# CMTextFormatDescriptionGetDefaultTextBox(_:originIsAtTopLeft:heightOfTextTrack:defaultTextBoxOut:) Returns the default text box. ``` func CMTextFormatDescriptionGetDefaultTextBox(_ desc: CMFormatDescription, originIsAtTopLeft: Bool, heightOfTextTrack: CGFloat, defaultTextBoxOut: UnsafeMutablePointer) -> OSStatus ``` ## Parameters `desc` FormatDescription being interrogated. `originIsAtTopLeft` Pass true if the `CGRect` will be used in an environment where (0,0) is at the top-left corner of an enclosing rectangle and y coordinates increase as you go down. Pass false if the `CGRect` will be used in an environment where (0,0) is at the bottom-left corner of an enclosing rectangle and y coordinates increase as you go up. `heightOfTextTrack` If `originIsAtTopLeft` is false, pass the height of the enclosing text track or destination. This value will be used to properly compute the default text box for the given origin. Ignored if `originIsAtTopLeft` is true. `defaultTextBoxOut` On output, receives the default text box. ## Return Value A result code. Returns `noErr` if successful. ## Discussion Within a text track, text is rendered within a text box. There is a default text box set, which can be over-ridden by a sample. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)