我前面写了篇文章讲解如何给图片添加文字水印，而如果想要添加图片类型的水印也很简单，只要把原来代码里添加文字的部分改成图片即可。
1，效果图如下：
（在图片左上角添加了一个半透明的logo图片）
2，为方便使用，我们通过扩展UIImage类来实现添加图片水印功能
（水印图片透明度，位置，边距都可以设置）
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//--- UIImageExtension.swift ---extension UIImage{
//水印位置枚举
enum WaterMarkCorner{
case TopLeft
case TopRight
case BottomLeft
case BottomRight
}
//添加图片水印方法
func waterMarkedImage(waterMarkImage:UIImage, corner:WaterMarkCorner = .BottomRight,
margin:CGPoint = CGPoint(x: 20, y: 20), alpha:CGFloat = 1) -> UIImage{
var markFrame = CGRectMake(0, 0, waterMarkImage.size.width, waterMarkImage.size.height)
let imageSize = self.size
switch corner{
case .TopLeft:
markFrame.origin = margin
case .TopRight:
markFrame.origin = CGPoint(x: imageSize.width - waterMarkImage.size.width - margin.x,
y: margin.y)
case .BottomLeft:
markFrame.origin = CGPoint(x: margin.x,
y: imageSize.height - waterMarkImage.size.height - margin.y)
case .BottomRight:
markFrame.origin = CGPoint(x: imageSize.width - waterMarkImage.size.width - margin.x,
y: imageSize.height - waterMarkImage.size.height - margin.y)
}
// 开始给图片添加图片
UIGraphicsBeginImageContext(imageSize)
self.drawInRect(CGRectMake(0, 0, imageSize.width, imageSize.height))
waterMarkImage.drawInRect(markFrame, blendMode: .Normal, alpha: alpha)
let waterMarkedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return waterMarkedImage
}
} |
3，使用样例
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import UIKit
class ViewController: UIViewController {
@IBOutlet weak var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
//给图片添加水印
imageView.image = UIImage(named:"bg")?
.waterMarkedImage(UIImage(named: "logo7")!,corner: .TopLeft,
margin: CGPoint(x: 20, y: 20), alpha:1)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
} |