Qt Documentation

Contents

TouchPoint QML Type

Describes a touch point in a MultiPointTouchArea. More...

Import Statement: import QtQuick 2.12

Properties

Detailed Description

The TouchPoint type contains information about a touch point, such as the current position, pressure, and area.

Property Documentation

ellipseDiameters : size

This property holds the major and minor axes of the ellipse representing the covered area of the touch point.

This property was introduced in Qt 5.9.


pointId : int

This property holds the point id of the touch point.

Each touch point within a MultiPointTouchArea will have a unique id.


pressed : bool

This property holds whether the touch point is currently pressed.


pressure : real

These properties hold additional information about the current state of the touch point.

  • pressure is a value in the range of 0.0 to 1.0.
  • velocity is a vector with magnitude reported in pixels per second.

Not all touch devices support velocity. If velocity is not supported, it will be reported as 0,0.


previousX : real

These properties hold the previous position of the touch point.


previousY : real

These properties hold the previous position of the touch point.


rotation : real

This property holds the angular orientation of this touch point. The return value is in degrees, where zero (the default) indicates the finger or token is pointing upwards, a negative angle means it's rotated to the left, and a positive angle means it's rotated to the right. Most touchscreens do not detect rotation, so zero is the most common value.

This property was introduced in Qt 5.9.

See also QTouchEvent::TouchPoint::rotation().


sceneX : real

These properties hold the current position of the touch point in scene coordinates.


sceneY : real

These properties hold the current position of the touch point in scene coordinates.


startX : real

These properties hold the starting position of the touch point.


startY : real

These properties hold the starting position of the touch point.


uniqueId : PointingDeviceUniqueId

This property holds the unique ID of the touch point or token.

It is normally empty, because touchscreens cannot uniquely identify fingers. But when it is set, it is expected to uniquely identify a specific token (fiducial object).

Interpreting the contents of this ID requires knowledge of the hardware and drivers in use (e.g. various TUIO-based touch surfaces).

This property was introduced in Qt 5.9.


velocity : vector2d

These properties hold additional information about the current state of the touch point.

  • pressure is a value in the range of 0.0 to 1.0.
  • velocity is a vector with magnitude reported in pixels per second.

Not all touch devices support velocity. If velocity is not supported, it will be reported as 0,0.


x : real

These properties hold the current position of the touch point.


y : real

These properties hold the current position of the touch point.


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