kDefaultTrackpadScrollToScaleFactor top-level constant
The default conversion factor when treating trackpad scrolling as scaling.
This factor matches the default kDefaultMouseScrollToScaleFactor of 200 to feel natural for most trackpads, and the convention that scrolling up means zooming in.
Implementation
const Offset kDefaultTrackpadScrollToScaleFactor = Offset(0, -1/kDefaultMouseScrollToScaleFactor);