NSAttributedString：使图像适应容器 [英] NSAttributedString: Fit image to container

问题描述

我有一个由HTML制作的NSAttributedString，它显示一些图像。问题是，图像比容器大，我不知道如何适应它。

感谢您的帮助

  content.enumerateAttribute 
 
 （NSAttachmentAttributeName，inRange：NSMakeRange（0，content.length），options：NSAttributedStringEnumerationOptions（0））{（value，range，stop） - >如果让attachement = value为？，则在
中作废？ NSTextAttachment {
 let image = attachement.imageForBounds（attachement.bounds，textContainer：NSTextContainer（），characterIndex：range.location）
 let screenSize：CGRect = UIScreen.mainScreen（）。bounds 
 if image.size.width> screenSize.width-2 {
 let newImage = image.resizeImage（（screenSize.width-2）/image.size.width）
 let newAttribut = NSTextAttachment（）
 newAttribut.image = newImage 
 content.addAttribute（NSAttachmentAttributeName，value：newAttribut，range：range）
} 
} 
} 
  

函数 resizeImage（）定义如下：

 扩展名UIImage {
 func resizeImage（scale：CGFloat） - > UIImage {
 let newSize = CGSizeMake（self.size.width * scale，self.size.height * scale）
 let rect = CGRectMake（0，0，newSize.width，newSize.height）
 
 UIGraphicsBeginImageContext（newSize）
 self.drawInRect（rect）
 let newImage = UIGraphicsGetImageFromCurrentImageContext（）
 UIGraphicsEndImageContext（）
 return newImage 
} 
 
 $ / code> 





Swift 3版本



<$ p $ b $ text.enumerateAttribute（NSAttachmentAttributeName，in：NSMakeRange（0，text.length），options：.init（rawValue：0），使用：{（value，range，stop）in $ b $如果让attachchement = value为？NSTextAttachment {
let image = attachement.image（forBounds：attachement.bounds，textContainer：NSTextContainer（），characterIndex：range.location）！
let screenSize：CGRect = UIScreen .main.bounds
if image.size.width> screenSize.width-20 {
let newImage = image。 resizeImage（scale：（screenSize.width-2）/image.size.width）
let newAttribut = NSTextAttachment（）
newAttribut.image = newImage
text.addAttribute（NSAttachmentAttributeName，value：newAttribut ，范围：
}
}
}）


函数 resizeImage（）定义如下：

  func resizeImage规模：CGFloat） - > UIImage {
 let newSize = CGSize（width：self.size.width * scale，height：self.size.height * scale）
 let rect = CGRect（origin：CGPoint.zero，size：newSize） 
 
 UIGraphicsBeginImageContext（newSize）
 self.draw（in：rect）
 let newImage = UIGraphicsGetImageFromCurrentImageContext（）
 UIGraphicsEndImageContext（）
 return newImage！ 
} 
  

I have a NSAttributedString which is made from HTML and it displays some images. The problem is that the images are bigger than the container and I wonder how to fit them in it.

Thanks for your help

解决方案

I finally found how to do that:

content.enumerateAttribute(NSAttachmentAttributeName, inRange: NSMakeRange(0, content.length), options: NSAttributedStringEnumerationOptions(0)) { (value, range, stop) -> Void in
    if let attachement = value as? NSTextAttachment {
        let image = attachement.imageForBounds(attachement.bounds, textContainer: NSTextContainer(), characterIndex: range.location)
        let screenSize: CGRect = UIScreen.mainScreen().bounds
        if image.size.width > screenSize.width-2 {
            let newImage = image.resizeImage((screenSize.width-2)/image.size.width)
            let newAttribut = NSTextAttachment()
            newAttribut.image = newImage
            content.addAttribute(NSAttachmentAttributeName, value: newAttribut, range: range)
        }
    }
}

The function resizeImage() is defined like that:

extension UIImage {
    func resizeImage(scale: CGFloat) -> UIImage {
        let newSize = CGSizeMake(self.size.width*scale, self.size.height*scale)
        let rect = CGRectMake(0, 0, newSize.width, newSize.height)

        UIGraphicsBeginImageContext(newSize)
        self.drawInRect(rect)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage
    }
}

Swift 3 version

text.enumerateAttribute(NSAttachmentAttributeName, in: NSMakeRange(0, text.length), options: .init(rawValue: 0), using: { (value, range, stop) in
    if let attachement = value as? NSTextAttachment {
        let image = attachement.image(forBounds: attachement.bounds, textContainer: NSTextContainer(), characterIndex: range.location)!
        let screenSize: CGRect = UIScreen.main.bounds
        if image.size.width > screenSize.width-20 {
            let newImage = image.resizeImage(scale: (screenSize.width-2)/image.size.width)
            let newAttribut = NSTextAttachment()
            newAttribut.image = newImage
            text.addAttribute(NSAttachmentAttributeName, value: newAttribut, range: range)
        }
    }
})

The function resizeImage() is defined like that:

func resizeImage(scale: CGFloat) -> UIImage {
    let newSize = CGSize(width: self.size.width*scale, height: self.size.height*scale)
    let rect = CGRect(origin: CGPoint.zero, size: newSize)

    UIGraphicsBeginImageContext(newSize)
    self.draw(in: rect)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return newImage!
}

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