enableZoomGestures property
Whether Ctrl/Cmd + wheel over the sheet zooms it.
This is also what a trackpad pinch arrives as: the platform reports the
pinch as a scroll stream carrying the primary modifier, so a single
handler covers both. A wheel with no modifier keeps scrolling the sheet,
untouched. Defaults to false so a sheet that never asked for zoom
behaves exactly as it did before this existed — mirroring
enableKeystrokes.
Enabling it also registers the zoom keyboard shortcuts (Ctrl/Cmd + '=', '+', '-' and '0'), which are delivered by the keystroke listener and so additionally need enableKeystrokes. Passing a zoomController enables them too, since the caller clearly intends the sheet to be zoomable.
Implementation
final bool enableZoomGestures;