#Infer local image size

7 messages · Page 1 of 1 (latest)

versed cloudBOT
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Hi @heady cargo. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

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To get the width and height from a local image in Astro using its relative path, you need to import the image. When you import a local image in Astro, it automatically provides metadata including dimensions.

Here's how to do it:

---
// Import your local image
import myImage from '../path/to/your-image.jpg';

// Now you can access the image dimensions
console.log(myImage.width);  // e.g. 1600
console.log(myImage.height); // e.g. 900
console.log(myImage.format); // e.g. 'jpg'
---

<!-- You can use these dimensions in your markup -->
<img src={myImage.src} width={myImage.width} height={myImage.height} alt="Description" />

When you import a local image in Astro, the imported image asset matches this signature:

interface ImageMetadata {
  src: string;
  width: number;
  height: number;
  format: string;
}

This approach works for images located in your src/ folder. Astro automatically analyzes these files and provides their metadata, which helps prevent Cumulative Layout Shift (CLS) by setting the correct dimensions on your images.

Note that this automatic dimension inference only works for local images in the src/ folder. For images in the public/ folder or remote images, you would need to manually specify dimensions.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

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heady cargo
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@versed cloud
But the path is dynamic, as i get it with:
const faviconOrigin = path.join('src', 'sites', siteName, 'img', 'favicon.png');

versed cloudBOT
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Let me check the knowledge base for you again. One moment! :books:

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I understand you're working with a dynamic path to an image. When dealing with dynamic image paths in Astro, you'll need to use Vite's import.meta.glob function instead of static imports.

Here's how you can handle this scenario:

---
import type { ImageMetadata } from 'astro';
import path from 'path';

const siteName = 'your-site-name'; // This would be your dynamic value
const faviconOrigin = path.join('src', 'sites', siteName, 'img', 'favicon.png');

// Use import.meta.glob to get all images that match a pattern
const images = import.meta.glob<{ default: ImageMetadata }>('/src/sites/*/img/favicon.png');

// Convert the path to the format expected by import.meta.glob
const globPath = '/' + faviconOrigin.replace(/\\/g, '/');

// Check if the image exists in the glob results
if (!images[globPath]) {
  throw new Error(`Image not found: ${globPath}`);
}

// Get the image metadata
const imageModule = await images[globPath]();
const imageMetadata = imageModule.default;

// Now you can access width and height
const { width, height, format } = imageMetadata;
---

<img src={imageMetadata.src} width={width} height={height} alt="Favicon" />

This approach uses Astro's dynamic image importing capabilities as described in the Dynamically importing images recipe. The import.meta.glob function returns an object with all matching image paths, and each path maps to a function that, when called, imports that image and provides its metadata.

Note that the path format used by import.meta.glob uses forward slashes and starts with a leading slash, so you may need to adjust your path accordingly.

If you're using this in a component that needs to be reusable with different site names, you can pass the site name as a prop and construct the path dynamically.

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Remember that this only works for images in the src/ directory, as Astro can only process and extract metadata from images in this location.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: