I am a beginner, and I have an iPhone app.
I want to convert iPhone app to iPad app.
I want to increase the size of all control, images and views according to iPad dimensions programmatically as I have no controls in XIB but in fact they are programmatically made.
I don't want to change the dimensions manually at every place because it is too much of a cumbersome work.
Is there any way I can do this in a better way?
The simple answer is NO.
You have to do it manually. There is no automatic system.
That is the correct answer.
if you have an absolutely trivial app - ie, with no images or controls or layouts! - you can of course just change it to an iPad app.
The questioner is asking specifically how to change all the images, layouts, and so on in a normal app. The answer is it must all be done completely manually. There is no automatic system for re-doing design or re-doing images in Photoshop, etc.
Note that similarly if you want to do both portrait and landscape layouts of an app, you or your designers have to of course simply design both layouts. There's no, say, "artificial intelligence" system that automatically does art direction for the app! You simply have to manually design both layouts and manually build in Photoshop all necessary images for each situation. The same applies to iPad v. iPhone.
(Note that sometimes you will have to do four totally different layouts, and sets of graphics .. for the phone/pad and portrait/landscape.)
This is exactly why iPad apps are sometimes labelled "HD" in the app store - they are of course totally different.