Swift，如何调整图像大小、添加填充和背景？

Question

I'm trying to create so simple image processing on a macOS app using Swift, to start a have a file URL (eg "../myFiles/myFile.png"), I would like to add paddings to the image and give it a background.

Here is one example, this would be the original image:

And this is the final result I would like to obtain:

Any idea on how to achieve this (preferably applying shadows)?

PS I took a look into some swift libraries but they seem very low level (eg https://github.com/koher/swift-image ), I don't know how to achieve what I want with them

Answer 1

For those looking for a solution using the native APIs the source code of my (now defunct app) is open source:

https://github.com/ospfranco/messer