What is PresentationStyle?

[snianu]

I'm working on adding a bit more detail about the ClipboardItem interface in #158. This question came up in the PR review and I wasn't sure what the purpose of presentationStyle member is in ClipboardItem that has unspecified, inline & attachment values. I don't see it being used in Chromium async clipboard API implementation, but I do see Safari using it for something that I don't quite understand. Can someone describe the scenario where it's being used and the description of this member so I can add it to the spec? @whsieh @rniwa

[whsieh]

The presentationStyle attribute helps distinguish between "inline" data (e.g. selecting text on a web page and copying), vs. file-like data (e.g. copying a plain text file). This difference is used to provide a hint when writing to the system pasteboard using NSItemProvider on iOS.

[mbrodesser]

It could help to understand how the pasteboard benefits from that hint and what it makes out of it.

This difference is used to provide a hint when writing to the system pasteboard using NSItemProvider on iOS.

Only when writing to the system clipboard?

[whsieh]

It could help to understand how the pasteboard benefits from that hint and what it makes out of it.

Would need to double check — but IIRC on iOS/iPadOS, this distinction allows the Notes app to insert a file attachment when copying a plain text file from the Files app, but insert text inline when copying a selected piece of plain text from another app.

In both cases, the MIME type in the pasteboard would be "text/plain".

This difference is used to provide a hint when writing to the system pasteboard using NSItemProvider on iOS.

Only when writing to the system clipboard?

Both reading and writing.

[snianu]

@whsieh Thank you Wenson! I'll add those details to the spec.