Hi I am available to create your UITextField subclass. Here is an overview:
+ Sample iPhone app created with latest version of Xcode and written in Objective-C.
+ The sample app will either use the UIKeyboard for text input, or the text is predefined/randomised from a list of text.
+ The suggested animation from your description would smoothly animate using CABasicAnimation/CAKeyframeAnimation to ensure smooth 60 FPS animations. The keyframes you suggested, to grow the height/width of the text field and font size can be animated independently or at the same time. (It would be great to see the reference animation of the same thing so I can visualise exactly the technique you require).
+ The sample app will contain a UITextField/UIView subclass that can be dropped into any other project. The subclass will be instantiated from a ViewController.m (as demonstrated in the provided code). No UI elements, XIBs or storyboards will be used, it will be 100% Objective-C code and will scale to fit on all iPhone screens.
+ I am available immediately and will have the first version back to you the same day of hire (start time dependant, if the not the very next day). I have added more days to give you un opportunity to request changes to the animation so it is just what you were looking for).
+ After this project, I will be available for future work, either expanding on this current project or to help with other aspects in iOS development as needed.
Best,
Elliott