Just out of curiosity. I observed that when I copied some webpage text in Firefox that contained font size and color (set by CSS) and pasted them into OneNote, the font size and color were copied along with it. How is this formatting information transferred between the two applications?

OneNote offers several paste operations: keep the original formatting, merge formatting, and keep only the text. But this formatting information is supposed to be saved to the Windows clipboard when the copy button is pressed? I have no knowledge of Windows application development, but I assume that Firefox is the active window when I press the copy key, so it is Firefox that accepts and handles this keyboard event?

I went searching for Firefox's guidance documentation and didn't find anything related to the system clipboard.

By reading Microsoft technical documentation I learned that there are many kinds of clipboard data formats (yes, because Windows' clipboard can handle many data formats, it needs so many formats). If you want to pass data between two applications, I think this format must be one of the standard formats, but I'm not sure which one.

Or is the truth a completely different mechanism from my guess?

CodePudding user response：

When an application is asked to copy something to the clipboard it can store "that something" in multiple formats simultaneously and when another application is asked to paste, it can pick from all the applicable formats.

OneNote perhaps picks CF_HTML > CF_RTF > CF_UNICODETEXT. On the other hand, when you ask it to paste without formatting it might pick CF_UNICODETEXT first (and if it is not available, manually strip the formatting from the HTML/RTF).

There are various tools that lets you see which formats are on the clipboard...