Weird behaviour of Caret/Cursor in UITextField

Question

(Xcode10.1 ,Swift, iOS 11&12)
Question: How to increase height of caret/cursor in UITextField

What i've tried so far:
i've done this, and problem solved.

class BPTextField: UITextField {
    override func caretRect(for position: UITextPosition) -> CGRect {
        //CGRect rect = [super caretRectForPosition:position];
        var rect = super.caretRect(for: position)
        let h = self.frame.height - 5
        let y_ = (self.frame.height - h)/2
        rect.origin.y = y_
        rect.size.height = h;
        return rect;
    }
}

but, when i changed Keyboard Language (from English-India to Japanese-Kana) and type single character , the caret/cursor moves to up side in TextField.

Please help me

i've gone through these links,
How to make the height of the cursor same with the height of text in UITextField?
UITextView lineSpacing make cursor height not same

EDIT i'm using YYText library, i'm inserting this BPTextField into YYLabel as a NSAttributedStringAttachment

here is NSAttributedString,

let main = NSMutableAttributedString(string: text_)
        main.yy_color = .darkGray
        main.yy_font = questionFont
        main.yy_lineSpacing = 5.0
        main.yy_lineBreakMode = .byWordWrapping

//Attachment

let attachment = NSMutableAttributedString.yy_attachmentString(withContent: self.tf, contentMode: UIView.ContentMode.center, attachmentSize: self.tf.frame.size, alignTo: questionFont, alignment: YYTextVerticalAlignment.bottom)
        attachment.yy_baselineOffset = -5.0
        root.append(attachment)

//BPTextField

self.tf = BPTextField(frame: CGRect(origin: CGPoint.init(x: 0, y: 13), size: CGSize(width: tfWidth.width + 7.5, height: tfWidth.height + 13.0)))
        self.tf.borderStyle = UITextField.BorderStyle.none
        self.tf.tag = 0
        self.tf.font = questionFont
        self.tf.autocorrectionType = UITextAutocorrectionType.no
        self.tf.textColor = .darkGray
        self.tf.setRoundedCorners(corners: UIRectCorner.allCorners, withRadius: 4.0)
//        self.tf.setLeftPaddingPoints(5.0)
//        self.tf.setRightPaddingPoints(0.0)
        self.tf.backgroundColor = #colorLiteral(red: 0.9058823529, green: 0.9529411765, blue: 1, alpha: 1)
        self.tf.tintColor = #colorLiteral(red: 0.2196078431, green: 0.6156862745, blue: 1, alpha: 1)
        self.tf.returnKeyType = .done
        self.tf.delegate = self

Answer 1

You can calculate origin y as below,

override func caretRect(for position: UITextPosition) -> CGRect {
    var rect = super.caretRect(for: position)
    let size = CGSize(width: rect.size.width, height: self.frame.height - 5)
    // Calculating center y
    let y = rect.origin.y - (size.height - rect.size.height)/2
    rect = CGRect(origin: CGPoint(x: rect.origin.x, y: y), size: size)
    return rect
}