If there are touch sequences being currently handled by this, returns true
and fills in rect with the bounding box containing all active touches.
Otherwise, false will be returned.
Note: This function will yield unexpected results on touchpad gestures. Since there is no correlation between physical and pixel
distances, these will look as if constrained in an infinitely small area, rect width and height will thus be 0 regardless of
the number of touchpoints.
| this |
a `GtkGesture` |
| rect |
bounding box containing all active touches. |
|
true if there are active touches, false otherwise |