BUILT-IN MATHEMATICA SYMBOL
GestureHandler
GestureHandler[expr, {"gesture1"⧴fun1, "gesture2"⧴fun2, ...]
displays as expr, evaluating 
whenever 
occurs within the screen space occupied by expr.
- GestureHandler is only active on touchscreen devices. Otherwise, it acts as an inert wrapper.
- Functions take arguments that are associated with the specific gesture. Typically, the argument is a value in scaled coordinates that represents the magnitude of the gesture.
- Standard gestures include:
-
| "Pinch" | two-fingered gesture where the fingers pinch together or apart; typically used for resizing |
| "Drag" | one-fingered dragging gesture |
- The arguments passed to the action function by gestures are:
-
| "Pinch" | value | magnitude of the pinch as a fraction of the size of expr; a positive number is an opening pinch |
| "Drag" | {valx,valy} | drag distance as a fraction of the horizontal and vertical sizes of expr |
Print when a pinch gesture happens:
Dynamically print the distance of the last drag gesture:
New in 9
