Why not just have a published API and work with the PDF editor/markup vendors to have a direct interface to the Zotero cloud store? Focus resources on adding things like grabbing the webpage content in addition to the metadata, establishing a standard for markup of pages, etc. No PDF vendor can or will do that. I'd let Goodnotes, etc keep progressing their product. IMHO, the basic markup features are sufficent in zotero. I'd love to see a Goodnotes addon that conencts to Zotero.
Because the whole point of the Zotero PDF reader is to create unique functionality — image annotations, annotation support in notes, tagging — that's deeply integrated into people's research workflows. If you want to use another tool, use another tool, but we're obviously not going to stop improving our own PDF readers.
(Also, the whole premise here is backwards. Anyone can use our API, but for an API to support new functionality, that functionality needs to actually be implemented in the data layer.)
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(Also, the whole premise here is backwards. Anyone can use our API, but for an API to support new functionality, that functionality needs to actually be implemented in the data layer.)