QTouchDevice Class

The QTouchDevice class describes the device from which touch events originate. More...

Header:	#include <QTouchDevice>
qmake:	QT += gui
Since:	Qt 5.0

This class was introduced in Qt 5.0.

List of all members, including inherited members

Public Types

enum	CapabilityFlag { Position, Area, Pressure, Velocity, RawPositions, …, MouseEmulation }
enum	DeviceType { TouchScreen, TouchPad }

Detailed Description

Each QTouchEvent contains a QTouchDevice pointer to allow accessing device-specific properties like type and capabilities. It is the responsibility of the platform or generic plug-ins to register the available touch devices via QWindowSystemInterface before generating any touch events. Applications do not need to instantiate this class, they should just access the global instances pointed to by QTouchEvent::device().

Member Type Documentation

enum QTouchDevice::CapabilityFlag

This enum is used with QTouchDevice::capabilities() to indicate what kind of information the touch device or its driver can provide.

Constant	Value	Description
`QTouchDevice::Position`	`0x0001`	Indicates that position information is available, meaning that the pos() family of functions in the touch points return valid points.
`QTouchDevice::Area`	`0x0002`	Indicates that touch area information is available, meaning that the rect() family of functions in the touch points return valid rectangles.
`QTouchDevice::Pressure`	`0x0004`	Indicates that pressure information is available, meaning that pressure() returns a valid value.
`QTouchDevice::Velocity`	`0x0008`	Indicates that velocity information is available, meaning that velocity() returns a valid vector.
`QTouchDevice::RawPositions`	`0x0010`	Indicates that the list returned by QTouchEvent::TouchPoint::rawScreenPositions() may contain one or more positions for each touch point. This is relevant when the touch input gets filtered or corrected on driver level.
`QTouchDevice::NormalizedPosition`	`0x0020`	Indicates that the normalized position is available, meaning that normalizedPos() returns a valid value.
`QTouchDevice::MouseEmulation`	`0x0040`	Indicates that the device synthesizes mouse events. This enum value has been introduced in Qt 5.5.

enum QTouchDevice::DeviceType

This enum represents the type of device that generated a QTouchEvent.

Constant	Value	Description
`QTouchDevice::TouchScreen`	`0`	In this type of device, the touch surface and display are integrated. This means the surface and display typically have the same size, such that there is a direct relationship between the touch points' physical positions and the coordinate reported by QTouchEvent::TouchPoint. As a result, Qt allows the user to interact directly with multiple QWidgets and QGraphicsItems at the same time.
`QTouchDevice::TouchPad`	`1`	In this type of device, the touch surface is separate from the display. There is not a direct relationship between the physical touch location and the on-screen coordinates. Instead, they are calculated relative to the current mouse position, and the user must use the touch-pad to move this reference point. Unlike touch-screens, Qt allows users to only interact with a single QWidget or QGraphicsItem at a time.