简单的图像处理。
iOS 8.4+
import DTImage
let image = UIImage()
let control = UIView()
// resize
image.dt_resize(to: CGSize(width: 200, height: 150))
// crop
image.dt_crop(to: CGRect(x: 150, y: 100, width: 100, height: 100))
// snapshot
UIImage.dt_snapshot(view: control)