Add 'reverse' option to wheel gesture #660
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This PR adds a
reverseoption to the wheel gesture, which inverts the direction of wheel scrolling. A few years ago, a similar PR #171 has been closed with the reason that the inversion could easily be done in userland.In my scenario, I'm using multiple gestures (drag, pinch-to-zoom, and wheel) to navigate around a canvas element, and I'm using the
fromandboundsproperties to limit the canvas movement. This led to some complications when I tried to invert the direction of the wheel scroll. Without having thereverseoption, it would require a complex bounds calculation which would be the inverse of the bounds which I'm already calculating for thedraggesture. This was my first approach, however I ran into some weird behaviour which is was not able to easily fix.The
reverseoption that is introduced by this PR allows developers in the invert the wheel gesture, while allowing to use the sameboundscalculation that is used by thedraggesture. This will make it easier for developers that wish to implement drag and wheel gesture behaviour similar to something like excalidraw.com.