Custom font in framework for SwiftUI

Question

I am creating a framework for iOS apps. It will contain some Label, Button, Lists, ... all as SwiftUI views, but in a special design. In the framework I've added a SwiftUI view called "ContentView" it has just the purpose of (visually) testing the UI-Elements in the canvas, later the ContentView will be deleted. I wanted to a add a custom font for the label design, I know how to do this:

add the *.ttf file to the project
adapt the info.plist "Fonts provided by app"
made sure, it is listed in "Build phases" (copy bundle resources)
use it with ".font(.custom("My-Font-Name", size: 34))"

But the custom font (that I already tried successfully in an other project, iOS application) is not shown in my ContentView. There is no compile error or any warning, the framework can be built and the ContentView is nicely rendered in the canvas. Only with the wrong font.

I tried restart Xcode, remove and add several times the font, but it didn't work. So here my questions:

Is it possible to use a custom font within a custom framework ?
As the custom font (*.ttf) is kind of an asset, has it to be treated different as part of a framework?
If so, is there anything else to do (besides step 1 to 4 above mentioned) ?

Thanks for helping.

jnpdx · Accepted Answer · 2021-02-08 16:44:56Z

11

Tricky little problem, but here's what worked for me:

In the custom framework, I created a FontLoader class:

public class FontLoader {
    static public func loadFont() {
        if let fontUrl = Bundle(for: FontLoader.self).url(forResource: "Opus", withExtension: "otf"),
           let dataProvider = CGDataProvider(url: fontUrl as CFURL),
           let newFont = CGFont(dataProvider) {
            var error: Unmanaged<CFError>?
            if !CTFontManagerRegisterGraphicsFont(newFont, &error)
                {
                    print("Error loading Font!")
            } else {
                print("Loaded font")
            }
        } else {
            assertionFailure("Error loading font")
        }
    }
}

Then, in my AppDelegate's didFinishLaunchingWithOptions, I made sure to import my framework and load the font:

import FontTestFramework
//...
FontLoader.loadFont()

Later, in my view, I used the font successfully with:

Text("Test")
  .font(.custom("Opus", size: 30))

I tested to make sure that it wasn't just loading the version installed on my Mac (since I was using the simulator) but commenting out the FontLoader.loadFont() call, and sure enough, it defaulted back to San Francisco

I tried this with an otf file, but I don't think there's any reason ttf should behave differently. Obviously, the otf file had to be part of the framework's target.

answered Feb 8, 2021 at 16:44

jnpdx

53.3k7 gold badges91 silver badges123 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

LukeSideWalker Over a year ago

Wow, man, thanks for your answer. I wonder how much time have you spent, to figure out that solution. Never I've heard of something like 'CTFontManagerRegisterGraphicsFont'. Guess, I will try this the next days.

jnpdx Over a year ago

I happened to run into a scenario recently where my custom font wasn't getting loaded inside a Catalyst application, so I had a running head start having figured out how to deal with that situation. Then it was just a matter of applying it to a framework and making sure it worked there.

itMaxence Over a year ago

This code is outdated, look here stackoverflow.com/questions/30507905/… and search for another Register method ( CTFontManagerRegisterFontsForURL ). Found in the GraphicFont method documentation: "Fonts that are backed by files should be registered using CTFontManagerRegisterFontsForURL(::_:)."

Zachary Olson · Accepted Answer · 2022-04-07 14:18:22Z

5

I had a similar issue sharing a font with a widget extension - the framework I was using was already built using code similar to the accepted answer (CTFontManagerRegisterGraphicsFont), and it worked just fine in apps themselves, but when I tried to use the framework and the fonts in my widget, it failed to render any of my view code.

What eventually solved it for me was the change suggested in the comment by @itMaxence and in this Apple thread - using CTFontManagerRegisterFontsForURL instead allowed it to work both in the app and in the widget extension.

Just wanted to highlight that comment in case anyone like me stumbles across this thread in the future.

answered Apr 7, 2022 at 14:18

Zachary Olson

1471 silver badge7 bronze badges

Collectives™ on Stack Overflow

Custom font in framework for SwiftUI

2 Answers 2

3 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related