Highlights is optimized for annotating with an Apple Pencil and supports advanced features like hover, double-tap and squeeze gestures. The different generations of Apple Pencil support different features and work with different devices as shown in the tables below. If you are curious as to why, we have an entire page dedicated to how the Apple Pencil works and the differences between hardware generations.
The Apple Pencil is a high-precision stylus made for the iPad and iPhone Duo. The low latency and palm rejection combined with tilt and pressure sensitivity make it great for drawing, note-taking and marking up PDFs. It might look like a white plastic pencil, but the addition of advanced features like hover, double-tap and squeeze gestures makes it clear that there is a lot going on inside. Here we will dive into how Apple Pencils actually work and how the hardware enables the different features.
A Digital Object Identifier (DOI) is a persistent link (digital identifier) to an object - typically articles, books, or other pieces of digital information. DOIs are commonly used to retrieve scientific works and often included in citations.
The DOI system is an ISO standard controlled by the International DOI Foundation and assigned through multiple registration agencies.
A DOI name is a unique string of characters with two components separated by a forward slash character:
The prefix is assigned to a registration agency and starts with “10.” typically followed by a sequence of four numbers. For scientific journals the registration agency is traditionally the publisher and the prefix is shared amongst all journals from the same publisher. The prefix can therefore give you a hint as to who published the work, but not the specific journal:
The suffix on the other hand is assigned by the registration agency and can be any unique string. The structure of the suffix varies widely between publishers.