How to resize an image in sharp with the option 'contain' but preserve the aspect ratio of the original dimensions?

Question

I have a 1000px by 750px image.

I use lovell/sharp to resize it:

await sharp(image)
    .resize({
        fit: sharp.fit.contain,
        width: 800,
        height: 800
    })
    .jpeg({ quality: 80 })
    .toBuffer()

This results in a new image that is 800px by 800px, with the original image 'contained' inside of that region.

What I would really like is to have a final image that is 800px by 600px. IOW, to resize the image and preserve the aspect ratio.

I realize it is possible to do this by specifying only a width. However it is useful to have a bounding box to contain the resized image in, to avoid creating images greater than a certain height.

Can I do this in sharp with different settings?

Solution

Keep either width or height so that the Sharp will maintain the ratio

Below the height will maintain its ratio when resizing;

await sharp(image)
    .resize({
        fit: sharp.fit.contain,
        width: 800
    })
    .jpeg({ quality: 80 })
    .toBuffer()

Comments

[user1031947]

ermagherd, shoulda just checked the docs first: github.com/lovell/sharp/blob/master/docs/api-resize.md sharp.fit.inside

[Methodician]

This is precisely what we are trying to achieve. Should be accepted answer. (didn't need the quality setting not sure it's relevant)

[Christos Lytras]

This should be the accepted answer. @Methodician the quality setting comes from the OP code; when answering questions, it's most likely and recomended to use and refactor the code that the OP contains.