Resize to Specific Height and Width with pyvips

Question

I find this answer, and I want to use pyvips to resize images. In the mentioned answer and the official documentation image resized by scale. However, I want to resize the image to a specific height and width. Is there any way to achieve this with pyvips?

score 3 · Accepted Answer · answered Sep 28 '21 at 14:12

3

The thumbnail operation in pyvips will resize to fit an area. For example:

thumb = pyvips.Image.thumbnail("some-file.jpg", 128)

Will load some-file.jpg and make a high-quality image that fits within 128x128 pixels.

Variations on thumbnail can load from strings, buffers or even pipes.

The libvips docs have a chapter on vipsthumbnail explaining how to use the (many) options.

answered Sep 28 '21 at 14:12

jcupitt

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Thumbnail operation crop image or only resize it to the desired size? – d4riush Sep 28 '21 at 14:16
It resizes to fit within the box. It has a mode which will also crop if necessary, but it's not the default. Have a look at the docs. – jcupitt Sep 28 '21 at 17:12

score 2 · Answer 2 · answered Feb 17 '23 at 18:37

You can use the more general affine function. An affine transformation does scaling, rotation and translation all at once. You can parameterize the affine matrix to do 0 rotation and 0 translation.

You first calculate the necessary factors to achieve the target shape

img = pyvips.Image.new_from_file("...")
height_factor = target_height / img.height
width_factor = target_width / img.width```

and apply them via

img.affine((width_factor, 0, 0, height_factor))

Resize to Specific Height and Width with pyvips

2 Answers2