Schema - OSD.BASIC - XPLProject

Contents

OSD.BASIC Message Specification

  • Class = OSD
  • Type = BASIC

This Schema provides a method of displaying text messages to an xPL implementation.

XPL-CMND Structure

osd.basic
{
command=clear|write|exclusive|release
[text=<text to display. each line should be seperated by the \n seperator>]
[row=<display row>]
[column=<display from column>]
[delay=<seconds to display>]
}

exclusive/release allow another device to take exclusive control of the osd device. The osd device should ignore all messages from any other source while locked. exclusive/release should be sent on their own only, and be targetted at the osd device. Both should perform a clear.


XPL-TRIG Structure

osd.confirm
{
command=clear|write|exclusive|release
[text=<text to display. each line should be seperated by the \n seperator>]
[row=<display row>]
[column=<display from column>]
[delay=<seconds to display>]
}

A Trigger Message with class osd.confirm MAY be sent by the application or device to confirm the actual actions taken in displaying a given message. This confirmation message should contain the original details, with the provisions that:

If the Display Device does not support overwriting, and executes a clear each time, the Trigger message should contain command=clear rather than command=write

If the Display Device does not support indefinite display, but clears after (for example, 15 seconds) the Trigger message should contain delay=15 rather than delay=0

XPL-STAT Structure

hbeat.*
{
(hbeat items)
} 


Schema Specific Notes

command is the only compulsory item.

When command=clear is used, the display device should execute a "clear screen" operation before displaying the message. It is valid to send a command=clear without any further text to display.

When command=write is used, the display device will simply process the text information, possibly overlapping any existing display. Devices are not required to support this mode of operation. When command=write is used, text is mandatory.

A Value of delay=0 should be interpreted by the application as either "maximum possible delay", or as appropriate, "do not clear". Delays are cumulative, that is, text that is placed on screen with a delay of 5 seconds will remain on screen if a subsequent message specifies a further delay.

row, column and delay should have default values appropriate to the class of display device within the device or application.


Standard Schema Notes

This page was last modified on 29 April 2011, at 15:07. This page has been accessed 3,961 times.