Xcode 9：自定义字体渲染异常问题问询

Hey there, let's work through this annoying Didot font problem you're dealing with—nothing's more frustrating than setting up custom fonts just to have them stick to the default style. Here are the most common fixes to get your bold/italic styles rendering correctly:

1. Verify the Font's Internal PostScript Name #

First up: don't trust the font file name alone. Many fonts have internal PostScript names that differ from their file names, and this is the exact string Xcode needs to recognize specific styles.

• Open the font in Font Book, right-click it, and select Show Font Info.
• Look for the PostScript name field—this is what you’ll use in your code, not the file name. For example, Didot Bold might be listed as Didot-Bold or DidotBold, depending on the font version.

2. Double-Check Project Configuration #

Even small oversights here can break font rendering:

• Confirm your Didot font files (bold/italic variants included) are added to your Xcode project, and they’re checked under the correct target in the File Inspector (right pane when selecting the font file).
• Go to your target’s Build Phases → Copy Bundle Resources and make sure all Didot font files are listed here. If they’re missing, click the + button to add them—this ensures they’re packaged with your app.
• Open your Info.plist file and verify the Fonts provided by application (UIAppFonts) array includes the full, exact file names of all your Didot fonts (e.g., Didot-Bold.ttf, Didot-Italic.ttf). Case sensitivity matters here—match the file name exactly.

3. Correctly Reference the Font in Code #

A lot of developers make the mistake of trying to add traits (bold/italic) to the base font, but many custom fonts require using their specific style names directly:

• Instead of trying to modify the base font like this:

  let baseFont = UIFont(name: "Didot", size: 17)
  let boldFont = baseFont?.withTraits(.traitBold) // This might not work!
  

• Use the exact PostScript name of the bold/italic variant you want:

  let boldDidot = UIFont(name: "Didot-Bold", size: 17)
  let italicDidot = UIFont(name: "Didot-Italic", size: 17)
  

• To confirm which font names Xcode sees, run this snippet in your app and check the console:

  for familyName in UIFont.familyNames {
      print("Font Family: \(familyName)")
      for fontName in UIFont.fontNames(forFamilyName: familyName) {
          print("  - \(fontName)")
      }
  }
  

  Look for your Didot variants in the output—this will tell you the exact string to use.

4. Clear Caches (Xcode & System) #

Sometimes cached font data messes things up:

• Clean your Xcode project with Cmd+Shift+K, then delete the derived data folder (go to Xcode → Preferences → Locations → Derived Data → Click the arrow to open the folder, then delete your project's folder).
• Remove Didot from Font Book, restart your Mac, then re-install the font files. Restart Xcode and rebuild your app.

If none of these steps fix the issue, sharing your screenshots (Font Book info, Copy Bundle Resources list, Info.plist settings, and your font setup code) will help narrow down the problem further.

内容的提问来源于stack exchange，提问作者djustus