If you are using coretext
, try
CTFontRef font = CTFontCreateWithName((CFStringRef)@"Helvetica", 16.0f, nil);
CFAttributedStringSetAttribute(textString,CFRangeMake(0, strLength-1), kCTFontAttributeName, font);
You can also try CGContextSetFont
NSString *fontName = @"Helvetica";
CGFontRef fontRef = CGFontCreateWithFontName((__bridge CFStringRef)fontName);
CGContextSetFont(context, fontRef);
CGContextSetFontSize(context, 30);
See my question, you will get an idea.