Fix image rerender jitter and layout shift (#896)

* fix image jitter and layout shift

* prevent unecessary context rerenders

components/block-height.js

@@ -20,7 +20,7 @@ export const BlockHeightProvider = ({ blockHeight, children }) => {
   })
   const value = useMemo(() => ({
     height: data?.blockHeight ?? blockHeight ?? 0
-  }), [data, blockHeight])
+  }), [data?.blockHeight, blockHeight])
   return (
     <BlockHeightContext.Provider value={value}>
       {children}

components/chain-fee.js

@@ -20,7 +20,7 @@ export const ChainFeeProvider = ({ chainFee, children }) => {
   })
   const value = useMemo(() => ({
     fee: Math.floor(data?.chainFee ?? chainFee ?? 0)
-  }), [data, chainFee])
+  }), [data?.chainFee, chainFee])
   return (
     <ChainFeeContext.Provider value={value}>
       {children}

components/image.js

@@ -1,5 +1,5 @@
 import styles from './text.module.css'
-import { Fragment, useState, useEffect, useMemo, useCallback, forwardRef, useRef } from 'react'
+import { Fragment, useState, useEffect, useMemo, useCallback, forwardRef, useRef, memo } from 'react'
 import { IMGPROXY_URL_REGEXP } from '../lib/url'
 import { useShowModal } from './modal'
 import { useMe } from './me'
@@ -63,7 +63,7 @@ function ImageOriginal ({ src, topLevel, rel, tab, children, onClick, ...props }
   }
 }
 
-function ImageProxy ({ src, srcSet: srcSetObj, onClick, topLevel, onError, ...props }) {
+function ImageProxy ({ src, srcSet: { dimensions, ...srcSetObj } = {}, onClick, topLevel, onError, ...props }) {
   const srcSet = useMemo(() => {
     if (!srcSetObj) return undefined
     // srcSetObj shape: { [widthDescriptor]: <imgproxyUrl>, ... }
@@ -82,19 +82,45 @@ function ImageProxy ({ src, srcSet: srcSetObj, onClick, topLevel, onError, ...pr
     }, { w: 0, url: undefined }).url
   }, [srcSetObj])
 
+  const handleError = useCallback(onError, [onError])
+  const handleClick = useCallback(() => onClick(bestResSrc), [onClick, bestResSrc])
+
   return (
-    <img
+    <Image
       className={topLevel ? styles.topLevel : undefined}
       // browsers that don't support srcSet and sizes will use src. use best resolution possible in that case
       src={bestResSrc}
       srcSet={srcSet}
       sizes={sizes}
-      onClick={() => onClick(bestResSrc)}
+      width={dimensions?.width}
-      onError={onError}
+      height={dimensions?.height}
+      onClick={handleClick}
+      onError={handleError}
     />
   )
 }
 
+const Image = memo(({ className, src, srcSet, sizes, width, height, bestResSrc, onClick, onError }) => {
+  const style = width && height
+    ? { '--height': `${height}px`, '--width': `${width}px`, '--aspect-ratio': `${width / height}` }
+    : undefined
+
+  return (
+    <img
+      className={className}
+      // browsers that don't support srcSet and sizes will use src. use best resolution possible in that case
+      src={bestResSrc}
+      srcSet={srcSet}
+      sizes={sizes}
+      width={width}
+      height={height}
+      onClick={onClick}
+      onError={onError}
+      style={style}
+    />
+  )
+})
+
 export default function ZoomableImage ({ src, srcSet, ...props }) {
   const showModal = useShowModal()
 
@@ -125,13 +151,15 @@ export default function ZoomableImage ({ src, srcSet, ...props }) {
       </Dropdown.Item>)
   }), [showModal, originalUrl, styles])
 
+  const handleError = useCallback(() => setImgproxy(false), [setImgproxy])
+
   if (!src) return null
 
   if (imgproxy) {
     return (
       <ImageProxy
         src={src} srcSet={srcSet}
-        onClick={handleClick} onError={() => setImgproxy(false)} {...props}
+        onClick={handleClick} onError={handleError} {...props}
       />
     )
   }

components/text.js

@@ -20,6 +20,7 @@ import { Button } from 'react-bootstrap'
 import { useRouter } from 'next/router'
 import Link from 'next/link'
 import { UNKNOWN_LINK_REL } from '../lib/constants'
+import isEqual from 'lodash/isEqual'
 
 export function SearchText ({ text }) {
   return (
@@ -34,7 +35,7 @@ export function SearchText ({ text }) {
 }
 
 // this is one of the slowest components to render
-export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, outlawed, ...outerProps }) {
+export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, outlawed, topLevel, noFragments }) {
   const [overflowing, setOverflowing] = useState(false)
   const router = useRouter()
   const [show, setShow] = useState(false)
@@ -79,7 +80,6 @@ export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, o
 
   const Heading = useCallback(({ children, node, ...props }) => {
     const [copied, setCopied] = useState(false)
-    const { noFragments, topLevel } = outerProps
     const id = useMemo(() =>
       noFragments ? undefined : slugger?.slug(toString(node).replace(/[^\w\-\s]+/gi, '')), [node, noFragments, slugger])
     const h = useMemo(() => {
@@ -114,7 +114,7 @@ export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, o
           </a>}
       </span>
     )
-  }, [outerProps, slugger.current])
+  }, [topLevel, noFragments, slugger.current])
 
   const Table = useCallback(({ node, ...props }) =>
     <span className='table-responsive'>
@@ -144,8 +144,8 @@ export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, o
       return url
     }
     const srcSet = imgproxyUrls?.[url]
-    return <ZoomableImage srcSet={srcSet} tab={tab} src={src} rel={rel ?? UNKNOWN_LINK_REL} {...props} {...outerProps} />
+    return <ZoomableImage srcSet={srcSet} tab={tab} src={src} rel={rel ?? UNKNOWN_LINK_REL} {...props} topLevel />
-  }, [imgproxyUrls, outerProps, tab])
+  }, [imgproxyUrls, topLevel, tab])
 
   return (
     <div className={`${styles.text} ${show ? styles.textUncontained : overflowing ? styles.textContained : ''}`} ref={containerRef}>
@@ -208,7 +208,7 @@ export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, o
             const youtube = href.match(/(https?:\/\/)?((www\.)?(youtube(-nocookie)?|youtube.googleapis)\.com.*(v\/|v=|vi=|vi\/|e\/|embed\/|user\/.*\/u\/\d+\/)|youtu\.be\/)(?<id>[_0-9a-z-]+)((?:\?|&)(?:t|start)=(?<start>\d+))?/i)
             if (youtube?.groups?.id) {
               return (
-                <div style={{ maxWidth: outerProps.topLevel ? '640px' : '320px', paddingRight: '15px', margin: '0.5rem 0' }}>
+                <div style={{ maxWidth: topLevel ? '640px' : '320px', paddingRight: '15px', margin: '0.5rem 0' }}>
                   <YouTube
                     videoId={youtube.groups.id} className={styles.youtubeContainer} opts={{
                       playerVars: {
@@ -236,4 +236,4 @@ export default memo(function Text ({ rel, imgproxyUrls, children, tab, itemId, o
         </Button>}
     </div>
   )
-})
+}, isEqual)

components/text.module.css

@@ -129,22 +129,26 @@
 }
 
 .text img {
+    --height: 35vh;
+    --width: 100%;
     display: block;
     margin-top: .5rem;
     margin-bottom: .5rem;
     width: auto;
-    max-width: 100%;
+    max-width: min(var(--width), 100%);
     cursor: zoom-in;
-    max-height: 25vh;
+    height: auto;
+    max-height: min(var(--height), 25vh);
     object-fit: contain;
     object-position: left top;
     min-width: 50%;
+    aspect-ratio: var(--aspect-ratio);
 }
 
 .text img.topLevel {
     margin-top: .75rem;
     margin-bottom: .75rem;
-    max-height: 35vh;
+    max-height: min(var(--height), 35vh);
 }
 
 img.fullScreen {

worker/imgproxy.js

@@ -1,6 +1,7 @@
 import { createHmac } from 'node:crypto'
 import { extractUrls } from '../lib/md.js'
 import { isJob } from '../lib/item.js'
+import path from 'node:path'
 
 const imgProxyEnabled = process.env.NODE_ENV === 'production' ||
   (process.env.NEXT_PUBLIC_IMGPROXY_URL && process.env.IMGPROXY_SALT && process.env.IMGPROXY_KEY)
@@ -100,21 +101,31 @@ export const createImgproxyUrls = async (id, text, { models, forceFetch }) => {
       console.log('[imgproxy] id:', id, '-- not image url:', url)
       continue
     }
-    imgproxyUrls[url] = {}
+    imgproxyUrls[url] = {
+      dimensions: await getDimensions(url)
+    }
     for (const res of resolutions) {
       const [w, h] = res.split('x')
       const processingOptions = `/rs:fit:${w}:${h}`
-      imgproxyUrls[url][`${w}w`] = createImgproxyUrl(url, processingOptions)
+      imgproxyUrls[url][`${w}w`] = createImgproxyUrl({ url, options: processingOptions })
     }
   }
   return imgproxyUrls
 }
 
-const createImgproxyUrl = (url, processingOptions) => {
+const getDimensions = async (url) => {
+  const options = '/d:1'
+  const imgproxyUrl = createImgproxyUrl({ url, options, pathname: 'info' })
+  const res = await fetch(imgproxyUrl)
+  const { width, height } = await res.json()
+  return { width, height }
+}
+
+const createImgproxyUrl = ({ url, pathname = '', options }) => {
   const b64Url = Buffer.from(url, 'utf-8').toString('base64url')
-  const target = `${processingOptions}/${b64Url}`
+  const target = path.join(options, b64Url)
   const signature = sign(target)
-  return `${IMGPROXY_URL}${signature}${target}`
+  return new URL(path.join(pathname, signature, target), IMGPROXY_URL).toString()
 }
 
 async function fetchWithTimeout (resource, { timeout = 1000, ...options } = {}) {