in GNOME's issues: https://gitlab.gnome.org/GNOME/epiphany/-/issues/2081
Apple ports do support this, but looks like the relevant code in webkit is just stubbed for some reason, not sure why. So we'd probably have to reimplement quite a lot here.
If I hold Ctrl and scroll the mouse wheel, it zooms properly, integrated with PDF.js's zoom. So this bug is really specific to the touchpad gesture.
Well yes, I mean touchpad zoom api is what we're missing.
https://kenneth.io/post/detecting-multi-touch-trackpad-gestures-in-javascript here are specifics. So we probably want to support the gesture events.