My service has both a web version and an iPhone version. On the iPhone, we ensure that users submit a square version by having it crop when it uploads. We are allowing uploads on the website as well, but we do not have such a feature.
As such, I would like to scale any uploaded image into fitting a 612 * 612 area. What would be the best way to accomplish this?
I am using Ruby / mini_magick
You'd just use the resize method from MiniMagick, there's an example on the Github page:
Presumably you have the image as a bunch of bytes in memory so something like this:
image = MiniMagick::Image.read(your_image_bytes)
image.resize('612x612')
scaled_image_bytes = image.to_blob
# Or image.write(filename)
MiniMagick uses standard ImageMagick geometry strings for sizing and, from the fine manual, a WxH geometry:
Maximum values of height and width given, aspect ratio preserved.
so using '612x612' will scale the image to fit within a 612px square while preserving the aspect ratio.
You could also use Jcrop to allow your web users to crop the their uploaded images to fit into a square.