Simple CoreText with CTFrameDraw

gistfile1.m

    CGContextRef context = UIGraphicsGetCurrentContext();
    
    // Flip the coordinate system
    
    // Make an attributed string
    NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:@"Hello CoreText!"];
    CFAttributedStringRef attributedStringRef = (CFAttributedStringRef)attributedString;
    
    // Simple CoreText with CTFrameDraw
    CTFramesetterRef framesetter =  CTFramesetterCreateWithAttributedString(attributedStringRef);
    CGPathRef path = CGPathCreateWithRect(self.bounds,NULL);
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter,CFRangeMake(0, 0),path,NULL);
    CTFrameDraw(frame, context);

gistfile2.m

    // Flip the coordinate system
    CGContextSetTextMatrix(context, CGAffineTransformIdentity);
    CGContextTranslateCTM(context, 0, self.bounds.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

gistfile3.m

    NSDictionary *attrs = @{NSFontAttributeName: [UIFont systemFontOfSize:20],
                            NSForegroundColorAttributeName: [UIColor blueColor],
                            NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle),
                            };
    
    // Make an attributed string
    NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:@"Hello CoreText!" attributes:attrs];