Touch Priority


Touch data is posted into the operating system using a number of different interfaces.

When using multiple touch devices and touching more than one device at the same time may cause undesired results, especially in the case of an operating system that is single user, single pointer or if the selected interface its expecting single touch / user.

In this situation it may be necessary to restrict touches from a single device at any given time.

To cater for this requirement you can define a touch priority for each device via the setting 'Interlock' as follows:

Priority setting  Meaning ‚Äč
none All touches are delivered to the operating system - this is the default setting.
interlock Whilst a touch is active on the device to which this setting relates touches on other devices are ignored except for admin devices.
admin Whilst a touch is active on the device to which this setting relates touches on other devices are ignored. A touch on another non admin device will be cancelled (forced pen up) if this device is touched

When two devices have admin set the one in control keeps control, i.e. an admin device cannot be interrupted even by another admin device.

A 'interlock_release_time' setting specifies a time period in milliseconds during which a device retains interlock control after a touch ends and is used if set >0.

Example

Use the updd command line interface to set one device to admin and one to interlock:

upddutils device 1 set interlock interlock

upddutils device 2 set interlock admin

A touch on the 'admin' device will be immediately actioned. A touch on the 'interlock' device will only work if the admin device is not being touched or past the 'interlock_release_time'.

Notes

The interlock function is applied prior to dispatching touch data on the driver's API so any UPDD client application will be affected by this setting

  1. This setting applies to the driver's Windows mouse/ virtual hid, Linux xtouch/uinput and Mac Simpletouch interfaces.
    In Windows, if the UPDD interlock feature is disabled when using UPDD Virtual HID interface the touches will be subject to any interlock processing implemented by Windows.
  2. If using UPDD Gestures / UPDD Commander these utilities have their own interlock processing.
  3. If using TUIO and interlock feature is enabled this will prevent multi-monitor support with TUIO client applications.
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