset]} }
// PrefixTag = "[" tag:PrefixTagList "]" content:(!("[/" ListTags "]" / LineBreak ) .)* { return {type:tag,unparsed:content.join('')} }
ListTags = "list" / "ul" / "ol" / "li"
NormalTagList = "list" / "spoiler" / "center" / "code" / "quote" / "img" / "sub" / "sup" / "left" / "right" / "ol" / "ul" / "h1" / "h2" / "h3" / "h4" / "hr" / "h" / "b" / "s" / "i" / "u"
DataTagList = "url"
PrefixTagList = "*"
Data
= text:(!"]". Data?) {
/*if(text[2] != null) {
return {type: "data", content:text[1] + text[2].content }
}
return {type: "data", content:text[1] }
*/
if(text[2] != null) {
return text[1] + text[2]
}
return text[1]
}
OpenTag = "[" tag:NormalTagList "]" { return {type:"open", content:tag, location:[location().start.offset,location().end.offset] } }
AttrTagProxy = "=" attr:Data? {return attr}
OpenDataTag = "[" tag:DataTagList attr:AttrTagProxy? "]" { return {type:"opendata", content:tag,attr:attr, location:[location().start.offset,location().end.offset]} }
CloseTag = "[/" tag:(DataTagList / NormalTagList / PrefixTagList ) "]" { return {type:"close", content:tag, location:[location().start.offset,location().end.offset]} }
Text
= text:(!(Tag / CloseTag / LineBreak). Text?) {
if(text[2] != null) {
return {type: "text", content:text[1] + text[2].content, location:[location().start.offset,text[2].location[1]] }
}
return {type: "text", content:text[1], location:[location().start.offset,location().end.offset] }
}
ContiguousText
= text:(!(Tag / CloseTag / LineBreak / _ ). ContiguousText?) {
if(text[2] != null) {
return {type: "text", content:text[1] + text[2].content, location:[location().start.offset,text[2].location[1]] }
}
return {type: "text", content:text[1], location:[location().start.offset,location().end.offset] }
}
LineBreak
= [\n] {
return {type: "linebreak", location:[location().start.offset,location().end.offset] }
}
ErrorCatcher
= errTxt:. {return {type: "error", content: errTxt, location:[location().start.offset,location().end.offset]} }
_ "whitespace"
= [ \t\n\r]*
`)
return generatedBBCodePegParser
}
// New steps:
// PegSimpleAST -> AST_WithHTML
// AST_WithHTML + cursor_location -> HtmlElement
// AST_WithHTML + text_change_location_and_range + all_text -> LocalAST_WithHTML_OfChange + local_ast_text_range -> LocalAST_WithHTML -> HtmlElement
function pegAstToHtml_v2(ast) {
if (ast == null) {
return []
}
if (typeof (ast) !== 'object') {
// This should never happen
return []
}
function pushIt(a ,ast ,element) {
a.push({
type: 'text'
,element
,location: ast.location
})
}
const res = ast.reduce((accum ,e) => {
if (e.type === 'text') {
pushIt(accum ,e ,document.createTextNode(e.content))
}
else if (e.type === 'linebreak') {
// pushIt(accum, e, document.createElement('br'), 'container')
const element = {
element: document.createElement('br')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
}
else if (e.type === 'error') {
pushIt(accum ,e ,document.createTextNode(e.content))
}
// Everything after this must have a tag attribute!
// not nesting to avoid right shift
else if (!(e.type === 'open' || e.type === 'prefix' || e.type === 'opendata')) {
// @ts-ignore: Not a string, but doesn't need to be. Make or edit type
throw new Error({
msg: `Unknown AST type "${e.type}" recieved!` ,child_ast: e ,container_ast: ast
})
}
else if (e.tag === 'u' || e.tag === 's' || e.tag === 'sub'
|| e.tag === 'sup' || e.tag === 'ol' || e.tag === 'code'
|| e.tag === 'h1' || e.tag === 'h2' || e.tag === 'h3'
|| e.tag === 'h4' || e.tag === 'h5' || e.tag === 'h6') {
const element = {
element: document.createElement(e.tag)
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'list' || e.tag === 'ul') {
const element = {
element: document.createElement('ul')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'hr') {
const element = {
element: document.createElement(e.tag)
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
// FIXME Contain children, in a non nested fashion
// element.contains=pegAstToHtml_v2(e.content)
pegAstToHtml_v2(e.content).forEach((e) => {
accum.push(e)
})
}
else if (e.tag === 'b') {
const element = {
element: document.createElement('strong')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'i') {
const element = {
element: document.createElement('em')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'h') {
const element = {
element: document.createElement('mark')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'url') {
// accum += `<a href="${e.data}" target="_blank">${pegAstToHtml(e.content)}</a>`
const element = {
element: document.createElement('a')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
if (e.data) {
element.element.href = e.data
}
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'img') {
// FIXME should Only pass url via image when parsing
let url = ''
if (e.content) {
// @ts-ignore
const urltest = e.content[0]
if (urltest && urltest.type === 'text') {
url = urltest.content
}
}
const imageCacheEntry = getImgForURL(url)
const element = {
element: imageCacheEntry.element
,location: e.location
,type: 'image'
,imagePromise: imageCacheEntry.loadPromise.then(() => url)
}
element.element.style.maxWidth = '100%'
element.element.classList.add('align-bottom')
// element.element.src=LOADING_IMG
accum.push(element)
}
else if (e.tag === 'quote') {
const element = {
element: document.createElement('div')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.element.style.width = '100%'
element.element.style.display = 'inline-block'
element.element.style.margin = '1em 0'
element.element.classList.add('well' ,'well-sm')
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === 'spoiler') {
const button = {
element: document.createElement('button')
,location: e.location
,type: 'container'
,contains: []
}
button.element.textContent = 'Spoiler'
button.element.classList.add('btn' ,'btn-sm' ,'btn-warning' ,'btn-spoiler')
accum.push(button)
const element = {
element: document.createElement('div')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.element.classList.add('spoiler' ,'display-none')
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
// NOTE: The world was fixed and mended together! This might be equivilent now
/* In a perfect world. it would work like this... but md is a bit broken
;(button.element as HTMLButtonElement).addEventListener('click',()=>{
;(element.element as HTMLDivElement).classList.toggle('display-none')
})
Code to do this is afer makepreview, to ensure buggieness is preserved */
}
else if (e.tag === 'center' || e.tag === 'left' || e.tag === 'right') {
// accum += `<p class="text-center">${pegAstToHtml(e.content)}</p>`
const element = {
element: document.createElement('div')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.element.classList.add(`text-${e.tag}`)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.tag === '*') {
const element = {
element: document.createElement('li')
,location: e.location
,type: 'container'
,contains: []
}
accum.push(element)
element.contains = pegAstToHtml_v2(e.content)
element.contains.forEach((child_ast_element) => {
element.element.appendChild(child_ast_element.element)
})
}
else if (e.content != null) {
// FIXME? Is this possible? Root?
pegAstToHtml_v2(e.content).forEach((e) => {
accum.push(e)
})
}
else {
// FIXME: Does this even happen?
throw Error(`Recieved unknown and unhandeled ast entry '${JSON.stringify(e)}'`)
/* accum.push({
type: 'text'
,element: document.createTextNode(e.content)
,location: e.location
}) */
}
return accum
} ,[])
/* TODO: Implement
res.filter(e => e.element.nodeName.toLowerCase() !== 'button')
.forEach((e) => {
e.element.addEventListener('click' ,() => {
selectTextAreaPosition(e.location[0])
})
}) */
return res
}
function makePreview(txt) {
const astHtml = pegAstToHtml_v2(bbcodePegParser().parse(txt))
const previewDiv = document.createElement('div')
previewDiv.style.flexGrow = '1'
astHtml.forEach(e => previewDiv.appendChild(e.element))
// Conform to MD style
previewDiv.classList.add('postbody' ,'mb-3' ,'mt-4')
// FIXME: Ensure this is equivilent
// Threads get wordWrap from tr.post
// Profile gets it from card
// Not sure why word break is needed, since I don't see it in md's css
previewDiv.style.wordWrap = 'break-word'
// previewDiv.style.overflowWrap = 'break-word'
previewDiv.style.wordBreak = 'break-word'
return [previewDiv ,astHtml]
}
function createPreviewCallbacks() {
const nav = document.querySelector('nav.navbar.fixed-top')
// @ts-ignore
let navY
if (nav === undefined) {
navY = 0
}
else if (nav.getBoxQuads !== undefined) {
navY = nav.getBoxQuads()[0].p3.y
}
else {
navY = nav.getBoundingClientRect().height
}
const navHeight = navY
// let image_buffers: Map<string, Blob>
let forms = Object.values(document.querySelectorAll('.post_edit_form'))
forms = forms.concat(Object.values(document.querySelectorAll('#post_reply_form')))
forms = forms.concat(Object.values(document.querySelectorAll('#change_profile_form, #start_thread_form')))
// FIXME Format change_profile_form better
forms.forEach((forum) => {
// Try to make it side by side
// e.parentElement.parentElement.insertBefore(previewDiv,e.parentElement)
// e.parentElement.classList.add("sticky-top", "pt-5", "col-6")
const textarea = forum.querySelector('textarea')
if (!textarea) {
// FIXME throw errors. Kind of want to short circit this one though
return Error('Failed to find text area for forum')
}
// Setup variables
let curDisplayedVersion = 0
let nextVersion = 1
let updateTimeout
let updateTimeoutDelay = 50
const maxAcceptableDelay = 10000
const useFallbackPreview = false
// Prepare form
if (!forum.parentElement) {
return undefined
}
// Setup our custom styles
forum.parentElement.style.alignItems = 'flex-start'
forum.parentElement.classList.add('d-flex')
forum.parentElement.style.flexDirection = 'row-reverse'
forum.style.position = 'sticky'
forum.style.top = '0px'
// Causes buttons to wrap on resize
forum.style.width = 'min-content'
// Padding keeps us from hitting the navbar. Margin lines us back up with the preview
forum.style.paddingTop = `${navHeight}px`
forum.style.marginTop = `-${navHeight}px`
textarea.style.resize = 'both'
// FIXME put textArea in avatar slot
// FIXME set textarea maxheight. form should be 100vh max.
textarea.style.minWidth = '120px'
textarea.style.width = '25vw'
textarea.style.paddingLeft = '0'
textarea.style.paddingRight = '0'
let [previewDiv ,astHtml] = makePreview(textarea.value)
forum.parentElement.insertBefore(previewDiv ,forum)
// Move editor to left column if in a thread.
const tableLeft = forum.parentElement.parentElement.firstElementChild
if (tableLeft !== forum.parentElement) {
if (tableLeft.firstChild.nodeName.toLowerCase() === 'img') {
// We are a thread post! Lets integrate into the thread
tableLeft.firstChild.remove()
tableLeft.appendChild(forum)
// Conform to MD thread post style
forum.parentElement.classList.remove('p-3')
forum.parentElement.classList.add('pb-3')
forum.parentElement.parentElement.classList.add('post')
// FIXME: Profile page also needs formating.
// md's wordWrap is break-word, but it seems to
// be acting like wordwrap: anywhere for some reason.
}
}
let currentSpoiler
function searchAst(ast ,cpos) {
// slice bc reverse is in place
const a = ast.slice().reverse().find(e => e.location[0] <= cpos && cpos <= e.location[1])
if (a) {
if (a.type === 'container') {
// unhide spoilers
// Ensure we are not a Text node and that we are a spoiler
if (!currentSpoiler && a.element.nodeType !== 3
&& a.element.classList.contains('spoiler')
&& a.element.style.display !== 'block') {
currentSpoiler = a.element
currentSpoiler.style.display = 'block'
}
const b = searchAst(a.contains ,cpos)
if (b) {
return b
}
}
return a.element
}
return undefined
}
// Auto scroll into view
function scrollToPos(pos = textarea.selectionStart) {
// Hide previous spoiler
if (currentSpoiler) {
currentSpoiler.style.display = 'none'
currentSpoiler = undefined
}
// Get element from ast that starts closest to pos
const elm = searchAst(astHtml ,pos)
if (elm) {
// FIXME Scroll pos is a bit hard to find.
// getBoxQuads, getClientRect, getBoundingClientRect all give the offset from the viewport
// Height of child elements not calculated in...
// SAFE for (text)nodes?, not safe for elements with nested content
if (elm.nodeType === 3) {
// @ts-ignore
let y
if (elm.getBoxQuads !== undefined) {
y = elm.getBoxQuads()[0].p1.y
}
else {
// if we do not have getBoxQuads, we will have to test from the
// container element instead of the text node;
y = elm.parentElement.getBoundingClientRect().top
}
// FIXME. Must be a better way to scroll (especialy in case of nested scroll frames)
// Scroll to top
document.scrollingElement.scrollBy(0 ,y)
}
else {
// FIXME. Must be a better way to scroll (especialy in case of nested scroll frames)
// Scroll to ~ center directly
// const y: number = (elm as HTMLElement).offsetTop
// document.scrollingElement!.scrollTo({top:y})
// Scroll to top
elm.scrollIntoView()
}
// Scroll out of nav
document.scrollingElement.scrollBy(0 ,-navHeight)
// Add this line to scroll to center
// document.scrollingElement!.scrollBy(0,-(window.innerHeight-navHeight)/2)
// Finally, ensure we keep the textarea in view
const bound = forum.getBoundingClientRect()
// document.scrollingElement!.scrollBy(0,bound.bottom - bound.height)
document.scrollingElement.scrollBy(0 ,bound.top)
}
}
textarea.addEventListener('selectionchange' ,() => {
// Only autoscroll if our ast is in sync with the preview.
if (curDisplayedVersion === nextVersion - 1
&& astHtml[astHtml.length - 1] != null
&& astHtml[astHtml.length - 1].location[1] === textarea.value.length) {
scrollToPos()
}
})
function UpdatePreview() {
// Measure load speed. Used for setting update delay dynamicly.
const startTime = Date.now()
// Create a preview buffer
const thisVersion = nextVersion++
const [newPreview ,newAstHtml] = makePreview(textarea.value)
// Setup spoilers the same way md does
$(newPreview).find('.btn-spoiler').click(function () {
// @ts-ignore
$(this).next('.spoiler').toggle()
})
// previewDiv, astHtml
const imgLoadPromises = []
Object.values(newPreview.querySelectorAll('img')).forEach((img) => {
imgLoadPromises.push(new Promise((resolve) => {
img.addEventListener('load' ,resolve)
// Errors dont really matter to us
img.addEventListener('error' ,resolve)
// Esure we are not already done
if (img.complete) {
resolve()
}
}))
})
// Wait for all images to load or error (size calculations needed) before we swap and rescroll
// This is the part that actualy updates the preview
Promise.all(imgLoadPromises).then(() => {
const endTime = Date.now()
const updateLoadDelay = endTime - startTime
if (!useFallbackPreview && updateLoadDelay > maxAcceptableDelay) {
// NOTE: Fallback preview removed. Focusing on speed improvments of normal preview
// useFallbackPreview = true
// dbg(`It took ${updateLoadDelay} milli to update. Max acceptable delay was ${maxAcceptableDelay}! Switching to fallback preview!`)
// We intentionally do not update the timout delay when we swap to fallback preview
}
else {
// average out the times
updateTimeoutDelay = (updateTimeoutDelay + updateLoadDelay) / 2
// dbg(`It took ${updateLoadDelay} milli to update. Changing delay to ${updateTimeoutDelay} `)
}
// Return if we are older than cur preview
if (thisVersion < curDisplayedVersion) {
newPreview.remove()
return
}
curDisplayedVersion = thisVersion
// Replace the Preview with the buffered content
previewDiv.parentElement.insertBefore(newPreview ,previewDiv)
previewDiv.remove()
previewDiv = newPreview
astHtml = newAstHtml
// Scroll to position
scrollToPos()
})
}
function UpdatePreviewProxy() {
// dbg(`Reseting timeout with delay ${updateTimeoutDelay} `)
clearTimeout(updateTimeout)
// @ts-ignore
updateTimeout = setTimeout(UpdatePreview ,updateTimeoutDelay)
}
const buttons = Object.values(forum.querySelectorAll('button'))
buttons.forEach((btn) => {
btn.addEventListener('click' ,UpdatePreviewProxy)
})
textarea.oninput = UpdatePreviewProxy
})
}
if (isUserscript) createPreviewCallbacks()
else {
// Import and wait for PegJS
// then createPreviewCallbacks()
loadScript('https://gitcdn.xyz/cdn/pegjs/pegjs/30f32600084d8da6a50b801edad49619e53e2a05/website/vendor/pegjs/peg.js')
.then(() => {
createPreviewCallbacks()
})
}