GestureRotate Event 495
Description
This event is reported when the user touches two fingers on an object and twists them clockwise or anticlockwise.
The event message reported as the result of ⎕DQ, or supplied as the right argument to your callback function, is a 5-element vector as follows :
[1] |
Object | ref or character vector |
[2] |
Event | 'GestureRotate' or 495 |
[3] |
Flags | integer which reports the state of the gesture |
[4] |
Location | 2-element integer vector containing the y and x-position respectively of the point midway between the two fingers. These are reported in pixel coordinates relative to the origin of the screen. |
[5] |
Angle | a scalar number which represents the angle of rotation of the twist measured in radians (0 → ○2 ) from the x-axis in a counter-clockwise direction. |
The Flags parameter [3] which reports the state of the Gesture, is an integer with the value 0, 1 (GF_BEGIN),or 4 (GF_END) with the following meanings:
| Name | Value | Description |
| 0 | A gesture is in progress | |
GF_BEGIN |
1 | A gesture is starting. |
GF_END |
4 | A gesture has finished. |
When the user first touches two fingers on an object and begins to twist, the object generates a GestureRotate event with a Flags parameter of 1 (GF_BEGIN). As the user continues to twist his fingers, the object generates a series of GestureRotate events with a Flags parameter of 0. When the user lifts one or both fingers away, the object generates a final GestureRotate event, with a Flags parameter of 4 (GF_END).
No other event will be reported between the start and end of a series of GestureRotate events.
The associated callback is run immediately while the windows notification is still on the stack. See High-Priority Callback Functions.
Returning zero from the callback disables any default handling by the operating system.