Can we get height and width of image using sharp?

user_13234895 0
Viewed 10573

I am using sharp to resize bulk of image. So I am resizing them to 500px by preserving their aspect ratio. Also I want to resize height to 500px and auto resize width if height is greater than with and vice versa. To do that I need to get image, height from Image buffer. I know there are pretty number of packages available to do so. But I was hoping if I can do that using sharp buffer itself.

sharp node.js
3 Answers

Yes you can get the width and height of an image with sharp by using the metadata() function :

const image = await sharp(file.buffer)
const metadata = await image.metadata()
console.log(metadata.width, metadata.height)

You can get a lot more information from metadata , here is the documentation : https://sharp.pixelplumbing.com/api-input#metadata

user_66955690

Sharp is very flexible, it has a number of options for resizing images. Using an option of fit: "contain" should accomplish what you wish.

Others are available of course, documented here: https://sharp.pixelplumbing.com/api-resize#resize

You can also specify the background color to fill space within the resized image, I'm using white here.

The code will look something like this:

const fs = require("fs");
const path = require("path");
const sharp = require("sharp");

const inputDir = "./input-images";
const outputDir = "./output-images";
const requiredDimension = 500;

const inputImages = fs.readdirSync(inputDir).map(file => path.join(inputDir, file));

function resizeImage(imagePath) {

    sharp(imagePath)
    .resize( { width: requiredDimension, height: requiredDimension,  fit: "contain", background: { r: 255, g: 255, b: 255, alpha: 1 }})
    .toFile(path.join(outputDir, path.basename(imagePath) + "-resized" + path.extname(imagePath)), (err, info) => { 
        if (err) {
            console.error("An error occurred resizing image:", err);
        }
    });
}

// Ensure output dir exists...
if (!fs.existsSync(outputDir)) {
    fs.mkdirSync(outputDir)
}
inputImages.forEach(resizeImage);
user_72372240

To get the dimensions that are recorded in the header of the input image:

const image = await sharp(file.buffer);
const metadata = await image.metadata();
console.log(metadata.width, metadata.height);

However, operations like image.resize(...) will not affect the .metadata(). To get the dimensions after performing operations on the image, use .toBuffer({ resolveWithObject: true }):

const image = await sharp(file.buffer);
const resizedImage = image.resize(640);
const { info } = await resizedImage.png().toBuffer({ resolveWithObject: true });
console.log(info.width, info.height);
user_2297920
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