Initial timeline HTML support.

ElementX/Sources/Other/HTMLParsing/UIFont+AttributedStringBuilder.m

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+//
+//  UIFont+AttributedStringBuilder.h
+//  ElementX
+//
+//  Created by Stefan Ceriu on 23/03/2022.
+//  Copyright © 2022 Element. All rights reserved.
+//
+
+#import "UIFont+AttributedStringBuilder.h"
+
+@import UIKit;
+@import CoreText;
+@import ObjectiveC;
+
+#pragma mark - UIFont DTCoreText fix
+
+@interface UIFont (vc_DTCoreTextFix)
+
++ (UIFont *)vc_fixedFontWithCTFont:(CTFontRef)ctFont;
+
+@end
+
+@implementation UIFont (vc_DTCoreTextFix)
+
++ (UIFont *)vc_fixedFontWithCTFont:(CTFontRef)ctFont {
+    NSString *fontName = (__bridge_transfer NSString *)CTFontCopyName(ctFont, kCTFontPostScriptNameKey);
+
+    CGFloat fontSize = CTFontGetSize(ctFont);
+    UIFont *font = [UIFont fontWithName:fontName size:fontSize];
+
+    // On iOS 13+ "TimesNewRomanPSMT" will be used instead of "SFUI"
+    // In case of "Times New Roman" fallback, use system font and reuse UIFontDescriptorSymbolicTraits.
+    if ([font.familyName.lowercaseString containsString:@"times"])
+    {
+        UIFontDescriptorSymbolicTraits symbolicTraits = (UIFontDescriptorSymbolicTraits)CTFontGetSymbolicTraits(ctFont);
+        
+        UIFontDescriptor *systemFontDescriptor = [UIFont systemFontOfSize:fontSize].fontDescriptor;
+        
+        UIFontDescriptor *finalFontDescriptor = [systemFontDescriptor fontDescriptorWithSymbolicTraits:symbolicTraits];
+        font = [UIFont fontWithDescriptor:finalFontDescriptor size:fontSize];
+    }
+
+    return font;
+}
+
+@end
+
+#pragma mark - Implementation
+
+@implementation UIFont(DTCoreTextFix)
+
+// DTCoreText iOS 13 fix. See issue and comment here: https://github.com/Cocoanetics/DTCoreText/issues/1168#issuecomment-583541514
+// Also see https://github.com/Cocoanetics/DTCoreText/pull/1245 for a possible future solution
++ (void)load
+{
+    static dispatch_once_t onceToken;
+    
+    dispatch_once(&onceToken, ^{
+        Class originalClass = object_getClass([UIFont class]);
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wundeclared-selector"
+        SEL originalSelector = @selector(fontWithCTFont:); // DTCoreText method we're overriding
+        SEL ourSelector = @selector(vc_fixedFontWithCTFont:); // Use custom implementation
+#pragma clang diagnostic pop
+        
+        Method originalMethod = class_getClassMethod(originalClass, originalSelector);
+        Method swizzledMethod = class_getClassMethod(originalClass, ourSelector);
+        
+        method_exchangeImplementations(originalMethod, swizzledMethod);
+    });
+}
+
+@end