Hi, actual WordStar-in-practice, wrote several hundred thousand words on it in both CP/M and DOS, user here (related: I am old). I think you're confusing WordStar's preview display with its editing display here. Later versions of WordStar for DOS (I think it started with version 5.0, but I wouldn't swear to it) could generate a surprisingly good for the day print preview using PostScript fonts, as described above in the text you're quoting. But that was a specific read-only mode. When editing, WordStar ran in DOS text modes and was limited to what DOS text modes were able to display: monospaced fonts, usually with the ability to display boldface text with "bright" text and sometimes -- not always -- with the ability to display underlined text with actual underlines. (This depended on your video hardware; IIRC, XyWrite seemed to be able to do that pretty reliably in DOS, but WordStar didn't). But you couldn't display proportional type in editing, or italics, or different typefaces.

Now, you could argue that WordStar anticipated WYSIWYG editors, because it did its best to faithfully reproduce margins, indents, line spacing, justification, etc. in its text editing mode -- but that attempt came from the era when printers could only output monospaced type, usually just one typeface, no italics, etc. Once printers got better, WordStar really wasn't WYSIWYG anymore, just "best effort within limitations". IIRC, the only major DOS-based word processor to actually attempt a WYSIWYG editing display was WordPerfect 6.2 in the late 1990s.

Not the original version, because DosBox is simpler than CP/M, but here you go: [0]

[0] https://imgur.com/CZxblEd

Thanks for this. I've never used WordStar, and my knowledge of early word processing software is certainly incomplete, but this is the first time I've seen such a screenshot that predates 1984.