I don’t know what would cause that, but maybe @mflatt or @greg would know.

When I (browse-syntax #'(module racket/base (displayln "hello"))) in an Emacs REPL the resulting frame text is nearly the same size as in DrRacket.

It’s definitely not something like a 2X difference, which if it were would suggest I’m seeing a HiDPI issue. So it seems to “just work” for me on Ubuntu 18.04 with Emacs 25.2.

Note that I have the “Text Scale” thing in Ubuntui tweaks set to 1.5, which is how most HiDPI things work OK-ish for me.

But IIRC @rntz you’re using Ubuntu 22.04, and probably a newer Emacs, too.

You might even be on Wayland instead of X.

So I’m not sure what HiDPI advice to give?

ISTR there is some env var that racket/gui looks for, which might affect 2X scaling; maybe ensuring that’s set in Emacs, would fix this?? (wild guess theory)

@rntz Had trouble finding this, probably needs an index tag like “HiDPI”, but here it is: PLT_DISPLAY_BACKING_SCALE: https://docs.racket-lang.org/gui/windowing-overview.html#%28idx._%28gentag._13._%28lib._scribblings%2Fgui%2Fgui..scrbl%29%29%29

So for example $ PLT_DISPLAY_BACKING_SCALE=3.0 drracket gives you a DrRacket scaled quite large. Now how to make this work in Emacs launching a syntax browser? I think something like setenv in Emacs, then (re)start the Racket Mode back end (which is the process supporting your user program and REPL)? Trying that…

Bingo. That works for me.

1. M-x eval-expression and enter (setenv "PLT_DISPLAY_BACKING_SCALE" "3.0").
2. M-x racket-start-back-end.
3. Start a REPL and do (require macro-debugger/syntax-browser) and (browse-syntax #'(module racket/base (displayln "hello"))) and you should get larger text.

But why would it be different when starting from Emacs in the first place? When PLT_DISPLAY_BACKING_SCALE is not set, racket/gui consults Gtk to get the scale; is it possible that GDK_SCALE or GDK_DPI_SCALE is getting set?

@rntz Does that work for you? If so, then move step 1 to your Emacs init file.

@mflatt AFAICT it’s not different for me, on my older Ubuntu system.

Hopefully @rntz can get you some details for a deeper fix if possible, on their end (??) or in racket/gui (??). (But meanwhile/instead I think the work-around I suggested could work.)

Racket is a procedural language organized into modules. Go is close to being a domain specific language that Thompson made for Google to solve their systems programming needs.