How to dynamically load a font under iOS. (for real) - ios

Question

I've seen this question asked and answered numerous times, but I haven't seen a real answer.
The common "solutions" are:
Add the font to the application bundle and register it in the info.plist file.
Use a custom font parsing and rendering library (like the Zynga's FontLabel).
It cannot be done.
So the question is: How to dynamically load a font under iOS?
Loading the font "dynamically" means loading any given font which is not known at the time of the app's compilation.

Answer 1

Fonts can easily be dynamically loaded from any location or any byte stream. See the article here: http://www.marco.org/2012/12/21/ios-dynamic-font-loading
NSData *inData = /* your font-file data */;
CFErrorRef error;
CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)inData);
CGFontRef font = CGFontCreateWithDataProvider(provider);
if (! CTFontManagerRegisterGraphicsFont(font, &error)) {
CFStringRef errorDescription = CFErrorCopyDescription(error)
NSLog(#"Failed to load font: %#", errorDescription);
CFRelease(errorDescription);
}
CFRelease(font);
CFRelease(provider);
You don't have to put the font in your bundle.
You don't have to explicitly register the font in your info.plist.
See also:
https://developer.apple.com/library/mac/#documentation/Carbon/Reference/CoreText_FontManager_Ref/Reference/reference.html#//apple_ref/doc/uid/TP40008278
https://developer.apple.com/library/mac/#documentation/GraphicsImaging/Reference/CGFont/Reference/reference.html#//apple_ref/c/func/CGFontCreateWithDataProvider

Answer 2

Great time for a recent post from Marco titled Loading iOS fonts dynamically.
NSData *inData = /* your decrypted font-file data */;
CFErrorRef error;
CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)inData);
CGFontRef font = CGFontCreateWithDataProvider(provider);
if (! CTFontManagerRegisterGraphicsFont(font, &error)) {
CFStringRef errorDescription = CFErrorCopyDescription(error)
NSLog(#"Failed to load font: %#", errorDescription);
CFRelease(errorDescription);
}
CFRelease(font);
CFRelease(provider);

Answer 3

// Note : add "CoreText.framework" into your project to support following code
// Put loadCustomFont function inside app delegate or any shared class to access any where in code...
-(void)loadCustomFont:(NSMutableArray *)customFontFilePaths{
for(NSString *fontFilePath in customFontFilePaths){
if([[NSFileManager defaultManager] fileExistsAtPath:fontFilePath]){
NSData *inData = [NSData dataWithContentsOfFile:fontFilePath];
CFErrorRef error;
CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)inData);
CGFontRef font = CGFontCreateWithDataProvider(provider);
// NSString *fontName = (__bridge NSString *)CGFontCopyFullName(font);
if (!CTFontManagerRegisterGraphicsFont(font, &error)) {
CFStringRef errorDescription = CFErrorCopyDescription(error);
NSLog(#"Failed to load font: %#", errorDescription);
CFRelease(errorDescription);
}
CFRelease(font);
CFRelease(provider);
}
}
}
// Use as follow inside your view controller...
- (void)viewDidLoad
{
[super viewDidLoad];
// pass all font files name into array which you want to load dynamically...
NSMutableArray *customFontsPath = [[NSMutableArray alloc] init];
NSArray *fontFileNameArray = [NSArray arrayWithObjects:#"elbow_v001.ttf",#"GothamRnd-MedItal.otf", nil];
for(NSString *fontFileName in fontFileNameArray){
NSString *fileName = [fontFileName stringByDeletingPathExtension];
NSString *fileExtension = [fontFileName pathExtension];
[customFontsPath addObject:[[NSBundle mainBundle] pathForResource:fileName ofType:fileExtension]];
}
AppDelegate *appDel = (AppDelegate *)[[UIApplication sharedApplication] delegate];
// load custom font into memory...
[appDel loadCustomFont:customFontsPath];
// Use font as below
[lblName setFont:[UIFont fontWithName:#"Elbow v100" size:15.0]];
[lblName2 setFont:[UIFont fontWithName:#"Gotham Rounded" size:20.0]];
}

Answer 4

Downloading a TTF file from server?
IF you are downloading a TTF file then you can do following to register your custom fonts with iOS Font Manager, this piece of code also takes care of TTF file updates (font updates):
+(void)registerFontsAtPath:(NSString *)ttfFilePath
{
NSFileManager * fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:ttfFilePath] == YES)
{
[UIFont familyNames];//This is here for a bug where font registration API hangs for forever.
//In case of TTF file update : Fonts are already registered, first de-register them from Font Manager
CFErrorRef cfDe_RegisterError;
bool fontsDeregistered = CTFontManagerUnregisterFontsForURL((__bridge CFURLRef)[NSURL fileURLWithPath:ttfFilePath], kCTFontManagerScopeNone, &cfDe_RegisterError);
//finally register the fonts with Font Manager,
CFErrorRef cfRegisterError;
bool fontsRegistered= CTFontManagerRegisterFontsForURL((__bridge CFURLRef)[NSURL fileURLWithPath:ttfFilePath], kCTFontManagerScopeNone, &cfRegisterError);
}

Answer 5

Here is an updated answer of #mt81 for Swift 3:
guard
let path = "Path to some font file",
let fontFile = NSData(contentsOfFile: path)
else {
print "Font file not found?"
}
guard let provider = CGDataProvider(data: fontFile)
else {
print "Failed to create DataProvider"
}
let font = CGFont(provider)
let error: UnsafeMutablePointer<Unmanaged<CFError>?>? = nil
guard CTFontManagerRegisterGraphicsFont(font, error) else {
guard
let unError = error?.pointee?.takeUnretainedValue(),
let description = CFErrorCopyDescription(unError)
else {
print "Unknown error"
}
print description
}

Answer 6

Here the swift version:
let inData: NSData = /* your font-file data */;
let error: UnsafeMutablePointer<Unmanaged<CFError>?> = nil
let provider = CGDataProviderCreateWithCFData(inData)
if let font = CGFontCreateWithDataProvider(provider) {
if (!CTFontManagerRegisterGraphicsFont(font, error)) {
if let unmanagedError = error.memory {
let errorDescription = CFErrorCopyDescription(unmanagedError.takeUnretainedValue())
NSLog("Failed to load font: \(errorDescription)");
}
}
}