Friday, August 10, 2012 5:02 PM
According to MSDN documentation, scale, translation, and rotation gesture all raise the manipulation events (ManipulationStarted, ManipulationUpdate, and ManipulationComplete). So given a sequence of manipulation events, how can I tell which gesture raises these events?
The second question is what events does a two-finger pinch (or stretch) gesture raise, what events does a mouse wheel rotation raise?
Friday, August 10, 2012 5:55 PMModerator
The manipulations are passed in the event args. You get the results of the manipulation in ManipulationUpdatedEventArgs.Cumulative and Delta, but not how they were generated. If your ManipulationDelta structure includes a Rotation value then you know the user rotated. If it includes a Scale then the user did a rotate. If it includes both then the user did both.
The overall concept is the same if you use UIElement manipulation events instead of the GestureRecognizer, but the details will be slightly different.
- Marked As Answer by Leonard Monday, August 13, 2012 3:53 PM
Saturday, August 11, 2012 4:18 PM
Thanks for your response, Rob.
While I think the unified approach using manipulations to represent all kinds of gestures makes sense, this approach make it difficult for programmers to customize the functions of certain gestures. In a map application for example, mouse wheel rotation gesture is usually used as zooming (or scale), whereas this same gesture also results in panning (or translation) in WinRT APIs. Although I managed to set MouseWheelParameters and do some tricks in my code to do the job, my method is unintuitive and may not work in the future.
Saturday, August 11, 2012 4:38 PM
Mapping is part of my app and I've found the following works (it may not be right but it works!):
1. Use an OnPointerWheelChanged event to handle the mouse wheel
2. Have OnManipulationDelta handler distinguish between touch and mouse events. For touch, allow translation and scaling. For mouse, allow only translation.
I haven't done any true touch testing, just used the simulator's touch-via-mouse mode, but it appears to work as one would expect.
Monday, August 13, 2012 3:53 PMThanks, henador.