为什么 UIFont 和 CGFont/CTFont 完全分离? [英] Why are UIFont and CGFont/CTFont separated completely?

问题描述

我试图用下载的字体绘制一些文本.我查看了 API 文档并搜索了 Web.我找到了一个解决方案，但问题是它仅适用于 CoreGraphics 级别的框架.所以我寻找了一种方法将CGFont 转换为UIFont，但没有办法做到这一点.

I was trying to draw some text with a downloaded font. I looked at API documentation and searched the Web. I found a solution, but the problem is that it's applicable to only the CoreGraphics level framework. So I searched for a way to convert CGFont to UIFont, but there was no way to do this.

我意识到 UIFont 和 CGFont/CTFont 是完全分离的，即使它们是从同一个字体文件创建的.CGFont 和 CTFont 可以相互转换，但对于 UIFont，唯一的方法是重新创建其属性，如名称和大小.并且适用的代码也分开了.

I realized UIFont and CGFont/CTFont are separated completely, even though they're created from same font file. CGFont and CTFont are convertible from/to each other, but for UIFont, the only way is recreating with its attributes like name and size. And applicable codes are also separated.

例如，CATextLayer 只接受 CGFont/CTFont — 不接受 UIFont.但所有 UIKit 控件只接受 UIFont.

For instance, CATextLayer accepts only CGFont/CTFont — no UIFont. But all UIKit controls accept only UIFont.

为什么会存在这种分离?还是我错了?(有没有办法在 UIKit 类中使用下载的字体?)

Why does this separation exist? Or am I wrong? (Any way to use a downloaded font in UIKit classes?)

推荐答案

简短的回答:只有 Apple 人才知道"

更详细的答案，稍微挖掘一下(逆向)框架:

The more detailed answer, after digging (reversing) frameworks a bit:

• UIKit.framework 不使用 CGFont 类型
• UIKit.framework 使用 CoreText CTFont 和 GSFont...
• GSFont 来自... GraphicsServices 私有框架
• GraphicsServices... 使用 CGFont

• UIKit.framework doesn't use at all CGFont type
• UIKit.framework use instead CoreText CTFont and GSFont...
• GSFont comes from... the GraphicsServices private framework
• GraphicsServices... use CGFont

所以这是我的猜测(可能完全错误) :

• UIFont > GSFont(私有) > CGFont

• UIKit > GraphicsServices > CoreGraphics :

• UIFont > GSFont(Private) > CGFont

• UIKit > GraphicsServices > CoreGraphics :

至少在字体方面，苹果工程师在UIKit之间建立了一个抽象层和 CoreGraphics 框架，通过晦涩的 GraphicsServices 一个.

At least Concerning fonts, Apple engineers have set up an abstraction layer between UIKit and CoreGraphics frameworks, via the obscur GraphicsServices one.

iOS > iOS (私有) > Mac OSX :

为什么他们这样做，我想说 CoreGraphics，它来自 Mac OSX，不是 iOS 设备的最佳选择，而且 UIKit 仅适用于 iOS，他们添加了一个两个api之间的层.或者更一般地说，他们计划有一天将 UIKit 与 CoreGraphics 完全分离……iOS 与 Mac OSX……谁知道呢！苹果公司，我的简短回答:)

Why they did this, I would say CoreGraphics, which comes from Mac OSX, wasn't optimal for iOS devices, and UIKit being iOS only, they added a layer between both apis. Or more generally they plan one day to separate completely UIKit from CoreGraphics... iOS from Mac OSX... Who knows! The apple folks does, my short answer :)

关于在 UIKit 中使用自定义字体，您可能有兴趣阅读 这个.

About using custom fonts with UIKit, you might be interested reading this.

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