feat: auto-img [w/h]

docs/getting-started/authoring.mdx

@@ -45,21 +45,20 @@ Relative images are supported. Eg, inside your [`MDX`](introduction#configuratio
 title: Authoring
 ---
 
-<img src="gutenberg.jpg" />
+![](gutenberg.jpg)
 ```
 
 <details>
   <summary>Result</summary>
 
-<img src="gutenberg.jpg" />
+![](gutenberg.jpg)
 
 </details>
 
-> [!IMPORTANT]
-> To avoid layout-shifts, always provides `[width]`/`[height]` img's attributes:
-> ```md
-> <img src='gutenberg.jpg' width="1100" height="685" />
-> ```
+> [!TIP]
+> You are encouraged to use relative images, since dimensions are automatically added as `img[width][height]` attributes.
+>
+> For others, think about adding them to **prevent layout shift**.
 
 > [!NOTE]
 > See [`MDX_BASEURL`](introduction#configuration:~:text=MDX_BASEURL) to understand how it is converted to a full URL.

docs/getting-started/introduction.mdx

@@ -4,7 +4,7 @@ description: Documentation generator for `pmndrs/*` projects.
 nav: 0
 ---
 
-<img src="gutenberg.jpg" width="1100" height="685" alt="Gutenberg lithography" />
+![Gutenberg lithography](gutenberg.jpg)
 
 ## INSTALL
 
@@ -70,9 +70,7 @@ becomes (for a `MDX_BASEURL=http://localhost:60141` value):
 
 We implement [m3 design system](https://m3.material.io/styles/color/system/overview), using [Tailwind Material Colors](https://tailwind-material-colors-docs.vercel.app).
 
-<a href="https://tailwind-material-colors-docs.vercel.app#palette">
-  <img src="color-scheme.png" width="1506" height="864" alt="" />
-</a>
+[![color scheme](color-scheme.png)](https://tailwind-material-colors-docs.vercel.app#palette)
 
 > [!NOTE]
 > - [Material Color](https://www.youtube.com/playlist?list=PLsoLz-E4Os4WWkrvRuQ7BJuVF-WfOyfWT) for more information

package.json

@@ -34,6 +34,7 @@
     "@tailwindcss/typography": "^0.5.14",
     "clsx": "^2.1.1",
     "gray-matter": "^4.0.3",
+    "image-size": "^1.1.1",
     "match-sorter": "^6.3.4",
     "next": "^14.2.5",
     "next-mdx-remote": "^5.0.0",

src/components/mdx/Img/Img.tsx

@@ -1,7 +1,21 @@
 import cn from '@/lib/cn'
 import { ComponentProps } from 'react'
 
-export function Img({ src, alt = '', className, ...props }: ComponentProps<'img'>) {
+import sizeOf from 'image-size'
+import { resolve } from 'path'
+
+export async function Img({ src, alt = '', className, ...props }: ComponentProps<'img'>) {
+  const dims: Partial<Pick<ComponentProps<'img'>, 'width' | 'height'>> = {
+    width: undefined,
+    height: undefined,
+  }
+  if (process.env.MDX_BASEURL && src?.startsWith(process.env.MDX_BASEURL)) {
+    const path = resolve(src.replace(process.env.MDX_BASEURL, process.env.MDX!))
+    const { width, height } = sizeOf(path)
+    dims.width = width
+    dims.height = height
+  }
+
   return (
     // eslint-disable-next-line @next/next/no-img-element
     <img
@@ -10,6 +24,7 @@ export function Img({ src, alt = '', className, ...props }: ComponentProps<'img'
       loading="lazy"
       alt={alt}
       className={cn('bg-surface-container inline-block rounded-lg', className)}
+      {...dims}
       {...props}
     />
   )