GUI to add acrofields to existing pdf

I have a pdf created by some source which does not have any acrofields in it. I know that I can add acrofields programmatically provided I know the co-ordinates.

But I would want to add the acrofields visually (drag-drop). Is there any opensource GUI tool available that allows me to edit a PDF and add acrofields ?

Once I add the acrofields, I would be filling up the values programmatically. But right now all iam looking for is a GUI (opensource) that allows me to开发者_如何学Python add acrofields.

I don't think there are any open source acroForm editors.

There are several "free trial" apps floating around however.