GESTUREMETRICS (Compact 2013)

3/28/2014

This structure defines the constraints that the gesture recognizer uses to detect touch gestures. When you call the SystemParametersInfo function, you can use this structure to query or set system-wide parameters for the gestures API.

Syntax

typedef struct tagGESTUREMETRICS {
    UINT cbSize;
    DWORD dwID;
    DWORD dwTimeout;
    DWORD dwDistanceTolerance; 
    DWORD dwAngularTolerance;
        DWORD dwExtraInfo;
} GESTUREMETRICS, *LPGESTUREMETRICS;

Parameters

• cbSize
  Specifies the size, in bytes, of this structure. Set this value to sizeof(GESTUREMETRICS).

• dwID
  Contains the ID of the gesture to get or set the parameters for.

• dwTimeout
  Specifies a value, in milliseconds, for one of the following dwID values.

  Value	Timeout definition	Default value
  GID_SCROLL	The maximum period of touch contact with the screen for the gesture to be recognized as a flick.	250
  GID_HOLD	The minimum period of touch contact with the screen for the gesture to be recognized as a hold gesture.	901
  GID_SELECT	The maximum amount of time between the beginning of a touch contact to the end of the touch contact for a select gesture to be recognized. This value must be smaller than the timeout value for GID_HOLD.	900
  GID_DOUBLESELECT	The maximum amount of time between two consecutive select gestures for a double select gesture to be recognized. If the time between the two select gestures is greater than this, a select gesture is recognized instead.	350
  GID_PAN	None.	None.

• dwDistanceTolerance
  Specifies a value in 1/1000 of an inch for one of the following dwID values.

  Value	Distance limit	Default value
  GID_SCROLL	The minimum distance a touch contact can move across the screen to be recognized as a flick. This value must be greater than the dwDistanceTolerance for GID_PAN.	198
  GID_HOLD, GID_SELECT	The maximum distance a touch contact can move across the screen for a hold or select gesture detection to be recognized. Setting this value for GCI_COMMAND_HOLD also sets this value for GCI_COMMAND_SELECT and vice versa. This value must be smaller than or equal to the dwDistanceTolerance for GID_PAN. This value must be greater than or equal to the dwDistanceTolerance for GID_SELECT.	197
  GID_DOUBLESELECT	The maximum distance between two consecutive select gestures for a double select gesture to be recognized. If the distance between the two consecutive select gestures is greater than this double select tolerance, a select gesture is recognized instead.	197
  GID_PAN	The minimum distance that a touch contact must move across the surface for a pan gesture to be recognized.	198

• dwAngularTolerance
  Specifies a value in radians.

  Value	Angle limit	Default value
  GID_SCROLL	The angle of the maximum arc that a touch contact can trace for a flick to be recognized. If the angle of the arc is less than the set limit, the gesture is a flick.	0.34586
  GID_HOLD, GID_SELECT, GID_DOUBLESELECT, GID_PAN	None.	None.

• dwExtraInfo
  Specifies a gesture specific DWORD value.

  Value	Additional information	Default value
  GID_SCROLL	The maximum angle that a flick direction can vary from the x-axis or the y-axis for the gesture recognizer to identify the flick direction as right, left, up, or down. If the direction of the flick is not identified, the direction is set to none, and the control scrolls on both the x-axis and the y-axis.	0.5 (radians)
  GID_HOLD, GID_SELECT, GID_DOUBLESELECT, GID_PAN	None.	None.

Remarks

This structure is used by SystemParametersInfo.

Requirements

See Also

Reference

Gesture Structures
Touch Structures