CapyPDF is approaching feature sufficiency

In the past I have written many blog posts on implementing various PDF features in CapyPDF. Typically they explain the feature being implemented, how confusing the documentation is, what perverse undocumented quirks one has to work around to get things working and so on. To save the effort of me writing and you reading yet another post of the same type, let me just say that you can now use CapyPDF to generate PDF forms that have widgets like text fields and radio buttons.What makes this post special is that forms and widget annotations were pretty much the last major missing PDF feature Does that mean that it supports everything? No. Of course not. There is a whole bunch of subtlety to consider. Let's start with the fact that the PDF spec is massive, close to 1000 pages. Among its pages are features that are either not used or have been replaced by other features and deprecated.The implementation principle of CapyPDF thus far has been "implement everything that needs special tracking,…