crop.py

# coding: utf-8

from wand.image import Image


def resize(blob, min=300, max=1200):
    image = Image(blob=blob)
    width = image.width
    height = image.height
    if width < min:
        raise ValueError('Image is too small for displaying.')

    if width > max:
        height = int(round(float(max) / width * height))
        width = max
        image.resize(width, height)
    return image

宽度大于某个固定值的时候才缩放或者裁剪，高度等比缩放。这个很好理解。

关键是 resize(width, height) 的行为是怎么样的？它是仅仅缩放吗？还是会裁剪？缩放的时候又是先满足宽度呢，还是高度？