CNImageView.swift

//
//  CNImageView.swift
//  ImageView
//
//  Created by Chiharu Nameki on 2015/08/02.
//  Copyright (c) 2015 Chiharu Nameki. All rights reserved.
//

import UIKit

class CNImageView: UIImageView {
    var imageCenter: CGPoint = CGPointMake(0.5, 0.5) {
        didSet {
            updateContentsRect()
        }
    }

    override var image: UIImage? {
        didSet {
            updateContentsRect()
        }
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        updateContentsRect()
    }
    
    private func updateContentsRect() {
        if let image = image {
            let scale = max(bounds.width / image.size.width, bounds.height / image.size.height)
            let w = min(1.0, bounds.width / (scale * image.size.width))
            let h = min(1.0, bounds.height / (scale * image.size.height))
            let x = imageCenter.x * (1.0 - w)
            let y = imageCenter.y * (1.0 - h)
            layer.contentsRect = CGRectMake(x, y, w, h)
        }
    }
}