SUMMARY The Zoom and Magnifier effects currently use keyboard shortcuts to zoom in/out. There should also be an option to use the trackpad or scroll-wheel while holding the Meta key (similar to macOS, e.g. https://www.youtube.com/shorts/3TXOHl8knsE). Trackpad can either use a 2D pinch or two-finger scroll. STEPS TO REPRODUCE 1. Open Desktop Effects settings 2. Open settings for Zoom/Magnifier 3. Enable scroll control through checkbox/radio button
Just to add a note, this feature might conflict with an existing feature: custom Window Actions in Window Behavior KCM. For example, currently I'm using Meta as a modifier key with a Mouse Wheel action to change window opacity. So, future developers are advised to keep the implementation cooperative with existing gestures, and warn users about duplicated gestures, just like we currently warn about duplicated shortcuts.
This already exists, but the keyboard keys you need to hit are Ctrl+Meta scroll.
(In reply to Nate Graham from comment #2) > This already exists, but the keyboard keys you need to hit are Ctrl+Meta > scroll. I just found your blog post on this and it does seem interesting that this isn't documented anywhere in the UI yet. Didn't really look into it much before coming here, thanks for the info though!