Because ZotPad is a native iOS app, there are many development options available that would be difficult to implement in Zotero for Firefox or Zotero Standalone. For example, while Zotero has a full-text search capability for PDF attachments, it would be difficult to highlight the search results in the PDFs. Also, it would be cumbersome to show the parts of the PDFs where the search terms are found. This is something that I would like to have in ZotPad in the long run. The previews could work in the same way that they work in Google Books.
In an ideal case ZotPad would have the following three features:
While Apple has a really great development environment for iPad, they do not include a PDF library that would make it easy to implement this functionality. I have been looking at different third-party libraries. These commercial libraries cost thousands of euros, so it is not feasible include one with the current price point. One idea that I have been thinking about is to have a more expensive "Pro" version of ZotPad that would be powered by a commercial PDF library. To check the feasibility of this idea, I am doing some market research in the form of a small poll on this site.