CFAttributedString更改字体大小不起作用

// 原始字符串
NSString *originalString = @"Hello, World!";

// 创建CFAttributedString对象
CFStringRef stringRef = (__bridge CFStringRef)originalString;
CFMutableAttributedStringRef attributedStringRef = CFAttributedStringCreateMutable(NULL, 0);
CFAttributedStringReplaceString(attributedStringRef, CFRangeMake(0, 0), stringRef);

// 设置新的字体大小属性
CTFontRef fontRef = CTFontCreateWithName(CFSTR("Helvetica"), 12, NULL);
CFAttributedStringSetAttribute(attributedStringRef, CFRangeMake(0, CFAttributedStringGetLength(attributedStringRef)), kCTFontAttributeName, fontRef);

// 创建新的CFAttributedString对象
CFAttributedStringRef newAttributedStringRef = CFAttributedStringCreate(NULL, attributedStringRef, NULL);

// 获取最终的字符串
NSString *finalString = (__bridge_transfer NSString *)CFAttributedStringGetString(newAttributedStringRef);

// 释放资源
CFRelease(attributedStringRef);
CFRelease(fontRef);
CFRelease(newAttributedStringRef);

NSLog(@"%@", finalString);