Swift - 将 html 字符串转换为属性字符串并再次返回时字体大小会增加 [英] Swift - Font size increases when converting html string to attributed string and back again

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问题描述

我有一个 textView 允许用户输入 NSAttributedString,转换为 html 字符串,然后存储到数据库中.我还有代码可以将 html 字符串转换回并在 textView 中显示以进行编辑.我拥有的转换代码是

I have a textView that allow user to enter NSAttributedString, convert into html string and then store into database. I also have code to convert the html string back and display in textView for editing. The conversion codes I have are

extension String {
    func htmlAttributedString() -> NSAttributedString? {
        guard let data = self.data(using: String.Encoding.utf16, allowLossyConversion: false) else { return nil }
        guard let html = try? NSMutableAttributedString(
            data: data,
            options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
            documentAttributes: nil) else { return nil }
        return html
    }
}

extension NSAttributedString {
    func htmlString() -> String? {
        let documentAttributes = [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType]
        do {
            let htmlData = try self.data(from: NSMakeRange(0, self.length), documentAttributes:documentAttributes)
            if let htmlString = String(data:htmlData, encoding:String.Encoding.utf8) { return htmlString }
        }
        catch {}
        return nil
    }
}

但是问题是每次我保存和显示字符串时,所有字体大小都会增加.例如,我有一个 html 字符串

However the problem is that every time when I save and display the string, all font size increases. For example, I have a html string

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta http-equiv="Content-Style-Type" content="text/css">
<title></title>
<meta name="Generator" content="Cocoa HTML Writer">
<style type="text/css">
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 17.0px '.SF UI Text'; color: #000000}
span.s1 {font-family: '.SFUIText'; font-weight: normal; font-style: normal; font-size: 17.00pt}
</style>
</head>
<body>
<p class="p1"><span class="s1">text</span></p>
</body>
</html>

在我将其转换为 NSAttributedString 并再次返回后,其他一切都相同,但 css 行更改为此.

After I convert it into NSAttributedString and back again, everything else are the same but the css lines are changed to this.

<style type="text/css">
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; line-height: 28.0px; font: 22.7px '.SF UI Text'; color: #000000; -webkit-text-stroke: #000000}
span.s1 {font-family: '.SFUIText'; font-weight: normal; font-style: normal; font-size: 22.67pt; font-kerning: none}
</style>

我错过了什么吗?任何帮助表示赞赏!

Am I missing anything? Any helps are appreciated!

推荐答案

试试这个我从一些帮助中找到的方法,然后转换为 Swift 3:

Try this method I found from some help and then converted to Swift 3:

func newAttrSize(blockQuote: NSAttributedString) -> NSAttributedString
{
    let yourAttrStr = NSMutableAttributedString(attributedString: blockQuote)
    yourAttrStr.enumerateAttribute(.font, in: NSMakeRange(0, yourAttrStr.length), options: .init(rawValue: 0)) {
        (value, range, stop) in
        if let font = value as? UIFont {
            let resizedFont = font.withSize(font.pointSize * 0.75)
            yourAttrStr.addAttribute(.font, value: resizedFont, range: range)
        }
    }

    return yourAttrStr
}

这篇关于Swift - 将 html 字符串转换为属性字符串并再次返回时字体大小会增加的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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